Antifungal activity of pomegranate peel extract and isolated compound punicalagin against dermatophytes

Abstract

Background: Dermatophyte species infect the epidermis and appendages, often with serious social and health-economic consequences. The hydroalcoholic extract of pomegranate fruit peel showed activity against the dermatophyte fungi Trichophyton mentagrophytes, T. rubrum, Microsporum canis and M. gypseum.

Methods: Hydroalcoholic extract was prepared with pomegranate peels. This crude extract was fractionated and submitted to liquid-liquid partition, resulting in an active fraction which was fractionated in a Sephadex LH-20 column, followed by a Lobar column. The structure of the active compound was established with the use of spectroscopic methods.

Results: The crude extract of pomegranate fruit peel showed activity against the dermatophytes Trichophyton mentagrophytes, T. rubrum, Microsporum canis, and M. gypseum, with MICs values of 125 μg/ml and 250 μg/ml, respectively for each genus. Punicalagin was isolated and identified by spectroscopic analysis. The crude extract and punicalagin showed activity against the conidial and hyphal stages of the fungi. The cytotoxicity assay showed selectivity for fungal cells than for mammalian cells.

Conclusions: These results indicated that the crude extract and punicalagin had a greater antifungal activity against T. rubrum, indicating that the pomegranate is a good target for study to obtain a new antidermatophyte medicine.

Figure 1

Disc diffusion method . Antifungal activity in solid medium against T. rubrum. ( A ) Crude extract – 1000, 500, 250, 125, 62.5 μg/ml. ( B ) Nystatin – 6.25, 3.15, 1.56, 0.78, 0.39 μg/ml. Water was used as control (C-). Data correspond to one representative experiment out of three.

Figure 2

Fluorescence microscopy by Calcofluor White Stain. Spore germination inhibition of T. rubrum on cover slips. ( A ) Control cells; ( B ) Treated with 125 μg/ml crude extract; ( C ) Treated with 62.5 μg/ml punicalagin; ( D ) Treated with 0.78 μg/ml Nystatin. Data correspond to one representative experiment out of three.