Protective properties of Terminalia superba extracts against fungal pathogens in Drosophila melanogaster (Diptericin-lacZ II) as a Model

Fungal infections pose significant health challenges, and the identification of natural antifungal agentsremains a growing area of research. Terminalia superba, known for its bioactive components, wasinvestigated for its protective properties against fungal pathogens using Drosophila melanogaster(Diptericin-lacZ II) as a model organism. The plant materials were air-dried, pulverized, and extracted usingsolvents (n-hexane, ethyl acetate, methanol, and water) based on solvent polarity. The percentage yield wascalculated, and phytochemical screening was carried out using standard methods. Antifungal susceptibilitytesting was conducted using the agar well diffusion method against Aspergillus niger and Fusariumoxysporum. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) weredetermined using broth dilution techniques. Additionally, D. melanogaster flies were infected with A. niger toevaluate the in vivo antifungal efficacy of the extracts. Acute toxicity testing of the extracts was performed,and survival rates were recorded over seven days. The extraction process revealed that methanol producedthe highest percentage yield of bioactive components, with 21.6% from the stem and 12.7% from the leaves.Hexane yielded 9% and 4.3% from the stem and leaves, respectively, while aqueous and ethyl acetateextracts produced lower yields. Phytochemical screening demonstrated the presence of tannins, saponins,flavonoids, steroids, and terpenoids in all extracts, whereas alkaloids were absent. Antifungal activity washighest in the hexane extracts, showing zones of inhibition ranging from 6 ± 1.53 to 18 ± 0.84 mm for stemextracts and from 4 ± 0.00 to 18 ± 0.55 mm for leaf extracts. Methanolic extracts also displayed significantinhibition, whereas ethyl acetate and aqueous extracts exhibited the least activity. The MIC and MFC assaysrevealed that most extracts had an MIC of 250 mg/ml and an MFC of 500 mg/ml. Probit analysis determinedthe LD50 values to be 47.18 mg/ml and 53.03 mg/ml for the methanolic and hexane extracts, respectively,while the standard drug, Fluconazole, had an LD50 value of 29.07 mg/ml. In infection studies, 60 mg/ml ofthe methanolic extract achieved a survival rate of 62.22%, comparable to fluconazole’s 75.56%, whereasthe hexane extract achieved a survival rate of 53.33%. These findings suggest that T. superba extracts,particularly the methanolic and hexane extracts, possess significant antifungal properties and may serve aspotential alternative therapeutic agents against fungal pathogens.