New benzophenone and quercetin galloyl glycosides from Psidium guajava L.

New benzophenone and flavonol galloyl glycosides were isolated from an 80% MeOH extract of Psidium guajava L. (Myrtaceae) together with five known quercetin glycosides. The structures of the novel glycosides were elucidated to be 2,4,6-trihydroxybenzophenone 4-O-(6aEuro(3)-O-galloyl)-beta-d-glucopyranoside (1, guavinoside A), 2,4,6-trihydroxy-3,5-dimethylbenzophenone 4-O-(6aEuro(3)-O-galloyl)-beta-d-glucopyranoside (2, guavinoside B), and quercetin 3-O-(5aEuro(3)-O-galloyl)-alpha-l-arabinofuranoside (3, guavinoside C) by NMR, MS, UV, and IR spectroscopies. Isolated phenolic glycosides showed significant inhibitory activities against histamine release from rat peritoneal mast cells, and nitric oxide production from a murine macrophage-like cell line, RAW 264.7.