Carbohydrate Modifications of Neoandrographolide for Improved Reactive Oxygen Species-Mediated Apoptosis through Mitochondrial Pathway in Colon Cancer

摘要

Modifications at the carbohydrate moiety of neoandrographolide, isolated from the medicinal plant Andrographis paniculata, result in more potent and less toxic derivatives, namely, 4′,6′-benzylidene neoandrographolide (2b) and 4′6′-p-methoxybenzylidene neoandrographolide (2c). These showed improved cytotoxicity against SW-620, PC-3, and A549 cancer cell lines. Nuclear morphology studies were conducted on compound 2b by 4′,6-diamidino-2-phenylidole staining and detection of intracellular reactive oxygen species (ROS) accumulation. It showed an increase in the generation of cellular and mitochondrial ROS level. The probable relation of B-cell lymphoma-2 (Bcl-2, an apoptosis inhibitor) to B-cell lymphoma-2-associated X protein (Bax, an apoptosis promoter) ratio with caspase-3 (apoptosis coordination enzyme) in the colon cancer cell line SW-620 was investigated, and it was discovered that upon 2b treatment, the expression of caspase-3 Bax increased remarkably. However, in 2b-treated cells, the expression of Bcl-2 was downregulated as compared to untreated cells.