RESUMO
Arbutin is utilized in traditional remedies to cure numerous syndromes because of its anti-microbial, antioxidant, and anti-inflammatory properties. This study aimed to evaluate chemopreventive effects of arbutin on azoxymethane (AOM)-induced colon aberrant crypt foci (ACF) in rats. Five groups of rats were used: normal control group (rats injected hypodermically with sterile phosphate-buffered saline once per week for two weeks) and groups 2-5, which were subcutaneously inoculated with 15 mg/kg AOM once a week for two weeks. AOM control and 5-fluorouracil (5-FU) control groups were fed 10% Tween orally daily for 8 weeks using a feeding tube. The treated groups were fed 30 and 60 mg/kg arbutin every day for 2 months. ACF from the AOM control group had aberrant nuclei in addition to multilayered cells and an absence of goblet cells. The negative control group displayed spherical cells and nuclei in basal positions. Histological examination revealed a reduced number of AFC cells from colon tissues of the 5-FU reference group. Arbutin-fed animals showed down-regulation of proliferating cell nuclear antigen (PCNA) and up-regulation of Bax protein compared to AOM control. Rats fed with arbutin displayed a significant increase of superoxide dismutase (SOD) and catalase (CAT) activities in colon tissue homogenates compared to the AOM control group. In conclusion, arbutin showed therapeutic effects against colorectal cancer, explained by its ability to significantly decrease ACF, down-regulate PCNA protein, and up-regulate Bax protein. In addition, arbutin significantly increased SOD and CAT, and decreased malondialdehyde (MDA) levels, which might be due to its anti-proliferative and antioxidant properties.
Assuntos
Focos de Criptas Aberrantes , Arbutina , Azoximetano , Antígeno Nuclear de Célula em Proliferação , Proteína X Associada a bcl-2 , Animais , Focos de Criptas Aberrantes/induzido quimicamente , Focos de Criptas Aberrantes/patologia , Focos de Criptas Aberrantes/prevenção & controle , Focos de Criptas Aberrantes/tratamento farmacológico , Antígeno Nuclear de Célula em Proliferação/metabolismo , Masculino , Arbutina/farmacologia , Ratos , Proteína X Associada a bcl-2/metabolismo , Colo/efeitos dos fármacos , Colo/patologia , Ratos Wistar , Fluoruracila , CarcinógenosRESUMO
INTRODUCTION: Arbutin is a phenol glucoside found in high concentrations in bearberry leaves and associated with the antimicrobial activity of the plant. Hydroquinone can also be found in leaves or be formed by degradation of arbutin. Lengthy exposure to free hydroquinone is associated with induction of toxicity in different organs. OBJECTIVE: To develop and validate a stability-indicating method by high-performance liquid chromatography diode array detector (HPLC-DAD) for simultaneous quantification of arbutin and hydroquinone in bearberry leaves and perform a comprehensive forced degradation study comparing synthetic arbutin and the arbutin in bearberry leaves. METHODS: Separation was performed using a C18 column, mobile phase with water-methanol (95:5), flow rate 1.0 mL/min and detection at 280 nm. Bearberry leaves were assayed and a forced degradation study of arbutin was performed in different conditions. RESULTS: The method complied with all required validation parameters. Contents varied from 1.19 to 4.15% (w/w) of arbutin and from 0.022 to 0.604% (w/w) of hydroquinone. Synthetic arbutin was susceptible to acid hydrolysis and oxidative degradation, forming hydroquinone as the main degradation product. The same study using bearberry leaves showed that constituents of the plant matrix may act as antioxidants, reducing the oxidative degradation of arbutin, however acid hydrolysis of arbutin occurred in higher intensity. CONCLUSION: Analysis of bearberry leaves evidenced high variation in arbutin and hydroquinone levels, demonstrating the need for standardisation and control. The stability profiles of synthetic arbutin and the arbutin in bearberry leaves were considerably different and the results may be useful for determining the most appropriate conditions for extraction and production of bearberry-based formulations.
Assuntos
Arctostaphylos , Arbutina , Cromatografia Líquida de Alta Pressão , Extratos Vegetais , Folhas de PlantaRESUMO
The skin is the largest and most exposed organ of the human body, therefore subject to diseases and alteration of its appearance. Among these alterations, the cutaneous hyperchromia may be cited. Currently, the market offers numerous products with depigmenting action to the treatment of such disorders. The aim of this work was to analyze depigmenting products commercialized in establishments in the city of Bento Gonçalves (RS, Brazil) and websites of cosmetic companies. It was found 45 products with depigmenting action and, from these, 59 different active agents were identified. The main active compounds found were kojic acid, arbutin, ascorbic acid, hydroquinone and glycolic acid. Another observed data was that in 78% of the studied products the active substances were being used in combination. The most used vehicles were also studied as a reference to the use of sunscreen in the treatment of cutaneous hyperchromia. The present work had identified in the market a variety of products with depigmentation action and, because of this, it aims to serve as a reference to the healthcare professionals, especially at the prescribing moment, looking for the best results, with regards to treatment efficiency and safety.(AU)
Assuntos
Humanos , Pigmentação da Pele/efeitos dos fármacos , Hiperpigmentação/tratamento farmacológico , Cosméticos , Fármacos Dermatológicos/análise , Arbutina , Ácido Ascórbico , Pironas , Brasil , Combinação de Medicamentos , Glicolatos , HidroquinonasRESUMO
Epidermal melasma is a common hyperpigmentation disorder that can be challenging to treat. Although current treatment options for melasma are limited, topical skin-lightening preparations have widely been used as alternatives to hydroquinone. In this prospective, single-arm, open-label study, treatment of epidermal melasma with a novel cream formulation containing nicotinamide 4%, arbutin 3%, bisabolol 1%, and retinaldehyde 0.05% was associated with reductions in Melasma Area and Severity Index (MASI) scores as well as total melasma surface area as measured by medical imaging software. Treatment outcomes including tolerance and safety profiles as well as patient satisfaction and product appreciation showed this novel cosmetic compound may be valuable in the treatment of epidermal melasma.
Assuntos
Fármacos Dermatológicos/administração & dosagem , Melanose/tratamento farmacológico , Satisfação do Paciente , Administração Cutânea , Adolescente , Adulto , Arbutina/administração & dosagem , Fármacos Dermatológicos/efeitos adversos , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Melanose/patologia , Pessoa de Meia-Idade , Sesquiterpenos Monocíclicos , Niacinamida/administração & dosagem , Estudos Prospectivos , Retinaldeído/administração & dosagem , Sesquiterpenos/administração & dosagem , Índice de Gravidade de Doença , Creme para a Pele , Software , Resultado do Tratamento , Adulto JovemRESUMO
The first total synthesis of the 7,7-dimethylaporphinoid, 4,5-didehydroguadiscine (6), originally isolated from the stems and roots of Hornschuchia oblique (Annonaceae), was achieved by the condensation of homopiperonylamine (7) with an α,α-dimethylphenylacetic acid derivative (8) and subsequent Pschorr reaction of the resulting benzylisoquinoline intermediate (22). The reported (13)C NMR data were partially revised on the basis of the analysis of HMBC spectra measured under different conditions. The melanogenesis inhibitory activity (IC50 = 4.7 µM) of 6 was 40 times stronger than that of arbutin (174 µM), which was used as reference standard. Furthermore, 6 was the most potent natural melanogenesis inhibitor within this class of compounds.
Assuntos
Annonaceae/química , Aporfinas/síntese química , Aporfinas/farmacologia , Melaninas/antagonistas & inibidores , Plantas Medicinais/química , Aporfinas/química , Arbutina/farmacologia , Brasil , Ésteres , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Raízes de Plantas/químicaRESUMO
Bacteria have evolved various mechanisms to extract utilizable substrates from available resources and consequently acquire fitness advantage over competitors. One of the strategies is the exploitation of cryptic cellular functions encoded by genetic systems that are silent under laboratory conditions, such as the bgl (β-glucoside) operon of E. coli. The bgl operon of Escherichia coli, involved in the uptake and utilization of aromatic β-glucosides salicin and arbutin, is maintained in a silent state in the wild type organism by the presence of structural elements in the regulatory region. This operon can be activated by mutations that disrupt these negative elements. The fact that the silent bgl operon is retained without accumulating deleterious mutations seems paradoxical from an evolutionary view point. Although this operon appears to be silent, specific physiological conditions might be able to regulate its expression and/or the operon might be carrying out function(s) apart from the utilization of aromatic β-glucosides. This is consistent with the observations that the activated operon confers a Growth Advantage in Stationary Phase (GASP) phenotype to Bgl+ cells and exerts its regulation on at least twelve downstream target genes.
Assuntos
Escherichia coli/enzimologia , Escherichia coli/genética , Regulação da Expressão Gênica , beta-Glucosidase/genética , beta-Glucosidase/metabolismo , Arbutina/metabolismo , Álcoois Benzílicos/metabolismo , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Glucosídeos/metabolismo , ÓperonRESUMO
Bacteria have evolved various mechanisms to extract utilizable substrates from available resources and consequently acquire fitness advantage over competitors. One of the strategies is the exploitation of cryptic cellular functions encoded by genetic systems that are silent under laboratory conditions, such as the bgl (β-glucoside) operon of E. coli. The bgl operon of Escherichia coli, involved in the uptake and utilization of aromatic β-glucosides salicin and arbutin, is maintained in a silent state in the wild type organism by the presence of structural elements in the regulatory region. This operon can be activated by mutations that disrupt these negative elements. The fact that the silent bgl operon is retained without accumulating deleterious mutations seems paradoxical from an evolutionary view point. Although this operon appears to be silent, specific physiological conditions might be able to regulate its expression and/or the operon might be carrying out function(s) apart from the utilization of aromatic β-glucosides. This is consistent with the observations that the activated operon confers a Growth Advantage in Stationary Phase (GASP) phenotype to Bgl+ cells and exerts its regulation on at least twelve downstream target genes.
Assuntos
Escherichia coli/enzimologia , Escherichia coli/genética , Regulação da Expressão Gênica , beta-Glucosidase/genética , beta-Glucosidase/metabolismo , Arbutina/metabolismo , Álcoois Benzílicos/metabolismo , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Glucosídeos/metabolismo , ÓperonRESUMO
Bacteria have evolved various mechanisms to extract utilizable substrates from available resources and consequently acquire fitness advantage over competitors. One of the strategies is the exploitation of cryptic cellular functions encoded by genetic systems that are silent under laboratory conditions, such as the bgl (ß-glucoside) operon of E. coli. The bgl operon of Escherichia coli, involved in the uptake and utilization of aromatic ß-glucosides salicin and arbutin, is maintained in a silent state in the wild type organism by the presence of structural elements in the regulatory region. This operon can be activated by mutations that disrupt these negative elements. The fact that the silent bgl operon is retained without accumulating deleterious mutations seems paradoxical from an evolutionary view point. Although this operon appears to be silent, specific physiological conditions might be able to regulate its expression and/or the operon might be carrying out function(s) apart from the utilization of aromatic ß-glucosides. This is consistent with the observations that the activated operon confers a Growth Advantage in Stationary Phase (GASP) phenotype to Bgl(+) cells and exerts its regulation on at least twelve downstream target genes.
Assuntos
Escherichia coli/enzimologia , Escherichia coli/genética , Regulação da Expressão Gênica , beta-Glucosidase/genética , beta-Glucosidase/metabolismo , Arbutina/metabolismo , Álcoois Benzílicos/metabolismo , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Glucosídeos/metabolismo , ÓperonRESUMO
From the aerial parts of Salvia mexicana var. mexicana, two C-10 epimers (α and ß) of salvimexicanolide were isolated. Our interpretation of the data, especially the 13C NMR, led us to conclude that the previously described 13C-NMR spectrum of the α-epimer was not accurately assigned and it actually corresponds to the ß-epimer. The structures proposed for the salvimexicanolides were verified by means of NOESY experiments. Dugesin B, arbutin, naringenin and the mixture of oleanolic and ursolic acids were also isolated from this Salvia spp.
Assuntos
Diterpenos/química , Diterpenos/isolamento & purificação , Extratos Vegetais/química , Salvia/química , Arbutina/isolamento & purificação , Flavanonas/isolamento & purificação , Lamiaceae , Espectroscopia de Ressonância Magnética , Ácido Oleanólico/isolamento & purificação , Componentes Aéreos da Planta , Triterpenos/isolamento & purificação , Ácido UrsólicoRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: In folk medicine, Turnera diffusa Wild (Turnera diffusa, Turneraceae) is considered as an aphrodisiac, but its ability to restore copulation in sexually inhibited subjects has not been reported. AIM OF THE STUDY: To determine whether Turnera diffusa recovers sexual behavior in sexually exhausted (SExh) male rats and to identify the main components in an aqueous extract. MATERIALS AND METHODS: SExh males were treated with Turnera diffusa, 20-80 mg/kg, yohimbine, 2 mg/kg, or vehicle. RESULTS: Yohimbine and Turnera diffusa (80 mg/kg) significantly increased the percentage of males achieving one ejaculatory series and resuming a second one. In addition, Turnera diffusa significantly reduced the post-ejaculatory interval. These effects were not associated to an increase in locomotor activity or anxiety-like behaviors. The HPLC-ESI-MS analysis showed the presence of caffeine, arbutine, and flavonoids as the main compounds in the active extract. CONCLUSION: The results support the use of Turnera diffusa as an aphrodisiac in traditional medicine and suggest possible therapeutic properties of Turnera diffusa on sexual dysfunction. The flavonoids present in active extract may participate in its pro-sexual effect, which is analogous to those produced by yohimbine, suggesting a shared mechanism of action.