Antioxidant, Antibacterial, and Antiproliferative Activities of Free and Bound Phenolics from Peel and Flesh of Fuji Apple

This study was conducted to investigate the antioxidant, antibacterial, and antiproliferative activities of flesh free (FF), flesh bound (FB), peel free (PF), and peel bound (PB) phenolics from Fuji apple. The PB, which had highest total phenolic contents (126.15 +/- 2.41 mg/100 g wet weight) and lowest total carbohydrate contents (34.68 +/- 2.78 mg/100 g wet weight), showed the strongest 2,2'-azinobis-(3-ethylbenthiazoline-6-sulphonate) (ABTS) radical scavenging activity (EC50 = 0.36 +/- 0.02 mg/mL), 1,1-diphenyl-2-picryhydrazyl (DPPH) radical scavenging activity (EC50 = 0.26 +/- 0.01 mg/mL), and ferric reducing antioxidant power (Ferric reducing antioxidant power; EC50 = 0.19 +/- 0.02 mg/mL) compared with those of FF, FB, and PF. The PB also showed the strongest antibacterial activities on Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes and it also showed the highest antiproliferative effects on Caco-2 human colonic cancer cell (EC50 = 1.44 +/- 0.01 mg/mL) and Hela human cervical cell (EC50 = 2.81 +/- 0.01 mg/mL). Both free and bound phenolics from Fuji apple showed good antioxidant, antibacterial, and antiproliferative activities in our study, and bound phenolics had significantly higher activities compared with those of free phenolics.