Usefulness of plant derived products to protect rice against fungi in western europe

Abstract

The ethnopharmacobotanical usages of aromatic plants, from the Mediterranean region, as spices, for human or animal health applications, among other purposes, are well-known. However, natural products from plant origin can also play a role as natural chemical substances for crop and food protection leading to an increased interest on the plants auto protective capacity against pathogenic agents. Search on plant derived bioactive products, which could be less toxic to the environment and more biologically selective than synthetic compounds are of major importance, for rural and agro-industrial economic sectors. Naturally occurring biologically active compounds from plant extracts and essential oils are examples of GRAS compounds, that are of increased importance due to restrictions on pesticides and to environmental and food safety concerns. Rice is a staple food for over half of the world population being one of the cheapest sources of food energy and protein. This crop cereal raises interest in Europe. It is cultivated in the south of Europe for centuries, being Italy the major rice producer and Portugal the main rice consumer. Fungi infection and the inherent occurrence of mycotoxins can be responsible for serious economic losses and public health risks. Knowledge about the origin of the growth of toxigenic fungi is a prerequisite to the establishment of mycotoxins control programs. Rice samples collected in Portuguese farms or from factories were analyzed for fungal infection. Several fungi taxa were isolated (Absidia, Alternaria, Aspergillus, Bipolaris, Botrytis, Chaetomium, Curvularia, Cunninghamella, Epicoccum, Fusarium, Geotrichum, Helicoma, Nigrospora, Penicillium, Pyricularia, Rhizopus, Scytalidium, Stemphylium, Sordaria, Trichoconiella, Trichoderma, Trichothecium, and Ulocladium), some of them being potentially mycotoxigenic. The knowledge on the plant synthesis of substances potentially useful to control microbial infections, led to evaluate the bioactivity of extracts, and essential oils of a set of aromatic plants against fungi affecting rice. We enhance the good results achieved with Cuminum cyminum, Laurus nobilis, Mentha pulegium, Origanum vulgare, and Satureja montana both with extracts and essential oils against Aspergillus candidus, Aspergillus flavus, Aspergillus niger, Botrytis cinerea, Cladosporium cucumerinum, Fusarium culmorum and Penicillium sp.