ANTI-OXIDANT ACTIVITY OF AQUEOUS AND ORGANIC EXTRACTS FROM KENYAN RUELLIA PROSTRATA

Ruellia species belong to Acanthaceae family, and are perennial creepers with widespread medicinal uses including analgesic and anti-inflammatory activity. 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. Whole parts of the plants were collected, air-dried under shade and organic extraction was done by cold maceration using ethyl acetate and methanol. Aqueous extraction was done by boiling. Anti-oxidant activity was performed based on the ability of the aqueous, methanolic and ethyl acetate extracts to scavenge free radicals produced by 2,2-Diphenyl-1-picrylhydrazyl (DPPH). Ascorbic acid was used as the standard. Anti-oxidant tests were done at eight concentrations (3.9, 7.8, 15.6, 31.3, 62.5, 125, 250 and 500 µg/ml). The anti-oxidant activity of both plant extracts and ascorbic acid increased with increase in concentration. Methanolic and ethyl acetate extracts exhibited a higher anti-oxidant activity with IC₅₀ values of 20.58 and 22.26 µg/ml respectively, relative to aqueous extract (IC₅₀ of 51.92µg/ml). Ascorbic acid standard exhibited high anti-oxidant activity with IC₅₀ value of 2.11µg/ml. The phytochemical screening tests were based on visual observation of colour change and precipitate formation. 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 anti-oxidants. The presence of these compounds could attribute to the potent anti-oxidant activity of R. prostrata extracts. From this study, it was concluded that Ruellia prostrata could have anti-inflammatory activity.