Biological activities and nutritional value of Tapinanthus bangwensis leaves
The cytotoxic and antioxidant properties of the ethanolic extract and fractions of the leaves of Tapinanthus bangwensis were evaluated. The investigation of their total phenol and flavonoid contents, proximate analysis and their mineral composition were also carried out. In the brine shrimp lethality assay, the ethyl acetate and dichloromethane fractions showed cytotoxic activity with LD50 values of 11.22 and 15.84 μg/ml, respectively. The ethyl acetate and dichloromethane fractions exhibited significant cytotoxic effects towards HeLa cells with IC50 values of 24.25 and 24.43 μg/ml respectively. In the DPPH assay, the ethyl acetate fraction showed the highest activity while the butanol fraction showed the highest activity in the metal chelating and the lipid peroxidation assays. The quantitative analysis gave the total phenol and flavonoid contents in the range of 13.38 to 668.65 mg gallic acid equivalent (GAE)/g and 0.53 to 34.52 mg quercetin equivalent (QE)/g, respectively. For the proximate analysis, the crude fibre, carbohydrate, protein, total ash and moisture content values were 58.03, 17.80, 7.79, 13.70 and 0.60%, respectively while iron occurred in the highest amount and sodium in the least in the mineral composition analysis. These results demonstrate the cytotoxic and antioxidant activities of T. bangwensis leaves and support the traditional use of the plant in cancer treatment.
Keywords: Tapinanthus bangwensis, brineshrimp, HeLa, antioxidant