Antidiabetic Potential Yacon (Smallanthus sonchifolius (Poepp.) H. Rob.) Leaf Extract via Antioxidant Activities, Inhibition of α-glucosidase, α- amylase, G-6-Pase by In Vitro Assay

Background: Diabetes is a chronic disease characterized by glucose levels and results in impaired insulin secretion. This disorder has triggered oxidative stress and excess free radicals condition. Smallanthus sonchifolius is a traditional medicine that acts as a diabetic therapy. This research aims to bring out the antidiabetic and antioxidant potential of S. sonchifolius extract (SSE). 
Materials and Methods: This study was conducted to measure the qualitative phytochemical identification, antioxidant and anti-diabetic activity of SSE. The antioxidant assay was carried out using 2,2-diphenyl-1-picrylhydrazine (DPPH)- scavenging activity, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)-scavenging and hydrogen peroxide (H2O2)-reducing activity assays, ferric reducing antioxidant power (FRAP) potency, while anti-diabetic activity of SSE assay was carried out using inhibitory of α-amylase, α-glucosidase, and Glucose-6-Phosphatase (G-6-Pase). 
Results: SSE contained phenols, flavonoids, steroids/triterpenoids, saponins, tannins, and alkaloids. The antioxidant and antidiabetic activities of samples were calculated based on median inhibitory concentration (IC50). The IC50 values of SSE antioxidant, respectively, were DPPH (IC50 = 62.72 μg/mL), ABTS (IC50 = 61.03 μg/mL), H2O2 (IC50 = 438.36 μg/mL), the highest FRAP activity was 125.31 μM Fe(II)/μg extract at a concentration level of SSE 50 μg/mL. The IC50 values of SSE antidiabetic were α-amylase inhibition (IC50 = 37.86 μg/mL), α-glucosidase inhibition (IC50 = 90.41 μg/ mL), and G-6-Pase inhibition (IC50 = 98.07 μg/mL), respectively. 
Conclusions: SSE has antidiabetic potential through antioxidant activities and α-glucosidase, α-amylase, and G-6-Pase inhibition activities.