In Vitro Studies on the Antioxidant Property and Inhibition of α-Amylase, α-Glucosidase, and Angiotensin I-Converting Enzyme by Polyphenol-Rich Extracts from Cocoa (Theobroma cacao) Bean

Background . This study sought to investigate the antidiabetic and antihypertensive mechanisms of cocoa ( Theobroma cacao ) bean through inhibition of α -amylase, α -glucosidase, angiotensin-1 converting enzyme, and oxidative stress. Methodology . The total phenol and flavonoid contents of the water extractable phytochemicals from the powdered cocoa bean were determined and the effects of the extract on α -amylase, α -glucosidase, and angiotensin-1 converting enzyme activities were investigated in vitro . Furthermore, the radicals [1,1-diphenyl-2 picrylhydrazyl (DPPH), 2,2..-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), hydroxyl (OH), and nitric oxide (NO)] scavenging ability and ferric reducing antioxidant property of the extract were assessed. Results . The results revealed that the extract inhibited α -amylase (1.81 ± 0.22 mg/mL), α -glucosidase (1.84 ± 0.17 mg/mL), and angiotensin-1 converting enzyme (0.674 ± 0.06 mg/mL [lungs], 1.006 ± 0.08 mg/mL [heart]) activities in a dose-dependent manner and also showed dose-dependent radicals [DPPH (16.94 ± 1.34 mg/mL), NO (6.98 ± 0.886 mg/mL), OH (3.72 ± 0.26 mg/mL), and ABTS (15.7 ± 1.06 mmol/TEAC · g] scavenging ability. Conclusion . The inhibition of α -amylase, α -glucosidase, and angiotensin-1 converting enzyme activities by the cocoa bean extract could be part of the possible mechanism by which the extract could manage and/or prevent type-2 diabetes and hypertension.