Christine Ong’ayo Wangia
Jomo Kenyatta University of Agriculture and Technology, Kenya.
Christine Ong’ayo Wangia is a senior lecturer in the Department of Pharmacology, Jomo Kenyatta University of Agriculture and Technology-Kenya.She completed her Bachelor of Pharmacy Degree from the University of Nairobi, Kenya and a Master’s Degree in Drug Assay (Department of Pharmacology) at the All India Institute of Medical Sciences-New Delhi.She is currently pursuing her PhD program in Medicinal Phytochemistry at the Jomo Kenyatta University of Agriculture and Technology.She has presented her research findings in both local and international conference (4th Annual conference on medicinal plants and herbal products, Rockville-USA from 6th September to 8th September 2012).
The objective of this study was to determine the qualitative phytochemical constituents and anti-oxidant Activity of crude extracts from whole plant parts of Kenyan Ruellia species viz. Ruellia prostrata (RPM), Ruellia bignoniiflora (RBK) and Ruellia lineari-bracteolata (RLB). Kenyan Ruellia (Acanthaceae family) species are perennial creepers with widespread medicinal uses including analgesic and anti-inflammatory activity. Sequential extraction by cold maceration was done using petroleum ether, chloroform, ethyl acetate and methanol. Aqueous extraction was done by boiling. The phytochemical screening tests were based on visual observation of colour change and precipitate formation. Antioxidant activity was performed based on the ability of the aqueous, methanol and ethyl acetate extracts to scavenge the free radicals produced by 2,2-Diphenyl-1- picryl hydrazyl (DPPH). Ascorbic acid was used as a reference standard. The tests were evaluated at eight concentrations (3.9, 7.8, 15.6, 31.3, 62.5, 125, 250 and 500ug/ml). The antioxidant activity of plant extracts and ascorbic acid increased with increase in concentration. Methanolic extract exhibited a higher antioxidant activity with IC50 values in (ug/ml) of 2.87(RLB), 20.58(RPM) and 24.44(RBK). Aqueous extracts revealed IC50 values of 7.23 (RLB), 51.92(RPM) (and 66.42(RBK). The ethyl acetate extract showed a lower activity with IC50 values of 22.26(RPM), 29.33(RLB) and 237.17(RBK). Ascorbic acid standard exhibited a comparable activity with IC50 value of 2.11ug/ml. Phytochemical analysis revealed the presence of terpenoids, saponins, flavonoids, tannins and cardiac glycosides. Flavonoids and tannins are a major group of compounds that act as primary antioxidants. The presence of these compounds could attribute to their potent antioxidant activity.