Abstract:
Fermentation with microorganisms has been reported to enhance the antioxidant activities of plants. Therefore, the present study was conducted to investigate the comparative effects of fermentation with typed microorganisms and wild fermentation on the antioxidant Potentials of leaf extracts of S. mombin. P. aeruginosa and E. coli were isolated from leaf and employed for its fermentation for a period of 24 to 96 h, compared with wildly fermented (with no microbes) leaf samples for the same period of time. The phytochemical constituents, total phenolic contents, antioxidant activities (DPPH Radical Scavenging Activity, reducing power assay, Hydroxyl Radical Scavenging Activity, Nitric Oxide Radical Scavenging Activity, Lipid Peroxidation assay) of the fermented samples of S. mombin were evaluated.
Phytochemical screening revealed the presence of saponins, cardiac glycosides, flavonoids, tannins, anthraquinones and steroids. Quantification of phenolic compounds in the microorganism fermented leaf of S. mombin for 24 h revealed the presence of some phenolic acids and flavonoids with lower quantities of phenolic compounds in the wildly fermented S. mombin. S. mombin fermented with P. aeruginosa for 72 h had the highest Iron Chelating activities with IC50 value of 251.9, while the one fermented with E. coli for 24 h had the highest reducing power with IC50 value of 119.2, for Nitric Oxide (NO) and diphenyl picrylhydrazyl (DPPH) Radical Scavenging assays. It was also observed that wildly fermented S. mombin for 24 hours with IC50 value of 132.8 and 174.2 had the highest Activity in the protection of brain and liver against Lipid Peroxidation respectively. S. mombin fermented with P. aeruginosa for 96h had the highest Nitric Oxide Scavenging and DPPH Radical Scavenging activities.
In conclusion, fermentation with typed microorganisms enhanced the phytochemical constituents and antioxidant activities of leaf extract of S. mombin when compared to the wildly fermented leaf which was accompanied with increased antioxidant activities. However, P. aeruginosa appeared to have a pronounced effect on the antioxidant properties when compared to E. coli and the wildly fermented extracts of S. mombin.
