Muyocopronones A and B: azaphilones from the endophytic fungus Muyocopron laterale

Abstract

Two new azaphilones, namely muyocopronones A (1) and B (2), were isolated from the cultures of an endophytic fungus Muyocopron laterale ECN279. Their structures were elucidated by extensive spectroscopic analysis. Their absolute configurations were determined using the modified Mosher’s method and through comparisons of experimental and calculated electronic circular dichroism data. In addition, muyocopronone B (2) was found to exhibit a weak antibacterial activity against some Gram-positive bacteria.

Recent Findings in Azaphilone Pigments

“…YE3033, and active against A/Puerto Rico/8/34 (H1N1) in CPE assay (IC 50 0.80 µg/mL) with low cellular toxicity on MDCK cells (CC 50 184.75 µg/mL) [62]. In vitro HIV-1 replication inhibitory effects in C8166 cells were demonstrated for Helotialins A and B (EC 50 8.01 and 27.9 nM, respectively) [63]. In 2019, comazaphilone D was reported as a non-competitive inhibitor of neuraminidase from recombinant rvH1N1 (IC 50 30.9 µM) while rubiginosin A was active against H5N1 (IC 50 29.9 µM) [64].…”

“…The chemical investigation of the endophyte Muyocopron laterale ECN279 isolated from a health leaf of Conavalia lineata led to the isolation of the two new azaphilones muyocopronones A and B ( 54–55 ) [ 50 ]. An endophyte fungus F53 from the traditional Chinese medicine plant Taxus yunnanensis had its genome sequenced and mined, and the multi-locus phylogeny of F53 allowed its placement within the genus Muyocopron with its closest relative being Muyocopron atromaculans (MUCL 34983) [ 51 ].…”

“…A great number of azaphilones present anti-inflammatory activity [ 35 , 37 , 38 , 42 , 49 , 50 , 52 , 53 , 58 , 59 ]. The compounds ( 21 ), ( 51 ), ( 52 ) and ( 100 ) exhibited anti-inflammatory activities due to potent anti-NO production activity, with IC 50 values of 11.9, 2.6, 12.5, and 10.0 μM, respectively, compared to the known iNOS inhibitor quercetin (34.6 ± 1.4 μM) on lipopolysaccharide (LPS) -induced nitric oxide (NO) production [ 35 , 46 , 57 ].…”

“…The compounds ( 54–55 ) also presented a 2,4-dimethyl-3-hydroxyhexanoate moiety that was reported in only eight compounds in this genus. The cyclohexanone ring and 2,4-dimethyl-3-hydroxyhexanoate moiety might be biomarkers of the Dothideomycetes class and constitute a noteworthy point to be more investigated [ 50 ].…”

“… Chemical structures of Monascus and Muyocopron azaphilones: 51 : monapilonitrile; 52 : monapilosine; 53 : N-ethanolic monapilosine; and Muyocopron azaphilones: 54–55 : muyocoprones A and B; 56 : lijiquinone 1 [ 50 , 51 ]. …”