(±)-Pestalachloride D an Antibacterial Racemate of Chlorinated Benzophenone Derivative from a Soft Coral-Derived Fungus Pestalotiopsis sp

摘要

A new antibacterial chlorinated benzophenone derivative, (±)-pestalachloride D (>1), along with a related analog, (±)-pestalachloride C (>2), was recently isolated from the marine-derived fungus Pestalotiopsis sp. isolated from a soft coral Sarcophyton sp. collected from Yongxing Island in the South China Sea. Both chiral HPLC analysis and single-crystal X-ray data indicated that >1 is a racemic mixture. Interestingly, >1 did not exhibit any effect in the zebrafish embryo teratogenicity assay, while >2 led to abnormal growth. The potential impact on zebrafish embryo growth is discussed based on their crystal structures. The main difference of crystal structures between >1 and >2 is that the six-member non-aromatic ring (O4, C10, C9, C8, C2′, and C3′) in >1 exhibits a distorted chair conformation, while >2 shows a distorted boat conformation. Moreover, compounds >1 and >2 both exhibited moderate antibacterial activity.