Ten picrotoxane-type sesquiterpenoids from the stems of Dendrobium wardianum Warner.

Ten undescribed picrotoxane-type sesquiterpenoids, dendrowardins A-J, together with two known ones, were isolated from the stems of Dendrobium wardianum Warner (Orchidaceae). Dendrowardins A-D feature the unusual 5,2-δ-lactone and additionally dendrowardins C-D are the first examples containing the 11,10-γ-lactone moiety. The structures were established using spectroscopic methods and by comparison with literature data. Further, dendrowardin E, amotin, and aduncin exhibited significant effects of promoting the proliferation on human lens epithelial cells (HLECs) induced by D-galactose.

Structural characterization and antitumor activity of a polysaccharide from Dendrobium wardianum.

Through hot water extraction, protein removal and chromatographic purification, DWPP-Is was found to be the major polysaccharide present in the stem of D. wardianum. The Mn and Mw of DWPP-Is were 29.0 kDa and 98.6 kDa, respectively. Furthermore, mannose and glucose were found to be the most abundant monosaccharides in DWPP-Is. Their backbones consist of (1 â†’ 4)-ß-d-Glcp and O-acetylated (1 â†’ 4)-ß-d-Manp, which are similar to the structures of other anti-tumour Dendrobium polysaccharides. The inhibition rate of DWPP-Is treatment on SPC-A-1 cells (2 mg/mL, 72 h) reached 56.0%. Intragastric administration of DWPP-Is on A549 tumour-bearing KM mice (10 mg/mL, 0.2 mL) exhibited similar inhibition ratios to that of erlotinib hydrochloride (2 mg/mL). Moreover, the highest inhibition was observed in P-CK treatment combined with DWPP-Is, reaching an inhibition rate of 23.4%. These results suggest that DWPP-Is has the potential to be a functional agent for lung cancer prevention.

Sesquiterpene amino ether and cytotoxic phenols from Dendrobium wardianum Warner.

A new bibenzyl derivative, dendrocandin V (1) and a new sesquiterpene amino ether, wardianumine A (2), together with eleven known compounds, including phenanthrenes (denbinobin (3), 9,10-dihydro-denbinobin (4), mostatin (5), loddigesiinols A (6)), bibenzyls (moscatilin (7), 5-hydroxy-3,4'-dimethoxybibenzyl (8), 3,4-dihydroxy-5,4'-dimethoxy bibenzyl (9), dendrocandin A (10), gigantol (11), dendrocandin U (12)) and an alkaloids (dihydroshihunine, 13) were isolated from the EtOH extraction of stems of Dendrobium wardianum Warner. Isolation of the new compound 2 indicated that N,N-dimethylethanolamine as the key adduction in the synthesis of dendroxine and its analogs in Dendrobium species. The hypothetical biosynthetic pathway of 2 was then postulated. Inspired by literature and traditional usage of the herbal medicine, some compounds were sent for cytotoxic activity and the results indicated that compounds 1, 3, 4, 5 showed cytotoxic activities against five human cancer cell lines (HL-60, A-549, SMMC-7721, MCF-7, and SW-480) with IC50 from 2.33-38.48µM. Among those compounds, 3 and 4 showed cell line selectivity with strong activity comparable to DDP.