Hao Liu

China Agricultural University, Beijing, Beijing Shi, China

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Publications (10)16.4 Total impact

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    ABSTRACT: Ustiloxins are cyclopeptide mycotoxins produced by the pathogenic fungus Villosiclava virens of rice false smut. Ustiloxins A and B as two main mycotoxins were determined conveniently by LC-ESI-MS in the water extract from rice false smut balls which were mostly composed of the chlamydospores and mycelia of the pathogen. Both ustiloxins A and B in the water extract were also quantitatively analyzed by HPLC. This is the first report on the determination and analysis of ustiloxins A and B simultaneously by LC-ESI-MS and HPLC in false smut balls of rice.
    International Journal of Molecular Sciences 01/2012; 13(9):11275-87. · 2.46 Impact Factor
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    ABSTRACT: The essential oil obtained by hydro-distillation from the flowers of Halimondendron halodendron (Leguminosae) was analyzed for its chemical composition by gas chromatography-mass spectrometry (GC-MS). Undecane (16.4%), dodecane (15.3%), tridecane (12.5%), decane (8.2%), 6,10,14-trimethyl-pentadecan-2-one (6.3%), methyl palmitate (6.0%), methyl linolenate (4.1%) and ethylcyclohexane (4.1%) were the major compounds of the thirty-five identified components of the oil. The essential oil was shown to have a broad spectrum of antimicrobial activity with MIC values ranging from 100 to 250 microg/mL, and IC50 values from 40.4 to 193.8 microg/mL. The oil also showed strong antioxidant activity, with an especially high metal chelating capacity of ferrous ions with an IC50 value of 7.4 microg/mL on ferrozine-Fe2+ complex formation.
    Natural product communications 11/2011; 6(11):1749-53. · 0.96 Impact Factor
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    ABSTRACT: The root bark essential oil of Periploca sepium Bunge (Asclepiadaceae/ Apocynaceae) obtained by hydrodistillation was investigated by GC and GC-MS. 2-Hydroxy-4-methoxybenzaldehyde was found to be the main component (78.8% of the total) among 17 identified compounds. 2-Hydroxy-4-methoxybenzaldehyde was separated and purified by preparative thin layer chromatography, and was further identified by means of physicochemical and spectrometric analysis. Both the essential oil and 2-hydroxy-4-methoxybenzaldehyde exhibited antimicrobial activities on all test bacteria and fungi, with MBC/MFC values ranging from 125 microg/mL to 300 microg/mL, MIC values from 80 microg/mL to 300 microg/mL, and IC(50) values from 63.29 microg/mL to 167.30 microg/mL. They also showed moderate antioxidant activity in the DPPH free radical scavenging, beta-carotene bleaching and ferrozine-ferrous ions assays. The results indicated that the major portion of these antimicrobial and antioxidant activities was due to the presence of 2-hydroxy-4-methoxy-benzaldehyde in the oil, which could potentially be developed as an antimicrobial and antioxidant agent in the future.
    Molecules 08/2010; 15(8):5807-17. · 2.43 Impact Factor
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    ABSTRACT: Seven flavonoids have been isolated from the aerial parts of Halostachys caspica C. A. Mey. (Chenopodiaceae) for the first time. By means of physicochemical and spectrometric analysis, they were identified as luteolin (1), chrysin (2), chrysin 7-O-β-D-glucopyranoside (3), quercetin (4), quercetin 3-O-β-D-glucopyranoside (5), isorhamentin-3-O-β-D-glucopyranoside (6), and isorhamentin-3-O-β-D-rutinoside (7). All flavonoids were evaluated to show a broad antimicrobial spectrum of activity on microorganisms including seven bacterial and one fungal species as well as pronounced antioxidant activity. Among them, the aglycones with relatively low polarity had stronger bioactivity than their glycosides. The results suggested that the isolated flavonoids could be used for future development of antimicrobial and antioxidant agents, and also provided additional data for supporting the use of H. caspica as forage.
    Molecules 01/2010; 15(11):7933-45. · 2.43 Impact Factor
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    ABSTRACT: Three antimicrobial sphingolipids were separated by bioassay-guided isolation from the chloroform fraction of the crude methanol extract of cucumber (Cucumis sativus L.) stems and identified as (2S,3S,4R,10E)-2-[(2'R)-2-hydroxytetra-cosanoylamino]-1,3,4-octadecanetriol-10-ene (1), 1-O-β-D-glucopyranosyl(2S,3S,4R,10E)-2-[(2'R)-2-hydroxy-tetracosanoylamino]-1,3,4-octadecanetriol-10-ene (2) and soya-cerebroside I (3) by their physicochemical properties and spectroscopic analysis. They were evaluated to show antifungal and antibacterial activity on test microorganisms including four fungal and three bacterial species. Among them, compound 1, a relatively low polarity aglycone, exhibited stronger antimicrobial activity than its corresponding glycoside 2. The results indicated that sphingolipids could be the main antimicrobial compounds in the crude methanol extract of cucumber stems.
    Molecules 01/2010; 15(12):9288-97. · 2.43 Impact Factor
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    ABSTRACT: In order to investigate essential oils with biological activity from local wild plants, two valerianaceous species, Nardostachys chinensis and Valeriana officinalis, were screened for their antimicrobial and antioxidant activity. The essential oils were obtained from the roots and rhizomes of the two plants by hydro-distillation, and were analyzed for their chemical composition by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Calarene (25.31%), aristolone (13.35%), α-selinene (7.32%) and β-maaliene (6.70%) were the major compounds of the 23 identified components which accounted for 92.76% of the total oil of N. chinensis. Patchoulol (16.75%), α-pinene (14.81%), and β-humulene (8.19%) were the major compounds among the 20 identified components, which accounted for 88.11% of the total oil of V. officinalis. Both oils were rich in sesquiterpene hydrocarbons as well as their oxygenated derivatives. Essential oils were shown to have broad spectrum antibacterial activity with MIC values that ranged from 62.5 μg/mL to 400 μg/mL, and IC(50) values from 36.93 μg/mL to 374.72 μg/mL. The oils were also shown to have moderate antifungal activity to Candida albicans growth as well as inhibition of spore germination of Magnaporthe oryzae. Two essential oils were assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, β-carotene bleaching and ferrozine-ferrous ions assays, respectively, to show moderate antioxidant activity. Results suggest that the isolated essential oils could be used for future development of antimicrobial and antioxidant agents.
    Molecules 01/2010; 15(9):6411-22. · 2.43 Impact Factor
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    ABSTRACT: Bioassay-guided fractionation of the crude extract of the whole plant of Macleaya cordata R. Br. led to the isolation of four alkaloids, which were identified as sanguinarine (1), chelerythrine (2), protopine (3) and alpha-allocryptopine (4) on the basis of their physicochemical and spectrometric data. Compounds 1 and 2 demonstrated a significant antifungal activity against the six test fungi with median inhibitory concentrations (IC50) ranging from 0.47 to 6.13 microg/mL. Compound 1 was the most effective with an IC50 of 0.47 microg/mL on Rhizoctonia solani. Furthermore, compounds 1 and 2 also demonstrated strong antibacterial activity, with IC50 values ranging from 5.01 to 11.3 microg/mL, and minimum inhibitory concentrations (MIC) ranging from 8.0 to 32.0 microg/mL. This is the first report on the activity of the alkaloids from M. cordata against economically important phytopathogenic fungi and bacteria.
    Natural product communications 11/2009; 4(11):1557-60. · 0.96 Impact Factor
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    ABSTRACT: Bioassay-guided fractionation of an ethyl acetate extract from the aerial parts of Anabasis aphylla, a Chenopodiaceous species widely distributed in the northwest of China, led to the isolation of six phenolic compounds, which were identified by means of spectrometric analysis as 1-(2-hydroxy-4,6-dimethoxyphenyl)-ethanone (1), 3,4-dihydroxy cinnamic acid tetracosyl ester (2), 4-hydroxy-3-methoxy benzoic acid (3), 2-hydroxy benzoic acid (4), 3,4-dihydroxy cinnamic acid methyl ester (5) and 4-hydroxy benzoic acid pentadecane ester (6). These compounds were further screened for their minimum inhibitory concentration (MIC) and median inhibitory concentration (IC50) by use of the micro-dilution-MTT assay for antimicrobial activity against one Gram-positive bacterium (Bacillus subtilis), three Gram-negative bacteria (Agrobacterium tumefaciens, Pseudomonas lachrymans, and Xanthomonas vesicatoria), and one yeast (Candida albicans). Apart from compound 6, which had no activity against any of the tested microorganisms, the other compounds showed selective inhibitory activity. This is the first report on the antimicrobial activity of the phenolic compounds isolated from A. aphylla. The obtained results provide promising baseline information for the potential use of the extract and some isolated compounds from this plant as antimicrobial agents to control plant and animal diseases.
    Natural product communications 04/2009; 4(3):385-8. · 0.96 Impact Factor
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    ABSTRACT: Stem blister canker is a serious stem disease in the Populus genus in China. The pathogen was confirmed as Botryosphaeria dothidea (Moug. ex Fr.) Ces. et de Not. based on its morphological, pathological and molecular features. Seven selected plant species Artemisia annua, Gleditsia sinensis, Lonicera japonica, Macleaya cordata, Phyllodendron chinense, Polygonum cuspidatum and Scutellaria baicalensis, belonging to different families from China, were extracted with the solvent 95% (v/v) ethanol to yield ethanol extracts which were used to evaluate their antifungal activity against poplar stem canker pathogen by a mycelial radial growth inhibition test. Of them, the extracts of M. cordata, P. cuspidatum and S. baicalensis showed stronger antifungal activity, the median inhibitory concentration (IC50) was 0.3125, 1.0219 and 0.9675mgml−1 separately. The control effect of extracts of M. cordata, P. cuspidatum and S. baicalensis on poplar stem canker disease was between 62% and 85%. The inhibitory effect of the extracts indicated the importance of some plant species as possible natural source of fungicidal material.
    World Journal of Microbiology and Biotechnology 01/2008; 24(8):1579-1584. · 1.35 Impact Factor
  • Journal of Biotechnology - J BIOTECHNOL. 01/2008; 136.

Publication Stats

66 Citations
16.40 Total Impact Points

Institutions

  • 2008–2012
    • China Agricultural University
      • • College of Agronomy and Biotechnology
      • • Department of Plant Pathology
      Beijing, Beijing Shi, China