The Experts below are selected from a list of 429 Experts worldwide ranked by ideXlab platform
Shuying Liu - One of the best experts on this subject based on the ideXlab platform.
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studies on alkaloids binding to gc rich human survivin promoter dna using positive and negative ion electrospray ionization mass spectrometry
Journal of Mass Spectrometry, 2008Co-Authors: Zhaofu Wang, Xinhua Guo, Zhiqiang Liu, Meng Cui, Fengrui Song, Shuying LiuAbstract:Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the binding of 13 alkaloids to two GC-rich DNA duplexes which are critical sequences in human survivin promoter. Negative ion ESI-MS was first applied to screen the binding of the alkaloids to the duplexes. Six alkaloids (including berberine, Jatrorrhizine, palmatine, reserpine, berbamine, and tetrandrine) show complexation with the target DNA sequences. Relative binding affinities were estimated from the negative ion ESI data, and the alkaloids show a binding preference to the duplex with higher GC content. Positive ion ESI mass spectra of the complexes were also recorded and compared with those obtained in negative ion mode.
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studies on alkaloids binding to gc rich human survivin promoter dna using positive and negative ion electrospray ionization mass spectrometry
Journal of Mass Spectrometry, 2008Co-Authors: Zhaofu Wang, Xinhua Guo, Zhiqiang Liu, Meng Cui, Fengrui Song, Shuying LiuAbstract:Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the binding of 13 alkaloids to two GC-rich DNA duplexes which are critical sequences in human survivin promoter. Negative ion ESI-MS was first applied to screen the binding of the alkaloids to the duplexes. Six alkaloids (including berberine, Jatrorrhizine, palmatine, reserpine, berbamine, and tetrandrine) show complexation with the target DNA sequences. Relative binding affinities were estimated from the negative ion ESI data, and the alkaloids show a binding preference to the duplex with higher GC content. Positive ion ESI mass spectra of the complexes were also recorded and compared with those obtained in negative ion mode. Only the 1 : 1 complex with berbamine was observed with lower abundance in the positive ion mass spectrum while complexes with the other alkaloids were absolutely absent. Collision-induced dissociation (CID) experiments indicate that the complexes with the protoberberine alkaloids (berberine, Jatrorrhizine, and palmatine) dissociate via base loss and covalent cleavage. In contrast, product ion spectra of the complexes with the alkaloids reserpine, berbamine, and tetrandrine show the predominant loss of a neutral alkaloid molecule, accompanied by base loss and covalent cleavage to a lesser extent. A comparison of the gas-phase behaviors of complexes with the alkaloids to those with the traditional DNA binders has suggested an intercalative binding mode of these alkaloids to the target DNA duplexes.
Zhaofu Wang - One of the best experts on this subject based on the ideXlab platform.
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studies on alkaloids binding to gc rich human survivin promoter dna using positive and negative ion electrospray ionization mass spectrometry
Journal of Mass Spectrometry, 2008Co-Authors: Zhaofu Wang, Xinhua Guo, Zhiqiang Liu, Meng Cui, Fengrui Song, Shuying LiuAbstract:Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the binding of 13 alkaloids to two GC-rich DNA duplexes which are critical sequences in human survivin promoter. Negative ion ESI-MS was first applied to screen the binding of the alkaloids to the duplexes. Six alkaloids (including berberine, Jatrorrhizine, palmatine, reserpine, berbamine, and tetrandrine) show complexation with the target DNA sequences. Relative binding affinities were estimated from the negative ion ESI data, and the alkaloids show a binding preference to the duplex with higher GC content. Positive ion ESI mass spectra of the complexes were also recorded and compared with those obtained in negative ion mode.
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studies on alkaloids binding to gc rich human survivin promoter dna using positive and negative ion electrospray ionization mass spectrometry
Journal of Mass Spectrometry, 2008Co-Authors: Zhaofu Wang, Xinhua Guo, Zhiqiang Liu, Meng Cui, Fengrui Song, Shuying LiuAbstract:Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the binding of 13 alkaloids to two GC-rich DNA duplexes which are critical sequences in human survivin promoter. Negative ion ESI-MS was first applied to screen the binding of the alkaloids to the duplexes. Six alkaloids (including berberine, Jatrorrhizine, palmatine, reserpine, berbamine, and tetrandrine) show complexation with the target DNA sequences. Relative binding affinities were estimated from the negative ion ESI data, and the alkaloids show a binding preference to the duplex with higher GC content. Positive ion ESI mass spectra of the complexes were also recorded and compared with those obtained in negative ion mode. Only the 1 : 1 complex with berbamine was observed with lower abundance in the positive ion mass spectrum while complexes with the other alkaloids were absolutely absent. Collision-induced dissociation (CID) experiments indicate that the complexes with the protoberberine alkaloids (berberine, Jatrorrhizine, and palmatine) dissociate via base loss and covalent cleavage. In contrast, product ion spectra of the complexes with the alkaloids reserpine, berbamine, and tetrandrine show the predominant loss of a neutral alkaloid molecule, accompanied by base loss and covalent cleavage to a lesser extent. A comparison of the gas-phase behaviors of complexes with the alkaloids to those with the traditional DNA binders has suggested an intercalative binding mode of these alkaloids to the target DNA duplexes.
Zhi-hong Jiang - One of the best experts on this subject based on the ideXlab platform.
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spacer length and attaching position dependent binding of synthesized protoberberine dimers to double stranded dna
Bioorganic & Medicinal Chemistry, 2006Co-Authors: Yuhua Long, Wen-hua Chen, Yong Qin, Zongwei Cai, Liping Bai, Jiyan Pang, Zhi-hong JiangAbstract:Abstract Six Jatrorrhizine homodimers and berberine–Jatrorrhizine heterodimers have been synthesized in moderate to good yields from the reaction of Jatrorrhizine with α,ω-dibromoalkanes and 9- O -(ω-bromoalkyl)berberines, respectively. Their binding activities toward calf thymus (CT) DNA and three double-stranded oligodeoxynucleotides, d(AAGAATTCTT) 2 , d(TAAGAATTCTTA) 2 , and d(TTAAGAATTCTTAA) 2 , were investigated by means of spectrofluorimetric and spectrophotometric titrations. The results indicate that these dimers exhibit enhanced DNA-binding affinities due to the cooperative interaction of the two protoberberine subunits. A comparative study of the DNA-binding behaviors of berberine homodimers, Jatrorrhizine homodimers, and berberine–Jatrorrhizine heterodimers suggests that spacer length and attaching position are of great importance in modulating their DNA-binding affinities.
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Spectrometric studies of cytotoxic protoberberine alkaloids binding to double-stranded DNA.
Bioorganic & Medicinal Chemistry, 2005Co-Authors: Wen-hua Chen, Yong Qin, Zongwei Cai, Chi-leung Chan, Guo-an Luo, Zhi-hong JiangAbstract:Abstract The noncovalent complexes of five cytotoxic protoberberine alkaloids, that is, berberine, palmatine, Jatrorrhizine, coptisine, and berberrubine with several double-stranded oligodeoxynucleotides were systematically investigated by using electrospray ionization mass (ESI-MS) and fluorescence spectrometric methods, with the aim of establishing the structure–activity relationships. ESI-MS spectrometric studies indicated that these five alkaloids showed both 1:1 and 1:2 binding stoichiometries with d(AAGAATTCTT)2, d(AAGGATCCTT)2, and d(AAGCATGCTT)2. Their relative binding affinities toward these three double-stranded DNA were semi-quantitatively evaluated by measuring the ratios of the complex signals ([ds+alkaloid–5H]4−+[ds+2alkaloid–6H]4−) to those of the duplexes ([ds-4H]4−) and also by ESI-MS competitive binding experiments. These experiments established the relative binding affinities of five protoberberine alkaloids in the order of palmatine > Jatrorrhizine > coptisine > berberine > berberrubine with d(AAGAATTCTT)2, palmatine ⩾ coptisine > Jatrorrhizine ⩾ berberine > berberrubine with d(AAGGATCCTT)2 and palmatine > Jatrorrhizine ⩾ coptisine > berberine > berberrubine with d(AAGCATGCTT)2. Significantly, these alkaloids except berberrubine bound to d(AAGGATCCTT)2 and d(AAGCATGCTT)2 with the affinities comparable to Hoechst 33258, a typical DNA minor groove binder. The relative binding preferences of berberine, palmatine, and coptisine with these three double-stranded DNA were further quantitatively assessed by their association constants obtained from fluorescence titration experiments. The values revealed the order of relative binding affinities as berberine > coptisine > palmatine with d(AAGAATTCTT)2 and coptisine > berberine > palmatine with d(AAGGATCCTT)2 and d(AAGCATGCTT)2. These results were not in full agreement with those obtained from ESI-MS experiments, maybe due to the different measuring solution conditions. The results from ESI-MS and fluorescence titration experiments indicated that the sequence selectivities of these five alkaloids were not significant and remarkable AT- or GC-rich DNA binding preferences were not obtained, in contrast to the report that berberine binds preferentially to AT-rich DNA. To provide further insight into the sequence selectivities, the association constants of berberine with d(AAGATATCTT)2, 5′-AAGTAATCTT-3′/5′-AAGATTACTT-3′, d(AAGGGCCCTT)2, d(AAGGCGCCTT)2, and 5′-AAGGCCGCTT-3′/5′-AAGCGGCCTT-3′, that is double helical DNA from AT-rich to GC-rich sequences, were further measured by fluorescence titration methods. No significant differences in their association constants were observed, suggesting that berberine showed no remarkable sequence selectivities.
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study on noncovalent complexes of cytotoxic protoberberine alkaloids with double stranded dna by using electrospray ionization mass spectrometry
Bioorganic & Medicinal Chemistry Letters, 2004Co-Authors: Wen-hua Chen, Zongwei Cai, Chi-leung Chan, Guo-an Luo, Zhi-hong JiangAbstract:The noncovalent complexes of four cytotoxic protoberberine alkaloids that is, berberine, palmatine, Jatrorrhizine, and coptisine with double-stranded oligodeoxynucleotides d(AAGAATTCTT)(2) were investigated by electrospray ionization mass spectrometry. These four active components from Chinese herbal medicines showed both 1:1 and 1:2 binding stoichiometries, independent on the alkaloid-to-DNA ratios. Binding affinities in the order of palmatine> or =Jatrorrhizine>coptisine>berberine with d(AAGAATTCTT)(2) were obtained. Additionally, the preliminary results indicated that berberine had some sequence selectivities.
Matthias Hamburger - One of the best experts on this subject based on the ideXlab platform.
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anti protozoal activity of aporphine and protoberberine alkaloids from annickia kummeriae engl diels setten maas annonaceae
BMC Complementary and Alternative Medicine, 2013Co-Authors: Hamisi M Malebo, Tanja Wenzler, Monical Cal, Sauda Swaleh, Maurice O Omolo, Ahmed Hassanali, Urs Sequin, Daniel Haussinger, Petur Weihe Dalsgaard, Matthias HamburgerAbstract:Background: Malaria, trypanosomiasis and leishmaniasis have an overwhelming impact in the poorest countries in the world due to their prevalence, virulence and drug resistance ability. Currently, there is inadequate armory of drugs for the treatment of malaria, trypanosomiasis and leishmaniasis. This underscores the continuing need for the discovery and development of new anti-protozoal drugs. Consequently, there is an urgent need for research aimed at the discovery and development of new effective and safe anti-plasmodial, anti-trypanosomal and anti-leishmanial drugs. Methods: Bioassay-guided chromatographic fractionation was employed for the isolation and purification of antiprotozoal alkaloids. Results: The methanol extract from the leaves of Annickia kummeriae from Tanzania exhibited a strong anti-plasmodial activity against the multi-drug resistant Plasmodium falciparum K1 strain (IC50 0.12±0.01 μg/ml, selectivity index (SI) of 250, moderate activity against Trypanosoma brucei rhodesiense STIB 900 strain (IC50 2.50±0.19 μg/ml, SI 12) and mild activity against Leishmania donovani axenic MHOM-ET-67/82 strain (IC50 9.25±0.54 μg/ml, SI 3.2). Bioassay-guided chromatographic fractionation led to the isolation of four pure alkaloids, lysicamine (1), trivalvone (2), palmatine (3), Jatrorrhizine (4) and two sets of mixtures of Jatrorrhizine (4) with columbamine (5) and palmatine (3 )w ith (�)-tetrahydropalmatine (6). The alkaloids showed low cytotoxicity activity (CC50 30 - >90 μg/ml), strong to moderate anti-plasmodial activity (IC50 0.08 ± 0.001 - 2.4 ± 0.642 μg/ml, SI 1.5-1,154), moderate to weak anti-trypanosomal (IC50 2.80±0.001 – 14.3±0.001 μg/ml, SI 2.3-28.1) and anti-leishmanial activity IC50 2.7± 0.001 – 20.4±0.003 μg/ml, SI 1.7-15.6). Conclusion: The strong anti-plasmodial activity makes these alkaloids good lead structures for drug development programs.
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anti protozoal activity of aporphine and protoberberine alkaloids from annickia kummeriae engl diels setten maas annonaceae
BMC Complementary and Alternative Medicine, 2013Co-Authors: Hamisi M Malebo, Tanja Wenzler, Monical Cal, Sauda Swaleh, Maurice O Omolo, Ahmed Hassanali, Urs Sequin, Daniel Haussinger, Petur Weihe Dalsgaard, Matthias HamburgerAbstract:Malaria, trypanosomiasis and leishmaniasis have an overwhelming impact in the poorest countries in the world due to their prevalence, virulence and drug resistance ability. Currently, there is inadequate armory of drugs for the treatment of malaria, trypanosomiasis and leishmaniasis. This underscores the continuing need for the discovery and development of new anti-protozoal drugs. Consequently, there is an urgent need for research aimed at the discovery and development of new effective and safe anti-plasmodial, anti-trypanosomal and anti-leishmanial drugs. Bioassay-guided chromatographic fractionation was employed for the isolation and purification of antiprotozoal alkaloids. The methanol extract from the leaves of Annickia kummeriae from Tanzania exhibited a strong anti-plasmodial activity against the multi-drug resistant Plasmodium falciparum K1 strain (IC50 0.12 ± 0.01 μg/ml, selectivity index (SI) of 250, moderate activity against Trypanosoma brucei rhodesiense STIB 900 strain (IC50 2.50 ± 0.19 μg/ml, SI 12) and mild activity against Leishmania donovani axenic MHOM-ET-67/82 strain (IC50 9.25 ± 0.54 μg/ml, SI 3.2). Bioassay-guided chromatographic fractionation led to the isolation of four pure alkaloids, lysicamine (1), trivalvone (2), palmatine (3), Jatrorrhizine (4) and two sets of mixtures of Jatrorrhizine (4) with columbamine (5) and palmatine (3) with (−)-tetrahydropalmatine (6). The alkaloids showed low cytotoxicity activity (CC50 30 - >90 μg/ml), strong to moderate anti-plasmodial activity (IC50 0.08 ± 0.001 - 2.4 ± 0.642 μg/ml, SI 1.5-1,154), moderate to weak anti-trypanosomal (IC50 2.80 ± 0.001 – 14.3 ± 0.001 μg/ml, SI 2.3-28.1) and anti-leishmanial activity IC50 2.7 ± 0.001 – 20.4 ± 0.003 μg/ml, SI 1.7-15.6). The strong anti-plasmodial activity makes these alkaloids good lead structures for drug development programs.
Fengrui Song - One of the best experts on this subject based on the ideXlab platform.
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studies on alkaloids binding to gc rich human survivin promoter dna using positive and negative ion electrospray ionization mass spectrometry
Journal of Mass Spectrometry, 2008Co-Authors: Zhaofu Wang, Xinhua Guo, Zhiqiang Liu, Meng Cui, Fengrui Song, Shuying LiuAbstract:Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the binding of 13 alkaloids to two GC-rich DNA duplexes which are critical sequences in human survivin promoter. Negative ion ESI-MS was first applied to screen the binding of the alkaloids to the duplexes. Six alkaloids (including berberine, Jatrorrhizine, palmatine, reserpine, berbamine, and tetrandrine) show complexation with the target DNA sequences. Relative binding affinities were estimated from the negative ion ESI data, and the alkaloids show a binding preference to the duplex with higher GC content. Positive ion ESI mass spectra of the complexes were also recorded and compared with those obtained in negative ion mode.
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studies on alkaloids binding to gc rich human survivin promoter dna using positive and negative ion electrospray ionization mass spectrometry
Journal of Mass Spectrometry, 2008Co-Authors: Zhaofu Wang, Xinhua Guo, Zhiqiang Liu, Meng Cui, Fengrui Song, Shuying LiuAbstract:Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the binding of 13 alkaloids to two GC-rich DNA duplexes which are critical sequences in human survivin promoter. Negative ion ESI-MS was first applied to screen the binding of the alkaloids to the duplexes. Six alkaloids (including berberine, Jatrorrhizine, palmatine, reserpine, berbamine, and tetrandrine) show complexation with the target DNA sequences. Relative binding affinities were estimated from the negative ion ESI data, and the alkaloids show a binding preference to the duplex with higher GC content. Positive ion ESI mass spectra of the complexes were also recorded and compared with those obtained in negative ion mode. Only the 1 : 1 complex with berbamine was observed with lower abundance in the positive ion mass spectrum while complexes with the other alkaloids were absolutely absent. Collision-induced dissociation (CID) experiments indicate that the complexes with the protoberberine alkaloids (berberine, Jatrorrhizine, and palmatine) dissociate via base loss and covalent cleavage. In contrast, product ion spectra of the complexes with the alkaloids reserpine, berbamine, and tetrandrine show the predominant loss of a neutral alkaloid molecule, accompanied by base loss and covalent cleavage to a lesser extent. A comparison of the gas-phase behaviors of complexes with the alkaloids to those with the traditional DNA binders has suggested an intercalative binding mode of these alkaloids to the target DNA duplexes.