Antifungal activity of extracts from wild edible herbaceous species

The use of natural antimicrobial substances could be a useful alternative to synthetic pesticides for controlling postharvest pathogens of fresh fruit and vegetables. In the present work, the in vitro antifungal activity of extracts from some wild edible herbaceous species containing a phenolic fraction, was evaluated. Their activity was assessed on both conidial germination and germ tube elongation. The efficacy of extracts from Borago officinalis, Orobanche crenata, Plantago coronopus, P. lanceolata, P. major, Sanguisorba officinalis, Silene vulgaris, Sonchus asper, S. oleraceus, and Taraxacum officinale was tested against some important post-harvest pathogens: Botrytis cinerea, Monilia laxa, Penicillium digitatum, P. expansum, P. italicum, Aspergillus carbonarius, and A. niger. The most effective extracts were those obtained from S. officinalis and O. crenata. In particular, extracts of S. officinalis completely inhibited conidial germination of M. laxa, P. digitatum, P. italicum and A. niger, strongly reduced conidial germination of B. cinerea and P. expansum, and slightly affected A. carbonarius. The extract of O. crenata showed a good efficacy against B. cinerea and M. laxa and, to some extent, also against P. digitatum, P. expansum, P. italicum, and A. niger. Moreover, the extracts of both species were effective in reducing germ tube elongation also when a slight inhibition on conidial germination was observed. Further studies are in progress to test the activity of the extracts on stored fruit and vegetables and to identify the active compound(s).