Unlocking the nutritional and economic potential of cucurbitaceae seeds: a comprehensive review of their chemical composition, bioactive compounds, uses and global significance

Abstract

Cucurbitaceae fruits are cultivated globally, but their seeds are mostly a waste product, although compositional data suggest real potential for food, nutraceutical and industrial uses. Existing reviews generally summarize the reported values without discussing the variability among studies or providing an explanation of the status of the mechanistic evidence. The present paper attempts to fill this gap by reviewing the composition, bioactive profile and oil quality of Cucurbitaceae seeds based on the consistency of the existing literature.

The seeds are shown to be a genuine source of high-quality protein, essential fatty acids dominated by linoleic acid and a favourable complement of phenolic compounds, tocopherols and phytosterols with antioxidant activity supported across multiple in vitro systems. Their oils show physicochemical properties suitable for food, cosmetic and pharmaceutical use. The review also points out that much of the reported variation in phenolic content, flavonoid content and oil yield reflects methodological fragmentation rather than genuine biological differences.

Based on this evidence, specific valorisation directions are outlined, including the circular use of seed by-products in producing regions where they are currently wasted. Mechanistic and analytical gaps, particularly the scarcity of in vivo data, that need to be filled before Cucurbitaceae seeds become an established component of the functional food and bioeconomy landscape are highlighted.

Graphical abstract

Highlights

• •Cucurbitaceae seeds are rich in proteins and essential fatty acids.
• •Seed oils show favourable physicochemical and oxidative stability.
• •Seeds contain phenolics, flavonoids, sterols, and tocopherols.
• •Cucurbitaceae seeds have diverse food, medicinal, and industrial uses.

1. Introduction

The processing of fruits and vegetables in industry generally creates a large amount of waste, mostly peels and seeds (Rico et al., 2020). However, in recent years, there has been an increase in research interest in the seeds due to their myriad of nutritional, phytochemical, antioxidant, and other advantages (Mallek-Ayadi et al., 2019). Research studies have established an opportunity to assess the possible use that by-products could play as a raw material to create value-added products (Ravindran et al., 2018).

The Cucurbitaceae family was formally recognized by Linnaeus in 1792, based on floral characteristics (Guo et al., 2020), it contains approximately 123 genera and over 800 species and has a predominance in either tropical or subtropical nations while being less common in temperate regions (Cheng et al., 2023; Hussain et al., 2014). Cucurbits are among the crops most affected by climate change; this has to do with their susceptibility to water stress, their limited heat tolerance, and their particularly high sensitivity to soil pH, especially acidic soil (Parvathi et al., 2022).

Bitter apple (Citrullus colocynthis L.), squash/pumpkin (Cucurbita spp.), watermelon (Citrullus lanatus L.), melon (Cucumis melo L.), and bottle gourd (Lagenaria siceraria L.) are all species of the Cucurbitaceae family. The increase in cucurbit family production has resulted from economic value of certain species, and increased awareness of their health benefits (Tian et al., 2023). Gourds and pumpkins are generally eaten as cooked vegetables, melons and watermelons are eaten as dessert fruits, and cucumbers are commonly consumed in salads (Kates, 2019).

The Cucurbitaceae family has always played a vital role in human diets, especially in equatorial climates where they are commonly consumed. This intense commodification follows extensive cultivation in varied sites across global markets where their versatility as a food source has opened up significant economic wealth for many people in the world (Olarewaju et al., 2023).

Fruit and vegetable by-product, particularly seeds, are now being recognized for their nutritional and bioactive properties. Moreover, seeds are now generally recognized as renewable natural resources, which can be used to produce various high-value products (Karrar et al., 2019; Mallek-Ayadi et al., 2019). In this review, bioactive compounds are specifically defined as the constituents originating from the seeds known to exert a measurable biological or technological activity beyond basic nutrition, namely phenolic acids and flavonoids, cucurbitacins, storage proteins and derived peptides, unsaturated fatty acids, tocopherols and phytosterols, and selected minerals and vitamins. These classes of compounds are the basis for the antioxidant, anti-inflammatory and technological properties discussed in this work (Es-Sai et al., 2025; Gharby et al., 2025).They are rich in bioactive compounds such as proteins, polysaccharides, polyphenols, and fatty acids. These substances can be utilized as antioxidants, additives, and colorants, opening the door to the creation of innovative and valuable products (Chaouch & Benvenuti, 2020). These seeds contain a wealth of carotenoids, tocopherols, phenols, terpenoids, saponins, sterols, all contributing to their remarkable biological effects (Boggia et al., 2020).

Plant oils rich in potential biocomponents and naturally occurring antioxidants can be extracted from fruit seeds (Górnaś et al., 2016). Cucurbitaceae seeds are useful for the extraction of plant oils that carry several nutritional or beneficial biocomponents and naturally occurring antioxidants. These oils are said to serve many purposes in the cooking practices of countries, particularly in the African continent (Karrar et al., 2019).

Cucurbitaceae oil seeds are of great scientific and industrial interest mainly because of their high levels of unsaturated fatty acids (particularly linoleic and oleic) (Ait Nouisse et al., 2025), but also because of their beneficial physicochemical properties including appropriate viscosities, oxidative stability and thermal characteristics (Rabadán et al., 2020; Zhang, Li, & Charalampopoulos, 2024). These properties allow the oils to be both edible and used in a multitude of non-food applications like cosmetics, pharmaceuticals, biodiesel and agriculture applications (Raj et al., 2022; Sani et al., 2018; Schinas et al., 2009).

However, in practice Cucurbitaceae seeds remain an underexploited by-product: they are still discarded as processing waste in most producing regions, and the available literature on their composition and applications is scattered across individual species, disciplines and application sectors, with no unified synthesis linking seed composition to its downstream uses. This fragmentation limits researchers and industry stakeholders in identifying which compositional features support which applications and limits the translation of laboratory findings into scalable food, pharmaceutical or industrial products.

The objective of this review is therefore to provide a comprehensive and updated synthesis of the existing literature on Cucurbitaceae seeds, focusing on their nutritional composition, bioactive properties, lipid profiling, and diverse applications across food, medicinal, cosmetic, agricultural, and industrial sectors. By highlighting current advances, challenges, and future perspectives, this review aims to support the development of sustainable strategies for the effective exploitation of Cucurbitaceae seeds as high-value biobased resources.

2. Bibliometric analysis

This study was conducted using the Scopus database (n = 1090) and examined scientific research published between 2000 and 2026. The bibliometric analysis covered global publication trends, the most prolific authors, the most productive countries, the affiliations with the highest number of publications and the most frequently used keywords. The search string employed for this study was:

TITLE ((“cucurbitaceae*” OR “cucurbit*” OR “bitter apple*” OR “pumpkin*” OR “melon*” OR “watermelon*” OR “squash*” OR “citrullus*” OR “cucurbita*” OR “cucumis*” OR “lagenaria*” OR “bottle gourd*” OR “colocynth*”) AND (“nutrition*” OR “nutritional*” OR “composition*” OR “chemical composition*” OR “proximate*” OR “protein*” OR “lipid*” OR “fatty acid*” OR “mineral*” OR “micronutrient*” OR “fibre*” OR “carbohydrate*” OR “bioactive compound*” OR “phytochemical*” OR “phytochemistry*” OR “phenolic*” OR “flavonoid*” OR “saponin*” OR “antioxidant*” OR “oxidative stability*” OR “sterol*” OR “tocopherol*” OR “biochemical*” OR “biological*” OR “physicochemical*” OR “utilization*” OR “uses*” OR “application*” OR “valorization*” OR “economic potential*” OR “sustainability*” OR “significance*”) AND (“seed*” OR “oil*” OR “seed oil*”)) AND PUBYEAR >1999 AND PUBYEAR <2027.

2.1. Global publication trend

Fig. 1-A illustrates the number of scientific documents on Cucurbitaceae seeds indexed in the Scopus database from 2000 to 2026. Over this period, there is a clear upward trend in research output, reflecting growing interest in the field. Between 2000 and 2010, the number of publications remained relatively low, generally below 25 documents per year. Starting around 2011, the annual output began to rise steadily, reaching 53 publications per year by 2017. The exponential growth in the number of publications observed starting in 2018, peaking at more than 120 papers in 2025, reflects the convergence of three major scientific and societal factors. First, the global adoption of the principles of the circular bioeconomy has redefined byproducts of agri-food processing. Second, the COVID-19 pandemic (2020−2022) sparked interest among consumers and researchers in natural plant-based functional foods and compounds with immunomodulatory or anti-inflammatory properties, which directly accelerated research on underutilized oilseeds. Third, analytical advances and metabolomics platforms, have significantly reduced the barriers to establishing a comprehensive phytochemical profile. The apparent decline projected for 2026 is an artifact resulting from incomplete indexing of the current calendar year and should not be interpreted as an actual reduction in research activity.

Fig. 1.

Bibliometric analysis results: a) Publication trend of Cucurbitaceae seeds papers between 2000 and 2026, b) Top 10 authors publishing on Cucurbitaceae seeds c) Top 10 affiliations publishing on Cucurbitaceae seeds between 2000 and 2026, d) Top 10 countries publishing on Cucurbitaceae seeds between 2000 and 2026, e) Documents type distribution on Cucurbitaceae seeds topics, f) Cucurbitaceae seeds keywords distribution.

2.2. Authors participation and affiliations contribution

Fig. 1-B shows the lead authors of research on Cucurbitaceae seeds. According to the number of publications indexed in the Scopus database, Popović, L. leads with 11 papers, demonstrating a prominent and ongoing interest in the topic, likely indicating a central role in research projects or collaborations related to Cucurbitaceae seeds. Close behind, Li, S. and Yu, X. each have 8 publications, showing strong engagement in the field. A second group of authors, including Białek, A., Ghorbani, M., Nyam, K.L., Pacheco, A.F.C., Peričin, D., and Popović, S., have contributed 7 documents each, reflecting consistent and active research involvement. These authors are likely investigating the chemical composition, nutritional properties, or potential applications of Cucurbitaceae seeds in food, pharmaceutical, or agricultural contexts. This distribution highlights a mix of leading and consistently contributing researchers, suggesting a vibrant and collaborative research environment around the study of Cucurbitaceae seeds.

Fig. 1-C shows the main institutions contributing to research on Cucurbitaceae seeds based on Scopus data. The Ministry of Education of the People's Republic of China and the University of Novi Sad lead with the highest number of publications (n = 27), followed by Jiangnan University (n = 22). Other important contributors include Federal University of Technology (n = 19), King Saud University (n = 18), and Universiti Putra Malaysia (n = 16). The results show that research on Cucurbitaceae seeds is internationally distributed, with strong contributions from Asian institutions, especially China. This suggests that the topic is globally relevant and supported by universities focused on agriculture, food science, and technology.

2.3. Countries and documents contribution

Fig. 1-D presents the number of publications on Cucurbitaceae seeds by country. China clearly leads with the highest number of documents (n = 195), followed by India with about 135 publications. Nigeria ranks third with 97 documents, showing strong research activity in Africa. Iran, Turkey, and Brazil also contribute significantly, each with 63, 55 and 54 publications. The United States, Saudi Arabia, Poland, and Serbia show moderate contributions. Overall, the results indicate that research on Cucurbitaceae seeds is dominated by Asian countries, especially China and India, but it also has broad international participation across Africa, Europe, and the Americas.

Fig. 1-E shows the distribution of publication types related to Cucurbitaceae seeds based on Scopus data. Most documents are original research articles (1001), showing that the field is mainly focused on experimental and practical studies. These articles often investigate the nutritional composition, bioactive compounds, health benefits, and technological applications of Cucurbitaceae seeds. Reviews (27) represent a smaller portion, indicating some effort to summarize and analyse existing knowledge. Conference papers (26) and book chapters (18) make up a limited share, suggesting that most findings are published in peer-reviewed journals. Overall, the results highlight a strong emphasis on original scientific research in this area.

2.4. Keywords

2.4.1. Co-occurrence and research clusters

The raw bibliographic records were exported to VOSviewer. The minimum keyword occurrence threshold was set at 10, retaining 317 keywords out of 709 unique terms identified. Co-occurrence counts were normalised using the association strength measure to correct for differences in absolute keyword frequency. Clusters were detected using VOSviewer's modularity-based algorithm. Cluster labels were assigned on the basis of the highest-frequency terms within each cluster and their thematic coherence. The co-occurrence map identifies four major thematic clusters: (i) physicochemical and nutritional characterization, dominated by terms such as pumpkin seeds, fatty acids, linoleic acid, and vegetable oil, highlighting strong research interest in lipid profiling and oil quality; (ii) bioactive compound identification, particularly flavonoids and antioxidants, indicating a growing focus on nutraceutical potential; (iii) mechanistic and biochemical investigations involving oxidative stress markers and enzyme activity, reflecting the expansion of in vitro functional studies; and (iv) biomedical and nutritional applications explored through animal models, with emphasis on lipid metabolism, cholesterol modulation, and body weight regulation. The central positioning of broad terms such as plant seed and seeds demonstrates high interconnectivity among these thematic domains, suggesting a progressive shift in the field from descriptive compositional analyses toward integrative functional and metabolic research. Overall, the mapping underscores the increasing recognition of Cucurbitaceae seeds as high-value functional ingredients with significant applications in food science and biomedical research. From a forward-looking perspective, the keyword co-occurrence map highlights key emerging research areas. The near-total absence of terms such as “gut microbiota,” “microbiome,” “metabolomics,” and “proteomics” in the current lexical landscape indicates that, despite the growing maturity of knowledge regarding composition, the field has not yet widely adopted “omics”-based approaches or microbiome-centred perspectives.

3. Cucurbitaceae family and main genera

The Cucurbitaceae family, commonly known as cucurbits, consists of 130 genera and about 800 species of plants. Their name, derived from the Latin word “corbis” meaning bottle or basket, reflects the historical use of cucurbits in various applications, such as the use of ripe vegetables as containers and even musical instruments. (Rolnik & Olas, 2020; Singh, 2006). These plants are divided into two main subfamilies, Cucurbitoideae and Zanonioideae, with this classification being determined by their morphological, cytological, and floral traits. The two subfamilies are well characterized: the Zanonioideae by the small striated pollen grains, and the Cucurbitoideae by the fact that the styles are united in a single column (Jeffrey, 1990; Mukherjee et al., 2022). The Zanonioideae subfamily, also known as Nhandiroboideae, consists of 19 genera and about 60 species of no significant economic value. In contrast, the Cucurbitoideae subfamily is much larger, comprising 111 genera and around 740 species (Ekeke et al., 2019).

Fruits from the Cucurbitaceae family, harvested at different stages of ripeness, are used, with their flesh being incorporated into a variety of dishes, including soups, salads, roasted and boiled preparations, as well as pickled, fermented, and dried products (Visković et al., 2024).

3.1. Geographical distribution and origin

Domestication is the gradual process by which humans influence crops by both spreading and modifying their biotic and abiotic conditions, often across multiple regions and populations (Larson & Fuller, 2014; Meyer et al., 2012). As a result of this process, several species of the Cucurbitaceae family have been domesticated and cultivated around the world, but most common species are found in tropical and subtropical regions, where the warm, humid climate provides ideal conditions for their growth. About 90% of these species are concentrated in three main areas: Africa and Madagascar, Central and South America, and Southeast Asia, reflecting their importance in the ecosystems and cultures of these regions (Avinash & Rai, 2017; Hammiche et al., 2013; Mukherjee et al., 2022).

Among the tools used to determine the origin of plants include DNA analysis, phylogenetic and archaeological studies. According to several authors, different species of the Cucurbitaceae family have been cultivated since ancient times, originating from Africa (watermelons), Asia (melons and cucumbers) and America (pumpkins and squashes). The origins of the most common species are summarized in Table 1.

Table 1.

Origin of the most important species of Cucurbitaceae family.

Scientific name	Common name	Origin area	References
Citrullus lanatus	Watermelon	Africa and India	[31,32]
Cucumis melo L	Melon	Africa and Asia	[33]
Cucumis sativus L	Cucumber	India	[34,35]
Cucurbita maxima Duch	Winter squash, pumpkin	South America	[36]
Cucurbita moschata Duch	Winter squash	Mexico, South America	[32,37]
Cucurbita pepo L	Summer squash, pumpkin	North and Central Americas	[38]
Lagenaria siceraria (Mol)	Bottle gourd	Africa	[39,40]
Citrullus colocynthis	Colocynth	Northern Africa	[31,41]

3.2. Biological (general morphology)

Cucurbitaceae is an important and diverse family of plants, consisting of various species with vines, winding tendrils and some of the most unusual fruits in the world (Popoola et al., 2016). These plants are mainly herbaceous annual vines or perennial lianas and include many important vegetables and fruits (Guo et al., 2020). They are mostly climbing plants with hairy stems and branching vines. They have yellow or whitish flowers, separate male and female flowers, a lower ovary and many large seeds (Renner & Schaefer, 2017).

The Cucurbitaceae family has a wide variety of reproductive systems. Almost half of the species are monoecious, with both male and female flowers on the same plant, while the other half are dioecious, with male and female flowers on separate plants (Mahanty et al., 2023). This means that these plants are dependent on pollinators to transfer the pollen from the male flowers to the female flowers (Barman et al., 2023).

The colour of Cucurbitaceae petals varies from white to bright yellow and orange. These colours are mainly due to carotenoids, which play a very important role in the pollination of these plants. Cucurbits are generally pollinated by insects and birds, but economically important crops depend mainly on insect pollination (Cuong et al., 2021; Lu et al., 2021; Wijesinghe et al., 2020).

Bees provide self- and cross-pollination for melons, watermelons, squash, pumpkins, and cucumbers. These crops do not hybridize with each other except for squash and pumpkins being a part of the same species (Paris et al., 2017).

3.3. Main genera of cucurbitaceae

In botany, the genus represents a branch of the family or subfamily, grouping together closely related species. The genera Cucurbita, Citrullus and Cucumis are some of the most widely cultivated crops globally. Beyond these, other genera, such as Lagenaria, play an important role in local and regional economies (Esteras et al., 2011).

3.3.1. Cucurbita genus

The Cucurbitaceae family, encompassing numerous crop species, has seen pumpkins emerge as the leading crop within the Cucurbita genus (Hussain et al., 2022). This genus consists of 20–27 species, with five cultivated varieties: C. moschata, C. argyrosperma, C. maxima, C. pepo, and C. ficifolia. Among these, C. maxima, C. moschata, and C. pepo are the most extensively grown worldwide, underscoring their agricultural importance (Yoo et al., 2023).

3.3.2. Citrullus genus

The Citrullus genus encompasses both annual and perennial herb plants. It comprises four distinct species: C. rehmii, C. lanatus, C. ecirrhosus and C. colocynthis. These species grow naturally across tropical and southern Africa, Southwest Asia, and the eastern Mediterranean areas (Cheng et al., 2023; Zheng et al., 2020). Historically, the Citrullus genus was characterized by its bitter flavor. However, the emergence of sweet watermelons resulted from deliberate cultivation practices, including cross-pollination and selective seed breeding (Masoko et al., 2022). Among the species, C. lanatus, commonly referred to as watermelon, holds the highest economic significance (Chomicki et al., 2020).

3.3.3. Cucumis genus

The genus Cucumis includes around 30 species, both annual and perennial, found across Africa and Asia (Murthy et al., 2022). Among these, Cucumis includes key vegetable crops of significant economic value, such as C. sativus (cucumber) and C. melo (melon) (Ling et al., 2021).

3.3.4. Lagenaria genus

The genus Lagenaria includes six species, all native to Africa. Of these, L. siceraria is the only cultivated species, while the remaining five L. breviflora, L. abyssinica, L. rufa, L. sphaerica, and L. guineensis are wild (Mashilo et al., 2022). The term Lagenaria derives from the Latin word lagena (or lagenos), meaning “bottle” or “flask,” which refers to the bottle-like morphology of some fruits produced by plants in this genus (Roopan et al., 2016).

4. Compositional profile of cucurbitaceae seeds

4.1. Nutritional profile of cucurbitaceae seeds

Many parts of plants in the Cucurbitaceae family are used as food, especially the fruits and seeds. The latter, rich in proteins and carbohydrates, are highly appreciated in many countries, where they are often grilled or salted (Chaouch & Benvenuti, 2020; Ozuna & León-Galván, 2017).

The seeds of the Cucurbitaceae family are a rich source of essential nutrients. They are highly beneficial to human health (A. Hussain et al., 2022). Pumpkin seeds, especially those of C. pepo, are an excellent source of protein. They can contain up to 40%, as reported by Rezig et al. (2019) for Tunisian seeds (Rezig et al., 2019). For whole seeds, moisture and ash content varied from 4.00 to 4.62% and 2.24 to 3.40%, respectively, among the different cultivars. Protein and oil content ranged from13.01 to 15.60% and 23.09 to 27.52% respectively. Fibre content was highest in Madhu seeds with the value of 48.35%. Carbohydrate content, calculated by subtraction method, was found to be the highest for seeds of Madhu variety (9.31%). The nutritional composition of the seeds of the most common species of Cucurbitaceae is summarized in Table 2.

Table 2.

Nutritional composition of seeds from several common Cucurbitaceae species.

Seed	Region	Moisture (%)	Ash (%)	Proteins (g/100 g)	Carbohydrates (g/100 g)	Fibers	References
C. colocynthis	Niger	4.91 ± 1.66	2.00 ± 0.58	13.19 ± 1.31	–	–	[60]
	Nigeria	–	2.98 ± 0.09	19.16 ± 1.27	8.33 ± 0.05	3.94 ± 0.06	[61]
		4.93 ± 0.05	4.35 ± 0.05	12.06 ± 0.05	24.67 ± 0.05	45.83 ± 0.05	[62]
	Pakistan	6.90 ± 0.35	5.56 ± 0.21	15.98 ± 1.18	–	9.68 ± 1.26	[63]
	Saudi Arabia	–	2.58	12.95	–	45.37	[64]
C. lanatus	Tunisia	7.28 ± 0.81	3.97 ± 0.54	19.41 ± 2.01	1.85 ± 0.16	48.26 ± 5.26	[59]
	Nigeria	3.47 ± 1.15	3.97 ± 1.01	19.02 ± 2.01	25.91 ± 2.15	4.65 ± 0.01	[65]
	Pakistan	7.4 ± 0.05	2.1 ± 0.03	15.6 ± 0.04	–	7.8 ± 0.1	[66]
	India	3.64 ± 0.02	3.69 ± 0.46	29.56 ± 0.20	13.83 ± 1.54	4.73 ± 0.05	[67]
		5.1 ± 0.01	5.31 ± 0.02	35.43 ± 0.02	7.67 ± 0.03	6.69 ± 0.01	[68]
	Ghana	5.44 ± 0.14	3.18 ± 0.06	30.00 ± 0.39	4.13 ± 0.71	1.90 ± 0.39	[69]
	Sudan	4.17 ± 0.17	4.62 ± 0.13d	15.75 ± 0.25	17.01 ± 0.22	31.34 ± 0.23	[70]
L. siceraria	Morocco	6.24 ± 0.09	3.93 ± 0.03	18.21 ± 0.03	40.32 ± 0.81	–	[15]
	Egypt	4.92 ± 0.93	2.51 ± 0.73	11.54 ± 1.05	19.21 ± 1.14	32.41 ± 1.54	[71]
	Nigeria	4.00 ± 0.05	3.96 ± 0.10	36.46 ± 0.10	7.55 ± 0.05	2.29 ± 0.05	[72]
	Cameroon	7.10 ± 1.21	3.17 ± 0.03	25.23 ± 0.20	7.11 ± 0.18	2.34 ± 0.14	[73]
	Libya	–	4.21 ± 0.48	24.03 ± 0.19	14.92 ± 0.17	15.33 ± 0.28	[74]
C. pepo	Nigeria	6.48 ± 0.72	5.92 ± 0.81	27.05 ± 2.01	19.75 ± 2.47	7.24 ± 0.64	[75]
	Tunisia	6.96 ± 0.99	3.47 ± 0.51	40.00 ± 3.84	1.15 ± 0.11	12.89 ± 1.33	[59]
	Pakistan	7.09 ± 0.40	2.25 ± 1.04	27.41 ± 1.72	26.28 ± 1.79	4.96 ± 1.20	[76]
	Ghana	6.27 ± 0.26	4.56 ± 0.09	28.31 ± 0.04	11.46	5.37 ± 0.12	[77]
	Zimbabwe	5.66 ± 0.02	3.32 ± 0.01	32.86 ± 0.10	12.16 ± 0.14	2.58 ± 0.01	[78]
	Korea	7.41 ± 0.09	5.50 ± 0.10	30.88 ± 1.21	12.22 ± 0.75	14.84 ± 0.06	[79]
	Iran	5.20 ± 0.28	5.34 ± 0.04	25.40 ± 0.61	25.19 ± 3.3	2.49 ± 0.11	[80]
C. maxima	Morocco	5.82 ± 0.04	4.12 ± 0.02	30.32 ± 0.03	18.02 ± 0.84	–	[15]
	Tunisia	8.46 ± 0.62	3.97 ± 0.02	33.92 ± 3.16	0.11 ± 0.08	21.97 ± 4.32	[81]
	Brazil	5.16 ± 0.01	3.39 ± 0.04	32.09 ± 0.28	17.08	–	[82]
	Cameroon	6.77 ± 0.63	4.02 ± 0.01	20.11 ± 0.40	8.24 ± 0.23	2.18 ± 0.06	[73]
	Egypt	3.38–5.53	4,22-5,30	34.19–39.05	4.80–10.96	7.72–9.69	[83]
	Korea	2.75 ± 0.02	4.42 ± 0.04	27.48 ± 1.00	12.90 ± 0.83	16.15 ± 0.68	[79]
	Bangladesh	1.66 ± 0.24	3.77 ± 0.06	4.69 ± 2.13	12.75 ± 1.87	11.90 ± 0.05	[84]
	Greece	–	3.52 ± 0.09	37.67 ± 0.20	16.07 ± 0.03	–	[85]
	Indonesia	8.15 ± 0.08	5.40 ± 0.08	12.33 ± 0.08	63.70 ± 0.7	–	[86]
	Nigeria	3.08 ± 0.09	3.60 ± 0.15	14.31 ± 0.10	24.45 ± 0.12	2.55 ± 0.08	[87]
C. moschata	Morocco	6.40 ± 0.11	4.22 ± 0.01	34.14 ± 0.00	11.64 ± 0.19	–	[15]
	Indonesia	7.67 ± 0,05	5.18 ± 0.04	19.23 ± 0.06	39.51 ± 0.5	–	[86]
	Korea	5.18 ± 0.60	5.32 ± 0.02	29.81 ± 1.47	14.02 ± 0.76	10.85 ± 0.84	[79]
	Cameroon	7.47 ± 0.41	3.68 ± 0.07	28.94 ± 0.30	7.81 ± 0.10	2.93 ± 0.02	[73]
	brazil	6.80 ± 0.01	4.11 ± 0.02	32.98 ± 0.30	15.48	–	[82]
	India	5.6 ± 0.01	3.83 ± 0.02	23.55 ± 0.03	22.22 ± 0.03	18.4 ± 0.01	[68]
		6.37–6.56	2.91–5.47	31.24–34.52	9.83–17.45	9.21–10.63	[88]
C. melo	Tunisia	7.50 ± 0.65	2.78 ± 0.26	26.15 ± 3.01	1.05 ± 0.11	34.08 ± 3.64	[59]
		7.16 ± 0.14	4.83 ± 0.12	27.41 ± 0.53	29.96 ± 0.55	25.32 ± 0.13	[89]
	Pakistan	4.7 ± 0.03	2.2 ± 0.02	20.2 ± 0.06	–	10.2 ± 0.1	[66]
	India	5.85 ± 0.01	4.46 ± 0.01	19.14 ± 0.020	12.88 ± 0.026	15.67 ± 0.02	[68]
		2.57 ± 0.02	4.23 ± 0.02	29.21 ± 0.33	21.74 ± 0.75	3.16 ± 0.25	[67]
	Ghana	6.34 ± 0.17	3.56 ± 0.06	35.00 ± 0.39	3.11 ± 0.74	2.00 ± 0.33	[69]
	Sudan	4.27 ± 0.12	4.33 ± 0.14	28.58 ± 0.50	6.94 ± 0.55	24.75 ± 0.34	[90]
C. sativus	Cameroon	7.56 ± 0.99	2.70 ± 0.24	30.12 ± 0.02	8.12 ± 0.02	2.14 ± 0.03	[73]
	Nigeria	7.21	5.48	4.50	52.86	27.81	[91]
	Nigeria	12.3 ± 0.42	9.34 ± 0.62	24.5 ± 0.06	50.1 ± 0.30	3.00 ± 0.04	[92]

The wide range of values in Table 2 reflects variability in methods and biological variation. Protein content of C. maxima varies from 4.69% (Jahan et al., 2023) to 37.67% (Polyzos et al., 2024) which is largely a result of differences in conversion factors (N × 5.71 to N × 6.25) and reporting fresh and dry weight. Reliable cross-study comparisons are still limited without harmonised protocols such as that proposed by ISO and AOAC (Borecka & Karaś, 2025).

4.2. Antioxidant and bioactive content

Total phenolic content (TPC) and total flavonoid content (TFC) are used to assess phenolic and flavonoid compounds, respectively. These compounds are known to have antioxidant properties (Singh & Kumar, 2024). The data presented in Table 3 show marked differences among seeds according to species and geographical origin. Notably, C. moschata from Cameroon exhibited a TPC of 491.08 ± 8.89 mg GAE/100 g, while C. maxima from the same region reached 338.04 ± 3.90 mg GAE/100 g (Dimitry et al., 2022). C. melo seeds from Tunisia also displayed elevated levels (304.10 ± 0.83 mg GAE/100 g) (Mallek-Ayadi et al., 2018). In parallel, DPPH radical scavenging activity exceeded 80% in certain species (Gade et al., 2022), reinforcing the relationship between phenolic richness and antioxidant capacity. These results indicate that Cucurbitaceae seeds constitute a valuable reservoir of natural antioxidant compounds.

Table 3.

Antioxidant characteristics in Cucurbitaceae seeds of different species.

Properties	Seed	Region	Reported value	References
TPC	C. colocynthis	Saudi Arabia	60.45 ± 3.40 GAE/ g	[94]
		Yemen	0.010 ± 0.001 g GAE/g	[95]
		India	5.39 ± 0.73 mg GAE/100 g	[96]
	C. lanatus	Pakistan	9.8 ± 0.02 mg GAE/100 g	[66]
		Poland	1.01 ± 0.03 mg GAE/g	[98]
		India	170.86 ± 0.030 mg GAE/100 g	[68]
	L. siceraria	Cameroon	322.89 ± 6,70 mg GAE/100 g	[73]
		India	96.87 ± 0.80 mg TAE/g	[99]
	C. pepo	Ghana	160.74 mg GAE/g	[77]
		Portugal	0.97–6.12 mg GAE/g	[100]
	C. maxima	Bangladesh	8.27 ± 0.34 mg GAE/g	[84]
		Ethiopia	80.6–102 mg GAE/100 g	[101]
		Cameroon	338.04 ± 3.90 mg GAE/100 g	[73]
		Pakistan	224.61 ± 1.60 mg GAE/100 g	[102]
		Brazil	0.57–0.73 mg GAE/g	[82]
	C. moschata	India	175.11 ± 0.020 mg GAE/100 g	[68]
			30–40 mg GAE/ g	[88]
		Cameroon	491.08 ± 8.89 mg GAE/100 g	[73]
		Brazil	1.45–1.21 mg GAE/g	[82]
	C. melo	Pakistan	11.1 ± 0.03 mg GAE/100 g	[66]
		India	175.28 ± 0.030 mg GAE/100 g	[68]
		Tunisia	304.10 ± 0.83 mg GAE/100 g	[89]
		Brazil	69.77–111.70 mg GAE/100 g	[103]
	C. sativus	Cameroon	260.18 ± 1.49 mg GAE/100 g	[73]
		India	80.9 ± 0.7 mg GAE/g	[104]
TFC	C. colocynthis	Saudi Arabia	46.66 ± 2.88 Rutin mg/g	[94]
	C. lanatus	India	140.12 ± 0.035 mg EQ /100 g	[68]
		Pakistan	62.0 ± 0.9 mg CE/100 g	[66]
	L. siceraria	India	7.88 ± 0.28 mg CE/g	[99]
	C. pepo	Ghana	44.04 ± 6.71 mg QE/g	[77]
	C. maxima	Ethiopia	51.1–67.4 mg QE/100 g	[101]
		Pakistan	139.37 ± 1.07 mg QE /100 g	[102]
	C. moschata	India	142.82 ± 0.030 mg QE /100 g	[68]
			21–26 mg QE/g	[88]
	C. melo	Pakistan	87.4 ± 1.3 mg CE/100 g	[66]
		India	148.57 ± 0.04 mg QE /100 g	[68]
		Tunisia	87.52 ± 0.17 mg QE/100 g	[89]
	C. sativus	India	22.5 ± 0.6 mg QE/ g	[104]
	C. lanatus	Pakistan	31.2 ± 0.03%	[66]
		India	80.02 ± 0.036%	[68]
	L. siceraria.	Cameroon	0.21 ± 0.01 mg QE/100 g	[73]
	C. maxima	Cameroon	0.22 ± 0.02 mg QE/100 g	[73]
	C. moschata	Cameroon	0.27 ± 0.02 mg QE/100 g	[73]
		India	81.55 ± 0.003%	[68]
	C. melo	Ghana Pakistan	82.31 ± 0.055% 50.0 ± 0.2% 46.8 ± 0.04%	[68] [97] [66]
	C.sativus	Cameroon	0.15 ± 0.01	[73]

All values expressed on a dry weight basis.

Table 3 reveals a degree of variation that cannot be explained by biology alone. TPC in C. maxima seeds varies from 0.57 mg GAE/g (Veronezi & Jorge, 2012) to over 491 mg GAE/100 g (Dimitry et al., 2022). This gap can be attributed to biological factors (genotype, UV exposure, water stress, maturity, drying), methodological choices (extractant polarity, solid-to-solvent ratio, temperature, duration) and analytical procedure (Folin-Ciocalteu standard used, absorbance linearity).

The variability that we have described above for TPC is not unique to Cucurbitaceae seeds. Onion bulbs have been shown to have similar genotype and practice-dependent differences in phenolic, flavonoid and anthocyanin content (Vojnović et al., 2025) and agrifood by-products are increasingly being recognized as potential sources of phenolics, terpenoids and other bioactive compounds with antioxidant and antimicrobial activity (Fernandes et al., 2025). These parallels reinforce the idea that Cucurbitaceae seeds are part of the underexploited plant byproducts landscape, where standardized analytical protocols are a common priority.

4.3. Antioxidant and anti-inflammatory mechanisms of action

The antioxidant activity of seed extracts of Cucurbitaceae is due to many complimentary processes operating together. The main ways flavonoids (quercetin, kaempferol, luteolin) and phenolic acids (caffeic, ferulic, p-coumaric) scavenge reactive oxygen species are via hydrogen-atom transfer and single-electron transfer pathways. The superoxide anion, hydroxyl radical and lipid peroxyl radicals are neutralized chain (Zheng et al., 2024). The B-ring ortho-catechol group (hydroxyls at positions 3′ and 4′ adjacent to each other) is the main structural determinant of the radical scavenging capacity and is responsible for the effectiveness of quercetin as a scavenger, stabilising the resulting flavonoid radical and breaking the lipid oxidation chain (Tang et al., 2025).

Besides this direct scavenging, quercetin and kaempferol also activate the Keap1/Nrf2/ARE pathway, resulting in the up-regulation of endogenous antioxidant enzymes (SOD, CAT, GPx, HO-1). Oh et al. (2024) demonstrated this effect in vivo using Cucurbita pepo seed extract in a rodent model (Oh et al., 2024) and the subsequent protection is much larger than what could be explained by direct radical scavenging alone.

As for the anti-inflammatory effect, quercetin and luteolin inhibit IκB kinase, thus preventing the NF-κB translocation into the nucleus and down-regulating the expression of pro-inflammatory cytokine (TNF-α, IL-1β, IL-6) and enzyme (iNOS, COX-2) (Piva et al., 2026). Linoleic and oleic acids activate PPAR-α/γ, which affects lipid metabolism and insulin sensitivity(Małodobra-Mazur et al., 2024). Tocopherols (mainly γ-tocopherol) inhibit lipid peroxidation by donating a hydrogen atom from the chroman ring, forming a stable tocopheroxyl radical that does not propagate oxidation (Es-Sai et al., 2025). These pathways are further supported by proteomics studies that have identified ACE-inhibitory and antioxidant peptides in pumpkin seed proteins (Cheong et al., 2025) and by investigations on protein–polyphenol interactions relevant for the co-delivery of these bioactive fractions within functional foods (Hou et al., 2020).

4.4. Structure–activity relationships of key bioactive compounds

Fig. 2 presents the structure-activity profile for the main bioactive groups of Cucurbitaceae seeds, which can be described by a few simple rules. The catechol B-ring is the major contributor to the radical scavenging and metal chelation in flavonoids and the addition of a sugar at C-3 removes some of the in vitro potency in favour of better absorption in the gut (Hu et al., 2025). Tocopherols have methyl groups on the chroman ring that determine antioxidant potency and circulation time for each form. Hepatic α-TTP preferentially retains α-tocopherol, which is why γ-tocopherol, despite being the dominant form in these seed oils, clears faster (Es-Sai et al., 2025). The location of the first double bond in fatty acids determines the eicosanoids synthesised by COX and LOX, the cis conformation preserves the fluidity of membranes, and an 18‑carbon chain is optimal for PPAR-γ binding. As for phytosterols, the additional ethyl group on the side chain of β-sitosterol inhibits its own absorption and displaces cholesterol, reducing the absorption of dietary cholesterol by about 8–10% (Du, 2025).

Fig. 2.

Structure-activity relationships of major bioactive compounds in Cucurbitaceae seeds. ROS, reactive oxygen species; Nrf2, nuclear factor erythroid 2–related factor 2; PPAR-α/γ, peroxisome proliferator-activated receptor alpha/gamma.

4.5. Lipid profile characterization and oil composition analysis

4.5.1. Oil content

The need for vegetable oils for food demands growing oilseed production, as fats and oils are significant energy sources, offering more calories than carbohydrates in human diets (Morya et al., 2022). The oil content (OC) is a essential indicator for the economic value (Ait Bouzid et al., 2024). Different types of apparatus and methods have been used to extract oil. The most common method of oil extraction is Soxhlet, using very simple equipment and, preferably, different solvents. The oil extraction required an organic solvent as n-hexane, petrol ether, cyclohexane or chloroform (Sultana & Ashraf, 2019). The OC of studied seeds is summarized in Table 4. Moroccan varieties of C. maxima (Pumpkin) is rich in oil (49.56%) than Sudan varieties (31.70%) (Ali et al., 2022; Boujemaa et al., 2024). The OC of C. colocynthis ranged from 16% (Morocco varieties) to 56.61% (Nigeria varieties). OC of C. moschata recorded a high value (45.68%) in Korea variety (Kim et al., 2012). Indian Bottle gourd (L. siceraria) had a value of 25.2% (V et al., 2024). Watermelon (C. lanatus) varied between 14.75 and 43.51%. C. melo is rich in oil, Egypt variety recorded a high value 60% (El-anssary et al., 2021), followed by C. melo oil seeds (50.42%) (Ahmad Warra et al., 2015). The OC recovered from Cucurbitaceae seeds varies depends on the plant used, growing circumstances, ripening, harvesting time, and the extraction process applied (Rezig et al., 2022). The high OC obtained by solvent could be attributed to extended contact and repeated washing to many cycles at high temperature (Irnawati et al., 2022). Some seeds contain a significant quantity of lipids are of great economic interest and could allow their use in number new applications in foods, cosmetics and pharmaceutics industry.

Table 4.

Comparison of oil yields from different Cucurbitaceae seed oils (%).

Seed	Region	Extraction method	Solvent used	Oil yield	References
C. maxima	Morocco	Soxhlet	n-hexane	47.32–53.59	[109]
	Sudan	Maceration		31.70 ± 0.63	[108]
	Bangladesh	Soxhlet		35.23 ± 1.08	[84]
	Ethiopia	Soxhlet	petroleum ether	43.6 ± 0.8	[115]
	Italy			29.0 ± 0.9	[116]
	Malawi			46.39 ± 0.06	[117]
	Indonesia	Hot pressing	–	24.12	[114]
		ultrasound.	–	28.13
		Soxhlet	n-hexane	39.65
L. siceraria	Egypt	Soxhlet	n-hexane	47.22 ± 0.01	[118]
	Indian			25.2	[110]
	Nigeria			42.3	[119]
C. colocynthis	Saudi Arabia	Soxhlet	n-hexane	23.16 ± 0.83	[120]
	Nigeria	–	–	56.61 ± 0.10	[121]
	Saudi Arabia	Soxhlet	n-hexane	17	[122]
	Morocco	Soxhlet	petrol ether	16	[123]
		Soxhlet	cyclohexane	17	[123]
	Pakistan	Soxhlet	n-hexane	29	[124]
C. lanatus	United States	Soxhlet	n-hexane	14.75 ± 1.11	[125]
	Nigeria	Soxhlet	petroleum ether	43.51 ± 3.15	[126]
		Soxhlet	n-hexane	43	[127]
C. moschata	Brazil	Maceration	Chloroform: methanol: distilled water	42.29 ± 0.09	[82]
	Korea	Soxhlet	Ether	45.68 ± 1.17	[79]
	Algeria		n-hexane	37.8 ± 1.70	[128]
	India			26.4 ± 0.020	[68]
	Nigeria			37.28 ± 0.01	[129]
C. melo	Nigeria			50.42 ± 0.01	[112]
	Sudan	shaker		31.13 ± 0.90	[90]
	Algeria	Soxhlet		30.7 ± 2.44	[128]
	India			42 ± 0.010	[68]
	Tunisia			30.65 ± 0.6	[89]
	Nigeria			31.38	[129]
	Indonesia Ecuador			25.34 ± 0.57	[130]
	Malaysia	mixeur Waring	Méthanol: chloroforme (2: 1)	11.10 ± 0.63	[131]
	Egypt	maceration	petroleum ether	60	[111]
	Iran	Soxhlet	n-hexane	47.3 ± 1.4	[132]
	Tunisia			30.65	[133]
	Spain	screw press	–	26.23 ± 1.08	[16]
		Hydraulic Press		6.80 ± 0.63	[16]

4.5.2. Physicochemical parameters of cucurbitaceae seed oils

Table 5 summarizes the physicochemical proprieties in terms of specific gravity, refractive index, viscosity, density, free fatty acids (FFA), acid value (AV), peroxide value (PV), iodine value (IV) and saponification value (SV) of the Cucurbitaceae seeds oil. Specific gravity of oil was determined as report between water and oil densities, ranged from 0.77 (L. siceraria) to 0.99 (C. moschata), which is within the acceptable range of less than 1, because the oils with lower values are highly appreciable to consumers (Abd El-Rahman et al., 2022). Viscosity represents a critical parameter in the design and optimization of industrial processes. It could be used to determine the oil quality used in frying purposes (Ali et al., 2022). Table 5 showed significant differences among the oil seeds in viscosity. The refractive index (RI) of oils tells about their purity, molecular weight, fatty acid chain length, degree of unsaturation, and degree of conjugation (Aminu et al., 2020). Seed oils have a refractive index range from 1.34 to 1.50. This parameter linked to various factors as density and reflects fatty acid chain length, degree of unsaturation and triglycerides level (Aminu et al., 2020).

Table 5.

Physico-chemical parameters of Cucurbitaceae seed oils.

Seed	Specific gravity	Refractive index	Viscosity	Density	FFA (%)	AV (mg/KOH)	PV mEq O2/kg	IV g I2/100g	SV mg KOH/g	References
C. maxima	–	1.47 ± 0.1	24.7 ± 0.8	0.91 ± 0.1	–	1.32 ± 0.2	3.60 ± 0.3	114 ± 0.8	191 ± 0.6	[115]
	0.9 ± 0.01 (25 °C)	1.4 ± 0.1	4.7 ± 0.6 cP	–	–	13.5 ± 0.6	–	113.2 ± 1.9	236.0 ± 0.6	[143]
	0.92 ± 0.00 (30 °C)				0.39 ± 0.01	0.78 ± 0.02	10.85 ± 0.62	104.36 ± 0.04	190.69 ± 1.40	[80]
C. colocynthis	0.9 ± 0.0	1.5 ± 0.0	–	–	16.1 ± 0.1	32.0 ± 0.2	3.4 ± 0.4	80.7 ± 0.9	88.4 ± 1.3	[144]
			36.9 cSt (40 °C)			2.2		126.4	189.7	[145]
C. lanatus	0.9 ± 0.00	1.5 ± 0.00	–	–	12.10 ± 0.3	24.0 ± 0.1	6.6 ± 0.1	78.7 ± 1.0	95.4 ± 1.0	[144]
	–	1.47 ± 0.00 (30 °C)	–	–	–	4.4 ± 0.1	3.24 ± 0.1	112 ± 0.2	218 ± 0.1	[146]
	0.86 ± 0.01	1.34 ± 0.06 (40)	0.55 ± 0.04 P	0.92 ± 0.02	1.87 ± 0.03	3.77 ± 0.06	3.27 ± 0.07	132.78 ± 0.43	140.33 ± 0.26	[147]
L. siceraria	0.77	–	–	–	–	10.77 ± 0.06	0.55 ± 0.04	–	71.52 ± 0.03	[118]
	0.9181	1.34	26.46 (P)		18.42	60.02	7.5	46.1	203.36	[148]
C. moschata	0.9567	1.463	62.0 cP	0.911 ± 0.00	–	0.593	7.04	108.9	189.93	[108]
	–	1.4677 ± 0.00 (40)	–	0.911 ± 0.00	–	1.49 ± 0.03	3.42 ± 0.14	145.09 ± 5.86	210.57 ± 0.20	[149]
C. melo	–	1.44 ± 0.03 (40 °C)	–	0.91 ± 0.02	1.51 ± 0.06	–	2.50 ± 0.20	110.99	186.20 ± 0.11	[90]
	0.88 ± 0.02	3.62 ± 0.9	–	–	–	9.16 ± 0.21	10.50 ± 1.50	64.80 ± 4.31	45.81 ± 5.19	[134]

Free fatty acids (FFA) are an estimation of the fatty acids separated from the triacylglycerol. The quantity of free fatty acids is linked to the predominant fatty acid for each vegetable oil (Aissa et al., 2023). Acid values (AV) are essential indices of the oil quality and show the concentration of KOH that is required for the neutralization of the organic acids (FFAs) present in one g of fat (Ani et al., 2023). The high AV could be associated with the prolonged extraction process at high temperature; the high temperature during the extraction process could cause the decomposition and oxidation of triacylglycerol to glycerol and FFA, resulting in an increase in the AV (Zhang, Li, & Fu, 2024). Peroxide value (PV) is the outcome of two different mechanisms: an oxidation step leading to the formation of primary oxidation substances, and a degradation step leading to the elimination of these compounds through the formation of secondary oxidation substances (Asbbane et al., 2024). The PV ranged from 1.90 (L. siceraria) to 8.78 mEq O₂/kg (C. moschata) which was lower than the limit of 10.00 mEq O₂/kg usually accepted for refined oils (Gharby et al., 2025). However, this is a single-timepoint measurement and does not by itself demonstrate long-term oxidative stability. In other vegetable oils, accelerated storage (e.g. 65 °C over 10–20 days) shows a steady rise in PV over time (Ansorena et al., 2023), so we regard our static PV values as an initial quality indicator rather than evidence of stability in storage, and note that kinetic monitoring under defined storage conditions is required to confirm the oxidative behaviour of these Cucurbitaceae oils over time.

Iodine value (IV) is a parameter to evaluate the oil's unsaturation bonds. It is defined as the amount of iodine absorbed per 100 g of oil. This parameter was determined from the level of UFAs (Ahmed et al., 2024). The saponification value (SV) is an indication of the average chain length of the FAs in oil, with lower SV values indicates triacylglycerols with longer fatty acyl chains (Gagour et al., 2025). Table 5 presented that IV of C. maxima can be up to 183 g I₂/100g. These high values suggest that the oil has high level of unsaturation and might be susceptible to oxidation (Nwachoko et al., 2023). The SV was found to be more than 80 mg KOH/g (Table 5). The results indicate that Cucurbitaceae seed oil is more suited for making liquid soap, shampoos, and cosmetics products such as creams (Hagos et al., 2023).

4.5.3. Fatty acid composition (FAC)

Vegetable oils include a wealth of unsaturated fatty acids, including omega-6 and omega-3 families, which are recognized as crucial for human health. However, they cannot be produced by the body alone, consequently requiring intake from diet (Kaur et al., 2014; Olarewaju et al., 2023). The FAC of the oil extracted from seeds was analyzed by transforming the fatty acids into methyl esters, and then using gas chromatography to determined their level (Bouzid et al., 2024). Table 6 presents the fatty acid composition of the different seed oils. The SFA of studied oil seeds is raged between 7.09% (L. siceraria) and 21.07% (C. maxima). The major SFA was palmitic acid (C16:0), varying between 6.41 and 15.97%, followed by stearic acid (C18:0) which ranged from 0.38 to 7.1%. The following SFA contents in trace Myristic and Arachidonic acid are all below 1%. The MUFA varied from 9.18% “C. colocynthis” to 50.51% (L. siceraria). Among the different MUFA present in cucurbitaceae seeds, oleic acid was found to be the major. The level of this acid was found to be 9.04 and 49.37% as shown in Table 6. The PUFA recorded higher level in C. colocynthis “75.15%” and lower in C. maxima “34.78%”. Linoleic acid was found to be the main fatty acid, making up most of the composition, ranged from 34.77 to 74.8%.

Table 6.

Fatty acid composition of Cucurbitaceae seed oils.

Fatty Acids (%)	C. maxima [81]	C. moschata [128]	C. lanatus [152]	C. melo [153]	L. siceraria [71]	C. colocynthis [154]
Myristic acid (C14:0)	–	–	0.04 ± 0.01	0.073 ± 0.002	–	0.017 ± 0.003
Palmitic acid (C16:0)	15.97 ± 0.39	15.01 ± 2.7	10.28 ± 0.36	8.51 ± 0.350	6.41 ± 0.41	8.35 ± 0.03
Stearic acid (C18:0)	4.68 ± 0.56	3.22 ± 0.5	6.79 ± 0.22	6.089 ± 0.173	0.38 ± 0.18	5.36 ± 0.06
Oleic acid (C18:1)	44.11 ± 0.63	31.02 ± 1.4	14.75 ± 0.84	31.5 ± 0.53	49.37 ± 1.14	9.04 ± 0.09
Linoleic acid (C18:2)	34.77 ± 0.95	50.75 ± 3.2	67.43 ± 0.97	51.6 ± 0.86	35.21 ± 1.05	74.8 ± 0.1
Linolenic acid (C18:3)	–	–	0.16 ± 0.02	0.190 ± 0.002	0.22 ± 0.08	0.099 ± 0.004
Arachidonic acid (C20:0)	0.41 ± 0.40	–	0.27 ± 0.09	0.285 ± 0.004	0.10 ± 0.02	0.177 ± 0.007
Gondoic acid (C20:1)	–	–	0.08 ± 0.01	0.164 ± 0.001	ND	0.083 ± 0.006
SFA	21.07 ± 1.19	18.23	17.49 ± 0.14	15.36	7.09	14.33 ± 0.02
MUFA	44.12 ± 0.57	31.02	14.92 ± 0.22	32.10	50.51	9.18 ± 0.03
PUFA	34.78 ± 0.85	50.75	67.59 ± 0.49	51.79	42.94	75.15 ± 0.04

Similar trends in fatty acids have been reported in other under-exploited seed oils. Oleic and linoleic acids in prickly pear (Opuntia ficus-indica) seeds also account for more than 50% of total fatty acids (Moraga-Babiano et al., 2025), which agrees with the values reported above for Cucurbitaceae. The extraction method also influences the final lipid profile: sequential supercritical CO₂ and accelerated solvent extraction, used for Espino maulino (Vachellia caven) seeds, resulted in fractions rich in tocopherols and unsaturated fatty acids (Flores et al., 2025), implying that the method used, not only the species, affects the composition of the fatty acids recovered.

4.5.4. Phytosterols and tocopherols

Sterols or phytosterols play important role in human health due to their antioxidant capacity (Abdalla et al., 2024). Those compounds are analyzed using GC–MS (Azizi et al., 2024). Sitosterol levels were high in most Cucurbitaceae oilseeds, except for C. maxima and moschata, while the high level is Δ5,24-Stigmastadienol and Δ7-Avenasterol, respectively. Brassicasterol was only detected in C.lanatus, C. melo and C. maxima. Campesterol is present in extremely low content.

The tocopherol composition is directly related with nutritional profiles, oxidative stability, and able to determine adulterations in oils (Abdalla et al., 2024). Tocopherols are analyzed using High-Performance Liquid Chromatography (HPLC) through various methods. They have the ability to act as anti-inflammatory and also act as a powerful antioxidant (Azizi et al., 2024).

Cucurbitaceae seeds are a good source of vitamin E. This vitamin includes four tocopherols (α, β, γ and δ). Gamma tocopherol is a major one in all seeds, except for L. siceraria, which, the alpha isomer recorded a high value 367.18 μg/g. Beta tocopherol presented a low content in all sample oils. The presence of tocopherol significantly increases the oxidative stability of the oil (Balakrishnan et al., 2025). Composition of phytosterols and tocopherols of different seeds oil of Cucurbitaceae family is summarized in Table 7.

Table 7.

Cucurbitaceae seed oils composition of phytosterols and tocopherols.

Sterol	C. lanatus (mg/kg) [158,159]	C. melo (%) [132]	L. siceraria (mg/100 g) [71]	C. maxima (mg/100 g) [160]	C. moschata (%) [161]	C. colocynthis [120,162]
Brassicasterol	38.7	0.06 ± 0.03	–	47.04 ± 1.33	–	–
Campestanol	2.10	–	–	29.45 ± 1.45	–	–
Campesterol	12.6	4.29 ± 0.66	59.61 ± 2.05	78.33 ± 1.36	1.82 ± 0.03	4.78
Cholesterol	5.05	0.53 ± 0.08	–	15.79 ± 4.70	–	0.18
Stigmasterol	77.4	8.17 ± 0.44	6.74 ± 0.54	124.93 ± 3.71	–	1.50
Δ5,23-Stigmastadienol	4.21	0.55 ± 0.02	–	–	–	–
Δ5,24-Stigmastadienol	158.2	–	–	1436.78 ± 23.48	–	–
Δ5-Avenasterol	1319.2	20.80 ± 0.48	1.94 ± 0.22	–	–	17.24
Δ7-Avenasterol	83.3	6.08 ± 0.52	–	695.48 ± 17.57	183.5 ± 3.9	0.11
Δ7-Campesterol	24.8	–	–	88.02 ± 2.29	–	–
Δ7-Stigmastenol	21.8	–	–	493.24 ± 18.75	26.89 ± 1.37	3.81
Sitosterol	2298.8	54.3 ± 1.1	332.66 ± 5.71	–	17.90 ± 0.75	69.86
α-tocopherol	1.68	23.50 ± 1.70	367.18 ± 4.26	74.27 ± 2.25	62.95 ± 1.39	0.72 ± 0.06
β - tocopherol	ND	3.90 ± 0.70	ND	ND	ND	0.57 ± 0.03
γ- tocopherol	62.8	77.40 ± 0.70	64.09 ± 2.14	359.56 ± 23.59	241.63 ± 6.11	116.36 ± 0.15
δ- tocopherol	0.69	11.30 ± 0.60	117.85 ± 3.71	76.45 ± 0.85	91.80 ± 2.25	4.19 ± 0.12

5. Applications of cucurbitaceae seeds

The fruit and vegetable processing industries generate substantial quantities of by-products, accounting for 25–60% of total production weight (Hussain et al., 2022; Rico et al., 2020). These by-products represent a significant untapped resource with considerable economic potential. Notably, seeds from Cucurbitaceae species – including pumpkin, watermelon, and cucumber - are frequently underutilized or discarded as waste, particularly in developed nations (Shetty et al., 2012a). However, emerging research has revealed that these seeds are nutritionally dense, containing valuable proteins, healthy fats, antioxidants, and bioactive compounds. This unique composition makes them particularly suitable for diverse applications spanning nutrition, medicine, and industrial uses. Among various agricultural by-products, Cucurbitaceae seeds stand out for their exceptional nutritional profile and functional properties, making them a promising resource for value-added applications, as summarized in Fig. 3, which links seed composition (proteins, lipids, phenolics, minerals) to their principal application domains and emerging research themes.

Fig. 3.

Cucurbitaceae seed composition and its applications in food, health, and industry.

5.1. Food and nutraceutical applications

Cucurbitaceae seeds are particularly rich in nutrients, containing high-quality proteins (25–40%), essential fatty acids (30–50%), dietary fibre, vitamins (B-complex, E), and minerals (magnesium, zinc, iron, potassium) (Glew et al., 2006). This composition gives to Cucurbitaceae seeds a large wide of food applications (Gholami & Ansari, 2021; Rezig et al., 2012). In some countries such as India, as well as in Middle East and African regions, these seeds are commonly consumed as snacks, incorporated into traditional dishes, or used as decorative elements in cakes and desserts like Kheer (Dimitry et al., 2022; Gholami & Ansari, 2021; Rezig et al., 2012; Yadav et al., 2010).

Several Cucurbitaceae species are integral to global food production, with China, Turkey, and the United States standing out as leading producers (Rolnik & Olas, 2020). In many regions, the seeds are eaten whole, not only for their nutritional value but also for their medicinal properties, particularly in the treatment of chronic or atopic eczema (Rezig et al., 2019; Wani et al., 2011). The seed kernels are frequently used in baking and as garnishes, often substituting for almonds or pistachios in Indian cuisine (Wani et al., 2011).

Pumpkin and watermelon seed flour is gaining attention in the development of non-allergenic and functional foods as they found to be rich is in essential nutrients such as proteins, unsaturated fatty acids, phenolic acids, carotenoids, tocopherol, phytosterol, squalene (Dimitry et al., 2022; Patel & Rauf, 2017). It can be used in products like low-fat spreads, serving as a nutritious alternative to traditional peanut butter substitutes (Nikolic et al., 2014).

In the biscuit industry, efforts are underway to replace conventional wheat flour with pumpkin seed flour to create gluten-free options, thus catering to consumers with specific dietary needs (Moskvicheva et al., 2019). The inclusion level of Cucurbitaceae seed flour in the food products is important for the quality, and therefore the right inclusion level must be found. Pumpkin seed flour 10–30% in biscuits increase protein from 6.2% to 9.8% and fibre from 2.1% to 5.9% with good sensory scores and no major texture problems (Ungureanu et al., 2025). Higher inclusion levels (up to 20% in wheat-flour blends) begin to affect dough rheology as the seed proteins interfere with the formation of the gluten network, as well as storage-related changes in product stability (Arshad et al., 2025). The high PUFA content of the flour also promotes the lipid peroxidation over shelf life. Spray-drying encapsulation with polysaccharide carriers is a validated method to protect it, and this approach recently improved oil oxidative stability by 32–60% (Toprakçı et al., 2025).

Furthermore, biodegradable packaging films derived from pumpkin seeds offer a sustainable alternative to synthetic polymer films for packaging various food items such as bread, cakes, and confectionery (Lalnunthari et al., 2019). The remaining pumpkin after oil extraction, is rich bioactive content, and holds potential for incorporation into dietary supplements (Balbino et al., 2019). Currently, Cucurbitaceae seed oils are widely utilized across the food industry in various applications, including cooking, frying, baking, salad dressings, and as carriers for flavors and nutrients (Lafarga, 2021).

Cucurbitaceae seeds were also suggested as a potential source of edible oils and also cosmetic and pharmaceutical purposes (Nyam et al., 2009). Pumpkin seeds (C. pepo and C. moschata) with, 30–50% oil yield, rich in linoleic acid (omega-6) and oleic acid (omega-9), making them suitable for cooking, salad dressings, and also nutraceuticals uses (Nyam et al., 2009; Rezig et al., 2012).

5.2. Traditional and ethnomedicinal uses

Cucurbitaceae seeds have long been valued in traditional medicine for their wide range of therapeutic properties (Mukherjee et al., 2022). C. colocynthis is renowned for their antidiabetic effects, helping to lower blood glucose levels and enhance insulin sensitivity (Bakchiche et al., 2021). Additionally, Cucurbita seeds have historically been used to promote digestive health, relieve constipation, and eliminate parasitic infections in the intestines due to their high levels of both soluble and insoluble fibre, as well as their bioactive compounds such as cucurbitacins and phytosterols (Gossell-Williams et al., 2006; Salehi et al., 2019). C. lanatus seeds are commonly used in traditional medicine as remedies for respiratory and urinary ailments based on their reported antispasmodic, diuretic, and bronchodilator effects, providing symptom relief (Wahid et al., 2022). Furthermore, pharmacological studies have shown that several species of the genera Cucumis and Lagenaria exhibit antioxidant, anti-inflammatory, and antimicrobial properties, thereby supporting their ethnomedicinal significance (Ayyad et al., 2011; Mallek-Ayadi et al., 2019)

5.3. Biofuel production, industrial, agricultural and other applications

Biodiesel production, and industrial raw materials from these seeds may provide the opportunity for greater resource efficiency and create additional sources of revenue (Ezema et al., 2023). Significant opportunities for smallholder farmers and agro-industries can be found by utilizing Cucurbitaceae seeds to create additional value through food, biofuels, and industrial uses; thereby enhancing rural livelihoods and helping to promote sustainable agro-industrial development (Atabani et al., 2012; Salam et al., 2025).

Many applications of Cucurbitaceae seeds have been reported by various researchers. In fact, after oil extraction, the residual seed cake can be repurposed as animal feed, compost, natural pesticides and pest repellents, biofertilizers and soil conditioners or raw material for many other applications (Shetty et al., 2012b). Melon seeds also present promising opportunities, particularly as an alternative source to soybean oil for biodiesel production (Sena & Pereira, 2017).

Residual seed cake from oil extraction can be used in protein-rich feed ingredients for livestock and poultry and supports efforts to improve sustainable animal nutrition (Mukherjee et al., 2022). The oils from pumpkin (Cucurbita spp.) and watermelon (C. lanatus) seeds have been studied as new sources of biodiesel since they have good fat profiles and fuel characteristics (Nwufo et al., 2023; Sani et al., 2018; Schinas et al., 2009). Studies have shown that crushed pumpkin seeds can reduce nematodes in organic farming systems (Akhtar & Malik, 2000; Oka, 2010), while compost made from watermelon seeds improves soil fertility and increases the ability to hold water (Diacono & Montemurro, 2010; Rouwane et al., 2017). Finally, oils from C. colocynthis and C. melo seeds have been investigated for biodiesel production and other industrial uses, showing they could be ancillary sources of non-food feedstock for sustainable energy and bioproducts (Al-Bawwat et al., 2024; Raj et al., 2022).

5.4. Gut microbiota interactions and emerging functional food design

Seed-derived bioactives also communicate with the gut microbiota. The fibre fractions found in seed hulls (pectins, hemicelluloses, resistant starch, β-glucans) are prebiotic substrates that promote genera such as Bifidobacterium, Lactobacillus, Roseburia and Faecalibacterium (Fu et al., 2022). Their fermentation results from short-chain fatty acids, butyrate, propionate, acetate that help colonocyte energy metabolism, hepatic lipid regulation and appetite control through GPR109A/AMPK/GPR41–43 signalling (Anachad et al., 2023). Moreover, seed polyphenols are further biotransformed by colonic bacteria into metabolites with specific bioactivity (Alqudah & Claesen, 2024), a bidirectional relationship making Cucurbitaceae seeds candidates for microbiome-targeted functional foods. Emerging multi-omics methods are starting to provide insight into these host-microbiota-diet interactions (Duan et al., 2025), providing pathways for rational design of next-generation functional products from seed flours, oils, or purified fractions.

In practice, defatted seed flours, already rich in fibre and protein, can be used as prebiotic-fibre fortifiers in bakery products, as shown for defatted hulless pumpkin seed meal in bread formulations, which improved antioxidant capacity and phenolic content and techno-functional properties (Raina et al., 2026). Seed extracts rich in polyphenols are also promising functional additives for synbiotic formulations, where co-encapsulation with targeted probiotic strains has improved probiotic survival and polyphenol bioavailability (Ji et al., 2025).

6. Economic and commercial importance

The economic and commercial significance of Cucurbitaceae seeds have gained importance for their versatility and role in supporting sustainable development (Zhang, Li, & Charalampopoulos, 2024). Because large amounts of seeds are produced through the processing of fruits, many seeds are disposed of, creating both economic losses and environmental problems (Rabadán et al., 2020).

In 2023, worldwide production of Cucurbitaceae exceeded 256 million tonnes. Watermelons are produced in greatest quantity (104.93 Megatons (Mt)), followed by cucumbers (97.81 Mt), melons (29.54 Mt), and pumpkins, squashes and gourds (23.68 Mt) (Table 8). All these numbers illustrate the importance of these crops in global agriculture. More than 109 countries around the world contribute to global production of Cucurbitaceae. China is the first producer of these crops, accounting for more than 50% of this production. Watermelon production represents about 40% of the world's production, which is what makes it so special (FAOSTAT, 2026).

Table 8.

Global Cucurbitaceae Crops Production by Top Ten Countries (Megatons) in 2023 [191].

Watermelons		Melons		Cucumbers		Pumpkins, squash and gourds
China	63.96	China	14.50	China	63.96	China	7.42
India	3.63	India	1.50	Türkiye	3.63	Russia	1.13
Türkiye	3.15	Türkiye	1.40	Russia	3.15	Ukraine	1.11
Algeria	2.51	Kazakhstan	1.37	Mexico	2.51	USA	0.998
Brazil	1.78	Brazil	0.86	Uzbekistan	1.78	Türkiye	0.727
Russia	1.77	Guatemala	0.85	Ukraine	1.77	Mexico	0.716
USA	1.68	Afghanistan	0.80	Spain	1.68	Spain	0.707
Uzbekistan	1.57	Italy	0.76	USA	1.57	Bangladesh	0.668
Pakistan	1.51	Mexico	0.65	Egypt	1.51	Italy	0.561
Senegal	1.49	Iran	0.63	Kazakhstan	1.49	Indonesia	0.557
World (136 countries)	104.93	World (109 countries)	29.54	World (139 countries)	97.81	World (126 countries)	23.68

Seeds of Cucurbitaceae have a great deal of economic and commercial significance worldwide because they can serve in diverse uses in food, agriculture, health and industry (Ajuru & Nmom, 2017; Patel & Rauf, 2017). They also have significant potential within agricultural economies. The overall nutritional profile of these seeds is very beneficial regarding proteins, oils, vitamins, minerals, dietary fibers and antioxidants. Cucurbitaceae seeds also play a significant role in food security (Ozuna & León-Galván, 2017; Romo-Tovar et al., 2024).

7. Conclusion

Cucurbitaceae seeds provide a highly valuable source of bioresources, with many health benefits, functional properties, and economic benefits. They are shown to be a rich source of high-quality protein, essential fatty acids, and bioactive compounds and exhibit high-quality antioxidant activity and functional properties. With respect to oil produced from their seeds, they have favourable fatty acid compositions and physicochemical properties which enable their use in multiple sectors, including food systems, nutraceuticals, biofuels and agricultural applications.

There are limitations to this evidence base that are worth noting: most reported bioactivities are based on in vitro assays, compositional data vary widely between cultivars, growth conditions and extraction protocols, and several economically important genera are under-represented compared to the widely studied Cucurbita, Citrullus and Cucumis.

Three priorities emerge for future work: in vivo and clinical studies to confirm that in vitro bioactivities translate into health outcomes, together with bioavailability data for key compounds; harmonised extraction and analytical protocols to enable comparability of compositional data across studies, together with safety and allergenicity profiling for novel applications; and techno-economic and life-cycle assessments to test the viability of pilot-scale valorisation of seed proteins, oils and by-products at industrial scale.

Ultimately, continued improvements in processing optimization, standardization, and sustainability evaluation, guided by the priorities above, will be critical to advancing broader industrial utilization of Cucurbitaceae seeds.

CRediT authorship contribution statement

Abdelghani Ait Nouisse: Writing – original draft, Resources, Formal analysis. Assia boukhair: Software, Resources, Formal analysis, Data curation. Abderrahim Asbbane: Writing – original draft, Software, Resources, Formal analysis. Mohamed Ibourki: Writing – original draft, Visualization, Resources, Methodology. Abdelhakim Bouyahya: Writing – review & editing, Validation, Supervision. Waleed Al Abdulmonem: Writing – review & editing, Visualization, Validation, Funding acquisition. Khalid Majourhat: Writing – review & editing, Visualization, Validation, Supervision. Said Gharby: Writing – review & editing, Visualization, Validation, Project administration.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability

Data will be made available on request.