Indole-based alkaloids from Ophiocordyceps xuefengensis.

Abstract Seven undescribed indole-based alkaloids, xuefengins A–D and xuefenglasins A–C, were isolated from natural Ophiocordyceps xuefengensis, along with six known alkaloids. Their structures were elucidated by comprehensive spectroscopy, with absolute configurations confirmed by comparison with calculated electronic circular dichroism spectra. Eleven of the isolates were tested for cytotoxicity against the U937, NB4, MCF-7, Hep G2, and A549 cancer cell lines. Two compounds exhibited moderate activities, with IC50 values of 2.83–25.68 μM and 1.54–12.16 μM. Further pharmacological studies showed that these two compounds inhibit cell proliferation by inducing apoptosis, and decreasing p38 and caspase-3 levels in A549 cells.