Chemical Composition, Toxicity and Antifungal Activities of Megaphrynium macrostachyum (K. Schum) Leaf Extract against Foodborne Fungi

Abstract

This study aimed to examine the preservative potential of Megaphrynium macrostachyum on fungi responsible for the deterioration of orange juice and corn Jell-O. The phytochemicals from plants’ leaves were extracted with four solvents: acetone, aqueous, ethanol and hexane. The solvents were differently and tested against fungi isolated from orange juice and corn Jell-O using disc diffusion method. Phytochemical screening of the extracts from the leaves was carried out, and the most active extract was tested via GC-MS for the essential oils and HPLC fingerprinting. The toxicity test of the extracts against brine shrimp was carried out after exposure for 24 hours. The toxicity test showed that the extracts were non-toxic on the Brine Shrimps at LC50 (379.21μg/ml and 107.21μg/ml for aqueous and ethanol extracts). The qualitative phytochemical test reported the presence of alkaloids, tannins, saponins, flavonoids, steroids, and terpenoids in different extracts of the plant’ leaves. The quantitative phytochemical determination of the most active extract revealed alkaloids with the highest contents of 107.48mg/100g. The GC-MS analyses of the fresh leaves of the plants revealed the presence of isodecane with the highest percentage at 15.56%. The GC-MS analyses of the dried leaves revealed isodecane with the highest percentage at 10.43%. The HPLC analysis revealed the presence of various phytochemical constituents in the dried leaves. This study has been able to establish the potency of Megaphrynium macrostachyum leaves on fungi associated with the spoilage of Citrus sinensis (orange) juice and Corn Jell-O (‘Eko’) which contribute to tremendous research towards the use and acknowledgment of natural antimicrobials for the preservation of food.