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.

Despite the presence of many antibiotics, bacterial resistance is growing steadily and some of these antibiotics have become ineffective, which poses a major challenge to the health sector. In this context, this work has demonstrated, in vitro, the inhibitory action of the bacterial growth resulting from methanolic and ethanolic extracts of Thymus algeriensis Boiss. & Reut., a medicinal plant species harvested from the Algerian South-west area, as well as the determination of the phenolic content of those crude extracts. The methanolic extract of Thymus algeriensis showed a significant antibacterial effect with 16.5 and 19 mm against Pseudomonas aeruginosa and Staphylococcus aureus, respectively. Klebsiella pneumoniae was not inhibited by both tested extracts. Besides, ethanol extract has not prevented the growth of the Enterobacter cloacae. This biological activity can be explained by the appreciable rates noted for both of the plant extracts in terms of total phenolic levels, which ranged between 79.45 and 67.13 mg GAE g-1 dry weight.