Determination of flavones in species of Thymus L. (Lamiaceae) from Macedonian flora

Svetlana Kulevanova,Jasmina Tonic,Trajce Stafilov,Marina Stefova,Tatjana Kadifkova Panovska

doi:10.33320/maced.pharm.bull.2001.47.002

Abstract

Assay of flavonoids in extracts of seven Thymus L. (Lamiaceae) species from Macedonia including identification and quantification was performed. Extracts obtained after hydrolysis of air dried samples (A1) were analyzed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Luteolin and apigenin were identified in comparison to authentic standard substances. The content of total flavonoids in plant samples determined by UV-Vis spectrometry (with AlCl3) ranged from 0.05-0.13 %. Two other extracts were prepared by extraction with a mixture of ethanol:water (7:3, V/V), evaporation until only water remained and extraction first with diethylether (A2) and secondly with ethyl acetate (A3). The content of flavonoids in diethyl-ether and ethyl acetate extracts ranged from 52.5-244.4 mg·ml-1 and 48.7 -117.5 mg·ml-1, respectively. For quantification of luteolin and total flavonoids the HPLC method was applied, using reverse phase column C18, mobile phase consisting of 5% acetic acid and methanol in gradient elution mode and column temperature set to 40 o C. The content of luteolin in the plant samples ranged from 0.23-0.48 % (m/m), while the content of total flavonoids was found to be 0.26-0.52 %.

Highlights

Certain biological and pharmacological effects of the Thymus species have been experimentally proved, such the expectorant (1), spasmolytic (1-3), antibacterial (1,4), antifungal (5), antioxidant (6-9), etc
The high performance liquid chromatography (HPLC) screening method confirmed the presence of a significant quantity of luteolin and a much smaller quantity of apigenin, which were identified according to the retention times and the UV spectra, compared to those for authentic samples (Fig. 1)
The content of total flavonoids in air dried plant material determined by spectrophotometric method ranged from 0.05-0.13 %, calculated as luteolin

Summary

Introduction

Certain biological and pharmacological effects of the Thymus species have been experimentally proved, such the expectorant (1), spasmolytic (1-3), antibacterial (1,4), antifungal (5), antioxidant (6-9), etc These activities are due to the specific composition of the essential oils (1, 4-9), flavonoids (1-3, 9), phenolic acids (4) and other chemical constituents of Thymus. In respect to the literature data, a lot of information on the identification and isolation of flavonoids is available, which cannot be said for quantitative data on these components of Thymus. Determination of their content could be important because the flavonoids are involved in spasmolytic, antioxidant and other activities of Thymus sp. The aim of the present study is to establish methods for determining the total flavonoid content as well as the content of the main flavone aglycones in Macedonian Thymus species

Objectives

Methods

Results

Conclusion