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J Food Drug Anal ; 26(2): 487-496, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29567217


Herbal tea kinkéliba prepared from the leaves of Combretum micranthum has been widely consumed in West African countries for its flavor, nutritional and medicinal properties. Under bio-guided screening, the kinkéliba leaves were chemically investigated using various chromatographic and spectrometric methods that led to the identification of thirteen different flavonoid compounds. Further biological tests illustrated that the identified compounds may have synergistic effects to decrease the expression of phosphoenolpyruvate carboxykinase (PEPCK) mRNA and glucose production in an H4IIE hepatoma cell line, indicating its potential use for insulin-resistant diabetes treatment. Further in vivo study on C57BL/6J mice indicates that kinkéliba can lower plasma glucose levels in a dose-dependent manner without significant weight loss and toxicity. The ethyl acetate extract in rich of flavonoids could also increase the glucose tolerance (GT) after seven weeks' administrations. Both in vitro and in vivo experiments support a potential new application of kinkéliba leaves as an anti-diabetes agent.

ACS Appl Mater Interfaces ; 10(10): 8443-8450, 2018 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-29481051


While the antibacterial properties of silver nanoparticles (AgNPs) have been demonstrated across a spectrum of bacterial pathogens, the effects of AgNPs on the beneficial bacteria are less clear. To address this issue, we compared the antibacterial activity of AgNPs against two beneficial lactobacilli ( Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus casei) and two common opportunistic pathogens ( Escherichia coli and Staphylococcus aureus). Our results demonstrate that those lactobacilli are highly susceptible to AgNPs, while the opportunistic pathogens are not. Acidic environment caused by the lactobacilli is associated with the bactericidal effects of AgNPs. Our mechanistic study suggests that the acidic growth environment of lactobacilli promotes AgNP dissolution and hydroxyl radical (•OH) overproduction. Furthermore, increases in silver ions (Ag+) and •OH deplete the glutathione pool inside the cell, which is associated with the increase in cellular reactive oxygen species (ROS). High levels of ROS may further induce DNA damage and lead to cell death. When E. coli and S. aureus are placed in a similar acidic environment, they also become more susceptible to AgNPs. This study provides a mechanistic description of a pH-Ag+-•OH bactericidal pathway and will contribute to the responsible development of products containing AgNPs.

J Agric Food Chem ; 59(19): 10586-93, 2011 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-21879745


A rapid and comprehensive qualitative method has been developed to characterize the different classes of polyphenols, such as anthocyanins, flavonols, phenolic acids, and flavanols/proanthocyanidins, in grape products. The detection was achieved by two runs with the same LC gradient in different MS ionization modes and mobile phase modifiers (positive ionization mode and 0.4% trifluoroacetic acid for anthocyanins and flavonols; negative ionization mode and 0.1% formic acid for phenolic acids and flavanols). From an analysis of the MS and UV data and in comparison with the authenticated standards, a total of 53 compounds were identified, including 33 anthocyanins, 12 flavonols, 4 phenolic acids, and 4 flavanols/proanthocyanidins. With the method developed, a survey was then conducted to qualitatively assess the composition of polyphenols among 29 different grape products including original grape, grape juice, grape wine, and grape-derived dietary supplements, and their chemical profiles were systematically compared. This method provided a comprehensive qualitative insight into the composition of polyphenols in grape-derived products.

Frutas/química , Polifenóis/análise , Vitis/química , Antocianinas/análise , Bebidas/análise , Cromatografia Líquida de Alta Pressão , Flavonoides/análise , Hidroxibenzoatos/análise , Espectrometria de Massas , Sementes/química , Vinho/análise
N Z Dent J ; 106(4): 137-42, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21197817


OBJECTIVE: To describe trends in sports-related dental injuries reported to ACC in the past 10 years. DESIGN: Retrospective case series. METHODS: De-identified data on orofacial injuries were obtained from ACC for the financial years 1999-2008, and new claims were identified for each year (with recurring claims omitted from the analysis). Patterns in new-claim data were identified by age, sex, region and the sport involved. Trends in claims for the sport categories were also identified RESULTS: The annual number of claims ranged from 24,998 to 31,257; overall, 38.7% of claims were made by females and 61.3% by males, and these proportions remained largely unchanged during the observation period. For sports-related claims, those aged 11-20 years had the highest percentage of claims (with between 41.7% and 44.4%, depending on year) while those older than 60 had the smallest percentage of claims, with 0.5% to 1.1%. Sport was involved in 20.6% to 26.2% of new claims. The highest percentage of injuries was attributable to rugby (between 22.2% and 33.1%, depending on the year). Water sports contributed to between 14.2% and 20.8% of claims. Cycling increased from 1.5% in 1999 to 15.3% in 2006, and then decreased to 10.6% in 2008. Hockey, basketball, soccer, cricket and netball had 4.4%, 4.8%, 6.9%, 4.7% and 3.9% respectively. CONCLUSIONS: Although its share has decreased in recent years, rugby remained the greatest contributor to sport-related orofacial injuries, with water sports consistently second (cycling had the largest change, with a rapid increase in the past 3 years). There is a need to re-examine mouthguard (and other injury prevention) policies for particular sports.

Traumatismos em Atletas/epidemiologia , Formulário de Reclamação de Seguro/estatística & dados numéricos , Traumatismos Dentários/epidemiologia , Adolescente , Adulto , Ciclismo/lesões , Criança , Pré-Escolar , Feminino , Futebol Americano/lesões , Humanos , Masculino , Pessoa de Meia-Idade , Nova Zelândia/epidemiologia , Estudos Retrospectivos , Natação/lesões , Adulto Jovem
J Alzheimers Dis ; 18(1): 113-24, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19625746


The present study explored the bioavailability and brain deposition of a grape seed polyphenolic extract (GSPE) previously found to attenuate cognitive deterioration in a mouse model of Alzheimer's disease (AD). Plasma pharmacokinetic response of major GSPE phenolic components was measured following intragastric gavage of 50, 100, and 150 mg GSPE per kg body weight. Liquid chromatography-mass spectrometry (LC-MS) analysis identified gallic acid (GA), catechin (C), and epicatechin (EC) in plasma of rats gavaged acutely with GSPE. Additionally, 4-methylgallic acid (4-OMeGA), 3'-methylcatechin (3'-OMeC), and 3'-methylepicatechin (3'-OMeEC) were identified as circulating metabolites of GSPE phenolic constituents. Cmax for individual GSPE constituents and their metabolites increased in a dose-dependent fashion (with increasing GSPE oral dose). Repeated daily exposure to GSPE was found to significantly increase bioavailability (defined as plasma AUC0-8h) of GA, C, and EC by 198, 253, and 282% relative to animals receiving only a single acute GSPE dose. EC and C were not detectable in brain tissues of rats receiving a single GSPE dose but reached levels of 290.7 +/-45.9 and 576.7 +/- 227.7 pg/g in brain tissues from rats administered GSPE for 10 days. This study suggests that brain deposition of GA, C, and EC is affected by repeated dosing of GSPE.

Doença de Alzheimer/tratamento farmacológico , Catequina/administração & dosagem , Flavonoides/administração & dosagem , Ácido Gálico/administração & dosagem , Extrato de Sementes de Uva/administração & dosagem , Fenóis/administração & dosagem , Doença de Alzheimer/metabolismo , Animais , Disponibilidade Biológica , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Catequina/farmacocinética , Esquema de Medicação , Flavonoides/farmacocinética , Ácido Gálico/farmacocinética , Extrato de Sementes de Uva/farmacocinética , Masculino , Fenóis/farmacocinética , Extratos Vegetais/administração & dosagem , Extratos Vegetais/farmacocinética , Polifenóis , Ratos , Ratos Sprague-Dawley
Curr Anal Chem ; 4(2): 75-101, 2008 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-19946465


Anthocyanins are a class of polyphenols responsible for the orange, red, purple and blue colors of many fruits, vegetables, grains, flowers and other plants. Consumption of anthocyanins has been linked as protective agents against many chronic diseases and possesses strong antioxidant properties leading to a variety of health benefits. In this review, we examine the advances in the chemical profiling of natural anthocyanins in plant and biological matrices using various chromatographic separations (HPLC and CE) coupled with different detection systems (UV, MS and NMR). An overview of anthocyanin chemistry, prevalence in plants, biosynthesis and metabolism, bioactivities and health properties, sample preparation and phytochemical investigations are discussed while the major focus examines the comparative advantages and disadvantages of each analytical technique.