Chemical composition, lethality and antifungal activities of the extracts of leaf of Thaumatococcus daniellii against foodborne fungi

The consumers' interest in natural preservatives seemed to have increased because of the apathy and negative effect of synthetic preservatives. This study explored the use of Thaumatococcus daniellii leaves as potential preservatives against fungi responsible for the spoilage of orange juice and corn jell-o. The leaves of the plant were extracted with different solvents - acetone, aqueous, ethanol and hexane - and assayed against test fungi using disc diffusion method. The minimum inhibitory and fungicidal concentrations were determined. The qualitative and quantitative phytochemical analyses of leaves of the plants were carried out, the most active extract of the fresh and dried leaves was assayed via GC-MS for the essential oils and HPLC fingerprinting was used to determine the phytochemical constituents of the most active extracts. The toxicity test of the extracts against Brine shrimp was carried out after 24 hours of exposure. The ethanol extracts of the plants were the most active based on the antifungal assay. The toxicity test revealed that the extracts of the plants were non-toxic on the Brine shrimps at LD50 (592.95 µg/ml and 281.12 µg/ml for aqueous and ethanol extracts). The qualitative phytochemical screening revealed the presence of alkaloid, tannin, saponins, flavonoids, steroids and terpenoids in the leaf of the plant. The quantitative phytochemical analysis of the most active extract in the plants revealed alkaloids with the highest content of 107.48 mg/100 g. The GC-MS analyses of the fresh leaves of the plants revealed the presence of isodecane at 15.16%. The GC-MS analyses of the dried leaves revealed 1,2,3-trimethylbenzene in T. danielli with the highest percentage of 15.48%. The HPLC analysis revealed the presence of various phytochemical constituents in the dried leaves of the plant. This study has been able to ascertain the potency of T. daniellii leaves on fungi responsible for spoilage of sweet Citrus sinensis (orange) juice and Corn Jell-O ('Eko') which contribute to continuous drive towards the use and total acceptance of natural antimicrobials.