Phaeosphamides A and B, Cytotoxic Cyclodecadepsipeptides from the Mangrove-Derived Fungus <i>Phaeosphaeriopsis</i> sp. S296
Siwen Niu,
Jianlin He,
Shuhuan Huang,
Shouyuan Wu,
Ling Zeng,
Juan Wang,
Bihong Hong,
Ziming Chen
Affiliations
Siwen Niu
School of Chemistry and Chemical Engineering, Lingnan Normal University, Zhanjiang 524048, China
Jianlin He
Technology Innovation Center for Exploitation of Marine Biological Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
Shuhuan Huang
Technology Innovation Center for Exploitation of Marine Biological Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
Shouyuan Wu
School of Chemistry and Chemical Engineering, Lingnan Normal University, Zhanjiang 524048, China
Ling Zeng
School of Chemistry and Chemical Engineering, Lingnan Normal University, Zhanjiang 524048, China
Juan Wang
Technology Innovation Center for Exploitation of Marine Biological Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
Bihong Hong
Technology Innovation Center for Exploitation of Marine Biological Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
Ziming Chen
School of Chemistry and Chemical Engineering, Lingnan Normal University, Zhanjiang 524048, China
Chemical examination of the fermented broth of the mangrove-derived fungus Phaeosphaeriopsis sp. S296 resulted in the isolation of two new cyclodecadepsipeptides, namely phaeosphamides A (1) and B (2), as well as one known congener Sch 217048 (3). The structures of new metabolites, including absolute configurations, were established on the basis of extensive spectroscopic data analyses, chemical conversion, and Marfey’s method. The 2-hydroxy-3-methylpentanoic acid (Hmp) moiety and pipecolic acid (Pip) unit in structures were rarely discovered in nature. Interestingly, compounds 1–3 are examples of peptides discovered from the fungal genus Phaeosphaeriopsis for the first time. All identified compounds were evaluated for their cytotoxicity against five tumor cell lines of AGS, BEL-7402, HepG2, B16, and BIU87. Among them, compound 1 showed inhibitory activities against these tumor cell lines with IC50 values ranging from 5.14 to 66.38 μM. A further mechanistic investigation found that 1 arrested AGS cells in the G2 phase and induced their apoptosis in a dose-dependent manner.
