Antifungal activity of black tea polyphenols (catechins and theaflavins) against Candida species.
ABSTRACT The polyphenols catechins and theaflavins in black tea have been shown to possess many medicinal properties, including anticancer activity and some antifungal characteristics, but there have been few studies of their anti-Candida activity. In this paper we report the results of our study of the anti-Candida activity of tea polyphenols.
The effects of 4 different concentrations of catechins and theaflavins were evaluated on 5 isolates each of 5 Candida species employing an agar diffusion growth inhibition assay. The minimum inhibitory concentration (MIC) of the polyphenols against C. albicans was determined. The post-antifungal effect (PAFE) of the polyphenols for C. albicans was investigated. C. albicans cells exposed to polyphenols were studied using a scanning electron microscope (SEM).
Both polyphenols showed anti-Candida activity against all tested Candida species and demonstrated a MIC of 6.25 mg/ml for C. albicans. C. glabrata was found to be the most sensitive species followed by C. parapsilosis, C. albicans, C. krusei and C. tropicalis (p < 0.05 for all). Significant intraspecies variations in sensitivity were noted among C. parapsilosis and C. tropicalis (p < 0.001) for both polyphenols. Theaflavins displayed standard PAFE while catechins showed a paradoxical PAFE with all isolates of C. albicans. SEM revealed considerable cell wall damage of C. albicans cells exposed to the polyphenols.
The study reveals for the first time the anti-Candida properties of black tea polyphenols that may find therapeutic applications in future.
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ABSTRACT: Blister blight (causal agent, Exobasidium vexans) is an economically devastating disease of tea (Camellia sinensis). To determine what metabolite changes occur with tea blister that could be linked to disease progression, metabolomic approaches were used on E. vexans infected tea from a Darjeeling (India) plantation. Samples were classified according to disease phenotypes; i.e. either healthy or at one of three stages of disease progression. Initial metabolite fingerprinting using Fourier transform infrared (FTIR) spectroscopy indicated that metabolite changes could be related to disease stage. Electrospray-ionization mass spectrometry (ESI-MS) highlighted caffeine and flavonoid metabolism changes as disease progressed. High-performance liquid chromatography (HPLC) with online photodiode array detection and electrospray ionization-tandem mass spectrometry (HPLC-DAD-ESI/MSn) was used to characterize the caffeine, flavan-3-ol, flavone and flavonol profiles. There were increases in quercetin and kaempferol glucosides, kaempferol triglycosides and some catechin-class antioxidants, but also substantial reductions in apigenin and myricetin glycosides and, particularly, caffeine as disease progressed. The content of important defence hormones, salicylic acid and jasmonic acid, was also reduced in blister blight diseased samples. Thus, E. vexans infections perturb defence signalling and reduce many potentially antimicrobial compounds, such as caffeine, to aid disease progression.This article is protected by copyright. All rights reserved.Plant Pathology 02/2015; DOI:10.1111/ppa.12364 · 2.97 Impact Factor
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ABSTRACT: The prevalence of antibiotic resistance has resulted in the need for new approaches to be developed to combat the previously easily treatable infections. This work aims to evaluate the antifungal and antioxidant effects of the chitosan, as a new alternative or complementary anti-fungal drug, alone or in combination with amphotericin B against a pathogenic Candida albicans in mice. Eighty neutropenic infected mice were randomly assigned into four main groups (20 mice/group). The 1st group was treated with saline, neutropenic infected (NI group) (IPC group, invasive pulmonary candidiasis), the 2nd group was treated with chitosan (ED50) (CE group), the 3rd group was treated with amphotericin B (150 mg/kg) (AMB group) and the 4th group was treated with chitosan plus amphotericin B (CE + AMB group). Treatment was started at 24 h after fungal inoculation and was administered for 3 consecutive days. All the previous treatments demonstrated notable growth inhibition against a C. albicans isolate as indicated by measuring the mean diameter of the inhibition zone. Compared with IPC group, CE, AMB, and AMB + CE-treated animals had 73%, 87%, and 90% reduction in fungal burden, respectively. Furthermore, treatment with CE and/or AMB for 24 and 72 h significantly decreased MDA, SOD, CAT and NO levels and increased GSH and in the lung tissues as compared with the infected untreated group. In conclusion, CE treatment, with the combination of antifungal therapy, can alleviate oxidative stress and lung injury associated with IPC in neutropenic mice.01/2015; 105. DOI:10.1016/j.jobaz.2014.12.001