Bo Liu

Peking Union Medical College Hospital, Beijing, Beijing Shi, China

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Publications (9)13.73 Total impact

  • Article: Dammarane glycosides from the root of Machilus yaoshansis.
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    ABSTRACT: Nine new dammarane triterpene glycosides (1-3 and 8-13) and 12 known analogues have been isolated from an ethanol extract of the roots of Machilus yaoshansis. Compounds 1-7 have an uncommon 20,23-dihydroxydammar-24-en-21-oic acid-21,23-lactone moiety that was previously reported in compounds isolated from Gynostemma pentaphyllum. The configurations of the lactone moieties in 1-3 were determined by comparison of the experimental ECD spectra of 1-3 and the hydrolysates, 1a and 1b, with the corresponding calculated ECD spectra. On the basis of NMR and ECD data analysis of 1-7, the previously reported C-20 and C-23 configurations of 4-7 and related derivatives from Gynostemma pentaphyllum were revised. In addition, the application of NMR data and Cotton effects to the determination of the relative and absolute configurations of the γ-lactone moiety in 3β,20,23-trihydroxydammar-24-en-21-oic acid-21,23-lactone derivatives is discussed.
    Journal of Natural Products 07/2012; 75(7):1373-82. · 3.13 Impact Factor
  • Article: [Non-anthraquinones constituents from the roots of Knoxia valerianoides].
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    ABSTRACT: Twenty-one non-anthraquinones constituents were isolated for the first time from an ethanol extract of the roots of Knoxia valerianoides by using a combination of various chromatographic techniques including column chromatography over silica gel, Sephadex LH-20, and reversed-phase HPLC. Their structures were identified by their physical-chemical properties and spectroscopic analysis including NMR and MS. The compounds include ten triterpenoids: ursolic acid (1), oleanolic acid (2), 2-oxo pomolic acid (3), pomolic acid (4), maslinic acid (5), rotungenic acid (6), tormentic accid (7), rotundic acid 3,23-acetonide (8), arjungenin (9), and 2alpha, 3beta, 19alpha, 23-tetrahydroxy-urs-12-en-28-oic acid (10), four sitosterones: (24R)-24-ethylcholesta-4,22-dien-3-one (11), 3-oxo-4-en-sitosterone (12), 7-oxostigmasterol (13), and 7-oxo-beta-sitosterol (14), two lignans: eudesmin (15) and ciwujiatone (16), one coumarin: cnidilin (17), and four simple aromatic analogues: 5-hydroxymethylenefural (18), 3-hydroxy-4-methoxybenzoic acid (19), benzoic acid (20), and 2-hydroxy-5-methxoycinnamaldehydes (21). In the in vitro assays against human cancer cell lines (HCT-8, Bel7402, BGC-823, A549, and A2780), against deserum and glutamate induced PC12-syn cell damage, and against HIV-1 replication, and inhibiting protein tyrosine phosphatase 1B (PTP1 B), LPS induced NO production in macrophage, and Fe(2+)-cystine induced rat liver microsomal lipid peroxidation, at a concentration of 1 x 10(-5) mol x L(-1), no compound showed activity.
    Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica 07/2012; 37(14):2092-9.
  • Article: Butanolide derivatives from the bark of Machilus yaoshansis.
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    ABSTRACT: Six new butanolide derivatives with long aliphatic side chains (1-6), together with 23 known lipophilic constituents, were isolated from the bark of Machilus yaoshansis. Their structures were elucidated by spectroscopic and chemical methods. All the isolates were evaluated for cytotoxic and anti-inflammatory activities.
    Journal of Asian natural products research 05/2012; 14(8):713-20. · 0.61 Impact Factor
  • Article: Cucurbitane glucosides from the root of Machilus yaoshansis.
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    ABSTRACT: Seven new cucurbitane triterpene glucosides (1-5, 8, and 9) and five known analogues (6, 7, 10, cucurbitacin I 2-O-β-d-glucopyranoside, and khekadaengoside K) have been isolated from an ethanol extract of roots of Machilus yaoshansis. Compounds 1 and 2 have an unusual 16,23:22,25-diepoxy unit, 4 is an uncommon cucurbitane 25-carbamate with the carbamoyl amino group attached at C-24 to form an oxazolidinone ring in the side chain, and 8 is the first example of a trinorcucurbitane derivative. The configurations in several pairs of C-24 epimeric cucurbitacins with 24,25-dihydroxy-22-one side chains were assigned, and the validity of J(23a,24) and J(23b,24) values to differentiate the configuration at C-24 in these cucurbitane derivatives is discussed. Compounds 2-4 showed in vitro activity against protein tyrosine phosphatase 1B with IC50 values of 8.63, 2.81, and 4.26 μM, respectively. Cucurbitacin E 2-O-β-d-glucopyranoside (10) showed selective cytotoxicity against BGC-823 and A549 cancer cells with IC50 values of 4.98 and 3.20 μM, respectively.
    Journal of Natural Products 11/2011; 74(11):2431-7. · 3.13 Impact Factor
  • Article: [Anthraquinones from the roots of Knoxia valerianoides].
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    ABSTRACT: To investigate the chemical constituents of the roots of Knoxia valerianoides and their biological activities. The anthraquinones were isolated by using a combination of various chromatographic techniques including column chromatography over silica gel, Sephadex LH-20, and reversed-phase HPLC. Structures of the isolates were identified by their physical-chemical properties and spectroscopic analysis including 2D NMR and MS. Antioxidant, anti-HIV, neuroprotective, and cytotoxic activities were screened by using cell-based models. Twenty-two constituents were isolated from an ethanolic extract of the roots of K. valerianoides. Their structures were identified as nordamnacanthal (1), ibericin (2), rubiadin (3), damnacanthol (4), 2-ethoxymethylknoxiavaledin (5), 3-hydroxymorindone (6), knoxiadin (7), 2-formyl knoxiavaledin (8), lucidin (9), xanthopurpurin (10), 1, 3-dihydroxy-2-methoxy-9, 10- anthraquinone (11), lucidin(-methyl ether (12), digiferruginol (13), 3-hydroxy-2-methyl-9,10-anthraquinone (14), rubiadin-1-methyl ether (15), 6-methoxylucidin (-ethyl ether (16), 1,3,6-trihydroxy-2-methyl-9,10-anthraquinone (17), 1,3-dihydroxy-2-hydroxy methyl-6-methoxy-9,10-anthraquinone (18), 1,3,6-trihydroxy-2-methoxymethyl-9,10- anthraquinone (19), 3,6-dihydroxy-2- hydroxymethyl-9,10-anthraquinone (20), and 1,6-dihydroxy-2-methyl-9,10-anthra quinone (21). In the in vitro assays, at a concentration of 1 x 10(-5) mol x L(-1), no compounds were active against human cancer cell lines (HCT-8, Bel7402, BGC-823, A549, and A2780), deserum and glutamate induced PC12-syn cell damage, LPS induced NO production in macrophage, Fe2+-cystine induced rat liver microsomal lipid peroxidation, HIV-1 replication, and protein tyrosine phosphatase 1B (PTP1B). Compounds 9-21 were obtained from the roots of K. valerianoides for the first time.
    Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica 11/2011; 36(21):2980-6.
  • Article: Anthraquinones from the roots of Knoxia valerianoides.
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    ABSTRACT: Five new 9,10-anthraquinones (1-5) were isolated from an ethanol extract of the roots of Knoxia valerianoides. Their structures including absolute configuration of 1 were determined by spectroscopic analysis. Compounds 4 and 5 showed moderate activity against nitrogen oxide production in macrophages induced by lipopolysaccharide, at 10(- 5) M, with inhibition ratios of 50.4 ± 3.6 and 41.7 ± 2.1%, respectively.
    Journal of Asian natural products research 10/2011; 13(11):1023-9. · 0.61 Impact Factor
  • Article: Homosecoiridoids from the flower buds of Lonicera japonica.
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    ABSTRACT: Homosecoiridoids (1-15) were isolated from the flower buds of Lonicera japonica. Compounds 1-4, designated as loniphenyruviridosides A-D, possess unprecedented skeletons featuring phenylpyruvic acid derived moieties coupled with an iridoid or a secoiridoid nucleus. Compounds 5-15 (lonijaposides D-N) are additional examples of the unusual pyridinium alkaloid-coupled secoiridoids (lonijaposides A-C). The validity of the CD data to determine the configuration of the secoiridoid derivatives is discussed on the basis of detailed CD data analysis and semisynthesis of 2 and 3 with the co-occurring secologanic acid. The configuration of secologanic acid was determined by a single-crystal X-ray crystallographic analysis using anomalous scattering of Cu Kα radiation. Biosynthetic pathways of the homosecoiridoids were postulated. Compounds 1-4 inhibited STAT-3 activity of HELF cells, and lonijaposides F (7), H (9), I (10), and K (12) showed activity against the release of glucuronidase in rat polymorphonuclear leukocytes induced by platelet-activating factor.
    Journal of Natural Products 09/2011; 74(10):2151-60. · 3.13 Impact Factor
  • Article: [Studies on constituents of cultures of fungus Phellinus igniarius].
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    ABSTRACT: To investigate the chemical constituents of the culture of Phellinus igniarius and their phamacological activities. The constituents were isolated by using a combination of various chromatographic techniques including column chromatography over silica gel, Sephadex LH-20, and reversed-phase HPLC. Structures of the isolates were identified by spectroscopic data analysis. Cytotoxic, neuroprotective, hepatoprotective, anti-inflammatory, and anti-HIV activities were screened by using cell-based models. Twenty-nine constituents were isolated. Their structures were identified as three sesquiterpenes: 3S,9R,10S-3-hydroxy-11, 12-O-isopropyldrimene(1), 3S, 9R, 10S-3, 11, 12-trihydroxydrimene (2), and 3S, 4S, 9R, 10S-11, 12, 14-trihydroxydrimene(3); three steriods: 24R-ergosta-4, 6, 8(14), 22-tetraen-3-one (4), stigmasta-7, 22-diene-3b, 5a, 6a-triol (5), and 5a, 8a-epi dioxyergosta-6, 22-diene-3b-ol (6); fourteen cyclo-dipeptide: cyclo (L-Pro-L-Val) (7), cycle (L-Leu-D-Pro) (8), cyclo (L-Leu-L-Pro) (9), cyclo (ILe-Pro) (10), cyclo (Gly-Leu) (11), cyclo (Phe-Ser) (12), cyclo (Ala-Pro) (13), cyclo (Ala-Phe) (14), cyclo (4-HyP-Phe) (15) , cyclo (L-Phe-D-Pro) (16), cyclo (D-Phe-D-Pro) (17), cyclo (6-HyP-Phe) (18), cycle (Gln-Pro) (19), and cycle (Asn-Leu) (20); and nine other compounds: N-acetyl-phenylalanine (21), adenosine (22), phenyldiethanol (23), o-hydroxy-phenylethanol (24), benzoic acid (25), p-methoxybenzoic acid (26), m-methoxybenzoic acid (27), hexadecanoic acid (28), and 3-pyridinecarboxylic acid (29). In the in vitro assays, at a concentration of 1 x 10(-5) mol x L(-1), compounds 5 and 8 showed neuroprotective activity against MPP+ induced PC12-syn cell damage, with a relative cell proliferation rate of 90.3% and 87.5% (P < 0.05). At 1 x 10(-5) mol x L(-1), compounds 12 and 18 showed hepatoprotective activities against DL-galactosamine-induced toxicity examined in WB-F344 cell, with cell survival rates of 25% and 24%, respectivily. Compounds 1-29 were obtained from P. igniarius for the first time. Compounds 5 and 8 showed potent PC12-syn protective activities, while 12 and 18 showed hepato cytes (WB-F344 cells) protective activities.
    Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica 04/2011; 36(7):874-80.
  • Article: Homo- and heptanor-sterols and tremulane sesquiterpenes from cultures of Phellinus igniarius.
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    ABSTRACT: Four steroids, a homopregnene (1) and three heptanorergosterane derivatives (2-4), nine tremulane sesquiterpenes (5-13), and 18 known compounds have been isolated from cultures of the fungus Phellinus igniarius. Their structures and absolute configurations were elucidated by spectroscopic data analysis. In preliminary in vitro assays, at 10(-5) M, compounds 8, 9, 13, and 3beta-hydroxy-11,12-O-isopropyldrimene (14) showed significant vascular-relaxing activities against phenylephrine-induced vasoconstriction with relaxing rates of 35.7%, 45.4%, 46.6%, and 32.1%, respectively, as compared with the blank control.
    Journal of Natural Products 07/2010; 73(7):1294-300. · 3.13 Impact Factor