Two new cyclopiane diterpenes and a new cladosporin precursor, together with four known related compounds, were isolated from the marine sediment-derived fungus KMM 4670, which was re-identified based on phylogenetic inference from ITS, , , and gene regions. The absolute stereostructures of the isolated cyclopianes were determined using modified Mosher's method and quantum chemical calculations of the ECD spectra. The isolation from the natural source of two biosynthetic precursors of cladosporin from a natural source has been reported for the first time.
View Article and Find Full Text PDFIn this study, we isolated a new isoflavanostilbene maackiapicevestitol () as a mixture of two stable conformers and as well as five previously known dimeric and monomeric stilbens: piceatannol (), maackin (), scirpusin A (), maackiasine (), and maackolin () from heartwood, using column chromatography on polyamide, silicagel, and C-18. The structures of these compounds were elucidated by NMR, HR-MS, and CD techniques. Maksar obtained from heartwood and polyphenolics - possessed moderate anti-HSV-1 activity in cytopathic effect (CPE) inhibition and RT-PCR assays.
View Article and Find Full Text PDFFour new diketopiperazine alkaloids, citriperazines A-D were isolated from algae-derived sp. KMM 4672. The structures of compounds were determined using spectroscopic methods.
View Article and Find Full Text PDFAn investigation of the oxidative coupling products of some substituted hydroxynaphthazarins led to a revision of the proposed structure of islandoquinone, previously isolated from the lichen Cetraria islandica, and yielding (7aS*, 13aS*)-6,7a-diethyl-2,5,9,11,12,13a-hexahydroxy-7, 4-dioxabenzo[a]tetracene-1,4,8,13(7aH, 13aH)-tetraone through X-ray diffraction analysis of its 2,11-dimethyl ether.
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