Cassia auriculata Linn. extracts induce apoptosis and cell cycle arrest of A549 lung cancer cell lines: An in vitro approach

Abstract

Cassia auriculata is an ethnobotanically important traditional medicinal plant of tropical Asia and recently, phytochemicals and their derivatives have gained scientific attention for their use as agents in cancer treatment and prevention. The aerial parts of Cassia auriculata plant were subjected to successive cold maceration to yield four fractions viz., n-hexane, dichloromethane, ethyl acetate, and ethanol extract. The extracts were fractionated by GC–MS (Gas Chromatography-Mass Spectrometry) and HPLC (High-Performance Liquid Chromatography) analysis for their phytochemical content. The chromatographic techniques revealed the presence of mainly the flavonoid compounds like flavone, chrysin, and quercetin. The anti-proliferative properties of ethanolic extract of C. auriculata on A549 human lung cancer cells have been reported. The cancer cell survival rate (MTT 3- [4, 5- dimethythiazol-2-yl] 2, 5-diphenyl tetrazolium bromide) was found to be reduced with lung cancer cells (IC50 26.24 μg/ml) when treated with C. auriculata ethanol extract (CAEE) when compared to the non-cancerous cells L132. The toxicity of the extract on L132 cells was low (IC50 55.78 μg/ml). The mode of cell death induced by CAEE on A549 cells was examined by various fluorescent staining techniques and characteristic nuclear and morphological changes for apoptosis were evaluated. The expression of caspase 9 activity was documented, which might have triggered cell death through apoptosis by the activation of caspase 9 in the ethanolic fraction treated A549 cells. Cell cycle analysis of treated A549 cells revealed a promising S phase cell cycle arrest. The flavonoid compounds identified in the present study might be responsible for the remarkable anticancer and other activities of the plant. From these findings, the plant C. auriculata can be further exploited to develop promising candidate molecules, particularly for lung cancer chemotherapy.