New Polyphenols from a Deep Sea Spiromastix sp. Fungus, and Their Antibacterial Activities

Abstract

Eleven new polyphenols namely spiromastols A–K (1–11) were isolated from the fermentation broth of a deep sea-derived fungus Spiromastix sp. MCCC 3A00308. Their structures were determined by extensive NMR data and mass spectroscopic analysis in association with chemical conversion. The structures are classified as diphenyl ethers, diphenyl esters and isocoumarin derivatives, while the n-propyl group in the analogues is rarely found in natural products. Compounds 1–3 exhibited potent inhibitory effects against a panel of bacterial strains, including Xanthomanes vesicatoria, Pseudomonas lachrymans, Agrobacterium tumefaciens, Ralstonia solanacearum, Bacillus thuringensis, Staphylococcus aureus and Bacillus subtilis, with minimal inhibitory concentration (MIC) values ranging from 0.25 to 4 µg/mL. The structure-activity relationships are discussed, while the polychlorinated analogues 1–3 are assumed to be a promising structural model for further development as antibacterial agents.

Hansforesters A–M, polyesters from the sponge-associated fungusHansfordia sinuosaewith antibacterial activities

“…The tests for antibacterial effects of compounds were performed by the broth microdilution method. 10,11 Four Gram-negative agricultural pathogenic bacterial strains (Pseudomonas lachrymans ATCC11921, Agrobacterium tumefaciens ATCC11158, ) and carbonyl (1713 cm À1 ) groups. The 1 H NMR data exhibited six phenolic protons in the range of 9.10-10.93 ppm, seven aromatic protons ranging from 6.05 to 6.18 ppm, four oxymethine, four methyl doublets, and a number of alkyl protons ( Table 2).…”

“…2) established the substructure from unit B to unit E to be identical to those of 1. The signicant difference was attributed to the substituent in unit A, in which a (E)-pent-3-en-2-one moiety to replace a methyl group of 1 was recognized by the COSY relationships from the olenic proton H- 11 . The substitution of this moiety at C-6 (d C 139.7) was evident from the HMBC correlations from H 2 -8 to C-5 (d C 112.9), C-6, and C-1 (d C (Fig.…”

New Resorcinol Derivatives from a Sponge‐Derived Fungus Hansfordia sinuosae

“…The NMR data of the aromatic nucleus in 4 were identical to those of 1, and the NMR data of their side chains were also mostly similar. The differences were attributed to the two additional olefinic (20), together with the HMBCs from CH 2 (7) to C(1), C(2), C(6); Me(23) to C(21), C(22); CH 2 (19) to C (22) and CH 2 (20) to C(22) gave the structure of the side chain, and the two olefinic double bond were located at D 14 and D 17 (Fig. 4).…”

“…The HMBCs from CH 2 (7) to C(1)/C(2)/C(6) indicated the alkyl side chain was located at C(1). The 1 H, 1 H-COSY correlations between CH 2 (21)/H-C(22) and CH 2 (21)/Me(23) gave the terminal structure of the side chain, and the OH group was located at C (22) (Fig. 2).…”

“…[19] [20] Antibacterial Assay Antibacterial activities were measured against a panel of bacterial strains, including P. lachrymans ATCC11921, A. tumefaciens ATCC11158, X. vesicatoria ATCC 11633, R. solanacearum ATCC 11696, B. subtilis CMCC 63501, and B. thuringensis ATCC 10792 by the broth microdilution method. [21] [22] Antioxidant Assays…”