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Gopinatha Suresh Kumar - One of the best experts on this subject based on the ideXlab platform.
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studies on α β and γ cyclodextrin inclusion complexes of isoquinoline alkaloids berberine Palmatine and coralyne
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2014Co-Authors: Soumitra Hazra, Maidul Hossain, Gopinatha Suresh KumarAbstract:The complexation of three isoquinoline alkaloids berberine, Palmatine and coralyne with α-, β-, and γ-CDs were studied by absorption, fluorescence, circular dichroism, NMR spectroscopy and microcalorimetric assay techniques. Their binding constant (KBH) values were determined by Benesi–Hildebrand equation. All the alkaloids formed 1:1 stoichiometry complexes with the cyclodextrins (CDs). The binding affinity is largest in β-CD followed by γ-, and α-CD for coralyne, followed by berberine and then Palmatine. The thermodynamic parameters of the complexation were determined by calorimetry. The stoichiometry of complex formation and the variation of the apparent binding constant from spectroscopic studies were confirmed by calorimetry. The formation of the inclusion complexes was entropy driven in almost all the systems. Coralyne formed the strongest complex with all the CDs, followed by berberine and Palmatine in that order. Coralyne-β-CD complex was studied through NMR, indicating more than one interaction mode.
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binding of isoquinoline alkaloids berberine Palmatine and coralyne to hemoglobin structural and thermodynamic characterization studies
Molecular BioSystems, 2013Co-Authors: Soumitra Hazra, Maidul Hossain, Gopinatha Suresh KumarAbstract:Berberine, Palmatine and coralyne, the isoquinoline alkaloids distributed in many botanical families, are extensively investigated due to their potential therapeutic actions and clinical utilities. In this work, their binding characteristics to hemoglobin (Hb) were studied by UV-vis absorption spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy, isothermal calorimetric titration and differential scanning calorimetric techniques. The results indicated that all the three alkaloids caused strong fluorescence quenching of Hb by the static quenching mechanism, but with differing quenching efficiencies. There was a single binding site on Hb for these alkaloids. According to the theory of Forster resonance energy transfer, the binding distances between β-Trp37 of Hb and berberine, Palmatine and coralyne were evaluated to be 2.78 nm, 2.64 nm and 3.29 nm, respectively. The result of synchronous fluorescence, circular dichroism and 3D fluorescence revealed that the polarity around Trp residues experienced a significant increase in the presence of alkaloids. The binding was favoured by enthalpy and entropy changes. Results of circular dichroism, 3D and synchronous fluorescence studies confirmed that the binding of the alkaloids significantly changed the secondary structure of Hb. The studies revealed that berberine and Palmatine bound to a site near to the α1β2 interface on Hb different than coralyne but the affinity of coralyne was one order higher than that of berberine and Palmatine.
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protoberberine alkaloids berberine Palmatine and coralyne binding to poly dt poly da poly dt triplex comparative structural aspects and energetics profiles of the interaction
Chemistry & Biodiversity, 2011Co-Authors: Ishita Saha, Rangana Sinha, Gopinatha Suresh KumarAbstract:The interaction of bioactive protoberberine alkaloids berberine, Palmatine, and coralyne with the DNA triplex poly(dT)⋅(poly(dA)⋅poly(dT)) was studied using biophysical and calorimetric techniques. All three alkaloids bound the triplex cooperatively. Berberine and Palmatine predominantly stabilized the triplex structure, while coralyne stabilized both triplex and duplex structures as inferred from optical thermal melting profiles. Fluorescence quenching, polarization, and viscometric studies hinted at an intercalative mode of binding for the alkaloids to the triplex, coralyne being more strongly intercalated compared to partial intercalation of berberine and Palmatine. The overall affinity of coralyne was two order higher (2.29×107 M−1) than that of berberine (3.43×105 M−1) and Palmatine (2.34×105 M−1). Isothermal titration calorimetric studies revealed that the binding to the triplex was favored by negative enthalpy change (ΔH=−3.34 kcal/mol) with favorable entropy contribution (TΔS = 4.07 kcal/mol) for berberine, favored by almost equal negative enthalpy (ΔH =−3.88 kcal/mol) and entropy changes (TΔS = 3.37 kcal/mol) for Palmatine, but driven by large enthalpy contributions (ΔH =−25.62 kcal/mol and TΔS =−15.21 kcal/mol) for coralyne. These results provide new insights on the binding of isoquinoline alkaloids to the DNA triplex structure.
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interaction of berberine Palmatine coralyne and sanguinarine to quadruplex dna a comparative spectroscopic and calorimetric study
Biochimica et Biophysica Acta, 2011Co-Authors: Kakali Bhadra, Gopinatha Suresh KumarAbstract:Abstract Background Interaction of isoquinoline alkaloids berberine, Palmatine, coralyne and sanguinarine with human telomeric quadruplex DNA, dAGGG(TTAGGG) 3 , has been investigated and compared with ethidium. Methods Biophysical techniques such as absorption, fluorescence, circular dichroism, optical melting and microcalorimetry have been used. Results Absorption and fluorescence studies revealed noncooperative 1:1 binding for all the molecules. Coralyne showed highest affinity (10 6 M −1 ) and for others it was ~ 10 5 M −1 . The binding affinity varied as coralyne > sanguinarine > berberine > Palmatine. Ethidium showed affinity close to sanguinarine. Comparative fluorescence quenching and polarization anisotropy of the emission spectra gave evidence for a stronger stacking interaction of coralyne and sanguinarine compared to berberine and Palmatine. Circular dichroic spectral perturbations were similar in all the cases, but a strong induced circular dichroism for the bound molecules was observed only for coralyne and sanguinarine. The interaction of all the alkaloids was exothermic. Binding of coralyne and sanguinarine was predominantly enthalpy driven while that of berberine and Palmatine was entropy driven. Heat capacity values of − 169, −198, −105 and − 95 cal/mol K, respectively, for coralyne, sanguinarine, berberine, and Palmatine suggested significant differences in the hydrophobic contribution to the binding. Conclusions This study presents a complete structural and thermodynamic profile of the binding of isoquinoline alkaloids with G-quadruplex. General significance These results suggest strong and specific binding of these molecules to the G-quadruplex and highlight the differences in their structure in the interaction profile.
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rna binding potential of protoberberine alkaloids spectroscopic and calorimetric studies on the binding of berberine Palmatine and coralyne to protonated rna structures
DNA and Cell Biology, 2009Co-Authors: Md Maidul Islam, Gopinatha Suresh KumarAbstract:Interaction of the protoberberine alkaloids berberine, Palmatine, and coralyne with the two double-stranded RNA homopolymers of cytidine-guanosine (CG) and inosine-cytidine (IC) sequences in the protonated conformation was investigated using various biophysical techniques. All the three alkaloids bound polyC(+)G in a cooperative way. The binding of coralyne to both the polyribonucleotides was stronger than that of berberine and Palmatine. Evidence for the intercalative binding of coralyne was revealed from fluorescence quenching studies. Isothermal titration calorimetry results suggested that the binding of berberine to both the polymers and Palmatine to polyIC(+) was very weak while that of Palmatine and coralyne to polyC(+)G and polyIC(+) was predominantly entropy driven. Circular dichroic results provided evidence for the perturbation of the RNA conformation with the bound coralyne in a more deeply intercalated position compared to berberine and Palmatine as revealed by induced circular dichroism peaks. Taken together, the present study suggests that planarity of coralyne results in a more favorable and stronger binding to the double-stranded RNA conformations compared to berberine and Palmatine that may potentiate its use in RNA-targeted drug design.
Zhi-hong Jiang - One of the best experts on this subject based on the ideXlab platform.
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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.
Na Ning - One of the best experts on this subject based on the ideXlab platform.
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hypolipidemic effect and mechanism of Palmatine from coptis chinensis in hamsters fed high fat diet
Phytotherapy Research, 2015Co-Authors: Na Ning, Kai He, Yanzhi Wang, Hao Wu, Xuegang Li, Xiaoli YeAbstract:Palmatine (PAL) is one of the main alkaloids in Coptis chinensis. The present aim was to investigate the hypolipidemic effect and mechanism of Palmatine in hamsters fed with high-fat diet (HFD). PAL treatment decreased serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels, as well as increased fecal excretion of TC and total bile acids (TBA) in hyperlipidemic hamsters. Furthermore, PAL treatment up-regulated low-density lipoprotein receptor (LDLR) and cholesterol 7α-hydroxylase (CYP7A1) mRNA and protein expression and down-regulated apical sodium-dependent bile salt transporter (ASBT) mRNA and protein expression. These results demonstrated that PAL as a potential natural cholesterol lowering agent works by up-regulating LDLR and CYP7A1 mRNA and protein expression, down-regulating ASBT mRNA and protein expression, as well as enhancing fecal excretion of TC and TBA. The findings in our study suggest that Palmatine could be a potential natural agent for treating hyperlipidemia. Copyright © 2015 John Wiley & Sons, Ltd.
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hypolipidemic effect and mechanism of Palmatine from coptis chinensis in hamsters fed high fat diet
Phytotherapy Research, 2015Co-Authors: Na Ning, Yanzhi Wang, Zongyao ZouAbstract:Palmatine (PAL) is one of the main alkaloids in Coptis chinensis. The present aim was to investigate the hypolipidemic effect and mechanism of Palmatine in hamsters fed with high-fat diet (HFD). PAL treatment decreased serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels, as well as increased fecal excretion of TC and total bile acids (TBA) in hyperlipidemic hamsters. Furthermore, PAL treatment up-regulated low-density lipoprotein receptor (LDLR) and cholesterol 7α-hydroxylase (CYP7A1) mRNA and protein expression and down-regulated apical sodium-dependent bile salt transporter (ASBT) mRNA and protein expression. These results demonstrated that PAL as a potential natural cholesterol lowering agent works by up-regulating LDLR and CYP7A1 mRNA and protein expression, down-regulating ASBT mRNA and protein expression, as well as enhancing fecal excretion of TC and TBA. The findings in our study suggest that Palmatine could be a potential natural agent for treating hyperlipidemia.
Zongyao Zou - One of the best experts on this subject based on the ideXlab platform.
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hypolipidemic effect and mechanism of Palmatine from coptis chinensis in hamsters fed high fat diet
Phytotherapy Research, 2015Co-Authors: Na Ning, Yanzhi Wang, Zongyao ZouAbstract:Palmatine (PAL) is one of the main alkaloids in Coptis chinensis. The present aim was to investigate the hypolipidemic effect and mechanism of Palmatine in hamsters fed with high-fat diet (HFD). PAL treatment decreased serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels, as well as increased fecal excretion of TC and total bile acids (TBA) in hyperlipidemic hamsters. Furthermore, PAL treatment up-regulated low-density lipoprotein receptor (LDLR) and cholesterol 7α-hydroxylase (CYP7A1) mRNA and protein expression and down-regulated apical sodium-dependent bile salt transporter (ASBT) mRNA and protein expression. These results demonstrated that PAL as a potential natural cholesterol lowering agent works by up-regulating LDLR and CYP7A1 mRNA and protein expression, down-regulating ASBT mRNA and protein expression, as well as enhancing fecal excretion of TC and TBA. The findings in our study suggest that Palmatine could be a potential natural agent for treating hyperlipidemia.
Xiaoli Ye - One of the best experts on this subject based on the ideXlab platform.
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hypolipidemic effect and mechanism of Palmatine from coptis chinensis in hamsters fed high fat diet
Phytotherapy Research, 2015Co-Authors: Na Ning, Kai He, Yanzhi Wang, Hao Wu, Xuegang Li, Xiaoli YeAbstract:Palmatine (PAL) is one of the main alkaloids in Coptis chinensis. The present aim was to investigate the hypolipidemic effect and mechanism of Palmatine in hamsters fed with high-fat diet (HFD). PAL treatment decreased serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels, as well as increased fecal excretion of TC and total bile acids (TBA) in hyperlipidemic hamsters. Furthermore, PAL treatment up-regulated low-density lipoprotein receptor (LDLR) and cholesterol 7α-hydroxylase (CYP7A1) mRNA and protein expression and down-regulated apical sodium-dependent bile salt transporter (ASBT) mRNA and protein expression. These results demonstrated that PAL as a potential natural cholesterol lowering agent works by up-regulating LDLR and CYP7A1 mRNA and protein expression, down-regulating ASBT mRNA and protein expression, as well as enhancing fecal excretion of TC and TBA. The findings in our study suggest that Palmatine could be a potential natural agent for treating hyperlipidemia. Copyright © 2015 John Wiley & Sons, Ltd.
