Comparative Anti-oxidant Activity of Aqueous and Organic Extracts from Kenyan Ruellia lineari-bracteolata and Ruellia bignoniiflora

Medicinal plants play a significant role in treatment and prevention of many diseases in humans worldwide. Ruellia species belong to the family Acanthaceae and have been used widely for medicinal purposes. The objective of this study was to evaluate the comparative In vitro anti-oxidant activity of two Kenyan Ruellia species viz. Ruellia lineari-bracteolata (RLB) and Ruellia bignoniiflora (RBK). The plant materials were extracted with aqueous, ethyl acetate and methanol. The extracts were subjected to phytochemical screening according to standard procedures and anti-oxidant activity determined using 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) assay. Comparative anti-oxidant activity for methanolic, ethyl acetate and aqueous extracts of RLB and RBK exhibited IC50 values of (2.7, 29.3, 7.2 and 24.4, 237.2, 66.4 μg/ml) respectively. Among the three extracts, methanolic extract showed better activity (2.7 μg/ml) comparable to ascorbic standard (2.1 μg/ml). Between the two Ruellia species, RLB showed a significant difference (p<0.05) in anti-oxidant activity as compared to RBK extracts. Phytochemical screening showed the presence of terpenoids, saponins, flavonoids, tannins and glycosides. Flavonoids and tannins are the main phytoconstituents responsible for anti-oxidant activity. In conclusion, the potent anti-oxidant activity of these plants makes them useful in development of medicinal drugs for treatment and prevention of degenerative diseases.