Partial identification of antifungal compounds from Punica granatum peel extracts

Aqueous extracts of pomegranate peels were assayed in vitro for their antifungal activity against six rot fungi that cause fruit and vegetable decay during storage. The growth rates of Alternaria alternata, Stemphylium botryosum, and Fusarium spp. were significantly inhibited by the extracts. The growth rates were negatively correlated with the levels of total polyphenolic compounds in the extract and particularly with punicalagins, the major ellagitannins in pomegranate peels. Ellagitannins were also found to be the main compounds in the bioactive fractions using bioautograms, and punicalagins were identified as the main bioactive compounds using chromatographic separation. These results suggest that ellagitannins, and more specifically punicalagins, which are the dominant compounds in pomegranate peels, may be used as a control agent of storage diseases and to reduce the use of synthetic fungicides.