Food Science Department, Faculty of Agriculture, Saba Basha and Vice Dean, Faculty of Specific Education, Alexandria University, Egypt.
The ancient Egyptian culture clearly documented their use of medicinal plants in their hieroglyphic records which are being used as pharmaceutical ingredients, and in food supplementation. Several medicinal plants have been reported to exhibit antioxidant activity. The present study aimed to evaluate the chemical composition of essential oils extracted from Egyptian artemisia, juniper, rosemary, sage and thyme and investigate their antioxidant activities in different test systems as well as in soybean oil. The results showed that rosemary, sage and thyme extracts had the highest amount of polyphenols. Essential oils from medicinal plants were found to contain 25 – 30 components at different concentrations. Camphor, α-thujene and artemisia ketone were the major components of artemisia, α-Pinene and β-phellandrene of the juniper, camphor, α-terpineol and 1,8-cineole of the rosemary, αthujene and camphor of the sage and carvacrol and p-cymene of the thyme. Generally, rosemary, sage and thyme essential oils showed highest antioxidative activities in test systems and were found to be the most effective in retarding the oxidation of soybean oil under both accelerated (60°C for 18 days) and ambient temperatures (22 ± 2°C for 180 days). Antioxidative activities of different essential oils could be related to their polyphenol contents and chemical composition.
Egyptian medicinal plants, chemical composition, antioxidant activity, test systems, soybean oil
