Nutritional and neuroprotective characterization of 'Tadanishiki' yuzu according to harvesting period or extraction condition

Abstract

The present study investigated the phenolic profile, antioxidant activity, and neuroprotective properties of ‘Tadanishiki’ yuzu (Citrus junos, a seedless variety of yuzu) according to harvesting period and extraction condition. High-performance liquid chromatography (HPLC) was used to identify the functional components. To evaluate the neuroprotective properties, scopolamine was used to induce cholinergic dysfunction in human neuroblastoma SH-SY5Y cells pretreated with yuzu extracts. Among the harvesting periods, September provided the optimum fruit weight of yuzu and relatively high amounts of total phenolics (3.67 mg/g DW), flavonoids (10.13 mg/g DW), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity (29.10 μg Vit. C eq.). Of the functional compounds, hesperidin (13.57 mg/100 g DW) and naringin (5.84 mg/100 g DW) were the highest in 5% (w/v) yuzu extracted with 80% ethanol and this extract showed the highest DPPH (289.2 μg Vit. C eq.) scavenging activity. This same extract showed the highest cell viability and lowest cortisol or acetylcholinesterase content in scopolamine-treated SH-SY5Y cells. These results indicate that ‘Tadanishiki’ yuzu harvested in September should be extracted at 5% (w/v) yuzu with 80% EtOH, and this extract might be useful for application as a natural functional additive.