In-vitro evaluation of antioxidant potential of rauwolfia vomitoria root extract and its inhibitory effect on lipid peroxidation as indication of aphrodisiac properties

Rauwolfia vomitoria (RV) Afzel (Apocynaceae) is a medicinal plant used in traditional medicinal practice for the treatment of hypertension. This research is devoted to phytochemical constituents, in particular, some specific alkaloids present in the RV root extract. The phytochemical evaluation revealed the presence of alkaloids, tannins, saponins, and flavonoids in this extract. The antioxidant activity of the RV root extract was also evaluated in a series of in vitro assays involving free radicals. The extract exhibited significant hydrogen peroxide scavenging effect relative to ascorbic acid (p < 0.05, IC₅₀ = 98 μg/ml), nitric oxide scavenging effect (50.37 ± 0.4% after 150 min), and metal chelating activity (89.08 ± 2.62%). In addition, it exhibited significant ferric reducing power relative to ascorbic acid (p < 0.05). The total content of phenolic substances was 233.3 ± 2.9 mg/g. The extract was also studied for its inhibitory capacity on lipid peroxidation as a possible mechanism of its aphrodisiac effect, by measuring thiobarbituric acid reactive substances in various male-cow tissues incubated in a 5% solution of the RV root extract, distilled water, and antioxidant vitamins C and E upon keeping the samples frozen for 35 days. Tissues incubated in the test solution had lower levels of malondialdehyde (MDA) compared to those in the samples incubated in distilled water. Results obtained from this study indicate that the RV root extract can be a potential source of natural antioxidants.