Chalcomycins from Marine-Derived Streptomyces sp. and Their Antimicrobial Activities
Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy/Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine & New Drug Research, Jinan University, Guangzhou 510632, China
Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Wuhan University, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China
Food and Drug Department, Qingyuan Polytechnic, Qingyuan 511510, China
Authors to whom correspondence should be addressed.
These authors have contributed equally to this work.
Mar. Drugs 2017, 15(6), 153; https://doi.org/10.3390/md15060153
Received: 8 March 2017 / Revised: 10 May 2017 / Accepted: 22 May 2017 / Published: 29 May 2017
(This article belongs to the Special Issue Antibacterial Marine Pharmacology)
Dihydrochalcomycin (1) and chalcomycin, (2), two known chalcomycins, and chalcomycin E (3), a new compound, were isolated from marine-derived Streptomyces sp. HK-2006-1. Their structures were elucidated by detailed spectroscopic and X-ray crystallographic analysis. The antimicrobial activities against Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus niger of 1–3 were evaluated. Compounds 1–2 exhibited activities against S. aureus with minimal inhibitory concentrations (MICs) of 32 µg/mL and 4 µg/mL, respectively. The fact that 1–2 showed stronger activity against S. aureus 209P than 3 indicated that the epoxy unit was important for antimicrobial activity. This structure–activity tendency of chalcomycins against S. aureus is different from that of aldgamycins reported in our previous research, which provide a valuable example for the phenomenon that 16-membered macrolides with different sugars do not have parallel structure–activity relationships.