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Bioactive Cyclopentenone Derivatives from Marine Isolates of Fungi
Zhile Feng,Alain S. Leutou,Guohua Yang,Viviane N. Nenkep,Xavier N. Siwe,Byeng Wha Son,Hong Dae Choi,강정숙 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.10
As part of an effort to discover bioactive natural products from marine sources, we investigated the bioactive secondary metabolites from two marine isolates of the fungi, Trichoderma viride and Rhizopus stolonifer. Three cyclopentenones, myrothenones A (1) and B (2) and trichodenone A (3), were isolated from T. viride and two cyclopentenones, 2-bromomyrothenone B (4) and botrytinone (5), were isolated from R. stolonifer. The molecular structures and absolute stereochemistries of the cyclopentenones were determined from chemical and physicochemical evidence, including quantum chemistry calculations, X-ray analysis, and the circular dichroism (CD) exciton chirality method. Myrothenone A (1) displays tyrosinase inhibitory activity, with an IC50 value of 6.6 μM,and is therefore more active than the positive control, kojic acid.
Zhiling He,Guangyi Liu,Xianglin Yang,Wei Liu 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.37 No.-
In this paper, a novel surfactant, N,N-diethyl-N0-cyclohexylthiourea (DECHTU) was synthesized and firstintroduced as a collector for chalcopyrite flotation. The micro-flotation results demonstratedchalcopyrite with adsorbed DECHTU exhibited good hydrophobicity and was effectively concentratedby nitrogen bubbles under pH 4–8. The adsorption of DECHTU onto chalcopyrite surfaces was fitted wellby the pseudo-second-order model and Langmuir isotherm, and was a spontaneously exothermicchemisorption process. The adsorption enthalpy change, entropy change and free energy change wereDH = 31.10 kJ mol 1, DS = 6.32 J mol 1 and DG (298 K) = 29.41 kJ mol 1, respectively. The activa-tion energy of the adsorption process was 17.39 kJ mol 1. The zeta potential results implied thatDECHTU adsorbed onto chalcopyrite surfaces as its anionic species with the release of H+ ion of NH–C(55S)–N group into aqueous solutions. The XPS spectra confirmed that there existed Cu(I)–DECHTUsurface complexes on chalcopyrite surface by bonding of copper atom with the sulfur atom of DECHTU,accompanying with the reduction of cupric to cuprous.
Bioactive Cyclopentenone Derivatives from Marine Isolates of Fungi
Feng, Zhile,Leutou, Alain S.,Yang, Guohua,Nenkep, Viviane N.,Siwe, Xavier N.,Choi, Hong-Dae,Kang, Jung-Sook,Son, Byeng-Wha Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.10
As part of an effort to discover bioactive natural products from marine sources, we investigated the bioactive secondary metabolites from two marine isolates of the fungi, Trichoderma viride and Rhizopus stolonifer. Three cyclopentenones, myrothenones A (1) and B (2) and trichodenone A (3), were isolated from T. viride and two cyclopentenones, 2-bromomyrothenone B (4) and botrytinone (5), were isolated from R. stolonifer. The molecular structures and absolute stereochemistries of the cyclopentenones were determined from chemical and physicochemical evidence, including quantum chemistry calculations, X-ray analysis, and the circular dichroism (CD) exciton chirality method. Myrothenone A (1) displays tyrosinase inhibitory activity, with an I$C_{50}$ value of 6.6 ${\mu}M$, and is therefore more active than the positive control, kojic acid.
Molecular mechanisms of 1,2-dichloroethane-induced neurotoxicity
Xiang Yang,Zhang Xiaoshun,Tian Zhiling,Cheng Yibin,Liu Ningguo,Meng Xiaojing 한국독성학회 2023 Toxicological Research Vol.39 No.4
The production of industrial solvents and adhesives often utilizes 1,2-dichloroethane (1,2-DCE), a highly toxic halogenated hydrocarbon compound. Occupational 1,2-DCE poisoning occurs frequently and is a public health concern. Exposure to 1,2-DCE can damage the brain, liver, and kidneys. The main and most severe damage caused by exposure to 1,2-DCE is to the nervous system, especially the central nervous system. Current research on 1,2-DCE mainly focuses on the mechanism of brain edema. Several possible mechanisms of 1,2-DCE neurotoxicity have been proposed, including oxidative stress, calcium overload, blood–brain barrier damage, and neurotransmitter changes. This article reviews the research progress on 1,2-DCE neurotoxicity and the mechanism behind it to provide a scientific basis for the prevention and treatment of 1,2-DCE poisoning.
Guohua Yang,Xavier N. Siwe,Alain S. Leutou,Zhile Feng,장대해,Hong Dae Choi,강정숙,손병화,Viviane N. Nenkep 한국생약학회 2009 Natural Product Sciences Vol.15 No.3
The crude extract of the mycelium of Cladosporium was found to exhibit antimicrobial activity against the Staphylococcus aureus, methicillin-resistant S. aureus, and multidrug-resistant S. aureus. Bioassayguided fractionation of an organic extract led to the isolation of an acetophenone derivative, clavatol (2',4'- dihydroxy-3',5'-dimethylacetophenone) (1), and a benzodiazepine alkaloid, circumdatin A (2). Compound 1 showed moderate antibacterial activity against S. aureus, methicillin-resistant S. aureus, and multidrug-resistant S. aureus with minimum inhibitory concentration (MIC) values of 62.5, 62.5, 31.0 µg/mL, respectively, but compound 2 was inactive. Compounds 1 and 2 exhibited UV-A protection activity with ED50 values of 227.0 and 82.0 µM, respectively, indicating that they were more potent than the positive control, oxybenzone (ED50 350 µM), a common sunscreen agent.
Li Huogen,Yang Xu,Yang Zhiling 한국식물학회 2018 Journal of Plant Biology Vol.61 No.3
Houpoëa officinalis is a traditional Chinese medicalplant, which has significantly declined in the past decadesbecause of human influence and habitat fragmentation. Twelveexpressed sequence tag SSR (EST-SSR) markers developedfrom the EST sequence of H. officinalis were used to analysethe genetic diversity and structure of fourteen naturalpopulations. The results indicated that moderate geneticdiversity and high genetic differentiation existed in this plant(Ho = 0.600, Fst = 0.327). STRUCTURE and UPGMAanalyses showed that H. officinalis populations could bedivided into 3 different groups, and the west group hadhigher genetic diversity than the central and east groups. Thehistorical migration rates among the groups were low andunsymmetrical, and there was no significant correlation betweenNei’s genetic distance and geographic distance. According to thegenetic consequences, conservation strategies (in situ or ex situ,artificial pollination) should be carried out in all populationsto preserve genetic diversity.