New perspectives on natural products in TB drug research

Pauli, Guido F.; Case, Ryan; Inui, Taichi; Wang, Yuehong; Cho, Sang Hyun; Fischer, Nikolaus H.; Franzblau, Scott G.

doi:10.1016/j.lfs.2005.09.004

Cited by 137 publications

(162 citation statements)

References 91 publications

(79 reference statements)

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“…Term 11 is the counterpart to X i +ΔX i in VelMod approach, and is proportional to the amount of stationary phase pumped into the column during sweep elution, Stage II; hence (12) This is solved as (13) Thus, at the point when the first droplet of stationary phase is ready to leave the column ( Figure 2D), solute i has traveled a volume represented by term 14 (14) This can be simplified to (15) Considering eq 1, term 15 is the same as …”

Section: The Volume Model (Volmod) Of Solute Retention In the Elutionmentioning

confidence: 99%

“…As i keeps traveling by ΔV i during the sweep stage until there is no more mobile phase behind it, the amount of stationary phase that needs to be pumped is V M ×V CM ×V Ri −1 + ΔV i . At the point where no more mobile phase is behind it (Figure 2C), solute i has traveled a column volume represented by term 11Term 11 is the counterpart to X i +ΔX i in VelMod approach, and is proportional to the amount of stationary phase pumped into the column during sweep elution, Stage II; hence (12) This is solved as (13) Thus, at the point when the first droplet of stationary phase is ready to leave the column ( Figure 2D), solute i has traveled a volume represented by term 14 (14) This can be simplified to (15) Considering eq 1, term 15 is the same as …”

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Elution−Extrusion Countercurrent Chromatography: Theory and Concepts in Metabolic Analysis

et al. 2007

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Elution-extrusion countercurrent chromatography (EECCC) takes full advantage of the liquid nature of the stationary phase in CCC by combining regular chromatographic elution with stationary phase extrusion. EECCC is shown to be a three-stage process consisting of classical elution (I), sweeping elution (II), and extrusion (III). After only two column volumes of solvent, it rapidly yields a highresolution chromatogram that covers an extended polarity range of solutes. As hydrophilicity/ lipophilicity balance is a crucial discriminatory property of analytes in highly complex mixtures such as metabolomic samples, the precise determination of CCC distribution constants (K D ) is vital to the analysis of metabolomes and other complex biological matrices. This work builds the EECCC concept by performing a full theoretical treatment and providing equations for retention volumes, peak widths, resolution factors, and distribution constants. Experimental validation utilizes natural products standards that resemble the zero to infinity range of the polarity continuum. EECCC extends the "sweet spot" of high-resolution in CCC, and provides access to the otherwise practically unapproachable high-K D portion of the high-resolution chromatograms in CCC. Its improved capabilities of K D -targeting make EECCC a promising tool for the specific analysis of "small" molecules in complex samples such as in metabolomic fingerprinting and footprinting.Countercurrent chromatography (CCC) is a liquid chromatography technique that uses a liquid stationary phase. 1-3 Typically, CCC employs biphasic liquid systems to separate solutes. One major advantage of working with a liquid as opposed to a solid stationary phase is that the solutes have access to the whole volume of the stationary phase. Historically, CCC has primarily been used as a preparative separation technique, 4 in particular for the separation and purification of natural products (5 -8 and references therein). Regarding CCC development and application, the entire body of relevant literature indicates a strong preference for separation problems that involve particularly complex samples, mainly of biological origin. Interestingly, * Corresponding authors. E-mail: berthodfv@univ-lyon1.fr and gfp@uic.edu. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript this inclination connects CCC to a recently evolving area of analytical chemistry dealing with the analysis of natural metabolites in their entirety, i.e., metabolomics.It is the combination of the complexity and the presence of "background" matrices that represents the major analytical challenge in the current state of metabolomics research 9 (and references therein). While, at present, the complexity of the biosynthetic metabolic cocktails can only be roughly approximated, with estimates ranging from 10 3 to >10 5 depending on the organism, any given metabolome undoubtedly represents a mixture of an extremely large number of "small" molecules originating from primary and secondary metabolism of the...

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Section: The Volume Model (Volmod) Of Solute Retention In the Elutionmentioning

confidence: 99%

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Elution−Extrusion Countercurrent Chromatography: Theory and Concepts in Metabolic Analysis

et al. 2007

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“…The advantage of subjecting the false positive extracts to further testing is that the probability of missing possible active fractions or compounds would be greatly reduced since all fractions were tested (Pauli et al, 2005).…”

Section: Biological Testingmentioning

confidence: 99%

Anti-mycobacterial assessment and characterization of 5-O-caffeoylquinic acid methyl ester and rutin from Pavetta crassipes

Odumosu¹,

Lough²,

Yakubu³

et al. 2016

J App Pharm Sci

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Pavetta crassipes leaf (Fam. Rubiaceae) is used as part of a combination herbal remedy for the treatment of tuberculosis (TB) and other respiratory infections in Nigerian ethno medicine. However, little scientific data is available to support the use in ethnomedical therapy so the objective of the study was to assess the antitubercular property and to identify the bioactive components. The dried powdered leaf was sequentially extracted with solvents to obtain hexane, dichloromethane, methanol and water extracts. Following which, the extracts were then screened against Mycobacterium aurum, a rapidly growing saprophytic mycobacterium species for activity. The methanol extract exhibited inhibitory activity at an MIC value of 250 µg/mL against M. aurum and two known polyphenolic compounds were isolated as 5-O-caffeoylquinic acid methyl ester and quercetin-3-rutinoside (rutin). Reversed phase semi-preparative HPLC, mass spectrometry and 1H and 13C NMR techniques were utilized in isolating and characterizing the two components. Th e assignments of the structures were consistent with data from the literature. The study has shown that the methanol extract has some activity and hyphenation of LC-MS can be used for the isolation of polyphenols from the methanol fraction without a rigorous purification process.

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“…Este método foi realizado para definir a interação entre os extratos e frações de I. lutea que apresentaram atividade antibacteriana nas concentrações utilizadas (≤ 200 µg/mL) e determinar a Concentração Inibitória Fracional destes (CIF) frente S. aureus. 21 Foram utilizadas placas de microtitulação de 96 poços, meio de cultivo Muller Hinton (Himedia ® ) e condições de incubação ao final da preparação do experimento de 24h a uma temperatura de 36ºC ± 1. As placas foram preparadas adicionando um dos compostos diluídos em série no eixo X e o outro composto, previamente diluído, …”

Section: Introductionunclassified

“…[26][27][28] Ao analisar a combinação das frações que apresentaram atividade antibacteriana (AcEO e MeOH) e a combinação dos extratos brutos etanólico e clorofórmico, podemos notar uma ação antibacteriana potencializada,-quando as frações são combinadas, podendo este fato estar ligado a uma possível interação ou aumento na taxa de constituintes fitoquímicos análogos com atividade antibacteriana. 21 Este fato demonstra que a combinação de produtos moderadamente ativos (como o caso da fração MeOH) decorre da possível ocorrência de substâncias ativos, as quais aumentam o potencial antibacteriano.…”

Section: Introductionunclassified

Avaliação de Ibicella lutea como agente antimicrobiano frente à Staphylococcus aureus

Volcão

Coelho

Vàsquez

et al. 2016

Rev Epidemiol Control Infect

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Exceto onde especificado diferentemente, a matéria publicada neste periódico é licenciada sob forma de uma licença Creative Commons -Atribuição 4. IS).Resultados: A fração de acetato de etila (AcOE) obteve o melhor potencial antibacteriano (6,25 µg/mL), entretanto nenhum dos compostos testados apresentaram atividade bactericida nas concentrações empregadas. Neste estudo pode-se observar uma ação aditiva entre as frações AcOE e metanólica (MeOH), sendo a interação entre os extratos brutos indiferente. De acordo com o teste de citotoxicidade, a fração AcOE apresentou um maior índice de sobrevivência das células macrofágicas (IC50%=30,35 µg/mL). Entretanto, quando calculado o IS, não houve resultados satisfatórios (IS < 10) para os extratos analisados. Conclusões: Neste estudo observou-se o potencial antibacteriano das frações AcOE e MeOH, assim como uma ação aditiva na combinação das frações, dando suporte para o isolamento e caracterização de seus componentes ativos. Apesar dos extratos não apresentarem um IS satisfatório, novos estudos de toxicidade devem ser realizados para determinar com segurança o potencial de uso dos produtos provenientes de I. lutea, como é o caso de medicamentos para uso tópico ou biocidas. Background and Objectives:The study aimed to evaluate the antibacterial activity of crude extracts and fractions of Ibicella lutea in inhibiting the growth of Staphylococcus aureus, by evaluating the combination of these compounds and their cytotoxic activity. Methods: To analyze the antibacterial activity of the extracts, the microdilution test in broth was used, followed by the checkerboard test. The extracts that showed antibacterial activity were submitted to the cytotoxicity test, with macrophage cells and determination of their Selectivity Index (SI). Results:The ethyl acetate fraction (AcOE) obtained the best antibacterial potential (6.25 μg/mL); however, none of the tested compounds showed bactericidal activity at the used concentrations. This study shows an additive action between the AcOE and methanolic fractions (MeOH), being the interaction between the crude extracts indifferent. According to the cytotoxicity test, the AcOE fraction showed a higher survival rate of macrophages (50%CI = 30.35 μg/mL). However, when the SI was calculated, there were no satisfactory results (SI <10) for the analyzed extracts. Conclusions:This study analyzed the antibacterial potential of the AcOE and MeOH fractions, as well as an additive action in the combination of the fractions, supporting the isolation and characterization of their active components. Although the extracts did not show a satisfactory SI, further toxicity studies should be carried out to safely determine the potential for use of products derived from I. lutea, for topical or biocidal use. RESUMO ABSTRACTRecebido em:

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New perspectives on natural products in TB drug research

Cited by 137 publications

References 91 publications

Elution−Extrusion Countercurrent Chromatography: Theory and Concepts in Metabolic Analysis

Elution−Extrusion Countercurrent Chromatography: Theory and Concepts in Metabolic Analysis

Anti-mycobacterial assessment and characterization of 5-O-caffeoylquinic acid methyl ester and rutin from Pavetta crassipes

Avaliação de Ibicella lutea como agente antimicrobiano frente à Staphylococcus aureus

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