Secondary volatile metabolite content of two Echi̇nacea species in two subsequent years in Ri̇ze, Türki̇ye

Abstract

The present research aimed to determine the secondary volatile metabolite composition of E. angustifolia and E. purpurea under the ecological conditions of Pazar/Rize over two years. Both species were investigated over two consecutive years and their secondary volatile metabolite profiles of the aboveground plant parts (totally stems, leaves, flowers, and inflorescences of 40 plants per plot) were determined using GC-MS analysis supported with SPME in triplicate. Remarkable variation could be detected between the two species. Major components detected in E. angustifolia in both years (2015–2016) were p Cymene (35.24% and 21.36%), β –Pinene (23.32% and 16.74%) and α – Pinene (11.23% and 8.09). On the other hand, main components obtained in E. purpurea in both years were Caryophyllene oxide (12.61 and 15.13%), Germacrene D (8.15% and 15.12%) and Allo-Aromadendrene (15.01% and 0.00%).

The combined results indicated that E. angustifolia and E. purpurea cultivated in Rize exhibited secondary volatile metabolite compositions that differed in concentration from those previously reported in the literature.

Several important secondary volatile metabolite components were detected in E. angustifolia and E. purpurea during both years of the study.

Introduction

Plants belonging to the family Asteraceae are widely used for therapeutic purposes due to the presence of bioactive compounds that exhibit a broad range of medicinal properties. This family is among the most well-known and extensively studied plant families worldwide [1, 2]. Within the Asteraceae family, the genus Echinacea, which is native to North America, occupies a prominent position among medicinal plants. Although nine different Echinacea species have been identified, only three are commonly used for therapeutic applications: Echinacea pallida (Nutt.) Nutt., Echinacea angustifolia DC., and Echinacea purpurea (L.) Moench [3, 4].

The present study focuses on Echinacea angustifolia DC. and Echinacea purpurea (L.) Moench. A brief description of the general morphological characteristics of these two species is provided below.

Echinacea angustifolia DC

The stems are simple, 10–50 cm tall, occasionally branching, sparsely to densely covered in thick, scratchy hairs, and sometimes enlarged at the base. In the Great Plains, it can be found on sandstone and limestone rock outcrops, thin soils, and arid, dry plains [5].

Echinacea purpurea (L.) Moench

The stems range in height from 60 to 180 cm, and they frequently have soft, short hairs at the top. The strongest feature for identifying this species is the coarsely serrated, irregularly toothed, oval to broadly lanceolate lowermost leaves. It is found in thickets, open forests, and prairies [5].

In Türkiye, Echinacea species are primarily imported as raw materials or pharmaceutical preparations and are used in various dosage forms. Preparations derived from the aerial parts and roots of Echinacea plants are recommended for the treatment of recurrent upper respiratory tract and urinary system infections [6]. These preparations are known to enhance and activate the body’s natural defense mechanisms, particularly in the context of infectious diseases [7, 8].

The primary aim of the present research was to characterize the secondary volatile metabolite composition of E. angustifolia and E. purpurea (collected the aboveground plant parts: stems, leaves, flowers, and inflorescences) grown under the ecological conditions of Pazar, Rize (Türkiye) using GC-MS analysis supported with SPME device, over two consecutive years. To the best of our knowledge, this is the first study dealing with E. purpurea and E. angustifolia.

Materials and methods

Field trial

Seeds of Echinacea purpurea and Echinacea angustifolia were obtained from the USDA (United States Department of Agriculture) Gene Bank. Seedlings of both species were initially grown in plant trays under controlled conditions. When the plants reached approximately 20 cm in height, they were transplanted to the experimental field located at the Research Area of the Faculty of Agriculture, Recep Tayyip Erdoğan University, Pazar, Rize (Türkiye).

The field experiment was arranged in a randomized complete block design with three replications. Each plot measured 4 m in length and 1.6 m in width. Plants were transplanted using 40 cm row spacing and within rows, resulting in a total of 40 plants per plot. Harvesting was conducted at the full flowering stage by cutting the plants approximately 15 cm above the ground.

For secondary volatile metabolite analysis, the aboveground plant parts (stems, leaves, flowers, and inflorescences) were collected as a whole. Due to the high relative humidity characteristic of the Rize region, whole plant parts plant materials were dried in a forced-air oven at 35 °C to achieve until a constant weight. Afterwards, dry samples were grounded with laboratory type stone crusher mill equipped with a 0.05 mm sieve.

Climatic characteristics of experimental Pazar location during 2014–2016

The Trabzon Meteorology 11th Regional Directorate provided meteorological data for the years 2014–2016. Information on the two year trial results is given in Table 1.

Table 1.

Climatic characteristics of the research area

	Mean Temperature (°C)			Long term Average	Total rainfall (mm)			Long term Average	Relative humidity (%)			Long term Average
	2014	2015	2016		2014	2015	2016		2014	2015	2016
January	8.7	6.7	5.7	6.6	67	160.4	217.8	225.8	66.5	70.7	72.3	69.6
February	8.5	8.4	9.9	6.6	65.2	99.4	72	178.4	69.3	72.1	68.3	68.7
March	10.3	8.3	10.4	8	126.8	125.4	151.2	156.5	71.2	82	69.7	73.6
April	12.5	10.5	13.6	11.7	57.8	171.4	70	91.9	77.6	74.6	71.2	74.3
May	17.2	15.6	16.0	16	15.6	58.4	103	97.4	78.8	84.1	80.9	77.2
June	20.5	20.4	21.0	20.3	14.2	53	220	136.2	78.6	89.1	77.8	77.7
July	23.2	22.3	22.5	22.9	102.6	10	195.8	143.9	81.8	82.5	80.3	79.7
August	24.6	24.6	24.5	23.1	185.6	241	140	189.4	82.4	85	81.8	81.7
September	20.7	22.8	19.3	20	392.2	80.2	577	249.7	82.5	83.4	78.3	81.0
October	16.4	16.6	15.2	15.9	108.6	510	524.2	291.1	81.8	85.4	84.5	79.5
November	11.1	12.4	11.2	11.7	388	325.8	214.8	250.7	74.6	71.5	69.4	72.8
December	10.7	7.1	4.7	8.4	281.6	245.4	264.8	234.3	73.6	76.1	78.3	71.5
Total/Mean	15.3	14.6	14.5	14.2	1805.2	2080.4	2750.6	2245.3	76.5	79.7	76.06	75.6

Tümas Meteorology General Directory Data Base (2016) [9] 

Soil properties of the experimental area

The experiment was conducted in the Medicinal and Aromatic Plants Research and Application Area of the Faculty of Agriculture, Recep Tayyip Erdoğan University. Prior to the establishment of the field trial, soil samples were collected from the experimental area and analyzed at the Pazar and Çamlıhemşin Chamber of Agriculture Şemsi Bayraktar Soil and Plant Analysis Laboratories.

Soil analyses were performed to determine physical and chemical properties, including pH, electrical conductivity (EC), organic matter content, lime content, available phosphorus, exchangeable potassium, and soil texture. The applied analytical methods and corresponding results are summarized in Table 2.

Table 2.

Some physical and chemical properties of the experimental area

Analysis	Method	Result	Result
pH	In Saturation Mud	5.34	Moderate acid reaction
EC( Electrical Conductivity) Ds/m	In Saturation Mud	0.37	Salt-free
Organic matter %	Wet burning (Walkey-Black) method	3.22	Overplus
Lime (CaC03) Content %	With Scheibler calsimeter	3.05	Less calcareous
Available Phosphorus (P). mg/kg	Extraction of 0.03 N NH4F + 0.025 N HCI	2.5	Less
Exchangeable Potassium (K) kg/da	1 N NH4FOA extraction (ph:7.0)	54	Sufficient
Saturation Sludge %	Soil saturation with water	74	Clay

Fertilization regime

Fertilization was determined based on soil analysis and agronomic recommendations for medicinal and aromatic plants. The following rates were applied:

• Nitrogen (N): 8–10 kg da⁻¹

• Phosphorus (P₂O₅): 6–8 kg da⁻¹

• Potassium (K₂O): 8–10 kg da⁻¹

Nitrogen was split into two applications (50% at planting and 50% at early vegetative stage)

Irrigation management

Echinacea plants were cultivated under open-field conditions using a drip irrigation system. Soil moisture was maintained at approximately 60–70% of field capacity.

Weed and pest management

Weed control was performed mechanically. No chemical herbicides were used. Pest and disease management followed integrated pest management (IPM) principles, minimizing synthetic pesticide application to avoid unintended metabolic alterations.

All agronomic practices were uniformly applied across experimental plots. Therefore, observed variations in volatile composition are unlikely to result from differences in irrigation, fertilization, or pest/weed management.

Sample preparation

A Shimadzu GC-2010 Plus gas chromatograph, a QP2020 mass spectrometer, and a multipurpose autosampler (AOC-5000 Plus) with a split/splitless injection system and a solid-phase microextraction (SPME) module were used for present analysis.

To extract SPME, a polydimethylsiloxane (PDMS) fibre (1 cm × 100 μm film thickness; Supelco, Sigma-Aldrich, Bellefonte, USA) was utilised. The fibre was conditioned at 250 °C for five minutes before to analysis, and it was then reconditioned at the same temperature for ten minutes following each run.

For each sample, 1.0 g of plant material was placed in a 20 mL SPME glass vial, fol lowed by the addition of 100 µL of hexane. Silicone/PTFE septa were used to seal the vials. Optimised headspace SPME (HS-SPME) conditions, which include a 5-minute equilibration time and a 15-minute extraction at 100 °C with agitation at 500 rpm, were used to extract volatile chemicals.

Analyte desorption was carried out using a straight Ultra Inert SPME liner running in split mode in the GC injection port at 250 °C for one minute. Every sample was examined in triplicate. After every fifth injection, blank samples were examined to check for possible contamination.

Secondary metabolite composition analysis

A Shimadzu GC-2010 Plus gas chromatograph fitted with a QP2020 mass selective detector was used to perform GC–MS studies. An Rtx-5MS low-bleed capillary column (30 m × 0.25 mm × 0.25 μm; Restek, USA) was used to separate the compounds. The carrier gas was helium at a steady pressure of 80 kPa. The oven temperature program was set to run for 55 min, starting at 40 °C and holding it there for two minutes, then increasing it to 250 °C at a rate of 4 °C min⁻¹ and holding it there for three minutes. The temperatures of the ion source and interface were kept at 200 °C and 250 °C, respectively. With a mass scan range of m/z 40–500 and a scan speed of 1666 u s⁻¹, electron ionisation (EI) was carried out at 70 eV.

Using GCMSsolution software (Shimadzu, Japan), compounds were identified by comparing mass spectra with those found in the Wiley FFNSC 3rd Edition Library and by comparing calculated Kovats retention indices (RI) with reference values found in the PubChem database, the NIST Chemistry WebBook (SRD 69), and the FFNSC 3rd Edition Library.

A homologous series of C7–C30 n-alkanes was analyzed under the same chromatographic conditions to calculate retention indices. Certified reference standards (1000 µg mL⁻¹ in hexane; Sigma-Aldrich) were used for RI determination.

Data analysis

The used experimental design was a randomized complete block design with 3 blocks (plots) and 2 treatments (Echinacea species) per block. Species, year, species × year interaction was included in the analysis. The primary statistical tool used in RCBD is the Analysis of Variance (ANOVA), which assesses whether there are statistically significant differences between the means of different treatment groups. To generate letter groupings LSD test was used. P < 0.01 significance level was applied. Percentage data were transformed using logaritmic transformation before analysis.

Biplot Analysis was performed using XLSTAT 2024 statistical software to visualize variability among samples based on secondary volatile metabolite composition. In addition, a biplot analysis was generated to further illustrate the distribution and differentiation of samples according to their chemical profiles [10].

Principal component analysis (PCA) is an multivariate analysis technique that simplifies the complexity of data by transforming them in a few dimensions showing their trends and correlations. XLSTAT PCA outputs successfully reduced the number of variables into 2 components that explaines a calculated percentage of the total variation of the data set. Biplot makes it possible to interpret the angles between the variables because they are directly related to the correlations between the variables. The position of two observations projected on a variable vector allows to conclude about their relative level on this same variable.

Results

Secondary volatile metabolite composition

Table 3 displays the composition of secondary volatile metabolites in E. angustifolia and E. purpurea plant samples from 2015 and 2016.

Table 3.

List of secondary volatile metabolite components present in E. angustifolia and E. purpurea (%) (2015-2016)

No	RI*	RI in library**	Component	E. angustifolia 2015	E. angustifolia 2016	E. purpurea 2015	E. purpurea 2016
Monoterpene Hydrocarbons
1	933	933	α – Pinene	11.23 ± 0.020 a	8.09 ± 0,006 b	ND	ND
2	943	943	β - Pinene	23.32 ± 0.010 a	16.74 ± 0.010b	ND	ND
3	969	969	α - Phellandrene	3.27 ± 0.080 a	2.33 ± 0.020a	ND	ND
4	972	972	Sabinene	3.34 ± 0.060 a	0.03 ± 0,002 b	ND	ND
5	991	991	β - Myrcene	ND	0.03 ± 0.002 b	1.52 ± 0.03a	ND
6	1030	1030	Limonene	2.46 ± 0.020 a	0.33 ± 0.006 b	ND	ND
7	1042	1042	p Cymene	35.24 ± 0.005 a	21.36 ± 0.002 b	ND	ND
	Total			78.86	48.91	1.52	0.00
Oxygenated Monoterpenes
8	1131	1131	İsopinocarveol	1.17 ± 0.060 b	2.43 ± 0.001 a	ND	ND
9	1140	1140	trans-Sabinol	1.89 ± 0.040 a	1.23 ± 0.006 a	ND	ND
10	1141	1141	Verbenol	1.01 ± 0.001 a	1.36 ± 0.006 a	1.49 ± 0.002 a	1.03 ± 0,002a
11	1114	1114	Pinocarvone	0.72 ± 0.005 a	0.83 ± 0.007 a	ND	ND
12	1136	1136	Myrtenal	1.25 ± 0.010 a	1.53 ± 0.003 a	ND	ND
13	1372	1372	Piperitonene oxide	0.23 ± 0.004 b	1.48 ± 0.002 a	1.65 ± 0.001 a	1.15 ± 0.003a
14	1754	1754	Nerolidyl acetate < (E)->	ND	0.91 ± 0.010 c	1.74 ± 0.006 b	4.58 ± 0.005a
	Total			6.27	9.77	4.88	6.76
Oxygenated Sesquiterpenes
15	1536	1536	Spathulenol	1.58 ± 0.02 b	0.03 ± 0.001 c	8.87 ± 0.003 a	7.41 ± 0.001a
16	1551	1551	1,5-Epoxysalvial-4(14)-ene	ND	2.86 ± 0.003 c	4.79 ± 0.01 b	7.48 ± 0.004a
17	1587	1587	Caryophyllene oxide	2.85 ± 0.009 c	0.03 ± 0.001d	12.61 ± 0.003 b	15.13 ± 0.004a
18	1613	1613	Humulene epoxide II	1.54 ± 0.006 b	0.03 ± 0.002 c	9.87 ± 0.01 a	9.53 ± 0.005a
19	1632	1632	Muurola-4,10(14)-dien-1-beta-ol	ND	0.03 ± 0.002 b	2.22 ± 0.006 a	ND
20	1646	1646	Thujopsanone (3-iso)	0.73 ± 0.007 c	1.34 ± 0.01 b	1.80 ± 0.02 a	1.54 ± 0.002a
21	1662	1662	β - Nootkatol	0.42 ± 0.003 c	1.62 ± 0.02 b	2.48 ± 0.001 a	1.64 ± 0.012b
22	1663	1663	Calamenen-10-ol (cis)	ND	1.47 ± 0.01 b	7.06 ± 0.015 a	1.41 ± 0.001b
23	1683	1683	Germacra-4(15),5,10(14)-trien-1-alpha-ol	ND	1.03 ± 0.002 b	2.05 ± 0.003a	2.48 ± 0.005a
24	1685	1685	Eudesma-4(15),7-dien-1-beta-ol	0.77d ± 0.005 d	4.620.002 b	2.31 ± 0.001c	10.87 ± 0.125a
25	1778	1778	14-hydroxy-α-Muurolene	1.18 ± 0.003 b	6.540 ± 0.012 a	ND	6.00 ± 0.015a
26	1797	1797	Lepidozenal	ND	1.13 ± 0.002a	ND	ND
27	2043	2043	nor-Copaanone	ND	1.19 ± 0.01 a	1.71 ± 0.001a	ND
	Total			9.07	21.29	55.77	63.49
Sesquiterpene Hydrocarbons
28	1344	1344	α - Cubebene	ND	0.03 ± 0.001 b	ND	1.57 ± 0.004a
29	1403	1403	α - Funebrene	ND	1.47 ± 0.002 b	3.08 ± 0.001a	0.12 ± 0.001c
30	1428	1428	β - Caryophyllene	ND	1.18 ± 0.004 b	1.50 ± 0.002b	3.39 ± 0.007a
31	1458	1458	Alloaromadendrene	ND	2.52 ± 0.03 b	15.01 ± 0.002a	ND
32	1469	1469	Epizonarene	2.47 ± 0.008 a	2.21 0.003 a	2.31 ± 0.021a	ND
33	1512	1512	γ - Cadinene	ND	1.15 ± 0.001 a	1.23 ± 0.001a	0.85 ± 0.001b
34	1515	1515	Germacrene D	1.05 ± 0.003 d	4.19 ± 0.002 c	8.15 ± 0.001b	15.12 ± 0.005a
35	1518	1518	δ - Cadinene	1.68 ± 0.005 b	3.26 ± 0.003 a	1.61 ± 0.015b	0.98 ± 0.001c
	Total			5.20	16.01	32.89	22.03
Alcohols, ketons, esters, others
36	1538	1538	Veltonal < (Z)->	ND	0.03 ± 0.002 b	ND	4.69 ± 0.004a
37	1553	1553	Veltonal < (E)->	0.60 ± 0.008 c	3.62 ± 0.003 b	4.64 ± 0.02a	3.34 ± 0.020b
	Total			0.60	3.65	4.64	8.03
Monoterpene Hydrocarbons				78.86	48.91	1.52	0
Oxygenated Monoterpenes				6.27	9.77	4.88	6.76
Oxygenated Sesquiterpenes				9.07	21.29	55.77	63.49
Sesquiterpene Hydrocarbons				5.20	16.01	32.89	22.03
Alcohols, ketons, esters, others				0.60	3.65	4.64	8.03
Totally				100	99.63	99.70	100.00

ND Not detected, totals slightly below 100% result from rounding

* Kovats Retention Index (RI)

** [11], there is no significant differences between values labeled with the same letter (P<0.01)

Major components detected in E. angustifolia in both years (2015-2016) were p Cymene (35.24 % and 21.36 %), β –Pinene (23.32 % and 16.74 %), α – Pinene (11.23 % and 8.09 %), 14-hydroxy-alpha-muurolene (1.18 % and 6.54 %), Eudesma-4(15),7-dien-1-beta-ol (0.77 % and 4.62 %) and Germacrene D (1.05 % and 4.19 %).

On the other hand, main components obtained in E. purpurea in both years were Caryophyllene oxide (12.61 and 15.13 %), Germacrene D (8.15 % and 15.12 %), Allo-Aromadendrene (15.01 % and 0.00 %), Eudesma-4(15),7-dien-1-beta-ol (2.31 % and 10.87 %), Humulene eoxide II (9.87 % and 9.53 %), Spathulenol (8.87 % and 7.41 %), 1,5-Epoxysalvial-4(14)-ene (4.79 % and 7.48) and Calamenen-10-ol (cis) (7.06 % and 1.41 %).

From the results, it can be seen that secondary volatile metabolite composition changed over years and between species.

Fig. 1 shows the obtained Biplot Diagram based on secondary volatile metabolite composition in E. angustifolia and E. purpurea plant samples in 2015 and 2016.

Fig. 1.

Biplot of secondary volatile metabolite composition of E. angustifolia and E. purpurea in 2015 and 2016

Created Biplot using secondary volatile metabolite composition of both species in two years are given in Fig. 1. Using the first two calculated principal components 80.43% of the present variation could be explained, PC1 contributing 54.67% and PC2 25.76% to the present total variation. Based on detected components, both species displayed different secondary volatile metabolite composition in both years.

E. purpurea 2015 differed from the other regarding α-Pinene, β-Pinene, trans Sabinol, Pİnocarvone, Cymene, Limone and Sabinene. E. purpurea 2016 differed regarding Lepidozenal. Components leading to the differentation of E. angustifolia were diffeent in two years. E.angustifolia 2015 separated based on Piperitone oxide, β-Nootkatol and Spathulenol. On the other side, the seperation of E. angustifolia 2016 separated based on Germacrene-D, Caryophyllene and Nerolydil acetate.

Discussion

This investigation on secondary volatile metabolite composition of E. angustifolia and E. purpurea grown in Rize revealed important results.

Secondary volatile metabolite composition

In total, 37 different secondary volatile metabolite components were discovered in E. angustifolia and E. purpurea throughout the two years. However, the amount and distribution of these chemicals differed greatly throughout species and years. In the current investigation, the secondary volatile metabolite profiles of the studied Echinacea species in both years were clearly distinguishable, as shown in Fig. 1.

Previous reports about the secondary volatile metabolite composition of E. purpurea are common. In a study, the root oils from E. purpurea were reported to contain P-caryophyllene, α-humulene and caryophyllene epoxide [12]. Bauer et al. reported that borneol, bornyl acetate, pentadeca-8-en-2-one, germacrene D, β-caryophyllene, caryophyllene oxide and palmitic acid occured in the oils obtained from the three species of Echinnacea [13].

Heinzer et al. determined that the root oil of E. purpurea contained mainly germacrene D, 8(Z)-pentadecen-%one, (E, E)-dodeca-2,4-dienylisovalerate, palmitic andlinoleic acids in addition to some alkene derivatives ofisovaleric acid [14]. Bauer et al. also identified a germacrene-4-01 derivative from the fresh aerial parts of E. purpurea [15]. In the ethanolic extract and the oils of the achene, Schulthess et al. reported the occurrence of α-pinene, P-pinene, myrcene, carvomenthone, P-caryophyllene and germacrene D as the major components [16].

Holla et al. analyzed the essential oil from the flowers of the cultivated plant E. purpurea (L.) Moench in Slovakia by water distillation and GC/MS method and determined that the essential oil consisted of 72 different components. The researchers stated that the main components of the examined samples were palmitic acid, α-pinene, germacrene D, β pinene and α-phelandrene [17].

The essential oil of E. purpurea cultivated in Dobrich, Bulgaria was primarily composed of germacrene D (42.0%), α-phellandrene (10.09), β-caryophyllene (5.75), γ-curcumene (5.03), α-pinene (4.44%), δ-cadinene (3.31%), and β-pinene (2.43%) [18].

Soltanbeigi and Maral determined Germacrene D (20.40–50.60%) as predominant constituent of E. purpurea during the 3-year trial. Other major compounds were β-pinene, β-myrcene, α-humulene, δ-cadinene, spathulenol, and α-cadinol [19].

In another study conducted in İzmir Türkiye [20] using SPME fibers detected components were germacrene D, observed were α-phellandrene, p-cymene, β-caryophllyene, α-humulene, (Z)-β-famesene, (E)-β-famesene, β-bisabolene, α-muurolene, spathulenol, α-eudesmol, shyobunol and Germacra-4(15),5,10(14)-trien-1-alpha-ol, aristolene and hexahydrofarnesyl acetone. Further, Vaverková et al. detected α and β - pinene, α – phellandrene, β – caryophyllene, Germacrene D, Nerolidol and cyclodeca-1.5-diene as mjor components in essential oils from flower heads of E. purpurea [21]. Thappa et al. observed α-pinene, β-pinene, myrcene, limonene,β-caryophyllene and germacrene D in E. purpurea flower heads [22].

Secondary volatile metabolite composition in E. purpurea differs also based on plant parts.

Literature about the secondary volatile metabolite composition of E. angustifolia is rarely. Bos et al. reported for the aerial parts oil of E. angustifolia, the occurrence of borneol, bornyl acetate, germacrene-D, caryophyllene and caryophyllene oxide as the principal constituents [23]. Further, acetaldehyde, dimethyl sulfide, cam phene, hexanal, â-pinene, and limonene were major components in roots, stems, leaves and flowers of E. angustifolia [24].

With major components detected in E. angustifolia like p Cymene, β –Pinene, α – Pinene, 14-hydroxy-alpha-muurolene and Eudesma-4(15),7-dien-1-beta-ol Germacrene D and on the other hand main components like Caryophyllene oxide, Germacrene D, Allo-Aromadendrene, Eudesma-4(15),7-dien-1-beta-ol, Humulene epoxide II, Spathulenol, 1,5-Epoxysalvial-4(14)-ene and Calamenen-10-ol (cis) in E. purpurea we detected a remarkable difference compared with given literature for both Echinacea species.

Furthermore, elements found in both species have significant biological functions. For instance, α-pinene exhibits antibacterial action [25] as well as anticoagulant, anti-inflammatory, anti-leishmania, antimalarial, antimicrobial, antioxidant, anticancer, analgesic, and antibiotic resistance modulating effects [26].

Further, the component Sabinene showed antioxidant and anti-inflammatory activities [27], β – Pinene are used as antibacterials [28] and has inhibitory effects on breast cancer and leukemia [29], β - Myrcene biological activities include analgesic [30], sedative [31], antidiabetic [32], antioxidant [33], anti-inflammatory [34], antibacterial [35], and anticancer effects [36], α – Phellandrene showed antitumoral, antinociceptive, larvicidal and insecticidal activities [37], p Cymene antioxidant, anti-inflammatory, antimicrobial, and anticancer properties [38], Limonene antitumor, antiviral, anti-inflammatory, and antibacterial activities [39], antibacterial and antioxidant activity [40], trans-Sabinol AChE inhibitory activity and antinociceptive activity [41] and Verbenol antibacterial activity [42].

Pinocarvone, only present in E. purpurea in both years, has antimicrobial properties [43], Myrtenal antimicrobial, antifungal, antiviral, anticancer, anxiolytic, and neuroprotective properties [44], α - Cubebene antioxidant, antibacterial and anti-mosquito activities [45], Piperitenone oxide Antimicrobial activity, anti-inflammatory properties, antioxidant effects, analgesic effects, relaxant properties, insecticidal activity, gastroprotective effects [46–47], α – Funebrene antimicrobial and antioxidant activities [48], β-Caryophyllene has been reported to possess antibacterial, antioxidant, gastroprotective, anxiolytic, and anti-inflammatory activities [49], Alloaromadendrene antibacterial activity [50], Epizonarene antibacterial activity [51–52], Germacrene D has notable antibacterial activity [53–54] and γ - Cadinene acaricidal activity [55].

Additionally, δ – Cadinene present in both species in both years displays antibacterial activity [56], Spathulenol has important bioactivity such as anticholinesterase [57], anti nociceptive and anti-hyperalgesic [58] and anti-mycobacterial activities [59–60], Veltonal < (Z)-> and < (E)-> [63], 1,5-Epoxysalvial-4(14)-ene antiradical scavenging activity [61]. Caryophyllene oxide, one of the known oxygenated sesquiterpenes, operates as a broad-spectrum antifungal agent in plant defence as well as insecticidal and antifeedant effects. [62–63]

Humulene epoxide anti-tumor, cytotoxic, gastroprotective, cicatrizing, analgesic and antioxidant activities [64], Muurola-4,10(14)-dien-1-beta-ol antioxidant, antibacterial, and cytotoxic activities [65], Thujopsanone antifungal activity [66]and β - Nootkatol calcium- antagonistic activity [67].

Further, Calamenen-10-ol (cis) displays acaricidal activity [68], Germacra-4(15),5,10(14)-trien-1-alpha-ol antioxidant, antifungal and antibacterial activities [69], Eudesma-4(15),7-dien-1-beta-ol insecticidal activity [70], nerolidyl acetate < (E)-> antioxidant, anti-microbial, anti-biofilm, anti-parasitic, insecticidal, anti-ulcer, skin penetration enhancer, anti-tumor, anti-nociceptive and anti-inflammatory activities [71], 14-hydroxy-α-muurolene cytotoxicity and antibacterial activity [72], lepidozenal cytotoxic activity [73–74] and nor-Copaanone antioxidant activity [75].

The growth and chemical features of medicinal and aromatic plants are influenced by a variety of factors, including the plant’s genetic makeup, climate, edaphic factors, agricultural techniques, harvest time, and post-harvest management [19].

Further, based on the analysed Echinacea species (E. purpurea, E. pallida or E. angustifolia), the investigate part of the plant (leaf, flower, stem or root), special conditions like growing, drying and storage conditions and extraction method are responsible for the change in chemical content [76–78].

Furthermore, AlZunaydi et al. stated that changes in environment and climate can led variation in growth and chemical composition of plant communities over years [79].

Our analysis clearly demonstrates the impact of climatic circumstances on succeeding years. All evaluated attributes differed throughout years and between two species. Analytical methods such as Biplot Analysis are especially useful for identifying genotypes and classifying them based on chemical similarity [80–81]. Biplot analysis is useful for differentiating plant materials and distinguishing species based on their chemical profiles [82–83]. When paired with other analytical tools, it can help uncover features that contribute to genetic variability in crop species [84]. A Biplot allows you to visualise and categorise variables that contribute to the distinction between different versions [85].

In some plant species, the composition of the essential oil also changes with the time of year [86]. This explains the differences in both years and in both species regarding their chemical content.

In this work, E. angustifolia and E. purpurea were clearly distinguished by their determined characteristics and secondary volatile metabolite composition.

Obtained results collectively suggest that the secondary volatile metabolite composition of E. angustifolia and E. purpurea investigated in Rize are distinct from given references. Furthermore, the compounds identified in E. angustifolia and E. purpurea in this study have notable biological activities, which will open a way to further Echinacea studies. Important secondary volatile metabolite components were determined in E. angustifolia and E. purpurea in both years.

Conclusions

Echinacea species are valuable medicinal plants. The production of these species can be a remarkable income under suitable conditions. The present study revealed that under the local conditions of Pazar, Rize/Türkiye E. angustifolia and E. purpurea displayed different secondary volatile metabolite composition compared with same species grown under different climatic conditions.

As a result, based on the data we obtained, it is possible to say that Echinacea cultivation is possible in Rize ecological conditions based on its high rate of important secondary volatile metabolite composition. It is an important product in terms of spreading Echinacea cultivation in our region and opening doors for new products.

Abbreviations

GC-MS

Gas Chromatography – Mass Spectrometry

EC

Electrical Conductivity

SPME

Solid Phase Microextraction

Authors’ contributions

Conceptualization, F.S. and E.Y.; methodology, F.S., E.Y. and A.Ö.A.; software, F.S.; validation, F.S., E.Y. and A.Ö.A.; formal analysis, F.S.; investigation, F.S., E.Y. and A.Ö.A.; data curation, F.S., E.Y. and A.Ö.A.; writing—original draft preparation, F.S., E.Y. and A.Ö.A.; writing—review and editing, F.S., E.Y. and A.Ö.A. All authors have read and agreed to the published version of the manuscript.

Funding

This study was supported by the Recep Tayyip Erdogan University Development Foundation (Grant number: 02025012003850).

There exists a bilateral agreement between BMC (Springer/Nature Journal Group) and Turkish Universities paying 75 % of submission fee. For Q1 journals the residual 25 % will be paid by the Recep Tayyip Erdoğan University Development Foundation.

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

Not necessary.

Competing interests

The authors declare no competing interests.