Antioxidant and Antibacterial Activities of Catharanthus roseus and Ocimum basilicum: Indian Traditional Medicinal Plants

Abstract

The objective of the present study was to evaluate the in vitro antioxidant and antibacterial activities of methanol extracts of Catharanthus roseus and Ocimum basilicum. Plants are a rich source of therapeutic compounds that have tremendous applications in the pharmaceutical industry. Medicinal plants have been used to treat human diseases for thousands of years because they have a vast and diverse assortment of organic compounds that can produce a definite physiological action on the human body. The methanol extracts of the leaves were used to investigate the antioxidant activity using DPPH (2,2-Diphenyl-1-picrylhydrazyl) and superoxide radical scavenging assays. The disc diffusion method was employed to evaluate the antibacterial activities of four major infective pathogenic agents, namely, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis. Phytochemical screening of the extract shows that the plant leaves are rich in flavonoids, alkaloids, glycosides, saponins, steroids, terpenoids, tannins and phenolic compounds. Both the plant extracts exhibited strong DPPH and superoxide radical scavenging activities in a dose-dependent manner. The DPPH scavenging activities by Catharanthus roseus and Ocimum basilicum extracts were found to be 78.62±5.4% and 62.72± 4.2%, respectively. At the concentration of 100 \(\mu\)g/ml, the superoxide radical-scavenging activities of methanol extracts of Catharanthus roseus and Ocimum basilicum were found to be 72.36±3.21 and 68.76±3.16, respectively. Moreover, both the extracts showed a remarkable inhibition of bacterial growth at a concentration of 300 \(\mu\)g/ml compared to the two other doses tested (100 and 200 \(\mu\)g/ml). The overall results of this study can be considered as very promising in the perspective of obtaining new drugs from plant sources, especially when the medical importance of the tested microorganisms is considered. The current research offers experimental proof that the leaves of Ocimum basilicum and Catharanthus roseus possess potential antibacterial and antioxidant properties, suggesting that they could be employed as a safe treatment for infectious diseases. Further studies are warranted to elucidate and understand the antioxidants and antibacterial constituents / active principles of these plants using various biochemical and molecular biology tools such as LC/MS and GC/MS and in vivo studies.