From the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Guettarda speciosa L., two new compounds (1, 2) were isolated together with six known compounds. Spectroscopic analysis of 1 and 2 established their structures to be derivatives of a glycerol α-glucuronide and a megastigmane glycoside, respectively. HPLC analysis of the hydrolyzate of 1 confirmed the presence of D-glucuronic acid in the structure, and the modified Mosher's method established the absolute structure of 2.

Thirteen compounds (1-13) were isolated from a MeOH extract of leaves of Glochidion rubrum. The structures of four new compounds were elucidated to be (-)-isolariciresinol 2a-O-beta-D-glucopyranoside (1), (7R,8S)- and (7R,8R)-4,7,9,9'-tetrahydroxy-3,3'-dimethoxy-8-O-4'-neolignan 7-O-beta-D-glucopyranosides (2 and 3, respectively), and tachioside 2'-O-4''-O-methylgallate (4) on detailed inspection of one- and two-dimensional NMR spectral data.

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ABSTRACT

Extensive phytochemical work on the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Symplocos cochinchinensis var. philippinensis resulted in the isolation of 14 new triterpenene saponins, along with four known ones. Their structures were elucidated by comparison of NMR spectroscopic data with related compounds reported in the literature. Three oleanane-type saponins, symplocosins K, M, and P, possessed glucuronic acid as a sugar component, and their carboxyl groups appeared as methyl esters. These are probably formed during extraction and isolation procedures. Symplocosin K (9) showed moderate cytotoxicity toward A549 cells. In addition, all isolated compounds did not show α-glucosidase inhibitory activity.