Comparative study of the total phenol content and antioxidant activity of some medicinal herbal extracts

Herbal medicines can be used as the potential sources of anti-oxidative compounds to help the treatment of diseases associated to oxidative stress. In this paper, the Ferric Reducing Antioxidant Power (FRAP) activity of four Lamiaceae herbal extracts, which traditionally applied in oxidative stress related diseases, has been evaluated and total phenolics contents of these extracts determined by using Folin-Ciocalteu reagent. The aqueous methanol extracts were prepared by percolation method and investigated for antioxidant properties and total phenolics content evaluation. All the extracts showed antioxidant effect from 123.6±4.6 mmol of FeSO4.7H2Oequivalent/100 g dried extract in Scutellaria tornefortii to 551.5±16.0 mmol of FeSO4.7H2Oequivalent/100 g dried extract in Satureja sahendica. Interestingly, although Satureja sahendica exhibited the most antioxidant activity, the highest content of polyphenolics belonged to Stachys byzantina. Taking together, antioxidant activity of the mentioned medicinal plants is not necessarily associated with polyphenolic compounds and might be partially due to the presence of other polar constituents like terpenoid-glycosides in aqueous extracts that traditionally used as decoction.