Genome mining of albocandins A-E from Streptomyces sp. YINM00030

The natural products of 2,5-diketopiperazines have attracted considerable attention due to their potent pharmacological activities. Guided by genome mining techniques, five albonoursin analogues, designated as albocandins A-E (1-5), were isolated from Streptomyces sp. YINM00030, an actinomycete sourced from the rhizosphere soil of medicinal plants. The structures and absolute configurations of these compounds were elucidated through comprehensive spectroscopic analyses, HRESIMS, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction analyses. The biosynthetic pathway of these compounds were proposed. The investigation of biological activity showed that albocandins C and D exhibited cytotoxic activity against five human cancer cell lines (HL-60, A549, SMMC-7721, MDA-MB-231, SW480) in vitro with IC₅₀ values ranging from 3.50 to 32.66 μM.