Publications by authors named "Ek Sangvichien"

The undescribed phosphatidylcholine (), along with twelve known compounds, was isolated from the cultures of white rot fungus PP17-20. In this work the fungus was cultivated in Yeast-Malt extract medium to explore active compound production. The chemical structures were elucidated on the basis of spectroscopic and HRESIMS data.

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A new eremophilane sesquiterpene, named engleromophilane () together with known eremoxylarin E () and steroids (-) were isolated from the fungus culture. The structures were deduced by the analysis of spectroscopic and MS data, together with the comparison of calculated C NMR chemical shifts and Electronic Circular Dichroism (ECD) spectra. Compound showed cytotoxic effects against Hela, PC-3, HT29 and A549 cell lines with IC in the ranges of 4.

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The rapid emergence of resistant bacteria is occurring worldwide, endangering the efficacy of antibiotics. Hence, there is a need to search for new sources of antibiotics that either exhibit novel structures or express a new mechanism of action. The lichen , with its wide range of unique, biologically potent secondary metabolites, may solve this problem.

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The Xylariaceae and its relatives rank as one of the best-known members of the Ascomycota. They are now well recognized for their diversity, global distribution, ecological activities and their outstanding novel metabolites with wide ranging bioactivity.

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In the continuing discovery and structure elucidation of natural xanthone dimers, which are still rarely reported in absolute configuration, three new xanthone dimers, eumitrins I-K (1-3) were isolated from the lichen Usnea baileyi, a rich source of natural xanthone dimers. Their structures were elucidated unambiguously by spectroscopic analyses, including high-resolution electrospray ionization mass spectrometry (HRESIMS), 1D and 2D nuclear magnetic resonance spectroscopy (1D and 2D NMR). The absolute configuration of all three compounds was established through DP4 probability and ECD calculation.

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Chromatographic purification of the CHCl extract of Myristica fragrans seeds provided 19 known compounds, four dihydrofuran neolignans, licarines A, B and maceneolignans A, B were among the isolates. Prior to hydrogenation, in order to obtain their di- and tetrahydrogenated products, the absolute configuration of these compounds was thoroughly investigated based on their optical rotations and ECD spectra. This report provides evidences concerning the disagreement between the use of an aromatic quadrant rule and time-dependent density function theory calculation for the prediction of the absolute configurations at C-7 and C-8 in these dihydrobenzofuran neolignans.

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Article Synopsis
  • The text talks about how some organisms, like fungi and cyanobacteria, work together in a friendship called mutualism, which makes them evolve slower than if they were fighting each other (like the Red Queen dynamic).
  • Researchers studied about 2000 genes in different types of fungi, including those that form lichen (a plant-like mix of fungus and algae) and those that don’t.
  • They found that lichen-forming fungi evolve slower because they have longer life cycles, and this discovery helps us understand how organisms can influence each other's evolution when they work together.
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The lichen is a fruticose lichen belonging to the . It is well known as a rich source of natural xanthone dimers and possesses various bioactivities. Nevertheless, the chemical investigation on this type of lichen is still rare as most of researches reported its components without structural elucidation.

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The isopimarane diterpene, 1α,11α-dihydroxyisopimara-8(14),15-diene (1), is the major constituents from the rhizomes of Kaempferia marginata (Zingiberaceae), a Thai medicinal plant. The microbial transformation of parent compound 1 by the fungus Cunninghamella echinulata NRRL 1386 gave five new metabolites, 7α,11α-dihydroxy-1-oxoisopimara-8(14),15-diene (2), 3β,7α,11α-trihydroxy-1-oxoisopimara-8(14),15-diene (3), 7β,11α-dihydroxy-1-oxoisopimara-8(14),15-diene (4), 7α-hydroxy-1,11-dioxoisopimara-8(14),15-diene (5) and 1α,7β,11α-trihydroxyisopimara-8(14),15-diene (6), together with three known metabolites, 7-9. The structures of the new metabolites were elucidated by spectroscopic techniques.

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Luangsuphabool, Lumbsch & Sangvichien is described for a crustose lichen occurring in dry evergreen forest in Thailand. It is characterised by a green to yellow-green corticated thallus, perithecia fused in black pseudostromata with white rim surrounding the ostiole and small, hyaline and muriform ascospores. Currently, all species in the genus have transversely septate ascospores, hence the discovery of this new species indicates that ascospore septation is variable within the genus, similar to numerous other groups of lichen-forming ascomycetes.

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A total of 292 lichen samples, representing over 200 species and at least 65 genera and 26 families, were collected, mainly in Thailand; 170 of the specimens discharged ascospores in the laboratory. Generally, crustose lichens exhibited the highest discharge rates and percentage germination. In contrast, foliose lichen samples, although having a high discharge rate, had a lower percentage germination than crustose species tested.

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Four xanthones were isolated from mycelia of Emericella variecolor, an endophytic fungus isolated from the leaves of Croton oblongifolius. Their structures were elucidated by spectroscopic analysis to be shamixanthone, 14-methoxytajixanthone-25-acetate, tajixanthone methanoate, and tajixanthone hydrate. All compounds were tested for cytotoxic activity against various human tumor cell lines including gastric carcinoma, colon carcinoma, breast carcinoma, human hepatocarcinoma, and lung carcinoma.

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