Investigation of Antifungal Activity of Some Medicinal Plants in Northern Vietnam Against the Postharvest Pathogen Penicillium digitatum and Other Fungi

As pathogens are increasingly becoming resistant to current antibiotics, the study of natural medicinal sources to find new active ingredients is important. In this study, among all extracts obtained from 12 medicinal plants collected from Northern Vietnam, extracts from Mahonia bealei, Ficus semicordata, and Gnetum montanum demonstrated the most potential in growth inhibitory activity against Penicillium digitatum, which is known to cause one of the most common and serious post-harvest diseases in citrus. M. bealei 95% ethanol extract, showed the best efficacy and broad spectrum against two more pathogenic fungi, which were Aspergillus fumigatus and Candida albicans. Subsequently, berberine and palmatine were determined as the major metabolites of the M. bealei extract, and berberine might appear to be the major active constituent in producing the antifungal activity of the plant. Finally, we found that 800 µg/ml of M. bealei extract fully inhibited the green mold in oranges up to 6 days of infection.