Two new sesquiterpene glycosides from Dendrobium findleyanum .

One new ylangene-type sesquiterpene glycoside, findlayanoside C ( 1 ), and one new picrotoxane-type sesquiterpene glycoside, findlayanoside D ( 3 ), together with five known sesquiterpene glycosides, dendrofindlayanoside C ( 2 ), dendronobiloside B ( 4 ), dendronobiloside A ( 5 ), dendroside F ( 6 ) and dendromoniliside D ( 7 ), have been isolated from the stems of Dendrobium findleyanum . The structures of compounds 1 and 3 were elucidated by means of extensive spectroscopic analyses, and their absolute configuration were confirmed by electronic circular dichroism (ECD) calculations. Cytotoxic activity assays against SMMC-7721, A-549 and MCF-7 human cancer cell lines revealed IC 50 values of 10.12, 12.32 and 14.13  μ M for compound 1 , and of 9.25, 13.16 and 16.26  μ M for compound 2 . This study enriches the anti-tumour sesquiterpenoids composition of D. findleyanum .