Phomopsichin A–D; Four New Chromone Derivatives from Mangrove Endophytic Fungus Phomopsis sp. 33#

Abstract

Four new chromone derivatives, phomopsichins A–D (1–4), along with a known compound, phomoxanthone A (5), were isolated from the fermentation products of mangrove endophytic fungus Phomopsis sp. 33#. Their structures were elucidated based on comprehensive spectroscopic analysis coupled with single-crystal X-ray diffraction or theoretical calculations of electronic circular dichroism (ECD). They feature a tricyclic framework, in which a dihydropyran ring is fused with the chromone ring. Compounds 1–5 showed weak inhibitory activities on acetylcholinesterase as well as α-glucosidase, weak radical scavenging effects on 1,1-diphenyl-2-picrylhydrazyl (DPPH) as well as OH, and weak antimicrobial activities. Compounds 1–4 showed no cytotoxic activity against MDA-MB-435 breast cancer cells. Their other bioactivities are worthy of further study, considering their unique molecular structures.

Chroman-4-one and pyrano[4,3-b]chromenone derivatives from the mangrove endophytic fungus Diaporthe phaseolorum SKS019

“…The molecular formula of C 16 H 16 O 7 was determined on the basis of (À)-HRESIMS m/z 319.0818 [M À H] À , representing nine degrees of unsaturation. The 1 H and 13 C NMR data (Table 3) of 5a were the same as the known phomopsichin A (5b), 9 which was previously isolated from mangrove endophytic fungus phomopsis sp. 33#.…”

“…Detailed analysis of the 1 H and 13 C NMR data (Table 3) of 6a indicated that the 1 H and 13 C NMR data of 6a were the same as phomopsichin B (6b). 9 As seen in compounds 5a and 5b, the optical rotation value [a] 25 D +16 (c 0.4, MeOH) of 6a was opposite to that of phomopsichin B (6b). Moreover, compounds 6a and 6b presented the reverse ECD absorption curves (Fig.…”

“…Compound 5b and 6b were identied as (+)-phomopsichin A (5b) and (À)-phomopsichin B (6b), respectively, by comparisons of the MS and NMR data with those previously reported. 9 Compound 1 was isolated as a brown powder. Its molecular formula was assigned as C 15 , and one methyl (d C 31.0) carbons.…”

“…Until now, only one 3-substituted-chroman-4-one compound and nine pyrano [4,3-b]chromenone analogues were found in nature. 9,10 Marine-derived fungi are widely recognized as prolic sources of biologically active and structurally unique natural products. 3,11 As part of our ongoing investigation on bioactive metabolites from mangrove endophytic fungi, [12][13][14][15][16][17] a chemical investigation of the mangrove endophytic fungus Diaporthe phaseolorum SKS019, isolated from a fresh branch of the mangrove plant Acanthus ilicifolius, was carried out.…”

Identification and Antifungal Activity of Compounds from the Mangrove Endophytic Fungus Aspergillus clavatus R7

“…269.0420). The characteristic UV absorption maxima at 229, 242, 263, 345 nm suggested the presence of a chromone pattern in 5 [ 16 , 17 ]. The 1 H and 13 C NMR spectral data of 5 are listed in Table 2 .…”