Two novel bibenzyls from Dendrobium trigonopus

Abstract

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.

Keywords:

• Dendrobium trigonopus
• bibenzyl
• anti-platelet aggregation activity
• trigonopols A and B

Acknowledgements

The authors wish to express their thanks to Dr Tina Tingya Dong, Professor Karl W. Tsin, Dr Jiang-Zhi-Yong, Department of Biology, Hong Kong University of Science and Technology for their help extended in carrying out antiplatelet aggregation activity. The authors are grateful to the members of the analytical group of the State Key Laboratory of Phytochemistry and Plant Resource in West China, Kunming Institute of Botany, for all the spectral measurements.