Two New Bisbibenzyl Derivatives from <i>Dendrobium findlayanum</i>

Objective This study aimed to isolate and structurally characterize compounds from Dendrobium findlayanum , and to evaluate their cytotoxic activities against human tumor cells. Methods Compounds were purified using conventional column chromatography combined with semi-preparative liquid chromatography. Structural elucidation was carried out by nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HR-MS). Cytotoxicity screening was performed in vitro using the MTT assay on human tumor cell lines. Results Two new bisbibenzyl derivatives, dronbibisline E ( 1 ) and dronbibisline F ( 2 ), together with six known analogues ( 3 - 8 ), were isolated from Dendrobium findlayanum . Among them, compounds 1 and 3 exhibited significant inhibitory activity against two breast cancer cell lines, MDA-MB-231 and MCF-7. Conclusion Two new bisbibenzyl derivatives were obtained from Dendrobium findlayanum . Compound 1 showed IC 50 values of 9.25 μM against MDA-MB-231 and 23.19 μM against MCF-7, whereas compound 3 exhibited an IC 50 of 5.89 μM against MDA-MB-231 cells.