Nutritional and Functional Potential of Mangosteen (Garcinia mangostana L.) By-products: Compositional, Color and Antioxidant Analysis of Leaves, Pericarp, Seeds and Pulp

Abstract

Garcinia mangostana L. is a tropical fruit widely recognized for its nutritional and functional properties; however, the compositional characteristics of its different anatomical parts remain insufficiently explored. This study evaluated the proximate composition, mineral content, fiber fractions, bioactive compounds, antioxidant capacity, and color of mangosteen leaves, pericarp, seeds, and pulp. Significant differences (p < 0.05) were observed among tissues. Leaves exhibited the highest concentrations of calcium (1716 mg/100 g dm), iron (117 mg/100 g dm), and total phenolic compounds (147.35 mg GAE/g dm), together with the highest FRAP values (585.53 µmol Trolox/g dm). The pericarp showed the greatest antioxidant activity determined by ABTS (2870.62 µmol Trolox/g dm) and DPPH (1036.61 µmol Trolox/g dm), as well as the highest anthocyanin content (3041.17 mg C3GE/100 g dm). Seeds were characterized by elevated lipid (53.65 g/100 g dm) and protein (15.10 g/100 g dm) contents, whereas the pulp exhibited the highest carbohydrate concentration (84.54 g/100 g dm). The distinct color profile of the pericarp was associated with its high anthocyanin levels. These findings demonstrate the marked compositional heterogeneity among mangosteen tissues and highlight the potential of leaves and pericarp as sources of bioactive compounds and antioxidants, while seeds represent a valuable source of oil and protein for food and nutraceutical applications.

Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1007/s11130-026-01575-0.

Introduction

Mangosteen (Garcinia mangostana L.) is a tropical fruit widely appreciated for its sensory attributes and recognized as a valuable source of nutrients and bioactive compounds. Often referred to as the “queen of tropical fruits,” it has attracted increasing scientific interest due to its reported antioxidant, anti-inflammatory, antimicrobial, and metabolic regulatory properties [1]. Native to Southeast Asia, mangosteen is currently cultivated in several tropical regions, where it represents an important agricultural resource [2]. Thailand reported a production of approximately 300,000 tons in 2023 and 2024 [3]. Other major producing countries include Indonesia, Vietnam, the Philippines, and Malaysia.

Beyond its edible pulp, mangosteen contains a large proportion of non-edible fractions, including the pericarp and seeds, which may account for up to 60–83% and approximately 2% of the fruit weight, respectively [1]. These by-products have traditionally been discarded, likely because of their unfavorable texture and/or sensory characteristics, despite evidence indicating that different anatomical parts of the plant, such as pericarp, leaves, and seeds, contain significant amounts of secondary metabolites and nutrients [4]. Among these fractions, the pericarp has been the most extensively investigated due to its high content of phenolic compounds, flavonoids, pectins, dietary fiber, and xanthones [5], which are considered the main bioactive constituents of G. mangostana. In particular, α-mangostin and γ-mangostin are the predominant xanthones, accounting for approximately 70–80% and 20–30% of the total xanthone content, respectively, depending on extraction method and purity [6]. These compounds have been associated with multiple pharmacological activities, including antioxidant, anti-inflammatory, antidiabetic, neuroprotective, and antimicrobial effects [7, 8]. In addition, the pericarp has been reported to contain high levels of vitamin C compared to the pulp, reinforcing its nutritional potential [9]. The edible pulp is mainly composed of carbohydrates and water, whereas other anatomical fractions contain higher concentrations of nutrients and bioactive compounds [10]. Seeds are regarded as promising sources of lipids and proteins, with potential applications in oil extraction and functional ingredient development [11]. Mangosteen leaves have recently attracted interest as a source of phenolic compounds and natural pigments with antioxidant and biological activities, suggesting potential nutraceutical applications [12]. In addition, several mangosteen tissues contain relevant concentrations of essential minerals such as potassium, calcium, magnesium and iron, which contribute to their nutritional value [9].

Despite the increasing body of research on mangosteen, most studies have focused on individual fractions, particularly the pericarp, or on specific groups of compounds. Comprehensive comparative studies that integrate proximal composition, structural carbohydrates, mineral profile and bioactive properties across all anatomical parts remain scarce. Furthermore, the potential application of these fractions as functional ingredients in human nutrition has not been fully addressed, particularly from a valorization and circular economy perspective [13, 14].

In this context, it is hypothesized that the different anatomical parts of mangosteen present distinct physicochemical and bioactive profiles that can be selectively exploited for nutritional and functional applications. Therefore, the aim of this study was to comprehensively evaluate the proximal composition, fiber fractions, mineral content, bioactive compounds, antioxidant capacity and color of mangosteen leaves, pericarp, seeds and pulp. This integrated approach seeks to identify their potential as functional ingredients and to support their valorization within sustainable food and nutraceutical applications.

Materials and Methods

This section is provided as Supplementary Material 1.

Results and Discussion

The proximal composition and fiber fractions of the different anatomical parts of mangosteen are presented in Table 1; Fig. 1, respectively. Significant differences (p < 0.05) were observed among all analyzed fractions, reflecting the biochemical specialization of each tissue. Overall, the results demonstrate a clear differentiation between metabolically active tissues, storage organs, and structural components of the fruit. Leaves exhibited the highest ash and crude fiber contents, together with relatively high protein levels. This composition is consistent with their physiological role as metabolically active tissues, where minerals and structural components accumulate to sustain photosynthesis and plant defense [15].

Table 1.

Proximate composition (g/100 g dm)

Sample	Ash	Moisture	Crude Fiber	Fat	Protein	Available Carbohydrates*
Leaves	6.315 ± 0.012a	9.48 ± 0.11c	43.32 ± 0.09a	2.59 ± 0.05c	8.80 ± 0.04b	38.97 ± 0.09c
Pericarp	4.34 ± 0.02b	10.56 ± 0.06b	36.9 ± 0.3b	4.18 ± 0.12b	3.89 ± 0.04c	50.7 ± 0.3b
Seed	4.31 ± 0.06b	5.58 ± 0.07d	19.3 ± 0.2c	53.65 ± 0.11a	15.1 ± 0.7a	7.7 ± 0.8d
Pulp	1.19 ± 0.02c	12.08 ± 0.09a	9.98 ± 0.03d	0.97 ± 0.12d	3.4 ± 0.3c	84.5 ± 0.3a

* Available carbohydrates: 100-(ash+crude fiber + fat+protein)

Identical letters within a column indicate homogeneous groups with 95% of significance level

Fig. 1.

Fiber composition (NDF: neutral detergent fiber; ADF: acid detergent fiber; ADL: acid detergent lignin; hemicellulose and cellulose) of mangosteen leaves, pericarp, seeds and pulp. Different letters of the same color indicate statistically homogeneous groups according to ANOVA (p < 0.05) for each fiber fraction among the analyzed tissues

The high crude fiber content observed in leaves was further confirmed by their elevated levels of neutral detergent fiber (NDF) and acid detergent fiber (ADF), indicating a well-developed lignocellulosic structure. Such a composition suggests that mangosteen leaves could be considered a promising source of structural fiber fractions for functional food applications, as also reported for other fiber-rich plant matrices [16]. In contrast, seeds showed a markedly different compositional profile, characterized by very high lipid and protein contents, reflecting their function as storage organs. The lipid fraction, exceeding 50 g/100 g dm, highlights a strong potential for oil extraction, while the protein content supports their possible use as a plant-based protein source. This profile is consistent with previous studies on mangosteen seeds and other oil-rich plant materials such as Chironji (Buchanania lanzan) [17, 18]. In agreement with their storage role, seeds exhibited lower fiber contents than leaves and pericarp, although still maintaining relevant levels of NDF, indicating the presence of structural polysaccharides associated with seed coats. The pericarp presented intermediate values of fat and protein, but stood out for its high fiber content, confirming its structural role as a protective tissue. The elevated levels of NDF and ADF, together with significant amounts of cellulose, hemicellulose and lignin, indicate a predominance of cell wall components. The fiber content of mangosteen pericarp was higher than that reported for several agro-industrial by-products, including banana peel, watermelon rind and cauliflower leaves [16], as well as other fruit residues such as persimmon peel and pitahaya pericarp [19, 20]. These results highlight the pericarp as an especially rich source of structural fiber with potential applications as a functional ingredient to improve water-holding capacity and textural properties in food systems. The pulp was characterized by the highest carbohydrate content and the lowest levels of fat, protein and fiber, confirming its role as the main energy-providing fraction of the fruit. These findings are consistent with previously reported values for mangosteen pulp [21]. In contrast to leaves and pericarp, the pulp exhibited very low NDF and ADF contents, reflecting a limited development of structural polysaccharides. This composition explains its high palatability but reduced contribution to functional properties compared to other anatomical parts.

The analysis of individual fiber fractions revealed that NDF was the predominant fraction in all tissues except the pulp, followed by ADF, indicating a high proportion of structural fiber. According to the Van Soest model, NDF includes hemicellulose, cellulose and lignin, while ADF mainly comprises cellulose and lignin [22]. The higher NDF and ADF values observed in leaves and pericarp are therefore associated with increased levels of hemicellulose and lignocellulosic components, which are essential for structural integrity and mechanical resistance in plant tissues exposed to environmental stress.

Elemental analysis (Table S1) revealed significant differences among mangosteen tissues. Seeds showed the highest C, H and N contents and the lowest C/N ratio, consistent with their lipid and protein rich composition. In contrast, pericarp and pulp exhibited higher C/N ratios associated with structural carbohydrates, while leaves presented intermediate values related to their metabolic activity. These results support the distinct physiological functions and potential applications of each tissue.

From a functional perspective, the differences in elemental composition and C/N ratio provide valuable information regarding the potential applications of each fraction. While seeds are suitable for applications involving energy-rich compounds (lipids and proteins), leaves exhibit characteristics associated with high metabolic activity and bioactive compound synthesis [23]. In contrast, pericarp and pulp display properties typical of lignocellulosic biomasses, suggesting potential uses in the development of dietary fiber ingredients, biomaterials or bio-based products [24].

Overall, the elemental analysis complements the proximal and fiber results, confirming the differentiated distribution of carbon and nitrogen resources among mangosteen tissues. These findings support a targeted valorization strategy based on the compositional and functional characteristics of each anatomical fraction.

In addition to the organic composition described above, the mineral profile of mangosteen tissues was evaluated to further understand their nutritional potential, particularly regarding the distribution of essential macro and micronutrients. The mineral composition of the different anatomical parts of mangosteen is presented in Table 2, showing significant differences (p < 0.05) among tissues and highlighting a heterogeneous distribution of macro- and micronutrients. Potassium was the predominant mineral in all fractions, with the highest concentration observed in the pericarp, followed by seeds and leaves. This pattern is consistent with the role of potassium as a key intracellular cation involved in osmotic regulation, enzyme activation and maintenance of cellular turgor in plant tissues [25]. The elevated potassium content found in mangosteen by-products suggests their potential as dietary sources of this essential mineral, which plays an important role in cardiovascular health and blood pressure regulation. Leaves exhibited the highest contents of calcium and iron, indicating a strong accumulation of micronutrients in metabolically active tissues. This behavior is consistent with their physiological function, as calcium contributes to cell wall stability and signaling processes, while iron is essential for photosynthesis and enzymatic activity. Comparable levels of calcium and iron have been reported in other plant leaves rich in micronutrients [26, 27]. From a nutritional perspective, these findings highlight the potential of mangosteen leaves as sources of essential minerals; however, their bioavailability may be influenced by the presence of antinutritional factors, which should be considered in future studies. Seeds showed intermediate levels of most minerals, with particularly high concentrations of magnesium and trace elements such as zinc and copper. This reflects their function as storage tissues, where minerals are accumulated to support early germination and plant development. Similar mineral profiles have been reported in various oilseed crops, including sesame, sunflower, flaxseed, rapeseed, safflower, cottonseed, and soybean, with relevant concentrations of minerals such as magnesium, zinc, and copper [28]. The relatively high magnesium content is nutritionally relevant, given its role as a cofactor in numerous metabolic reactions related to energy production and neuromuscular function [29]. In contrast, the pulp exhibited the lowest mineral concentrations across most elements, which is consistent with its primary role as a carbohydrate-rich tissue.

Table 2.

Mineral composition of mangosteen fractions (mg/100 g dry matter)

Sample	Ca	K	Mg	Cu	Fe	Mn	Zn
Leaves	1716 ± 69a	1990 ± 139c	133 ± 12b	0.28 ± 0.01b	117 ± 2a	3.85 ± 0.05a	3.9 ± 0.2b
Pericarp	45.1 ± 3.3c	4184 ± 144a	65 ± 2c	0.082 ± 0.003c	44 ± 5c	0.072 ± 0.002c	2.9 ± 0.2c
Seed	484 ± 16b	2882 ± 261b	158 ± 14a	0.55 ± 0.01a	84 ± 6b	0.78 ± 0.04b	5.9 ± 0.3a
Pulp	7.3 ± 0.3c	1218 ± 77d	113 ± 7b	ND	32 ± 4c	ND	1.34 ± 0.02d

ND not detected. Identical letters within a column indicate homogeneous groups with 95% of significance level

The observed differences in mineral composition can be attributed to variations in physiological function, tissue structure, and nutrient translocation mechanisms, as well as external factors such as cultivation conditions and maturity stage. Overall, the results indicate that non-edible fractions of mangosteen, particularly leaves and pericarp, represent promising sources of essential minerals, supporting their potential valorization as functional ingredients within a nutritional and sustainable framework.

The antioxidant capacity determined by DPPH, ABTS and FRAP assays and the content of total phenolic compounds, flavonoids, flavonols, and anthocyanins are presented in Fig. 2 and in Table 3, respectively. Significant differences (p < 0.05) were observed among the different anatomical parts of mangosteen, indicating a heterogeneous distribution of bioactive compounds across tissues.

Fig. 2.

Antioxidant capacity of mangosteen fractions determined by DPPH, ABTS and FRAP assays. Different letters of the same color indicate statistically homogeneous groups according to ANOVA (p < 0.05) for each assay among the analyzed tissues

Table 3.

Polyphenols, flavonoids, flavonols and anthocyanins content in mangosteen fractions

Sample	Polyphenols	Flavonoids	Flavonols	Anthocyanins
	(mg GAE/g dm)	(mg QE/g dm)	(mg QE/g dm)	(mg C3GE/g dm)
Leaves	147.4 ± 1.7a	5.17 ± 0.04a	5.55 ± 0.11a	30 ± 5b
Pericarp	102.57 ± 0.00b	ND	ND	3041 ± 55a
Seed	26.6 ± 0.2c	0.75 ± 0.01b	0.63 ± 0.02b	17.61 ± 0.00b
Pulp	3.66 ± 0.00d	0.24 ± 0.01c	0.58 ± 0.00b	18.69 ± 0.00b

mg GAE/g dm mg gallic acid equivalents per gram of dry matter, mg QE/g dm mg quercetin equivalents per gram of dry matter, mg C3G/g dm mg cyanidin-3-glucoside equivalents per gram of dry matter. ND no detected. Identical letters within a column indicate homogeneous groups with 95% of significance level

The antioxidant capacity results revealed a consistent pattern among the different assays, with pericarp and leaves showing the highest values, followed by seeds and pulp. This trend is consistent with Lim et al [30], who compared methanolic extracts of fresh mangosteen pericarp, pulp, and seed and reported significantly higher antioxidant capacity for pericarp than for pulp and seed in both FRAP and DPPH assays. It should be noted that their FRAP values were expressed as ferrous sulphate equivalents (FEAC, mM FE/g dw: 18.99 ± 4.43 for pericarp vs. 0.70 ± 0.21 and 2.20 ± 0.48 for pulp and seed, respectively), whereas our study expresses FRAP as Trolox equivalents (µmol ET/g dm); these two standards are not numerically interconvertible, so only the relative ranking among tissues can be compared, not the absolute magnitude. Their DPPH results, expressed as Trolox equivalents (TEAC, µM TE/g dw: 122.00 ± 2.00 for pericarp vs. 24.00 ± 4.00 and 80.00 ± 22.00 for pulp and seed), use the same reference standard as our study and therefore allow a more direct comparison; the pericarp > seed > pulp ranking observed by Lim et al [30] matches the pattern found here.

In general, ABTS values were higher than those obtained by DPPH and FRAP, which can be attributed to the different reaction mechanisms involved. The ABTS assay is capable of detecting both hydrophilic and lipophilic antioxidants, whereas DPPH shows higher selectivity toward lipophilic compounds, and FRAP mainly evaluates reducing power [31]. This suggests the presence of a complex mixture of antioxidant compounds in mangosteen, including both phenolic acids and more hydrophobic molecules such as xanthones. Leaves exhibited the highest contents of total phenolics, flavonoids and flavonols, which was consistent with their strong antioxidant capacity, particularly in the FRAP assay. This agrees with Rizaldy et al [32], who reported the highest total phenolic content (49.53 ± 4.26 g GAE/100 g) and DPPH antioxidant activity (up to 489.71 mg AAE/g) in ethanolic extracts of mangosteen leaves, supporting their role as one of the most antioxidant-rich fractions of the plant. This behavior reflects their physiological role as metabolically active tissues exposed to environmental stress, where the synthesis of phenolic compounds acts as a protective mechanism against oxidative damage and UV radiation [33]. The high antioxidant capacity observed in leaves suggests a significant presence of electron-donating compounds, mainly polyphenols, which contribute to their reducing power. In contrast, the pericarp showed a distinctive phytochemical profile, characterized by moderate levels of total phenolics but an exceptionally high concentration of anthocyanins, reaching values up to two orders of magnitude higher than in other fractions. This finding is consistent with the intense purple coloration of mangosteen pericarp and confirms its role as an important reservoir of pigment-type bioactive compounds. The high anthocyanin content may contribute to the strong antioxidant activity observed in the DPPH and ABTS assays [13]. Previous studies [34] have reported that the pericarp of Garcinia mangostana contains anthocyanins, including cyanidin-based pigments, as well as xanthones such as α-mangostin and γ-mangostin, which are recognized for their antioxidant properties.

Seeds exhibited moderate levels of phenolic compounds and antioxidant capacity, indicating that, despite their primary role as storage organs, they also contain bioactive molecules with potential functional applications. Previous studies have reported the presence of flavonoids and other phenolic compounds in mangosteen seeds, although at lower concentrations than in the pericarp [4]. These results suggest that seeds could represent a secondary but relevant source of antioxidants in addition to their lipid and protein content. The pulp showed the lowest concentrations of phenolic compounds and antioxidant activity across all assays. This behavior is consistent with its primary function as an energy-providing tissue, mainly composed of carbohydrates, and with previous reports indicating that most bioactive compounds in mangosteen are concentrated in non-edible fractions such as the pericarp [4]. Although the pulp contributes to the nutritional value of the fruit through sugars and vitamins, its role as a source of antioxidant compounds appears to be limited.

A strong correspondence between phenolic content and antioxidant capacity was observed, particularly in leaves and pericarp, confirming that phenolic compounds are the main contributors to the antioxidant activity of mangosteen tissues. A positive relation between total phenolic content and antioxidant activity (DPPH, ABTS and FRAP) was observed, indicating that phenolic compounds are the major contributors to the radical scavenging capacity of mangosteen tissues. In addition, the exceptionally high anthocyanin content detected in the pericarp showed a strong association with the elevated ABTS and DPPH values, suggesting that these pigment compounds play a key role in the radical scavenging activity of this fraction. This relationship has been widely reported in plant-based foods, where higher total phenolic and anthocyanin contents are typically associated with enhanced antioxidant capacity and free radical neutralization [35].

Overall, the integrated analysis of bioactive compounds and antioxidant activity highlights the relevance of mangosteen by-products, particularly pericarp and leaves, as valuable sources of phytochemicals. These findings support their potential application in the development of functional foods and nutraceutical products, contributing to the sustainable valorization of this tropical fruit within a circular economy framework.

The color differences observed among fractions are closely linked to their phytochemical composition, particularly the distribution of anthocyanins and other phenolic pigments. The color parameters (L*, a*, b*), chroma (C*) and hue angle (h°) of the different mangosteen fractions are presented in Table S2 (Supplementary Material 2). Significant differences (p < 0.05) were observed among tissues, reflecting the presence of distinct pigment profiles and their relationship with the compositional characteristics of each anatomical part. The pulp exhibited the highest luminosity (L*), indicating a lighter appearance, which is consistent with its low content of pigmented compounds such as phenolics and anthocyanins. This agrees with its compositional profile, characterized by a predominance of carbohydrates and low levels of bioactive compounds, as previously discussed. In contrast, the pericarp showed the lowest L* values, corresponding to its darker and more intensely colored appearance, which can be attributed to its high anthocyanin content. Color parameters for freeze-dried pericarp of this study were in the same order as reported by Soontornwat et al [7]. The a* parameter clearly differentiated the tissues, with negative values observed in leaves and positive values in pericarp. The negative a* values in leaves indicate a predominance of green hues associated with chlorophyll pigments, while soothe high positive a* values in the pericarp reflect the presence of red-purple pigments, mainly anthocyanins. This observation agrees with the high anthocyanin concentrations quantified in this fraction and supports the strong relationship between color parameters and phytochemical composition. The b* values and hue angle (h°) further confirmed the distribution of pigments among tissues. Leaves exhibited higher b* and h° values, indicating yellow-green tonalities related to chlorophylls and carotenoids, whereas the pericarp showed lower hue angle values, characteristic of reddish to purple colors. These differences demonstrate that colorimetric parameters can serve as indirect indicators of pigment composition in plant materials. Chroma (C*) values were higher in leaves and pericarp, indicating greater color saturation compared to seeds and pulp. This suggests a higher concentration or diversity of pigment compounds in these tissues, particularly phenolic pigments such as anthocyanins in the pericarp and chlorophyll-related compounds in leaves. The lower chroma observed in pulp is consistent with its reduced pigment content and more neutral appearance.

From a functional perspective, the strong relationship between color and bioactive composition highlights the potential of mangosteen by-products as natural sources of colorants. In particular, the pericarp, with its intense coloration and high anthocyanin content, could be exploited as a natural pigment for food applications. In addition, color parameters may be used as rapid, non-destructive indicators of bioactive compound content, facilitating quality control in processing and formulation.

Overall, the color analysis complements the compositional and antioxidant results, confirming the close association between pigment content and functional properties in mangosteen tissues. These findings reinforce the potential valorization of specific fractions, particularly the pericarp and leaves, as sources of natural colorants and bioactive ingredients within food and nutraceutical applications.

Conclusions

This study demonstrated the marked compositional heterogeneity of Garcinia mangostana tissues and highlighted their distinct nutritional and functional applications. Among the evaluated fractions, pericarp and leaves showed the greatest potential as functional ingredients. The pericarp was characterized by high structural fiber, potassium, anthocyanin content, and the highest antioxidant capacity, whereas leaves exhibited elevated levels of phenolic compounds, protein, calcium, iron, and strong antioxidant activity. Seeds were rich in lipids and proteins, supporting their potential for oil and plant-based protein production, while the pulp was mainly a carbohydrate-rich fraction with lower functional value. These findings confirm that mangosteen by-products represent valuable sources of bioactive compounds, minerals, and structural fiber that can be transformed into high-value ingredients for food and nutraceutical applications.

From a sustainability perspective, the selective valorization of mangosteen by-products supports circular economy strategies and contributes to reducing agro-industrial waste. Future studies should investigate the bioavailability of the identified bioactive compounds, their stability during food processing, and their performance when incorporated into functional food formulations.

Supplementary Information

Below is the link to the electronic supplementary material.

Author Contributions

Conceptualization: P.W., A.C.L., M.L.C., M.D.O.; Methodology: P.W., A.C.L., M.L.C., M.D.O.; Formal analysis and investigation: P.W.; Writing - original draft preparation: P.W.; Writing - review and editing: P.W., A.C.L., M.L.C., M.D.O.; Funding acquisition: P.W.; M.L.C.; M.D.O.; Resources: P.W.; Supervision: A.C.L., M.L.C., M.D.O.

Funding

This study was financially supported by the Universidad Estatal de Bolívar. The authors would like to thank Ecuaforestar for the donation of part of the raw material to carry out this work. The donating company was not involved in the study design, acquiring data, statistical analysis, results interpretation, or publication. Funding for open access charge: CRUE-Universitat Politècnica de València.

Data Availability

No datasets were generated or analysed during the current study.

Declarations

Competing Interests

The authors declare no competing interests.