A new essential-oil chemotype of Tanacetum sorbifolium (Boiss. ex Boiss.) Grierson from Trabzon-Turkey

Abstract

Previously, the essential oil of the aerial parts of Tanacetum sorbifolium (Boiss. ex Boiss.) Grierson (Asteraceae) from Gümüşhane-Turkey was reported to contain camphor (54.3%), pinocarvone (5.1%), and bornyl acetate (3.9%) [1]. There are a number of examples of Tanacetum species showing a high degree of chemotypification. During our fieldwork in Trabzon, we encountered T. sorbifolium and decided to reanalyze its essential oil due to the possibility of finding a new chemotype. The plant material used in this study was collected in July 2017 at an altitude of 1328 m. The essential oil was obtained from air-dried aerial parts by hydrodistillation (3 h) in a Clevenger-type apparatus in a yield of 0.09% (v/w). The essential oil was diluted 1:10 (v/v) with n-hexane and used as such for the GC-MS analysis. The GC-MS analysis was done on an Agilent 5977 MSD GC-MS system operating in EI mode with a split injection (1:50). An Innowax FSC column (60 m x 0.25 mm, 0.25 µm film thickness) and helium, as the carrier gas (1 mL/min), were used. The following temperature program was used in the GC-MS analysis–60 °C: 10 min→ 220 °C at 4 °C/min; 220 °C:
10 min→ 240 °C at 1 °C/min). Identification of essential-oil components was carried out by comparison of their retention indices (RI), relative to a series of
n-alkanes (C₅ to C₃₀), with the literature values, as well as by mass spectral comparison. One hundred seventy-four compounds were identified representing 84.1% of the detected GC-peak areas. The main components of the oil were sabinyl acetate (15.4%), spathulenol (7.5%), hexadecanoic acid (2.6%), artemisia ketone (2.4%), caryophyllenol-I (2.4%), salvial-4(14)-en-1ξ-ol (2.3%), and linalool (2.1%). The essential oil composition of T. sorbifolium from Trabzon is more complex in comparison to the previously reported composition. Additionally, the main components observed in the current study and those from the literature were considerably different. Previously, camphor, pinocarvone, and bornyl acetate were reported as the main components, however, in the current study, the essential oil completely lacked camphor and pinocarvone but it contained bornyl acetate in only 0.4%. AChE-inhibitory properties of the oil were also investigated and it was found that the oil (at 5 mg/ml) inhibited 7±2%
(n = 3) of the enzyme’s activity.