Determination of antioxidant potential of volatile extracts isolated from various herbs and spices

Antioxidant activities of volatile extracts isolated from thyme, basil, rosemary, chamomile, lavender, and cinnamon were evaluated by two independent assays: the, aldehyde/carboxylic acid assay and the conjugated diene assay. The volatile extracts were prepared from dried herbs and spices using liquid-liquid continuous extraction following steam distillation under reduced pressure (55 degreesC and 95 mmHg). The antioxidant activities of the extracts decreased in the following order in both of the lipophilic assay systems: thyme > basil > rosemary > chamomile > lavender and cinnamon. Thyme and basil extracts inhibited the oxidation of hexanal for 40 days at the levels of. 10 mug/mL and 50 mug/mL, respectively. The extracts of thyme and basil were effective in retarding methyl linoleate deterioration at 40 degreesC, with with concentration in the range 10-200 mug/mL. At a concentration of 50 mug/mL, thyme extract was similar in antioxidant activity to BHT and alpha-tocopherol in the conjugated, diene assay. The antioxidant potentials of the volatile extracts used in this study were accurately measured by the lipophilic, systems, such as the aldehyde/carboxylic acid assay and the-conjugated diene assay.