In the course of our screening program, the EtOAc extract of Micromonospora sp. A258 from the sponge Haliclona oculata exhibited antimicrobial activity against both gram positive S.aureus ATCC25923 and gram‐negative E.coli ATCC25922, S.enterica ATCC13076. This paper reports the isolation and structural elucidation of eight secondary metabolites including bacilsubteramide A (1), 4,9‐dihydroxy‐3‐isobutyl‐2,3,4,5‐tetrahydrobenzo‐azepin‐1‐one (2), indole‐3‐carboxylic acid (3), N‐acetyltryptamine (4), N‐(4‐hydroxyphenyl)ethyl‐methylbutanamide) (5), N‐phenyl‐acetamide (6), 2‐[(5‐methyl‐1,4‐dioxan‐2‐yl)methoxy]ethanol (7), (2R,3S)‐butane‐2,3‐diol (8) from the culture broth of Micromonospora sp. A258. Their structures were determined by spectroscopic analysis including MS, 1D NMR and 2D NMR, as well as comparison with literature data.

Macaranga tanarius is a medium‐sized tree that is widespread in the Southeast Asian and western Pacific regions. The ethyl acetate extract of this species was showed cytotoxic activity against KB cancer cell line. In this article, we report the isolation and structural elucidation of four known stilbenes from fruit glandular trichomes of M. tanarius including vedelianin (1), schweinfurthins E‐G (2‐4). The structures of the isolated compounds were elucidated from their mass and NMR spectral data. Cytotoxic activity of the isolated compounds (1‐4) against KB cell line was also discussed.

Five secondary metabolites including three flavonoids, 6‐lavandulyl‐5,7,2′,4′‐tetrahydroxyflavanone (1), 5′‐lavandulyl‐2′‐methoxy‐2,4,4′,6′‐tetrahydroxychalcone (2), 6‐lavandulyl‐7‐methoxy‐5,2′,4′‐trihydroxyflavanone (3), and two alkaloids, tryptoline (4), and norharman (5) were isolated from the culture broth of Streptomyces sp. C011. Their structures were determined by spectral data analysis, including MS, 2D NMR, and CD spectrum. All the separated compounds were evaluated for their antimicrobial activities. Compounds 1, 2, 3 and 5 exhibited antimicrobial activity.