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Helvolic Acid Derivatives with Antibacterial Activities against Streptococcus agalactiae from the Marine-Derived Fungus Aspergillus fumigatus HNMF0047.

Authors :
Kong FD
Huang XL
Ma QY
Xie QY
Wang P
Chen PW
Zhou LM
Yuan JZ
Dai HF
Luo DQ
Zhao YX
Source :
Journal of natural products [J Nat Prod] 2018 Aug 24; Vol. 81 (8), pp. 1869-1876. Date of Electronic Publication: 2018 Aug 02.
Publication Year :
2018

Abstract

Streptococcus agalactiae is a hazardous pathogen that can cause great harm to humans and fish. In the present study, the known fungal metabolite helvolic acid (10), seven new helvolic acid derivatives named 16- O-deacetylhelvolic acid 21,16-lactone (2), 6- O-propionyl-6,16- O-dideacetylhelvolic acid 21,16-lactone (3), 1,2-dihydro-6,16- O-dideacetylhelvolic acid 21,16-lactone (4), 1,2-dihydro-16- O-deacetylhelvolic acid 21,16-lactone (5), 16- O-propionyl-16- O-deacetylhelvolic acid (6), 6- O-propionyl-6- O-deacetylhelvolic acid (7), and 24- epi-6β,16β-diacetoxy-25-hydroxy-3,7-dioxo-29-nordammara-1,17(20)-diene-21,24-lactone (9), and two known ones (1 and 8) were isolated from the marine-derived fungus Aspergillus fumigatus HNMF0047 obtained from an unidentified sponge from Wenchang Beach, Hainan Province, China. The structures and the absolute configurations of the new compounds were unambiguously elucidated by spectroscopic data and electronic circular dichroism (ECD) spectroscopic analyses along with quantum ECD calculations. In addition, the spectroscopic data of compound 1 are reported here for the first time, the configuration of C-24 of known compound 8 was revised based on comparison of its ROESY data with its C-24 epimer 9, and the absolute configuration of 8 was also determined for the first time. Compounds 6, 7, and 10 showed stronger antibacterial activity than a tobramycin control against S. agalactiae with MIC values of 16, 2, and 8 μg/mL, respectively.

Details

Language :
English
ISSN :
1520-6025
Volume :
81
Issue :
8
Database :
MEDLINE
Journal :
Journal of natural products
Publication Type :
Academic Journal
Accession number :
30070829
Full Text :
https://doi.org/10.1021/acs.jnatprod.8b00382