Abstract

Plant extracts and their constituents have a long history as antifungal agents, but their use in biotechnology as preservatives, due to the increasing resistance of fungi to fungicides, has been rarely reported. The aim of this study was to assess in vitro antifungal and antimycotoxigenic power of methanolic and aqueous extracts of Citrullus colocynthis seeds, an aromatic and medicinal plant, of Algerian flora, against two toxigenic species of the genera Aspergillus responsible of contamination of wheat stored. The antifungal and antimycotoxigenic activity of methanolic and aqueous extracts were screened against Aspergillus ochraceus and Aspergillus flavus. Dillution method was used to investigate the antimicrobial and antimycotoxigenic activity. These bioassays are preceded by a phytochemical screening. The phytochemical analysis of seeds extracts revealed the presence of some chemical groups (polyphenols, steroids and alkaloids) which can express the desired activities. The results suggest that the extracts showed a very good antifungal activity against A. ochraceus, but for A. flavus any antifungal activity was recorded. The extracts have good antiochratoxigenic power in liquid medium. This evaluation confirms that the extracts of C. colocynthis seeds used at low concentration may have significant potential for biological control of fungi and theirs toxins.

Key words: Citrullus colocynthis, methanolic extract, aqueous extract, phytochemical screening, antifungal activity, antimycotoxigenic activity, antiochratoxigenic activity.

Abbreviation

Abbreviations:  AFs, Aflatoxins; OTA, ochratoxin A; TLC, thin-layer chromatography; DRBC, Dichloran Rose-Bengal chloramphenicol agar; CDA, Czapek dextrose agar; PDA, potatoes dextrose agar; YES, yeast extract sucrose; MIC, minimum inhibitory concentration; MFC, minimum fungicidal concentration.