Affiliation:
1. Collaborative Innovation Center of Ecological Civilization, School of Chemistry and Chemical Engineering, Hainan University, Haikou 570228, China
2. Institute of Applied Chemistry, Jiangxi Academy of Sciences, Nanchang 330096, China
3. Institute Research and Utilization on Seaweed Biological Resources, Key Laboratory of Haikou, Hainan University, Haikou 570228, China
Abstract
Five new naphthalene derivatives dalesconosides A–D, F (1–4, 6), a known synthetic analogue named dalesconoside E (5), and eighteen known compounds (7–24) were isolated from Daldinia eschscholzii MCZ-18, which is an endophytic fungus obtained from the Chinese mangrove plant Ceriops tagal. Differing from previously reported naphthalenes, compounds 1 and 2 were bearing a rare ribofuranoside substituted at C-1 and the 5-methyltetrahydrofuran-2,3-diol moiety, respectively. Their structures were determined by detailed nuclear magnetic resonance (NMR) and mass spectroscopic (MS) analyses, while the absolute configurations were established by theoretical electronic circular dichroism (ECD) calculation. Compounds 1, 3, 13–17 and 19 showed broad ranges of antimicrobial spectrum against five indicator test microorganisms (Enterococcus faecalis, Methicillin-resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans); especially, 1, 16 and 17 were most potent. The variations in structure and attendant biological activities provided fresh insights concerning structure−activity relationships for the naphthalene derivatives.
Funder
National Natural Science Foundation of China
Key Research Program of Hainan Province
Collaborative Innovation Center Foundation of Hainan University
Guangdong Key Laboratory of Marine Materia Medica Open Fund