Trichodestruxins A–D: Cytotoxic Cyclodepsipeptides from the Endophytic Fungus <i>Trichoderma harzianum</i>
Zhiguo Liu, Yi Sun, Mengyue Tang, Peng Sun, Anqi Wang, Yanqi Hao, Yanan Wang, Yue‐Hu Pei
Abstract
Four new cyclodepsipeptides, trichodestruxins A–D (1–4), together with destruxin E2 chlorohydrin (5) and destruxin A2 (6), were isolated from the plant endophytic fungus Trichoderma harzianum by a bioassay-guided fractionation method. Their planar structures were elucidated on the basis of 1D and 2D NMR and MS/MS spectroscopic analyses. The stereochemical configuration was established by application of the advanced Marfey’s method, J-based configuration analysis, Mosher’s method, and chemical derivatizations. Trichodestruxin B contains hydroxy acid fragments of the THPA unit, while trichodestruxins A and C contain the β-methylproline moiety. All cyclodepsipeptides displayed cytotoxicity against HT-29, A549, and/or P388 cell lines with IC50 values of 0.7–19.1 μM.