Flavonoids and alkaloids from marine-derived Actinomycete Streptomyces sp. C011

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...