Antiatherogenic effects of phyllanthus emblica associated with corilagin and its analogue

Oxidized low-density lipoprotein (ox-LDL) is the main etiologic factor in atherogenesis, and antioxidants are accepted as effective treatment of atherosclerosis. The aim of this study was to clarify whether the mechanism of the antiatherogenic effects of the herb Phyllanthus Emblica, which is widely used to treat atherosclerosis-related diseases, is associated with ox-LDL via its compounds of soluble tannin, corilagin (beta-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-d-glucose), and its analogue Dgg16 (1,6-di-O-galloyl-beta-d-glucose). Human umbilical vein endothelial cells, ECV-304, were incubated with ox-LDL (50 mg/l), treated with corilagin or Dgg16 at different doses (0.0001-0.1 mmol/l), and then incubated with monocytes. Malondialdehyde (MDA) in the culture media was determined and the number of monocytes adhering to ECV-304 cells was counted with cytometry. In another experiment, the rat vascular smooth muscular cells (VSMC) were incubated in media with or without ox-LDL (50 mg/l), and with corilagin or Dgg16 also at different doses (0.0001-0.1 mol/l), the proliferation of which was assayed with MTT. The results showed that both corilagin and Dgg16 were able to decrease MDA, prevented ECV-304 cells from being adhering to by monocytes, and inhibited VSMC proliferation activated by ox-LDL. The results suggest that the two compounds are effective in inhibiting the progress of atherosclerosis by alleviating oxidation injury or by inhibiting ox-LDL-induced VSMC proliferation, which may be promising mechanisms for treating atherosclerosis.