Maydisens, Sesterterpenoids with Anti-MDR Activity from .

Fourteen previously undescribed sesterterpenoids (-) were isolated from . Their structures with absolute configurations were elucidated by NMR, HRESIMS, DP4+ calculations, ECD calculations, single-crystal X-ray diffraction analyses, and the modified Mosher's method. Compounds - possess an uncommon 5/11 bicyclic ring system identified from for the first time. Compounds - have a 5/8/5 tricyclic ring system, and these compounds both possess carbonyl groups in ring A. Compound showed significant reversal of paclitaxel resistance in cancer cells.