Antiproliferative effect of Acacia nilotica (L.) leaf extract rich in ethyl gallate against human carcinoma cell line KB

OBJECTIVES: The objective of this study is to analyze the antiproliferative activity of Acacia nilotica (L.) leaf ethanolic extract against cancer KB cells and to determine the mode of cancer cytotoxicity. MATERIALS AND METHODS: In this study, high-performance liquid chromatography and liquid chromatography-mass spectrometry analysis were done to confirm the presence of ethyl gallate as a major bioactive phenolic in the leaf ethanolic extract of A. nilotica, further dose-dependent (0-120 mu g/mL) antiproliferative effect was investigated in human carcinoma cell line KB. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, reactive oxygen species, mitochondrial membrane potential loss, DNA damage, and apoptosis were evaluated. RESULTS: A. nilotica leaf ethanolic extract (ANLEE) showed effective concentration (EC50) of 40 mu g/mL. Interference of growth was significantly (P < 0.05) high in KB cells treated with ANLEE when compared to untreated control, but less when compared to the reference drug paclitaxel. In addition, the in vivo acute toxicity study demonstrated the safe limit of administration of 2000 mg/kg body weight ANLEE by the histological analysis in rats. The results from the present study indicate that mitochondria and DNA of KB cells are severely affected leading to apoptosis. CONCLUSIONS: ANLEE is a prospective source for cancer therapy and therefore should be highlighted to explore on its wide range of safety in rats and efficacy against human carcinoma cell line KB.