RELATIONSHIP BETWEEN PHENOLIC CONTENT AND ANTIOXIDANT CAPACITY IN SEVEN TRADITIONAL MEDICINAL PLANTS

Antioxidant potential of seven medicinal plants through total phenolic content using Folin - Ciocalteu's method has been studied in which five phenolic compounds were quantified by HPLC and their antioxidant activity was evaluated using DPPH radical scavenging and total antioxidant activity methods. Moreover, the correlation between their total phenolic content and chemical compositions with total antioxidant capacity was also analyzed. The data resulted from DPPH radical scavenging activities indicated that they displayed the good activities with low IC50 values. Importantly, L. rubra had the highest activities, approximately 32 times less than that of curcumin. Basex on the total antioxidant activity and HPLC analysis, the antioxidant capacity of H. parasitica wass found the highest among seven medicinal plants. The amount of the five phenolic compounds is closely correlated with either total phenolic compounds or total antioxidant capacity. Obviously, phenolic compounds were significantly contributed to their antioxidant capacity. In addition, the amount of methyl gallate could be used as a Marker for the evaluation of the total antioxidant capacity or total phenolic content, s experimental showing that these medicinal plants are considered as new promising resources of natural antioxidants. Keywords: Microdesmis casearifolia, Helixanthera parasitica, Pyrostegia venusta, Spilanthes oleracea, Leea rubra, Archidendron clypearia, Archidendron bauchei, antioxidant activity