Investigation of the Phytoconstituents and Antioxidant Activity of Diospyros malabarica Fruit Extracts

Diospyros malabarica (Deshi Gab) belonging to the family “Ebenaceae” grows well in the humid tropical climate of Bangladesh. In order to investigate the phytoconstituents both qualitatively and quantitatively, the seed and flesh extracts of D. malabarica were prepared using two polar solvents (i.e., water and 70% ethanol) and a nonpolar solvent (i.e., hexane). The maximum yield was obtained for aqueous and ethanolic seed extracts indicating that most of the phytoconstituents present in D. malabarica fruit are polar. The qualitative phytochemical analysis of the extracts revealed the presence of diverse amount of phytoconstituents in the extracts. On the other hand, the quantitative phytochemical analysis for phenols, tannins, flavonoids, alkaloids, saponin, proteins, reducing sugar and vitamin C revealed that the maximum amount of phenols, tannins, flavonoids and reducing sugar were present in aqueous seed extract. However, the maximum amount of total protein and vitamin C was found in ethanolic seed extract. D. malabarica seed powder contained more amount of alkaloids (i.e., 13.6%) than that of flesh (i.e., 3.4%). However, the content of saponin was more in flesh extract (0.74%) when compared to that of seed extract (0.42%). In vitro antioxidant properties of the extracts were also investigated by DPPH free radical scavenging assay, FRAP assay and reducing power assay. The highest antioxidant activity was observed for aqueous seed extract followed by the ethanolic seed, ethanolic flesh, and aqueous flesh extracts. The lowest antioxidant activity was obtained for hexane flesh extract. Furthermore, the lowest (i.e., 44.70 μg/ml) as well as the highest (2359.66 μg/ml) IC50 values were obtained for aqueous seed and hexane flesh extracts, respectively.