Brassinin and its derivatives as potential anticancer agents.

The aim of the study was to investigate the anti-proliferative activity of brassinin and its derivatives on human cancer cell lines. We found that among twenty-one tested compounds, 1- methoxybrassinin exerted the most potent anti-proliferative activity in Caco-2 cells with IC₅₀ 8.2 (±1.2)μmoll(-1). The flow cytometric analysis revealed a 1-methoxybrassinin-induced increase in the sub-G1 DNA content fraction which is considered to be a marker of apoptotic cell death. Apoptosis was also confirmed by DNA fragmentation assay. Moreover, quantitative real-time PCR showed that 1-methoxybrassinin upregulated the expression of pro-apoptotic Bax and downregulated the expression of anti-apoptotic genes Bcl-2 and Bcl-xL. The compound also increased activity of caspase-3, -7, cleaved PARP and decreased intracellular GSH content. The present study has assessed the in vitro anti-proliferative potential of 1-methoxybrassinin. The results generate a rationale for in vivo efficacy studies with this compound in preclinical cancer models.