Search

Two new bibenzyl derivatives, dendrocandin T (1) and dendrocandin U (2), together with eight known bibenzyls, were isolated from the stems ofDendrobium officinale. Those compounds were sent for the first time for central nervous system-related bioassay and the results indicated that compounds3,4, and5have a certain degree of neurite outgrowth-promoting activity, and compounds1,2,6, and7also have weak activity. The results indicated thatD. officinaleused as health food and traditional Chinese medicine “Tiepi Shihu” has a health function of neurotrophic effects. [ABSTRACT FROM PUBLISHER]

Three new stilbenoids, 1-(4′-hydroxybenzyl)-imbricatin (1), (E)-4′-hydroxy-2′,3,3′,5-tetramethoxystilbene (2), and (E)-3,4′-dihydroxy-2,6-bis(4-hydroxybenzyl)-2′,3′,5-trimethoxystilbene (3), together with 15 known stilbene derivatives, were isolated from Pholidota yunnanensis. Their structures were elucidated by spectroscopic methods and by comparison of their NMR data with those of related compounds. Furthermore, the inhibitory activities on nitric oxide (NO) production of the isolated compounds were examined in murine macrophages (RAW 264.7) activated by lipopolysaccharide. The cytotoxicity of 18 compounds was determined by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. Among the tested compounds, eight stilbenoids, including three dihydrophenanthrenes, three stilbenes, and one bibenzyl derivative showed inhibitory effects on NO production without cytotoxicity with IC50 values ranging from 4.07 to 7.77 μM, as compared to MG-132, which was used as a positive control (IC50 of 0.10 μM). One dihydrophenanthrene, phoyunnanin C (5), showed cytotoxic effects at the test concentrations. [ABSTRACT FROM AUTHOR]

Two novel bibenzyl trigonopols A (1) and B (2), together with seven known compounds, gigantol (3), tristin (4), moscatin (5), hircinol (6), naringenin (7), 3-(4-hydroxy-3-methoxyphenyl)-2-propen-1-ol (8), and ( - )-syringaresinol (9), have been isolated from the stems of Dendrobium trigonopus, of which compounds 6, 8, and 9 were isolated for the first time from this species. The structures of two new compounds were elucidated as threo-22-(17-hydroxyl-9-(3-hydroxyl-4-methoxy-phenethyl)-13,16,18-trimethoxy-21H-benzo[c]chromen-21-yl)ethane-22, 23-diol (1) and 9-(4-hydroxyl-3-methoxy-phenethyl)-17-(21-hydroxyl-20-methoxy-phenyl)chroman-11, 16-diol (2) on the basis of spectroscopic methods. Trigonopol A was found to exhibit antiplatelet aggregation activity in vitro with 67.55% inhibitory ration at 1.4337 × 10- 3 M. [ABSTRACT FROM AUTHOR]