Qing-He Liu

Chosun University, Gwangju, Gwangju, South Korea

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Publications (8)13.06 Total impact

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    ABSTRACT: The phytochemical (+)-Medioresinol, a furofuran type lignan identification and isolation on the stem bark of Sambucus williamsii, which is a folk medicinal plant used in traditional medicine. (+)-Medioresinol is known to possess a lesishmanicidal activity and cardiovascular disease risk reduction but its antifungal effects have not yet been identified. In this study, to confirm (+)-Medioresinol's antifungal properties and mode of action, we observed morphological and physiological change in Candida albicans. In cells exposed to (+)-Medioresinol, arrested the cell cycle and intracellular reactive oxygen species (ROS) which is a major cause of apoptosis were increased. The increase of ROS induced oxidative stress and the mitochondria dysfunction which causes release of pro-apoptotic factors. We investigated a series of characteristic cellular changes of apoptosis by using various apoptosis detection methods. We report here for the first time that (+)-Medioresinol has effects on mitochondria and induced the accumulation of ROS in C. albicans cells. We demonstrated that one of the important features of apoptosis, mitochondrial membrane depolarization is caused by ROS. Substantially, we investigated the release of cytochrome c, which is one of the factors of metacaspase activity. We also show that the effects of (+)-Medioresinol are mediated at an early stage in apoptosis acting on the plasma membrane phosphatidylserine externalization. In addition, (+)-Medioresinol induced apoptotic morphological changes, showing the reduced cell size (low FSC) and enhanced intracellular density (high SSC). In late stage of confirmation of diagnostic markers in yeast apoptosis include the effects of nucleus morphological change, DNA fragmentation and condensation by influence of oxidative stress. These apoptotic phenomena represent that oxidative stress and mitochondria dysfunctions by inducing the phytochemical (+)-Medioresinol must be an important factors of the apoptotic process in C. albicans. These results support the elucidation of the underlying antifungal mechanisms of (+)-Medioresinol.
    Biochimie 04/2012; 94(8):1784-93. · 3.14 Impact Factor
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    ABSTRACT: In this study, we investigated the antifungal activity and mechanism of action of (+)-pinoresinol, a biphenolic compound isolated from the herb Sambucus williamsii,used in traditional medicine. (+)-Pinoresinol displays potent antifungal properties without hemolytic effects on human erythrocytes. To understand the antifungal mechanism of (+)-pinoresinol, we conducted fluorescence experiments on the human pathogen Candida albicans. Fluorescence analysis using 1,6-diphenyl-1,3,5-hexatriene (DPH) indicated that the (+)-pinoresinol caused damage to the fungal plasma membrane. This result was confirmed by using rhodamine-labeled giant unilamellar vesicle (GUV) experiments. Therefore, the present study indicates that (+)-pinoresinol possesses fungicidal activities and therapeutic potential as an antifungal agent for the treatment of fungal infectious diseases in humans.
    Molecules 05/2010; 15(5):3507-16. · 2.43 Impact Factor
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    ABSTRACT: Key Words: Patrinia scabiosaefolia, Valerianaceae, 1-Isovaleryloxy-3,8-dimethyloxy-4-(3-methyl-butyr-yloxymethyl)-8-hydroxymethyl-cyclopenta-4,6-diene[c]pyran; patriscadoid I (1), 1-Isovaleryloxy-3-meth-yloxy-4-(3-methyl-butyryloxymethyl)-8-hydroxymethyl-8-hydroxy-cyclopenta-4,6-diene[c]pyran; patrisca-doid II (2), Iridoid Patrinia scabiosaefolia Fischer (Valerianaceae) is a perennial plant distributed across mountainous regions and fields of Korea, Japan and China. 1 The roots of P. scabiosaefolia have been widely used in traditional medicine for the treatment of edema, appendicitis and inflammation. 2 Previous phytoche-mical work on the roots as well as aerial parts of P. scabiosae-folia has resulted in the isolation of saponins, 3-5 coumarins, 6
    Bulletin of the Korean Chemical Society 06/2009; 30. · 0.84 Impact Factor
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 01/2009; 40(45).
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    ABSTRACT: We recently isolated a novel lignan, 4-hydroxykobusin from Geranium thunbergii (Liu et al., Arch. Pharm. Res., 29, 1109-1113, 2006). Here, we studied its effect on the expression of inducible nitric oxide synthase (iNOS) gene in RAW264.7 cells. 4-Hydroxykobusin inhibited nitric oxide (NO) production in a concentration-dependent manner and blocked the lipopolysaccharide (LPS)-induced expression of inducible nitric oxide synthase (iNOS). To identify the mechanistic basis for its inhibition of iNOS induction, we examined the effect of 4-hydroxykobusin on the transactivation of iNOS gene by luciferase reporter activity using -1.59 kb flanking region. The lignan suppressed the reporter gene activity and the LPS-induced reporter activations of nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) were also significantly blocked by 4-hydroxykobusin. These findings suggest that the inhibition of LPS-induced NO formation by 4-hydroxykobusin is due to its inhibition of NF-kappaB and AP-1 activation.
    Biological & Pharmaceutical Bulletin 07/2007; 30(6):1097-101. · 1.85 Impact Factor
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    ABSTRACT: This study isolated a lignan, 7,7'-dihydroxy bursehernin, from Geranium thunbergii and investigated whether or not the lignan affects the induction of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in RAW264.7 macrophages stimulated with lipopolysaccharide (LPS). The gel shift analysis and luciferase reporter gene assays using the iNOS promoter and nuclear factor-kappaB (NF-kappaB) minimal promoter showed that a treatment with 7,7'-dihydroxy bursehernin reduced the reporter activities and binding of NF-kappaB to the NF-kappaB consensus sequence, while it had no effect on the nuclear translocation of p65 and the phosphorylation/degradation of I-kappaBalpha. It was reported that a few natural compounds directly suppressed the binding activity of the NF-kappaB components to DNA. The NF-kappaB binding activity was not reversed by the in vitro exposure of the nuclear extracts to 7,7'-dihydroxy bursehernin, which suggest that a metabolite(s) of 7,7'-dihydroxy bursehernin might target the binding of the NF-kappaB complex to the DNA binding domain region in the promoter region of the iNOS gene. After incubation of RAW264.7 cells with 7,7-dihydroxy bursehernin for 18h, the levels of parent compound were negligible; while a main metabolite, 4-[4-(n-hydroxy-phenyl)-2,3-dimethyl-buta-1,3-dienyl]-benzene-1,2-diol was detected in cell lysates and culture medium.
    Nitric Oxide 04/2007; 16(2):274-85. · 3.27 Impact Factor
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    ABSTRACT: A new furofuran lignan, 4-hydroxykobusin (3), together with known lignans, kobusin (1), and 7,7'-dihydroxybursherenin (2), were isolated from the whole plant of Geranium thunbergii Sieb. et Zucc (Geraniaceae). The structures were determined based on the spectral data and a comparison with the published data. This is the first report of the presence of furofuran lignan in Geranium species.
    Archives of Pharmacal Research 01/2007; 29(12):1109-13. · 1.54 Impact Factor
  • Biological & Pharmaceutical Bulletin - BIOL PHARM BULL. 01/2007; 30(6):1097-1101.