Evaluation of Free Radical-Scavenging and Nitric Oxide Inhibition Activities of Selected Medicinal Plants

Abstract

ABSTRACT: The pharmaceutical industry is becoming dependent on plants with medicinal value because of their roles in the prevention and treatment of disease. Ten medicinal plant species namely Phyllanthus embelica, Mentha piperita, Ocimum tenuiflorum, Azadirachta indica, Syzgium aromaticum, Dalbergia sissoo, Allium sativum, Psidium guajava, Syzygium cumini and Allium cepa were evaluated for antioxidant potential using spectrophotometric assays. The results indicated that hyroalcoholic extracts of M. piperita showed the highest antioxidant capacity (202.56 ± 1.98 µgAAE/g) and DPPH radical scavenging activity (94% with IC50 value of 561 ± 1.13 μg /mL). Also, the extract of O. tenuiflorum showed 89 % inhibition at 1000 μg/mL concentration. The presence of phenolic and flavonoid compounds may be responsible for the free radical scavenging and antioxidant properties. The findings of the present study suggest that the plants might be exploited as a source of natural antioxidants. Further investigation is still required to identify the phytochemicals responsible for medicinal properties and to understand the mechanism of action of isolated bioactive compounds.