COMPARATIVE EVALUATION OF THE ANTIOXIDANT PROPERTIES OF PRUNELLA VULGARIS L. AND THYMUS VULGARIS L.

Use of synthetic materials in food industry has become undesirable. In the last few years, researchers have attempted to find natural sources that can displace well-known synthetic antioxidants (BHT, BHA), compounds that may have harmful side-effects. In the plant kingdom, herbs (such as rosemary, thyme, and sage) that have phenolic rich extracts can preserve food quality, but their intensive smell and taste, desirable in gastronomy, are not acceptable in the food industry. In regards to this problem, self-heal (Prunella vulgaris L.) seems to be a good solution as this plant is tasteless and odourless. Self-heal is common in Eurasia and is easy to collect and to cultivate. In this research, 8 populations of self-heal were examined for antioxidant properties and compared with thyme (Thymus vulgaris L.), a species known to have a strong antioxidant effect. According to tests, the total antioxidant capacity of self-heal was lower than thyme in alcohol extracts (self-heal = 0.189 mg ascorbic acid/mL, thyme = 0.283 mg ascorbic acid/mL) and in aqueous extracts (self-heal = 0.27 mg ascorbic acid/mL, thyme = 0.55 mg ascorbic acid/mL). This level of difference in antioxidant capacity can possibly be decreased by locating new populations or making selections of self-heal.