In vitro antioxidant potential of methanol extracts of Allamanda schottii Pohl and Thevetia peruviana (pers.) K.(Apocyanaceae)

Antioxidants are known for their potential in improving health and lowering the risk for certain metabolic diseases such as hypertension, cancer and heart disease. The uses of natural antioxidants from plant extracts have experience growing interest due to some human health professionals and consumer’s concern about the safety of synthetic antioxidants in foods. Phytochemical screening of both methanolic extract of Allamanda schottii and Thevetia peruviana methanol extract, as well as in vitro antioxidant activity of the aforementioned plants using Ferric Reducing Power Assay and DPPH-Radical Scavenging Assay were done in this research. Phytochemical screening result showed the presence of saponin, terpenoids, flavonoid, tannin and alkaloid in both plants, but the presence of cardiac glycoside was observed in T. peruviana only. The total antioxidant effect was found to be concenteration dependent in both plants, lowest and highest activity were observed at 20 and 100 μg/ml respectively for both plants, with A. schottii having the highest activity. A similar activity was noted in ferric reducing power assay, where no significant difference in activity of both plants P<0.5 was observed. The study indicates that both A. schottii and T. peruviana have radical scavenging activity and possibly may be relevant in preventing some diseases induced by oxidative stress