COMBINATION OF METHODS FOR DETERMINE THE AUTHENTICITY OF HERBS THYMUS SERPYLLUM AND THYMUS MARSHALLIANUS

Abstract

Relevance. Authentication of crushed medicinal plant raw materials (RM) is an actual issue because there are species similar in morphology or there is a possibility of interspecific hybridization. The characteristics of the absorption spectra of extracts and their chromatographic profile are significant indicators of the authenticity of RS. The aim of the study was a comparative analysis by TLC and spectrophotometry of water-alcohol extracts from the herb Thymus marshallianus Willd. (TM) and Thymus serpyllum L. (TP). Material and methods. Water-alcohol extracts were obtained from 1.0 g of RS (exact suspension) in two ways (extractant – 70% ethanol, heating in a boiling water bath; extractant – 50% ethanol, 20–22 °C). Absorption spectra were recorded in the range of 200–500 nm. Eluent – ethyl acetate : formic acid anhydrous : water (70:15:15) was used for chromatography. Detection of adsorption zones was carried out after treatment with a 5% alcohol solution of AlCl3 at 365 nm. Rutin, quercetin and cinaroside were used as standard samples. Results. Microscopic analysis revealed diagnostic signs of the TM and TP leaf – trichomes of various types. The absorption spectra of water-alcohol extracts from TM and TP (obtained with 50% and 70% ethanol) have two pronounced maxima. When AlCl3 is added, a bathochromic shift of the long-wavelength absorption bands is observed. The chromatograms of these extracts revealed a yellow zone at the level of cinaroside, and differences in the number and color of the adsorption zones of TM and TP extracts. Conclusion. The absorption spectra of water-alcohol extracts have two pronounced maxima for TP of the same intensity, for TM – different. The intensity of differential absorption spectra of water-alcohol extracts of TM is higher, which indicates a higher content of flavonoids in its extracts. Cinaroside was detected in TM and TP extracts by TLC, while 11 adsorption zones are distinguishable on the chromatogram of extracts from TM herb, and 9 from TP.