Bioactive components of the methanolic extracts of Terminalia spp. against fungal pathogens in Drosophila melanogaster (Diptericin-lacZ II) as a Model

Abstract

Fungal pathogens are becoming prospective agents of bioterrorism; there is widespread emergence of fungi such as Aspergillus species being implicated in invasive diseases, leading to increased use of antifungal prophylaxis and resistance to standard antifungal drugs. Drosophila melanogaster has gained appreciation as a useful model organism of human diseases. Comparative genomic studies estimate that up to 75% of the human genes implicated in diseases are conserved in Drosophila. The research was designed to evaluate the antifungal potency of the different methanolic extracts of five Terminalia species on three Aspergillus species using Drosophila melanogaster (Diptericin-lacZ II) as a model. Extraction and phytochemical screening of the methanolic extracts were carried out. The ingestion method was used to infect the flies and was treated on a diet containing 60 mg/ml of the extracts from the leaves, stems and roots of the five plants respectively. The results of the phytochemical screening indicated that the different extracts contained the presence of secondary metabolites such as Tannins, Saponins, Flavonoids, Steroids, Terpenoids, Alkaloids, Saponins and Cardiac glycosides. The result of the infectious studies showed that A. fumigatus was the most lethal to the flies with a survival of 8.89%, followed by A. terrues at 17.78% and A. flavus was the least lethal with a survival of 22.22% of flies infected and fed 5% glucose (control group). At p≤0.05 there was a significant difference in the survival rate of the flies infected with different Aspergillus species and treated with 60 mg/ml of the methanolic extracts of the plants from the five Terminalia species. All five Terminalia species had a broad spectrum activity against the Aspergillus species with more than 50% survival of the flies infected and treated on the extracts. These showed that all the Terminalia species induced the production of fungal peptides in the flies and supported the use of these plants in folk medicine. Keywords: Terminalia spp., Aspergillus spp., Fusarium oxysporium, Drosophila melanogaster, percentage survival, antifungal activities.