Antifungal Activity of Black Tea Polyphenols (Catechins and Theaflavins) against Candida Species

Faculty of Dental Sciences, University of Peradeniya, Peradeniya, Sri Lanka.
Chemotherapy (Impact Factor: 1.29). 05/2009; 55(3):189-96. DOI: 10.1159/000216836
Source: PubMed


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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    • "The most abundant flavan-3-ols are (–)-epicatechin and gallic acid derivatives, but other important chemical classes include flavonols, such as conjugates of quercetin and kaempferol, coumarate, some purine alkaloids, theobromine and also the purine alkaloid, caffeine (Finger et al., 1991, 1992; Kiehne & Engelhardt, 1996a,b; Kiehne et al., 1997). Even a cursory examination of the literature from clinical microbiology shows that certain tea metabolites have antimicrobial activity (Park et al., 2004; Song & Seong, 2007; Aron & Kennedy, 2008; Evensen & Braun, 2009; Sitheeque et al., 2009; Gordon & Wareham, 2010) but there have been relatively few attempts to examine how such metabolites change during disease development. "
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    • "After the incubation period, zones of growth inhibition (clear zone appeared around each well) were measured using an image analysis software program (Quantimet 500, Windows version; Leica). The diameter of each inhibition zone around a well (including the diameter of the well itself) was measured and the software automatically calculated the arithmetic mean of 4 measurements at different angles (Sitheeque et al., 2009). "
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    • "corroborated with the results of Sitheeque et al. (2009) who showed antifungal activity of both green and black tea catechins against C. albicans. "
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