Characterization of Bioactive Ligands with Antioxidant Properties of Kiwifruit and Persimmon Cultivars Using In Vitro and in Silico Studies

The current study attempted to understand the interaction profiles of phytoconstituents in new and traditionally used fruit cultivars with human serum albumin (HSA) in the context of predicting the biological role under in vivo conditions. Therefore, polyphenols, flavonoids, flavanols, tannins, vitamin C, secondary metabolites and their antioxidant capacities of organic kiwifruit Actinidia (A.) eriantha cv. Bidan (AEB) and A. arguta cv. Cheongsan (AAC), as new cultivars grown in Korea, and widely consumed A. deliciosa cv. Hayward (ADH) and Diospyros kaki Thunb. cv. Fuyu (DKF) were determined and compared. All investigated fruits showed relatively high antioxidant capacities. To complement the bioactivity of these fruits, the binding properties between extracted polyphenols and HSA were determined by 3D-fluorescence spectroscopy and docking studies. The most bioactive was AEB with the highest percentage of binding, following by AAC, ADH and DKF. Our study for the first time unveils the differential binding properties of kiwifruit and persimmon phytoconstituents with HSA. Although cultivars possess virtually the same phytoconstituents, presence of one unique compound significantly alters the binding properties of HSA. The results of fluorescence quenching and molecular docking showed that these fruits possess multiple properties, which have a great potential to be used in industry with emphasis on the formulation of functional foods and medicinal applications.