Antioxidative properties of water extracts obtained from herbs of the species Lamiaceae

Essential oils and extracts of aromatic herbs obtained by organic solvents have been extensively studied for their antioxidant activity in lipid subst rates. Very little is known about the possible presence of antioxidants in polar extracts from herbs used in preparation of infusions and decoctions. In this work water extracts of six different herbs of the Lamiaceae family (dittany, lemon balm, mint, sage, sideritis and sweet marjoram) were prepar ed. The extracts were examined for their effect against lipid oxidation in comparison to a tea water extract. Sweet marjoram, sage and dittany extract s were found to have a remarkable capacity in retarding lipid oxidation. Ex amination by thin-layer chromatography of the freeze-dried extracts, before and after hydrolysis, showed that the extracts were rich in bound forms of phenolic compounds such as hydroxycinnamic acids and flavonoids. Rosmarini c and caffeic acids were detected in all extracts with the exception of tho se from mint and sideritis. These results indicate that certain plants used for the preparation of infusions could be further studied like tea as sour ces of antioxidants.