Abstract
Tunicamycin E (1), featuring a methyl substitution at C-10′, was isolated from marine-derived Streptomyces xinghaiensis SCSIO S15077 originated from the South China Sea sediment together with six known compounds, tunicamycin B (2), tunicamycin X (3), tunicamycin A (4), streptovirudin D2 (5), tunicamycin C (6), and tunicamycin C3 (7). The structure of compound 1 was elucidated by detailed spectroscopic data analyses. All the compounds exhibited strong to moderate antibacterial activity against Gram-positive bacteria Bacillus thuringiensis BT01 and B. thuringiensis W102 with MIC values ranging from 0.008 to 2 μg/mL. Moreover, compounds 1–7 exhibited moderate antifungal activity against Candida albicans ATCC 96901 and C. albicans CMCC (F) 98001 with MIC values ranging from 2 to 32 μg/mL. This is the first report that tunicamycins exhibit antimicrobial activities against B. thuringiensis, C. albicans CMCC (F) 98001 and a fluconazole resistant strain C. albicans ATCC 96901.
Graphical Abstract
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Acknowledgements
This study was supported in part by the National Natural Science Foundation of China (81425022, U1501223 and U1706206), and Natural Science Foundation of Guangdong Province (2016A030312014). We thank Dr. Xiao, Ms. Sun, Ms. Zhang, Ms. Ma, and Mr. Li in the analytical facility at SCSIO for recording spectroscopic data.
Disclosure statement
No potential conflict of interest was reported by the authors.