Assessment of in vivo and in vitro cytotoxic activity of hydrolysable tannin extracted from Rhizophora apiculata barks

Abstract

Rhizophora apiculata is a common mangrove tree in Malaysia. The bark of this tree has been reported to contain a chemical constituent such as tannin that exhibited antimicrobial activity. Recently hydrolysable tannins have been studied for their potential effects against pathogenic microorganisms and cancer cells through different mechanisms. The essence of the present study was to focus on the in vivo and in vitro cytotoxicity of hydrolysable tannin which was extracted from barks of R. apiculata. Cytotoxicity of the hydrolysable tannin obtained was tested in an in vivo brine shrimp lethality assay, and in vitro anticancer cells assay. The results of the in vivo assay demonstrated that hydrolysable tannin showed a higher value of LC50 for the acute toxicity (LC50 = 4.67 mg/ml) than chronic toxicity (LC50 = 2.10 mg/ml), which means that it was essentially non-toxic. The hydrolysable tannin showed cytotoxicity effects on HepG2 cancer cells (IC50 = 12.26 μg/ml). It was found that the number of surviving HepG2 cancer cells became less as the concentration of the hydrolysable tannin increased. These findings demonstrate that hydrolysable tannin has high LC50 and low IC50 values, and could be used as potential source for pharmacologically useful products.