New Benzophenone and Diphenylmethane Glycosides from Psidium littorale

The methanol extract from the fresh leaves of P. littorale was subjected to various column chromatography. This resulted in the isolation of four benzophenone glycoside derivatives: one new benzophenone glycoside, 2,6-dihydroxy-3-methyl-4-O-beta-D-glucopyranosyl-benzophenone (1), one new diphenylmethane glycoside, 2,6-dihydroxy-3-methyl-4-O-(6aEuro(3)-O-galloyl-beta-D-glucopyranosyl)-diphenylmethane (2), along with two known benzophenones, 2,6-dihydroxy-4-O-beta-D-glucopyranosyl-benzophenone (3) and 2,6-dihydroxy-3-methyl-4-O-(6aEuro(3)-O-galloyl-beta-D-glucopyranosyl)-benzophenone (4). Their structures were elucidated using data obtained from FAB-MS, H-1, and C-13 NMR spectra and correlation experiments (HMQC and HMBC), as well as by comparison with published data. The activity of compounds 1-4 against five fungal species was investigated: the antimicrobial activity of all isolated compounds increased with concentration and varied according to the following rank: 1 a parts per thousand yen 4 > 3 > 2, thereby showing some structure-activity relationships.