Composition of the Essential Oils of Endemic Salvia ekimiana Growing in Two Different Areas of Turkey

Published in Khimiya Prirodnykh Soedinenii, No. 3, May–June, 2021, pp. 478–479.

The morphologically diverse genera Salvia L. is one of the largest genus of the Lamiaceae family and includes approximately 1000 species distributed all over the world [[1]]. Anatolia is a major center of diversity for the genus in Asia. The genus is represented by 86 species in the Flora of Turkey [[2]]. Since its publication, some synonyms and some new species and records have been reported on Salvia species in Turkey. The total number of Salvia species in Turkey has reached 99, and the ratio of endemism in the genus is approximately 50% [[3]].

As well as floral morphology, pollination biology, and growth forms, the genus Salvia displays remarkable diversity in secondary compounds. Most of the species from the genus Salvia have medicinal importance as they produce many useful natural compounds, including terpenes and flavonoids [[4]]. The secondary metabolites (essential oils and phenolic derivatives) isolated from Salvia species possess a long list of medicinal uses, such as spasmolytic, antiseptic, and astringent [[5]]. Some of the essential oils and phenolic compounds of plants belonging to this genus have also shown excellent antimicrobial activity as well as antioxidant capacity, and some are used as anticancer agents or have a hypoglycemic effects [[6]–[9]]. Some members of this genus, such as Salvia officinalis L., S. tomentosa Mill., and S. fruticosa Mill., are of economic importance since they are used as flavoring agents in perfumery and cosmetics. Many of the wild growing Salvia species are also used in the traditional medicine of different nations instead of sage or as an adulterant [[10]].

Salvia ekimiana Celep & Dogan is a perennial herb with a woody rootstock. Stems are ascending to erect, 10–30 (40) cm, branched or not. Leaves are oblong shaped. The inflorescence is widely branched and calyx grayish with violet stripe, tubular to campanulate, and corolla white with a lilac hood [[11]].

The chemical constituents and biological activities of the essential oils of some Salvia species have been investigated in Turkey [[12]–[18]]. A literature search did not reveal any reference to a previous work on the essential oil of S. ekimiana. In this study, we report on the chemical constituents of the essential oil of S. ekimiana growing in two different localities of Turkey for the first time. The water-distilled essential oils from aerial parts of Salvia ekimiana from Kayseri and Yozgat localities of Turkey were characterized by GC-FID and GC-MS. The compounds identified from the essential oils along with their relative percentages are listed in Table 1. A total of 43 and 54 compounds was identified from the essential oils of S. ekimiana, which represented 87.0 and 78.6% of the oils. Components of the oil can be grouped into seven main chemical classes: monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, diterpenes, fatty acids and their esters, and others. The oil of S. ekimiana was characterized by a high content of oxygenated sesquiterpenes (36.1 and 35.9%) and sesquiterpene hydrocarbons (28.4 and 17.6%). The major components were found to be germacrene D (17.1, 7.4%), caryophyllene oxide (11.9, 12.9%), 1,5-epoxy-salvial(4)14-ene (7.0, 4.6%), α-copaene (4.9, 3.5%) hexahydrofarnesyl acetone (4.2, 5.1%), and spathulenol (3.6, 4.5%) for Kayseri and Yozgat, respectively.

Table 1. The Composition of the Essential Oils of Salvia ekimiana

A: Kayseri, B: Yozgat. RRI: Relative retention indices calculated against n-alkanes; * tentative identification; % calculated from FID data; Tr.: trace (< 0.1%).

According to our results in Table 1, oxygenated sesquiterpenes are present in almost equal amounts in the oil of Kayseri locality, while sesquiterpene hydrocarbons are present in high amounts in the oil of Yozgat locality. However, some important differences were found regarding the constituents of the oils. As can be seen from Table 1, oxygenated monoterpenes in Kayseri oil and diterpenes in Yozgat oil of S. ekimiana were present in high amounts.

The essential oil composition of 64 Salvia taxa from Turkey has already been studied. Monoterpene hydrocarbons(α/β-pinene), oxygenated monoterpenes (1,8-cineole/camphor, linalyl acetate/linalool, carvacrol), sesquiterpene hydrocarbons (β-caryophyllene, germacrene D), oxygenated sesquiterpenes (spathulenol), and phenylpropanoid (methylchavicol) were reported as the main groups of constituents in Salvia oils [[13]]. According to our results, S. ekimiana has many oxygenated sesquiterpenes and sesquiterpene hydrocarbons. Thus, this plant can be categorized as being in the third and fourth groups.

Various factors, both endogenous and exogenous, can affect the composition of the essential oil of S. ekimiana. We believe that the time of flowering, altitude, and geographic and climatic factors may be very important. Several papers have reported on the variation in the essential oil composition induced by environmental, physiological, and edaphic factors, which can induce changes in biosynthesis accumulation or metabolism of the given compounds of the essential oil [[19]].

Salvia ekimiana samples were collected during the flowering period (June, 2017) from Kayseri (S.D. 3026) and Yozgat (S.D. 3027) Provinces of Turkey. Voucher specimens are deposited in the Herbarium of the Faculty of Education of Necmettin Erbakan University in Konya, Turkey (NEU Herb.).

The essential oils from air-dried plant materials were isolated by hydrodistillation for 3 h using a Clevenger-type apparatus to produce a small amount of essential oil, which was trapped in n-hexane. The obtained oil was dried over anhydrous sodium sulfate and stored at +4°C in the dark until analyzed and tested. Gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS) were performed following Kaya et al. [[16]]. The analysis results are given in Table 1.