Effects of sunlight ripening process on the biological activities of persimmon (Diospyros kaki L.) peel and pulp extracts

The aim of the study was to evaluate the biological properties of the peel and pulp extracts of persimmons, with consideration of the impact of different ripening conditions (B: on-branch ripened and S: sunlight ripened). The data demonstrated that the sunlight ripened persimmon peel (S. peel) extract exhibited a higher total phenolic and flavonoid content, with 157 and 7.3 µg/mL GAE respectively. The S. peel extract exhibited the highest antioxidant activity, exhibiting 1.1578 mg/mL IC50, 54.095 and 0.0262 µM Trolox equivalent (TE)/g fresh weight (FW), as determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging assay, ferric reducing antioxidant power (FRAP) and cupric reducing antioxidant capacity (CUPRAC) respectively. LC-MS/MS analysis revealed that the peel and pulp phenolic composition of persimmon ripening process different conditions changed. The activity of protocatechuic, chlorogenic, caffeic and ferulic acids identified in persimmon extracts was determined by HPLC-DAD-FRAP assay. ICP-OES analysis revealed that potassium exhibited the highest mineral content of persimmon, with values ranging from 575.680 to 2031.360 mg/kg. The S. peel extract was more inhibitory activity against bovine carbonic anhydrase (BCA) and α-glucosidase then other extracts. Moreover, the S. peel extract was found to demonstrate the highest level of antibiofilm activity, reducing the strong biofilm formation capacity of the A. baumannii isolate to negative, both qualitatively and quantitatively. The study suggests that the ripening of persimmon fruit in sunlight may increase biological activity and may be useful in the prevention and treatment of diseases associated with oxidative damage, diabetes and bacterial infections.