Centella Asiatica Fraction-3 Enhances Antioxidant Capacity and Apoptotic Cell Death in HEK293 Kidney Cells

The traditional medicinal plant Centella asiatica is commonly used in Chinese and Ayurvedic medicine due to its vast range of therapeutic properties. Previously, the ethanolic C. asiatica leaf extract was subjected to silica column fractionation, and the C3 fraction was obtained. We investigated the antioxidant and anti-proliferative effects of C3 in human embryonic kidney (HEK293) cells. In HEK293 cells, C3 cytotoxicity was assessed (viability assay; 24 h; [0.2-3 mg/mL]), and a half maximal inhibitory concentration (IC₅₀) was determined. Malondialdehyde (MDA), lactate dehydrogenase (LDH) (spectrophotometry), mitochondrial depolarization (Δψ_m), intracellular reactive oxygen species (flow cytometry), glutathione (GSH), oxidized glutathione (GSSG) concentrations, caspase activities, ATP levels (luminometry), and fragmentation of DNA (SCGE assay) were evaluated. Protein expressions were assessed by western blotting. Gene expressions were quantified by qPCR. Cell viability in HEK293 cells was decreased in a dose-dependent manner by C3. MDA, Δψ_m, LDH, caspase activities, and DNA fragmentation (P < .0004) were significantly increased by C3. Nuclear factor erythroid 2-related factor 2 (Nrf-2) protein expression, GSH, and GSSG concentrations were increased, whereas antioxidant (Nrf-2, GPx, SOD, and CAT) gene expression was significantly decreased by C3 (P < .001). C3 decreased both Bax and Bcl-2 protein expression (P < .03). Gene expression of c-myc was significantly increased, whereas OGG-1 was significantly reduced by C3 (P < .05). C3 reduced antioxidant gene expression, increased antioxidant levels, and elevated anti-proliferative effects in HEK293 cells, suggesting that high concentrations of C3 are potentially toxic to kidney cells, thus rendering cause for concern with its human use.