New cytotoxic lignan glycosides from Phyllanthus glaucus

During the process of exploring bioactive lead compounds from Phyllanthus species, two new glycosides including an arylnaphthalene lignan, diphyllin 4-O-alpha-L-arabinopyranosyl-(1 -> 3)-alpha-L-arabinopyranoside (1), and a phenolic compound, 3,4,5-trimethoxybenzyl alcohol 7-O-alpha-L-arabinofuranosyl-(1 -> 6)-beta-D-glucopyranoside (2), were isolated from the methanol extract of the whole plants of Phyllanthus glaucus Wall. ex Mull. Arg. In addition, 31 known compounds, including 19 lignan derivatives (3-21), four phenylpropanoids (22-25), seven simple phenolics (26-32) and one monoterpenoid (33) were obtained. Their structures were determined on the basis of the HR-ESI-MS, 1D and 2D NMR spectroscopic analysis, and pre-column derivative/chiral HPLC analysis in case of 1 for the absolute configurations. All these compounds were obtained from P. glaucus for the first time. Moreover, the known lignan glycoside, phyllanthusmin C (5) showed in vitro cytotoxicities against HL-60, MCF-7 and SW480 cells with IC50 values of 9.2 +/- 0.2, 19.2 +/- 1.7 and 20.5 +/- 0.9, respectively.