Immunosupressive Phenolic Constituents from Hypericum montbretii Spach.

 The MeOH extract of aerial parts of H. monbretii Spach. have yielded quercetin (1), kaempferol (2), quercitrin (3), hyperin (4), myricitrin (5), rutin (6), I 3 II 8′′ biapigenin (7), methyl chlorogenate (8), 5-O-p-coumaroylquinic acid (9), and chlorogenic acid (5-O-caffeoyl quinic acid) (10), mangiferin (11), and shikimic acid (12). Three compounds 1, 2 and 4 were found to have an immunomodulating inhibitory activity on the oxidative burst response of human neutrophils, as well on mouse peritoneal macrophages. E ffects of compounds on whole blood phagocytes activity was found to be with IC 50 ranging between 8.0-12.2 µg/mL. O nly compounds 1, and 2 were found to interfere with T-cell proliferation, and IL-2 release in PHA activated peripheral blood mononuclear cells system. To the best of our knowledge, this is the first report of phytochemical and biological activity study on H. montbretii Spach.