Morus alba L. (MA) is a natural source of many compounds with different
biological effects. It has been described to possess anti-inflammatory,
antioxidant, and hepatoprotective activities. The aim of this study was to evaluate cytotoxicity of three
flavonoids isolated from MA (kuwanon E,
cudraflavone B, and 4'-O-methylkuwanon E) and to determine their effects on proliferation of THP-1 cells, and on cell cycle progression of
cancer cells. Anti-inflammatory effects were also determined for all three given
flavonoids. Methods used in the study included quantification of cells by hemocytometer and WST-1 assays, flow cytometry, western blotting, ELISA, and zymography. From the three compounds tested,
cudraflavone B showed the strongest effects on cell cycle progression and viability of
tumor and/or immortalized cells and also on inflammatory response of macrophage-like cells. Kuwanon E and 4'-O-methylkuwanon E exerted more sophisticated rather than direct toxic effect on used cell types. Our data indicate that mechanisms different from stress-related or apoptotic signaling pathways are involved in the action of these compounds. Although further studies are required to precisely define the mechanisms of MA
flavonoid action in human
cancer and macrophage-like cells, here we demonstrate their effects combining antiproliferative and anti-inflammatory activities, respectively.