Study on α-glucosidase enzyme inhibitory activity and DPPH free radical scavenging of green coffee bean extract (Coffea canephora)

Abstract

Abstract: α-glucosidase enzyme is one of the important molecular targets in the treatment of diabetes. In addition, free radicals are the cause of insulin resistance, damage β- cell pancreatic, glucose uptake disorders and induced diabetes. In this study we evaluated the inhibitory effect of α-glucosidase enzyme and antioxidant effect by using DPPH free radical scavenging method of green coffee bean extract (Coffea canephora) and its fractions. Coffee beans were pulverized, extracted with ethanol 70% by sonications,  and fractionated with n-hexane, ethyl acetate (EtOAc) and n-butanol (n-BuOH) solvents. Our results showed that coffee bean extract has a strong α-glucosidase enzyme inhibitory activity, especially EtOAc fraction with an IC50 value of 2.21 ± 0.04 µg/mL. Furthermore, the coffee bean extract has an antioxidant effect by DPPH radical scavenging ability, and EtOAc fraction has the highest effect with an IC50 value of 25.69 ± 3.08 µg/ml. Our  results show that green coffee beans and EtOAc fraction have potential effect in preventing and supporting for the treatment of diabetes. Keywords Coffee; Coffea canephora; free radical; α-glucosidase; DPPH. References [1] Federation ID. IDF Diabetes Atlas 8th Edition (2017).[2] Wright Jr E, Scism‐Bacon J, Glass L. Oxidative stress in type 2 diabetes: the role of fasting and postprandial glycaemia. International journal of clinical practice 60(3) (2006) 308.[3] X. Chen. A review on coffee leaves: Phytochemicals, bioactivities and applications. Critical reviews in food science and nutrition 59(6) (2019) 1008.[4] Chu Y-F. Coffee: emerging health effects and disease prevention. John Wiley & Sons (2012).[5] N.T. Hai, D.K. Thu, B.T. Tung. Sarcandra glabra Extract Protects against Scopolamine Induced Cognitive Deficits by Modulating Neuroinflammation and the Cholinergic System. Current Enzyme Inhibition 14(3) (2018) 210.[6] B.T. Tung, D.K. Thu, P.T. Hai, N.T. Hai. Evaluation of α-glucosidase inhibitory activity of fractions from Punica granatum Linn fruits (in Vietnamese), Journal of Traditional Vietnamese Medicine and Pharmacy 5(18) (2018) 59.[7] S. Lenzen. The mechanisms of alloxan-and streptozotocin-induced diabetes. Diabetologia 51(2) (2008) 216.[8] K. Shapiro, W.C. Gong . Natural products used for diabetes. Journal of the American Pharmaceutical Association 42(2) (2002) 217.[9] O. Babova, A. Occhipinti, M.E. Maffei. Chemical partitioning and antioxidant capacity of green coffee (Coffea arabica and Coffea canephora) of different geographical origin. Phytochemistry 123 (2016) 33.[10] A. Priftis, D. Stagos, K. Konstantinopoulos, C. Tsitsimpikou, D.A. Spandidos, A.M. Tsatsakis, et al. Comparison of antioxidant activity between green and roasted coffee beans using molecular methods. Molecular medicine reports 12(5) (2015) 7293.[11] N. Liang, D.D. Kitts. Antioxidant property of coffee components: assessment of methods that define mechanisms of action. Molecules 19(11) (2014) 19180.[12] Vieira TMFdS. Potential antioxidant of brazilian coffee from the region of Cerrado. Food Science and Technology 38(3) (2018) 447.[13] S.D. Kim. α-Glucosidase inhibitor isolated from coffee. J Microbiol Biotechnol 25(2) (2015) 174.[14] Y. Zheng, K. Liu, G. Jia, H. Li, L. Han, Y. Kimura Effect of hot-water extract of coffee seeds on postprandial blood glucose concentration in rats. (2007).