In vitro antioxidant, anti-diabetic, cholinesterase and tyrosinase inhibitory potential of fresh juice from Citrus hystrix and C. maxima fruits

In the present study, antioxidant potential, α-amylase, α-glucosidase, cholinesterase and tyrosinase inhibitory activity of fresh juice from indigenous fruits of Citrus hystrix and C. maxima (Red & White var.) were investigated using an in vitro model. The contents of total phenolics, tannins, and total flavonoids ranged between 836.90 and 909.52 mg gallic acid equivalent (GAE)/L, 333.33 and 523.21 mg gallic acid equivalent (GAE)/L and 224.88 and 262.22 mg rutin equivalent/L, respectively. The antioxidant activity of fresh juice was evaluated by employing different in vitro assays such as reducing power assay, DPPH, ABTS+ and OH radical scavenging capacities, peroxidation inhibition activity, antihemolytic assay. In addition, 75.55%–79.75% of α-amylase and 70.68%–72.83% of α-glucosidase enzyme inhibition characteristics were found under in vitro starch digestion bioassay. Also, all the juice samples exhibited excellent tyrosinase (76.95%–80.79%), acetylcholinesterase (75.71%–79.74%) and β-glucuronidase inhibitory activity (68.13%–69.38%). These results indicated that fresh juice of C. hystrix and C. maxima (Red & White var.) could be used as a source of antioxidant agents, functional food and nutraceuticals.