Abstract: Two anthrabenzoxocinone metabolites,(-)-(6R,16R) 10-Cl-ABX (1) and (-)-(6R, 16R)-ABX (2),were isolated from the fermentation broth of Streptomyces sp.HS-NF-496.Their structures were determined on the basis of spectroscopic analysis,including 1D and 2D NMR techniques,CD as well as ESI-MS and comparison with data from the literatures.Bioassay results showed that 1 and 2 exhibited weak cytotoxic activity against three tumor cell lines A549,HCT-116 and SF-268 and moderate antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and Methicillin-resistant  S.aureus. The absolute configuration of 1 was reported for the first time.

Key words: Streptomyces sp, anthrabenzoxocinones, cytotoxicity, antibacterial activity