Phytochemical investigation and evaluation of in vitro free radical scavenging activity of Tabernaemontana divaricata Linn.

We evaluate the in vitro free radical scavenging activity of the leaves of Tabernaemontana divaricata Linn. Petroleum ether, ethanol and aqueous extracts of T. divaricata were prepared with successive extraction in a soxhlet apparatus. Each extract was selected to study the free radical scavenging activity by superoxide scavenging assay method. It was found that the aqueous extract contained carbohydrates, glycosides, amino acids, flavonoids, tannins, alkaloids, and steroids, and the ethanolic extract contained glycosides, amino acids, flavonoids, tannins, alkaloids and steroids. The ethanolic extract of T. divaricata showed 58.7 +/- 0.62% inhibition in the superoxide scavenging model. The aqueous extract also showed almost similar activity (54.9 +/- 0.53% compared to the ethanolic extract), while petroleum ether extract showed poor inhibition of superoxide scavenging activity. All extracts showed the dose- and time-dependent inhibition of the superoxide scavenging activity.