Indian medicinal herbs and plants are used since ancient times to treat different diseases and ailments as these natural products exert broad-spectrum actions. The present study was aimed to explore the hydrogen donating and  hydroxyl radical scavenging potential of methanol extract of 10 medicinal plants belonging to six families including mimosaceae, Apocynaceae, moraceae, sapindaceae, rutaceae and meliaceae using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and plasmid nicking assay, respectively. The total phenol and flavonoid content of these extracts was also estimated using Folin-Ciocalteu and colorimetric assay respectively. It was found that methanol leaf extract of Koelreutaria paniculata,Acacia catechu and Mimusops hexandra showed strong inhibitory activity whereas that of Hamelia patens exhibited moderate DPPH radical scavenging activity at concentration of 200 µg/ml. However, methanol extract of Swietenia mahogoni, Murraya exotica, Murraya koenigii, Alstonia scholaris, Ficus benjamina and Sapindus trifoliatus exhibited weak hydrogen donating potential in DPPH assay. The methanol extract of these plants was effective in plasmid nicking assay and the activity was found to be correlated to the phenolic and flavonoid content in these fractions. These results emphasized the benefit of the phenolic compounds rich plant extracts and thus augmented the urge of in vivostudies to further confirm the beneficial effect of these extracts.

Key words: Medicinal plants, flavonoid content, phenolic content, hydrogen donation, hydroxyl radical scavenging.