Two new cadinane-type sesquiterpene glycosides from Dendrobium findleyanum

Two novel and two previously identified cadinane-type sesquiterpene glycosides, findleyanosides E-F (1-2), balanoindicoside B (3) and pumilaside C (4), were extracted from the Dendrobium findleyanum stems. The establishment of structures was mainly conducted via spectroscopic techniques and by comparing with literature data. Electronic circular dichroism (ECD) computations helped determine the absolute configuration of the novel molecules. All molecules exhibited moderate cytotoxic effects against A-549 human tumour cell lines, with IC₅₀ values of 15.52, 17.68, 13.85 and 16.64 μM, respectively.