Apoptosis-inducing potential of the hexane fraction of Cassia fistula L. against MCF-7 cells via apoptosis signaling pathways

This study analyzed bioactive-phytoconstituents of the n-hexane fraction of Cassia fistula L. fruit extract using HPLC-DAD and investigated its anticancer potential using several biochemical and molecular methods, such as cell viability, induction of apoptosis, aberrant cell cycle progression, changes in the expression of pro/anti-apoptotic genes, and others. HPLC analysis revealed the possible presence of quercetin and kaempferol alongside catechin, rutin, caffeic acid, orientin, and iso-orientin. We observed a dose-dependent decline in cell viability in MCF-7 cell line with IC50 concentration of 99.7 μg/mL. The morphological alteration and wound healing assay indicated the presence of morphologically altered cells and non-significant closure of the wound in the IC50 treated cells. Moreover, flow cytometry investigations revealed rise in apoptotic cells (from 5% to 29%), increased reactive oxygen species (ROS) production (+17%), mitochondrial membrane potential (MMP) loss (from 23% to 13%), and cell cycle perturbation characterized by accumulation of cells in both G0/G1 (from 17.2% to 37.4%) and G2/M-phases (from 11.6% control 24%). Reverse transcription polymerase chain reaction (RT-PCR) revealed the upregulation of the p53 (4-fold) and Bax (4.5-fold) genes, as well as downregulation of Bcl-2 (2.5-fold) gene. Our findings highlight the anticancer efficacy of the n-hexane fruit extract of C. fistula L. However, further validation is required in a suitable in-vivo/xenograft model so that this potent plant can be exploited clinically, especially against breast cancer.