Quantitative determination of methanol and ethanol in traditional herbal distillates using headspace gas chromatography

Objectives: Herbal preparations are among highly consumed natural drugs. Since ancient times, traditional herbal extracts have been used as the primary care for the treatment of ranges of diseases. Medicinal plants and their distillated have played a key role in health management in Iran. Therefore there is a need to ensure about the safety of traditional herbal extracts and to quantify ethanol and methanol content in these highly consumed herbal preparations. The aim of the present study was to analyse traditional hand-made herbal extracts available in Tehran herb shops to determine ethanol and methanol concentrations.Methods: A total of 140 samples of traditional hand-made herbal distillates were analysed using headspace gas chromatography. Samples were selected from highly consumed ones. Ten samples of each herbal distillates including Rose Water, Camel’s thorn, Chicory, Fumitory, Caraway, Peppermint, Tarragon, Fenugreek, Willow, Fennel, Forty Plants, Sweet pane, Mallow and Cumin were gathered from herb shops in east, west, north and south of Tehran city, Iran.Results: Results showed that hand-made herbal distillates did not contain ethanol. Peppermint extract had significantly higher methanol content (334.62±153 ppm) in comparison to other distillates (p<0.05).Peppermint, Tarragon and Fenugreek had the highest methanol content. Sweet pane did not contain methanol and rose water had the lowest methanol content (14.61 ppm).Conclusion: Hand-made herbal distillates contained different amounts of methanol as by-product. Methanol content of many products were higher than the maximum allowable of methanol in herbal distillates (100 ppm) recommended by the Iranian standards for methanol content in beverages.