In-vitro antioxidant, antimicrobial and phytochemical properties of extracts from the pulp and seeds of the African baobab fruit (Adansonia digitata L.)

Adansonia digitata, commonly known as the African Baobab plant is used widely in traditional medicine for treating of many diseases. The current study investigates the antioxidant and antimicrobial properties, and nutritional composition of the pulp and seeds from the fruit of African Baobab plant. Matured fruits were harvested and processed by separating the fruit pulp and seeds. Water, 70 % Ethanol/water mixture, and Hexane were used as solvents for extraction. Antioxidant properties of extracts in this study were investigated using the 2,2-diphenyl-1-picrylhydrazyl, hydrogen peroxidescavenging assays., Total Flavonoid Content, Total Phenolic Content, Total Tannin Content, and Total Antioxidant Capacity were also investigated. Agar Well Diffusion and Broth Dilution methods were used to estimate the antimicrobial properties of the extracts. The proximate composition of the seeds and fruit pulps was also determined. GC-MS was employed to determine the fatty acid composition. Results obtained showed the presence of Total phenolics (range 4.1-5.5 mg GAE/g), Total flavonoids (range 10.1-16.5 mg QE/g), Total Tannins (range 1.7-15.6 mg CE/g), and Antioxidants (range 2.0-14.5 mg AAE/g). The H2O2 and DPPH assays gave IC50s in the ranges of 300-1800 mg/L and 700-1600 mg/L respectively. Extract from the fruit pulp was found to inhibit the growth of a panel of 2 g-positive bacteria, 2 g-negative bacteria, and two fungi microorganisms. Fatty acids such as myristic acid, palmitic acid, and stearic acid were found to be present in oil from the seeds. Proximate components such as crude protein, crude fat, and crude fibre were found to be high. From the results, seeds and the fruit pulp of the African Baobab plant have significant antioxidant properties and can inhibit microbial growth.