Phenolic Glucosides from Dendrobium aurantiacum var. denneanum and Their Bioactivities

A new 8,4￠-oxyneolignane glucoside 1 has been isolated from the stems of Dendrobium aurantiacum var. denneanum together with six known phenolic glucosides 2- 7. The structure of the new compound, including its absolute configuration, was determined by spectroscopic and chemical methods as (–)-(7 S,8 R,7￠ E)-4-hydroxy-3,3￠,5,5￠-tetramethoxy-8,4￠-oxyneolign-7￠-ene-7,9,9￠-triol 7,9￠-bis- O- β-D-glucopyranoside ( 1). In the in vitro assays, compound 1 and (-)-syringaresinol-4,4￠-bis- O- β-D-glucopyranoside ( 2) showed evident activity against glutamate-induced neurotoxicity in PC12 cells. Shashenoside I ( 4) showed a selective cytotoxic activity with the IC 50 value of 4.17 μM against the acute myeloid leukemia cell line MV4-11, while it was inactive against 10 other human tumor cell lines.