Abstract
The actinomycete strainStreptomyces coelicolorLY001 was purified from the spongeCallyspongia siphonella. Fractionation of the antimicrobial extract of the culture of the actinomycete afforded three new natural chlorinated derivatives of 3-phenylpropanoic acid, 3-(3,5-dichloro-4-hydroxyphenyl)propanoic acid (1), 3-(3,5-dichloro-4-hydroxyphenyl)propanoic acid methyl ester (2), and 3-(3-chloro-4-hydroxyphenyl)propanoic acid (3), together with 3-phenylpropanoic acid (4),E-cinnamic acid (5), and the diketopiperazine alkaloids cyclo(l-Phe-trans-4-OH-l-Pro) (6) and cyclo(l-Phe-cis-4-OH-d-Pro) (7) were isolated. Interpretation of nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectrometry (HRESIMS) data of1-7supported their assignments. Compounds1-3are first candidates of the natural chlorinated phenylpropanoic acid derivatives. The production of the chlorinated derivatives of 3-phenylpropionic acid (1-3) byS. coelicolorprovides insight into the biosynthetic capabilities of the marine-derived actinomycetes. Compounds1-3demonstrated significant and selective activities towardsEscherichia. coliandStaphylococcus aureus, whileCandida albicansdisplayed more sensitivity towards compounds6and7, suggesting a selectivity effect of these compounds againstC. albicans.