Antioxidant and free radical scavenging activity of H. officinalis L. var. angustifolius, V. odorata, B. hyrcana and C. speciosum.

Extracts of 4 medicinal and aromatic plants were investigated for their antioxidant potency employing six various established in vitro system: H. officinalis L. var. angustifolius aerial parts, C. speciosum flowers, V. odorata and B. hyrcana leaves.With regard to IC50 values (microg/ml), the order in DPPH radical-scavenging were CS (585.6) > HO (311) > VO (245.1) > and BH (113.1). Effectiveness in reducing powers were high and in a descending order of HO > CS > BH > VO (at the concentrations of 25-800 microg/ml). IC50 for Fe2+ chelating ability were 188, 750 and 980 microg/ml for VO, CS and HO, respectively. BH extract has shown only 38% inhibition at 800 microg/ml. The extracts showed weak nitric oxide-scavenging activity. All extracts exhibited very low and moderate concentration-dependent antioxidant activity in FTC methods. IC50 for scavenging of H2O2 were 169 for BH, 175 for CS, 640 for VO and 663 microg/ml for HO. The content of total phenolic compounds and flavonoids were measured in plant extracts. The data obtained in the in vitro models clearly establish the antioxidant potency of all extracts.