Evaluation of antioxidant and antimicrobial properties of selected Indian medicinal plants

The study examine the antioxidant and antimicrobial potential of the ethanolic and aqueous leaf extracts of ten selected Indian medicinal plants namely, Psidium guajava, Mangifera indica, Polyalthia longifolia, Allium cepa, Phyllanthus amarus, Thespesia populnea, Ricinus communis, Physalis angulata, Ixora coccinea, and Vinca rosea using 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, total phenol content (TPC) and ferric reducing antioxidant power assay (FRAP) methods. In DPPH scavenging assay, the highest radical scavenging effect was found in ethanolic extract of Psidium guajava (94.48±0.07) and the least in ethanolic extract of Physalis angulata (9.58±0.65). The TPC and FRAP value followed similar trend with highest found in Ixora coccinea ethanolic extract (427.25±0.86), (554.93±2.37) and lowest in Vinca rosea aqueous extract (41.04±1.58) and Physalis angulata ethanolic extract (111.94±6.34) respectively. All the plant extracts showed strong scavenging and reducing power in a dose dependent manner. From the antioxidant screening, five plant extracts with highest activity were selected for antibacterial study. The plant extracts were tested against three pathogenic bacteria Aeromonas hydrophila (MTCC 1739), Micrococcus luteus (MTCC 106) and Vibrio vulnificus (MTCC 1145) individually and in combination, and all the extracts exhibited varying level of antibacterial activity. Therefore based on the results obtained from the study the plant materials tested may act as an antioxidant agent for effective protection from free radicals and potential utilization in animal feed as nutraceutical.