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1.
Bioorg Med Chem Lett ; 109: 129825, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-38823730

RESUMO

Human African trypanosomiasis, or sleeping sickness, is a neglected tropical disease caused by Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense and is invariably fatal unless treated. Current therapies present limitations in their application, parasite resistance, or require further clinical investigation for wider use. Our work, informed by previous findings, presents novel 4-[4-(4-methylpiperazin-1-yl)phenyl]-6-arylpyrimidine derivatives with promising antitrypanosomal activity. In particular, 32 exhibits an in vitro EC50 value of 0.5 µM against Trypanosoma brucei rhodesiense, and analogues 29, 30 and 33 show antitrypanosomal activities in the <1 µM range. We have demonstrated that substituted 4-[4-(4-methylpiperazin-1-yl)phenyl]-6-arylpyrimidines present promising antitrypanosomal hit molecules with potential for further preclinical development.


Assuntos
Pirimidinas , Tripanossomicidas , Pirimidinas/farmacologia , Pirimidinas/química , Pirimidinas/síntese química , Tripanossomicidas/farmacologia , Tripanossomicidas/química , Tripanossomicidas/síntese química , Relação Estrutura-Atividade , Testes de Sensibilidade Parasitária , Estrutura Molecular , Trypanosoma brucei brucei/efeitos dos fármacos , Humanos , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Relação Dose-Resposta a Droga , Tripanossomíase Africana/tratamento farmacológico
2.
Molecules ; 29(2)2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38257336

RESUMO

Naturally occurring stilbenoids, such as the (E)-stilbenoid resveratrol and the (Z)-stilbenoid combretastatin A4, have been considered as promising lead compounds for the development of anticancer drugs. The antitumour properties of stilbenoids are known to be modulated by cytochrome P450 enzymes CYP1A1 and CYP1B1, which contribute to extrahepatic phase I xenobiotic and drug metabolism. Thirty-four methyl ether analogues of resveratrol were synthesised, and their anticancer properties were assessed, using the MTT cell proliferation assay on a panel of human breast cell lines. Breast tumour cell lines that express CYP1 were significantly more strongly affected by the resveratrol analogues than the cell lines that did not have CYP1 activity. Metabolism studies using isolated CYP1 enzymes provided further evidence that (E)-stilbenoids can be substrates for these enzymes. Structures of metabolic products were confirmed by comparison with synthetic standards and LC-MS co-elution studies. The most promising stilbenoid was (E)-4,3',4',5'-tetramethoxystilbene (DMU212). The compound itself showed low to moderate cytotoxicity, but upon CYP1-catalysed dealkylation, some highly cytotoxic metabolites were formed. Thus, DMU212 selectively affects proliferation of cells that express CYP1 enzymes.


Assuntos
Citocromo P-450 CYP1A1 , Família 1 do Citocromo P450 , Humanos , Resveratrol/farmacologia , Catálise , Linhagem Celular Tumoral
3.
Crit Rev Food Sci Nutr ; 63(16): 2773-2789, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-34554029

RESUMO

As a major ubiquitous secondary metabolite, flavonoids are widely distributed in planta. Among flavonoids, kaempferol is a typical natural flavonol in diets and medicinal plants with myriad bioactivities, such as anti-inflammatory activity, anti-cancer activity, antioxidant activity, and anti-diabetic activity. However, the natural sources, absorption and metabolism as well as the bioactivities of kaempferol have not been reviewed comprehensively and systematically. This review highlights the latest research progress and the effect of kaempferol in the prevention and treatment of various chronic diseases, as well as its protective health effects, and provides a theoretical basis for future research to be used in nutraceuticals. Further, comparison of the different extraction and analytical methods are presented to highlight the most optimum for PG recovery and its detection in plasma and body fluids. Such review aims at improving the value-added applications of this unique dietary bioactive flavonoids at commercial scale and to provide a reference for its needed further development.


Assuntos
Flavonoides , Quempferóis , Quempferóis/farmacologia , Quempferóis/metabolismo , Flavonoides/farmacologia , Flavonoides/metabolismo , Polifenóis , Antioxidantes/farmacologia , Suplementos Nutricionais
4.
Chem Biodivers ; 19(10): e202200352, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36149030

RESUMO

Polydatin or piceid, is the 3-O-glucoside of resveratrol and is found abundantly in grapes, peanuts, wine, beer, and cacao products. Although anticancer activity of polydatin was reported before, and potential antiproliferative mechanisms of polydatin have been proposed, its direct effects on DNA and inhibitory potential against topoisomerase enzymes have remained unknown. In this study we aimed to reveal the link between polydatin's effects on DNA and DNA-topoisomerases and its antiproliferative promise. For this purpose, we evaluated the effects of polydatin on DNA and DNA topoisomerase using in vitro and in silico techniques. Polydatin was found to protect DNA against Fenton reaction-induced damage while not showing any hydrolytic nuclease effect. Further, polydatin inhibited topoisomerase II but not topoisomerase I. According to molecular docking studies, polydatin preferably showed minor groove binding to DNA where the stilbene moiety was important for binding to the DNA-topoisomerase II complex. As a result, topoisomerase II inhibition might be another anticancer mechanism of polydatin.


Assuntos
Estilbenos , Resveratrol , Simulação de Acoplamento Molecular , Estilbenos/farmacologia , Estilbenos/química , Glucosídeos/farmacologia , DNA Topoisomerases Tipo II , DNA/metabolismo
5.
Molecules ; 27(22)2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-36431828

RESUMO

The importance of the circadian clock in maintaining human health is now widely acknowledged. Dysregulated and dampened clocks may be a common cause of age-related diseases and metabolic syndrome Thus, circadian clocks should be considered as therapeutic targets to mitigate disease symptoms. This review highlights a number of dietary compounds that positively affect the maintenance of the circadian clock. Notably the polymethoxyflavone nobiletin has shown some encouraging results in pre-clinical experiments. Although many more experiments are needed to fully elucidate its exact mechanism of action, it is a promising candidate with potential as a chronotherapeutic agent.


Assuntos
Citrus , Flavonas , Síndrome Metabólica , Humanos , Ritmo Circadiano , Síndrome Metabólica/tratamento farmacológico , Flavonas/farmacologia
6.
Mol Pharm ; 18(12): 4256-4271, 2021 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-34723557

RESUMO

Artemisinin (ART) is a most promising antimalarial agent, which is both effective and well tolerated in patients, though it has therapeutic limitations due to its low solubility, bioavailability, and short half-life. The objective of this work was to explore the possibility of formulating ART cocrystals, i.e., artemisinin-orcinol (ART-ORC) and artemisinin-resorcinol (ART2-RES), as oral dosage forms to deliver ART molecules for bioavailability enhancement. This is the first part of the study, aiming to develop a simple and effective formulation, which can then be tested on an appropriate animal model (i.e., mouse selected for in vivo study) to evaluate their preclinical pharmacokinetics for further development. In the current work, the physicochemical properties (i.e., solubility and dissolution rate) of ART cocrystals were measured to collect information necessary for the formulation development strategy. It was found that the ART solubility can be increased significantly by its cocrystals, i.e., 26-fold by ART-ORC and 21-fold by ART2-RES, respectively. Screening a set of polymers widely used in pharmaceutical products, including poly(vinylpyrrolidone), hydroxypropyl methylcellulose, and hydroxypropyl methylcellulose acetate succinate, based on the powder dissolution performance parameter analysis, revealed that poly(vinylpyrrolidone)/vinyl acetate (PVP-VA) was the most effective crystallization inhibitor. The optimal concentration of PVP-VA at 0.05 mg/mL for the formulation was then determined by a dissolution/permeability method, which represented a simplified permeation model to simultaneously evaluate the effects of a crystallization inhibitor on the dissolution and permeation performance of ART cocrystals. Furthermore, experiments, including surface dissolution of single ART cocrystals monitored by Raman spectroscopy, scanning electron microscopy and diffusion properties of ART in solution measured by 1H and diffusion-ordered spectroscopy nuclear magnetic resonance spectroscopy, provided insights into how the excipient affects the ART cocrystal dissolution performance and bioavailability.


Assuntos
Artemisininas/química , Artemisininas/farmacocinética , Disponibilidade Biológica , Cristalização , Difusão , Composição de Medicamentos , Excipientes/química , Polímeros/química , Solubilidade
7.
Mol Pharm ; 18(12): 4272-4289, 2021 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-34748332

RESUMO

We report the evaluation and prediction of the pharmacokinetic (PK) performance of artemisinin (ART) cocrystal formulations, that is, 1:1 artemisinin/orcinol (ART-ORC) and 2:1 artemisinin/resorcinol (ART2-RES), using in vivo murine animal and physiologically based pharmacokinetic (PBPK) models. The efficacy of the ART cocrystal formulations along with the parent drug ART was tested in mice infected with Plasmodium berghei. When given at the same dose, the ART cocrystal formulation showed a significant reduction in parasitaemia at day 4 after infection compared to ART alone. PK parameters including Cmax (maximum plasma concentration), Tmax (time to Cmax), and AUC (area under the curve) were obtained by determining drug concentrations in the plasma using liquid chromatography-high-resolution mass spectrometry (LC-HRMS), showing enhanced ART levels after dosage with the cocrystal formulations. The dose-response tests revealed that a significantly lower dose of the ART cocrystals in the formulation was required to achieve a similar therapeutic effect as ART alone. A PBPK model was developed using a PBPK mouse simulator to accurately predict the in vivo behavior of the cocrystal formulations by combining in vitro dissolution profiles with the properties of the parent drug ART. The study illustrated that information from classical in vitro and in vivo experimental investigations of the parent drug of ART formulations can be coupled with PBPK modeling to predict the PK parameters of an ART cocrystal formulation in an efficient manner. Therefore, the proposed modeling strategy could be used to establish in vitro and in vivo correlations for different cocrystals intended to improve dissolution properties and to support clinical candidate selection, contributing to the assessment of cocrystal developability and formulation development.


Assuntos
Artemisininas/farmacocinética , Animais , Artemisininas/química , Disponibilidade Biológica , Cristalização , Relação Dose-Resposta a Droga , Liberação Controlada de Fármacos , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Modelos Biológicos
8.
Phytochem Anal ; 32(1): 62-68, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32706176

RESUMO

INTRODUCTION: Analysis of biochemical pathways typically involves feeding a labelled precursor to an organism, and then monitoring the metabolic fate of the label. Initial studies used radioisotopes as a label and then monitored radioactivity in the metabolic products. As analytical equipment improved and became more widely available, preference shifted the use stable 'heavy' isotopes like deuterium (2 H)-, carbon-13 (13 C)- and nitrogen-15 (15 N)-atoms as labels. Incorporation of the labels could be monitored by mass spectrometry (MS), as part of a hyphenated tool kits, e.g. Liquid chromatography (LC)-MS, gas chromatography (GC)-MS, LC-MS/MS. MS offers great sensitivity but the exact location of an isotope label in a given metabolite cannot always be unambiguously established. Nuclear magnetic resonance (NMR) can also be used to pick up signals of stable isotopes, and can give information on the precise location of incorporated label in the metabolites. However, the detection limit for NMR is quite a bit higher than that for MS. OBJECTIVES: A number of experiments involving feeding stable isotope-labelled precursors followed by NMR analysis of the metabolites is presented. The aim is to highlight the use of NMR analysis in identifying the precise fate of isotope labels after precursor feeding experiments. As more powerful NMR equipment becomes available, applications as described in this review may become more commonplace in pathway analysis. CONCLUSION AND PROSPECTS: NMR is a widely accepted tool for chemical structure elucidation and is now increasingly used in metabolomic studies. In addition, NMR, combined with stable isotope feeding, should be considered as a tool for metabolic flux analyses.


Assuntos
Metabolismo Secundário , Espectrometria de Massas em Tandem , Isótopos de Carbono , Cromatografia Líquida , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética
9.
Molecules ; 26(13)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202844

RESUMO

The COVID-19 pandemic, as well as the more general global increase in viral diseases, has led researchers to look to the plant kingdom as a potential source for antiviral compounds. Since ancient times, herbal medicines have been extensively applied in the treatment and prevention of various infectious diseases in different traditional systems. The purpose of this review is to highlight the potential antiviral activity of plant compounds as effective and reliable agents against viral infections, especially by viruses from the coronavirus group. Various antiviral mechanisms shown by crude plant extracts and plant-derived bioactive compounds are discussed. The understanding of the action mechanisms of complex plant extract and isolated plant-derived compounds will help pave the way towards the combat of this life-threatening disease. Further, molecular docking studies, in silico analyses of extracted compounds, and future prospects are included. The in vitro production of antiviral chemical compounds from plants using molecular pharming is also considered. Notably, hairy root cultures represent a promising and sustainable way to obtain a range of biologically active compounds that may be applied in the development of novel antiviral agents.


Assuntos
Antivirais/farmacologia , Tratamento Farmacológico da COVID-19 , Extratos Vegetais/farmacologia , Plantas Medicinais/química , SARS-CoV-2/efeitos dos fármacos , Antivirais/química , Antivirais/imunologia , Antivirais/uso terapêutico , Simulação por Computador , Humanos , Agricultura Molecular/métodos , Extratos Vegetais/química , Extratos Vegetais/imunologia , Extratos Vegetais/uso terapêutico , Plantas Medicinais/imunologia , SARS-CoV-2/fisiologia , Replicação Viral/efeitos dos fármacos
10.
Phytochem Anal ; 31(3): 314-321, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31997462

RESUMO

INTRODUCTION: Tyrosinase is a multifunctional copper-containing oxidase enzyme that catalyses the first steps in the formation of melanin pigments. Identification of tyrosinase inhibitors is of value for applications in cosmetics, medicine and agriculture. OBJECTIVE: To develop an analytical method that allows identification of drug-like natural products that can be further developed as tyrosinase inhibitors. Results of in vitro and in silico studies will be compared in order to gain a deeper insight into the mechanism of action of enzyme inhibition. METHOD: Using an in vitro assay we tested tyrosinase inhibitor effects of five structurally related flavones, i.e. luteolin (1), eupafolin (2), genkwanin (3), nobiletin (4), and chrysosplenetin (5). The strongest inhibitors were further investigated in silico, using enzyme docking simulations. RESULTS: All compounds tested showed modest tyrosinase inhibitory effect compared to the positive control, kojic acid. The polymethoxy flavones 4 and 5 exhibited the strongest tyrosinase inhibitory effect with the half maximal inhibitory concentration (IC50 ) values of 131.92 ± 1.75 µM and 99.87 ± 2.38 µM respectively. According to kinetic analysis 2, 4 and 5 were competitive inhibitors, whereas 1 and 3 were non-competitive inhibitors of tyrosinase. Docking studies indicated that methoxy groups on 4 and 5 caused steric hindrance which prevented alternative binding modes in the tyrosinase; the methoxy groups on the B-ring of these flavones faced the catalytic site in the enzyme. CONCLUSIONS: The docking simulations nicely complemented the in vitro kinetic studies, opening the way for the development of predictive models for use in drug design.


Assuntos
Agaricales , Flavonas , Inibidores Enzimáticos , Cinética , Simulação de Acoplamento Molecular , Estrutura Molecular , Monofenol Mono-Oxigenase , Relação Estrutura-Atividade
11.
Bioorg Med Chem Lett ; 29(11): 1403-1406, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30935796

RESUMO

As part of a programme to develop anticancer prodrugs which are activated by cytochrome P450 (CYP)1B1, a library of 4,6-diaryl-2-pyridones was synthesised in yields of 6-60% from the corresponding chalcones. A number of these derivatives showed promising antiproliferative activities in human breast cancer cell lines which express CYP1B1 and CYP1A1, while showing little toxicity towards a non-tumour breast cell line with no CYP expression. Metabolism studies provided evidence supporting the involvement of CYP1 enzymes in the bioactivation of these compounds.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Citocromo P-450 CYP1A1/antagonistas & inibidores , Citocromo P-450 CYP1B1/antagonistas & inibidores , Piridonas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Citocromo P-450 CYP1B1/genética , Citocromo P-450 CYP1B1/metabolismo , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Células MCF-7 , Estrutura Molecular , Piridonas/síntese química , Piridonas/química , Relação Estrutura-Atividade
12.
Skin Pharmacol Physiol ; 31(2): 95-98, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29393263

RESUMO

Saffron extracts have a long history of application as skin protectant, possibly due to their ability to scavenge free radicals. In this work, the performance of a hydrogel enriched with antioxidant compounds isolated from saffron crocus (Crocus sativus L.) petals was tested. These hydrogels could be considered as new drug delivery system. Hydrogels are crosslinked polymer networks that absorb large quantities of water but retain the properties of a solid, thus making ideal dressings for sensitive skin. We tested antioxidant-enriched hydrogels on primary mouse fibroblasts. Hydrogels enriched with kaempferol and crocin extracted from saffron petals showed good biocompatibility with in vitro cultured fibroblasts. These new types of hydrogels may find applications in wound treatment and/or beautification.


Assuntos
Antioxidantes/farmacologia , Crocus/química , Hidrogéis/farmacologia , Cicatrização/efeitos dos fármacos , Animais , Antioxidantes/química , Carotenoides/química , Carotenoides/farmacologia , Sistemas de Liberação de Medicamentos/métodos , Fibroblastos/efeitos dos fármacos , Flores/química , Hidrogéis/química , Quempferóis/farmacologia , Camundongos , Extratos Vegetais/química , Extratos Vegetais/farmacologia
13.
Int J Mol Sci ; 19(4)2018 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-29587452

RESUMO

Linum flavum hairy root lines were established from hypocotyl pieces using Agrobacterium rhizogenes strains LBA 9402 and ATCC 15834. Both strains were effective for transformation but induction of hairy root phenotype was more stable with strain ATCC 15834. Whereas similar accumulation patterns were observed in podophyllotoxin-related compounds (6-methoxy-podophyllotoxin, podophyllotoxin and deoxypodophyllotoxin), significant quantitative variations were noted between root lines. The influence of culture medium and various treatments (hormone, elicitation and precursor feeding) were evaluated. The highest accumulation was obtained in Gamborg B5 medium. Treatment with methyl jasmonate, and feeding using ferulic acid increased the accumulation of aryltetralin lignans. These results point to the use of hairy root culture lines of Linum flavum as potential sources for these valuable metabolites as an alternative, or as a complement to Podophyllum collected from wild stands.


Assuntos
Antineoplásicos Fitogênicos/metabolismo , Linho/citologia , Lignanas/metabolismo , Acetatos/farmacologia , Antineoplásicos Fitogênicos/análise , Ácidos Cumáricos/farmacologia , Meios de Cultura/química , Meios de Cultura/farmacologia , Ciclopentanos/farmacologia , Linho/efeitos dos fármacos , Linho/crescimento & desenvolvimento , Linho/metabolismo , Lignanas/análise , Estrutura Molecular , Oxilipinas/farmacologia , Raízes de Plantas/citologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Técnicas de Cultura de Tecidos/métodos
14.
Phytother Res ; 31(3): 410-417, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28124400

RESUMO

Acne vulgaris, a chronic condition associated with overgrowth of Propionibacterium acnes and Staphylococcus epidermidis, is commonly treated with antibiotics. However, the emergence of antibiotic resistance has resulted in a need for alternative therapies. The aim of this study is to develop a topical preparation incorporating essential oils (EOs) for use against acne-associated bacteria and assess its efficacy against prescription therapies Dalacin T and Stiemycin. Antimicrobial screening of rosewood, clove bud and litsea EOs was conducted before interactions between binary and ternary combinations were determined against P. acnes and S. epidermidis (type and clinical isolates) using minimum inhibitory concentrations and fractional inhibitory concentrations. The EOs were characterised by both gas chromatography-mass spectrometry and nuclear magnetic resonance. A combination of 0.53 mg/mL litsea, 0.11 mg/mL rosewood and 0.11 mg/mL clove bud was formulated into herbal distillates and compared with Dalacin T and Stiemycin against antibiotic sensitive and resistant isolates (erythromycin). The distillate with EO had synergistic activity against P. acnes (7log10 reduction) and indifferent activity against S. epidermidis (6log10 reduction); antimicrobial activity was either significantly (p ≤ 0.05) more antimicrobial or equivalent to that of Dalacin T and Stiemycin. This formulation may serve as a valuable alternative for the control of acne vulgaris-associated bacteria. Copyright © 2017 John Wiley & Sons, Ltd.


Assuntos
Acne Vulgar/microbiologia , Antibacterianos/administração & dosagem , Óleos Voláteis/administração & dosagem , Óleos Voláteis/farmacologia , Propionibacterium acnes/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Acne Vulgar/tratamento farmacológico , Administração Tópica , Antibacterianos/farmacologia , Anti-Infecciosos/administração & dosagem , Clindamicina/administração & dosagem , Clindamicina/farmacologia , Combinação de Medicamentos , Sinergismo Farmacológico , Eritromicina/administração & dosagem , Eritromicina/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Propionibacterium acnes/crescimento & desenvolvimento , Staphylococcus epidermidis/crescimento & desenvolvimento
16.
Front Nutr ; 10: 1020950, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37032781

RESUMO

Diabetes mellitus is a chronic metabolic disorder caused either by inadequate insulin secretion, impaired insulin function, or both. Uncontrolled diabetes is characterized by hyperglycemia which over time leads to fatal damage to both macro-and microvascular systems, causing complications such as cardiovascular diseases, retinopathy and nephropathy. Diabetes management is conventionally delivered through modifications of diet and lifestyle and pharmacological treatment, using antidiabetic drugs, and ultimately insulin injections. However, the side effects and financial cost of medications often reduce patient compliance to treatment, negatively affecting their health outcomes. Natural phytochemicals from edible plants such as fruits and vegetables (F&V) and medicinal herbs have drawn a growing interest as potential therapeutic agents for treating diabetes and preventing the onset and progression of diabetic complications. Flavonoids, the most abundant polyphenols in the human diet, have shown antidiabetic effects in numerous in vitro and preclinical studies. The underlying mechanisms have been linked to their antioxidant, anti-inflammatory and immunomodulatory activities. Carotenoids, another major group of dietary phytochemicals, have also shown antidiabetic potential in recent in vitro and in vivo experimental models, possibly through a mechanism of action similar to that of flavonoids. However, scientific evidence on the efficacy of these phytochemicals in treating diabetes or preventing the onset and progression of its complications in clinical settings is scarce, which delays the translation of animal study evidence to human applications and also limits the knowledge on their modes of actions in diabetes management. This review is aimed to highlight the potential roles of flavonoids and carotenoids in preventing or ameliorating diabetes-related complications based on in vivo study evidence, i.e., an array of preclinical animal studies and human intervention trials. The current general consensus of the underlying mechanisms of action exerted by both groups of phytochemicals is that their anti-inflammatory action is key. However, other potential mechanisms of action are considered. In total, 50 in vivo studies were selected for a review after a comprehensive database search via PubMed and ScienceDirect from January 2002 to August 2022. The key words used for analysis are type-2 diabetes (T2DM), diabetic complications, flavonoids, carotenoids, antioxidant, anti-inflammatory, mechanisms of prevention and amelioration, animal studies and human interventions.

17.
Immunobiology ; 228(1): 152303, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36495597

RESUMO

Candida, as a part of the human microbiota, can cause opportunistic infections that are either localised or systemic candidiasis. Emerging resistance to the standard antifungal drugs is associated with increased mortality rate due to invasive Candida infections, particularly in immunocompromised patients. While there are several species of Candida, an increasing number of Candida tropicalis isolates have been recently reported from patients with invasive candidiasis or inflammatory bowel diseases. In order to establish infections, C. tropicalis has to adopt several strategies to escape the host immune attack. Understanding the immune evasion strategies is of great importance as these can be exploited as novel therapeutic targets. C. albicans pH-related antigen 1 (CaPra1), a surface bound and secretory protein, has been found to interact strongly with the immune system and help in complement evasion. However, the role of C. tropicalis Pra1 (CtPra1) and its interaction with the complement is not studied yet. Thus, we characterised how pH-related antigen 1 of C. tropicalis (CtPra1) interacts with some of the key complement proteins of the innate immune system. CtPra1 was recombinantly produced using a Kluyveromyces lactis yeast expression system. Recombinant CtPra1, was found to bind human C3 and C3b, central molecules of the complement pathways that are important components of the innate immune system. It was also found to bind human complement regulatory proteins factor-H and C4b-binding protein (C4BP). CtPra1-factor-H and CtPra1-C4BP interactions were found to be ionic in nature as the binding intensity affected by high sodium chloride concentrations. CtPra1 inhibited functional complement activation with different effects on classical (∼20 %), lectin (∼25 %) and alternative (∼30 %) pathways. qPCR experiments using C. tropicalis clinical isolates (oral, blood and peritoneal fluid) revealed relatively higher levels of expression of CtPra1 gene when compared to the reference strain. Native CtPra1 was found to be expressed both as membrane-bound and secretory forms in the clinical isolates. Thus, C. tropicalis appears to be a master of immune evasion by using Pra1 protein. Further investigation using in-vivo models will help ascertain if these proteins can be novel therapeutic targets.


Assuntos
Candida tropicalis , Candidíase , Proteína de Ligação ao Complemento C4b , Proteínas Fúngicas , Humanos , Candida tropicalis/imunologia , Complemento C3/metabolismo , Complemento C3b/metabolismo , Proteína de Ligação ao Complemento C4b/metabolismo , Concentração de Íons de Hidrogênio , Ligação Proteica , Proteínas Fúngicas/imunologia , Candidíase/imunologia , Candidíase/microbiologia
18.
Food Chem ; 366: 130521, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34314931

RESUMO

Though the instability of polyphenols in cell culture experiment has been investigated previously, the underlying mechanism is not completely clear yet. Therefore, in this study, the stability of epigallocatechin gallate (EGCG) in cell culture medium DMEM was investigated at 4 °C and 37 °C via UPLC-MS-MS analysis followed by determination of the antioxidant capacity of EGCG. EGCG was instable in DMEM and formed various degradation products derived from its dimer with increasing incubation time with many isomers being formed at both temperatures. The dimer products were more stable at 4 °C than at 37 °C. The structure and formation mechanism of five products were analyzed with four unidentified. Ascorbic acid significantly improved the stability of EGCG by protecting EGCG from auto-oxidation in DMEM, particularly at 4 °C. The antioxidative activity of EGCG in DMEM was determined by DPPH, ABTS and FRAP assay. The antioxidative properties of EGCG continuously decreased over 8 h in DMEM, which was consistent with its course of degradation.


Assuntos
Antioxidantes , Espectrometria de Massas em Tandem , Catequina/análogos & derivados , Cromatografia Líquida , Oxirredução
19.
Immunobiology ; 227(6): 152263, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36063565

RESUMO

Candida tropicalisis an opportunistic fungal pathogen and is one of the most frequently isolated non-albicans species. It can cause localised as well as invasive systemic infections particularly in immunocompromised patients. Increased resistance to common anti-fungal drugs is an emerging problem. In order to establish disseminated infections, Candida has evolved several strategies to escape the host immune system. A detailed understanding of how C. tropicalis escapes the host immune attack is needed as it can help develop novel anti-fungal therapies. Secreted aspartyl proteinases (Saps) of C. albicans have been shown to be determinants of virulence and immune evasion. However, the immune evasion properties of C. tropicalis Saps have been poorly characterised. This study investigated the immune evasion properties of C. tropicalis secreted aspartic protease 1 (Sapt1).Sapt1 was recombinantly produced using a Kluyveromyces lactis yeast expression system. A range of complement proteins and immunogloublins were screened to test if Sapt1 had any proteolytic activity. Sapt1 efficiently cleaved human mannose-binding lectin (MBL) and collectin-11, which are the initiating molecules of the lectin pathway of the complement system, but not l-ficolin. In addition, Sapt1 cleaved DC-SIGN, the receptor on antigen presenting dendritic cells. Proteolysis was prominent in acidic condition (pH 5.2), a characteristic of aspartyl protease. No proteolytic activity was detected against complement proteins C1q, C3, C3b, IgG and IgA. In view of the ability of Sapt1 to cleave MBL and collectin-11, we found that Sapt1 could prevent activation of the complement lectin pathway. RT-qPCR analysis using three different C. tropicalis clinical isolates (oral, blood and peritoneal dialysis fluid) revealed relatively higher levels of mRNA expression of Sapt1 gene when compared to a reference strain; Sapt1 protein was found to be secreted by all the tested strains. Lectin pathway and its initiating components are crucial to provide front line defence against Candida infections. For the first time, we have shown that a Candida protease can proteolytically degrade the key initiating components of lectin pathway and inhibit complement activation. Findings from this study highlight the importance of exploring Sapt1 as a potential therapeutic target. We conclude that C. tropicalis secretes Sapt1 to target the complement lectin pathway, a key pattern recognition and clearance mechanism, for its survival and pathogenesis.


Assuntos
Ácido Aspártico Proteases , Lectina de Ligação a Manose , Humanos , Candida tropicalis/metabolismo , Lectina de Ligação a Manose da Via do Complemento , Lectina de Ligação a Manose/metabolismo , Candida albicans/fisiologia , Candida , Ácido Aspártico Proteases/genética , Ácido Aspártico Proteases/metabolismo , Lectinas/metabolismo , Proteínas do Sistema Complemento/metabolismo
20.
Eur J Med Chem ; 209: 112871, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33070078

RESUMO

Human African trypanosomiasis, or sleeping sickness, is a neglected tropical disease caused by Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense which seriously affects human health in Africa. Current therapies present limitations in their application, parasite resistance, or require further clinical investigation for wider use. Our work herein describes the design and syntheses of novel antitrypanosomal 4-phenyl-6-(pyridin-3-yl)pyrimidines, with compound 13, the 4-(2-methoxyphenyl)-6-(pyridine-3-yl)pyrimidin-2-amine demonstrating an IC50 value of 0.38 µM and a promising off-target ADME-Tox profile in vitro. In silico molecular target investigations showed rhodesain to be a putative candidate, supported by STD and WaterLOGSY NMR experiments, however, in vitro evaluation of compound 13 against rhodesain exhibited low experimental inhibition. Therefore, our reported library of drug-like pyrimidines present promising scaffolds for further antikinetoplastid drug development for both phenotypic and target-based drug discovery.


Assuntos
Pirimidinas/química , Pirimidinas/farmacologia , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Tripanossomíase Africana/tratamento farmacológico , Animais , Linhagem Celular , Descoberta de Drogas , Humanos , Modelos Moleculares , Ratos
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