Leaf extract from Ardisia compressa protects against 1-nitropyrene-induced cytotoxicity and its antioxidant defense disruption in cultured rat hepatocytes

Herbal tea preparations of Ardisia compressa (AC) have been used in folk medicine against liver disorders. The objective of this study was to evaluate the in vitro protective effect of an aqueous extract of dry leaves of AC on 1-nitropyrene (1-NP) induced cytotoxicity on rat hepatocytes. Lipid peroxidation (malondialdehyde), antioxidant enzyme activities (glutathione reductase, glutathione peroxidase, superoxide dismutase) and glutathione levels were studied. After 2 h of incubation, 0.25 μg/ml of 1-NP had an approximately 50% cytotoxic effect on hepatocytes. This environmental toxicant also increased malondialdehyde (77%), and glutathione peroxidase (46%), producing a significant consumption of endogenous antioxidant glutathione. (-)Epigallocatechin 3-gallato (EGCG) and AC decreased the viability of hepatocytes after 2 h of incubation at concentrations above 3 μg/ml and 2.52 μg, equivalents of (+)catechin/ml, respectively. A 100% hepatocyte protection was observed when cells were first exposed to AC (2.52 μg, equivalents of (+)catechin/ml), and then followed by 1-NP (0.25 μg/ml). Cells incubated with AC, either simultaneously or before treatment with 1-NP, were protected 75 and 84%, respectively. Cell protection of AC was superior to EGCG. Addition of AC to 1-NP (1:10) modulated superoxide dismutase and glutathione reductase activities (P<0.005), as well as the cellular level of GSH. The results indicate that AC has an antioxidant protective effect on rat hepatocytes when exposed to 1-NP.