In Vitro α-Glucosidase and α-Amylase Inhibitory Activities of Free and Bound Phenolic Extracts from the Bran and Kernel Fractions of Five Sorghum Grain Genotypes

Abstract

Diabetes is a global health challenge. Currently, an effective treatment for diabetes is to reduce the postprandial hyperglycaemia by inhibiting the carbohydrate hydrolysing enzymes in the digestive system. In this study, we investigated the in vitro α-glucosidase and α-amylase inhibitory effects of free and bound phenolic extracts, from the bran and kernel fractions of five sorghum grain genotypes. The results showed that the inhibitory effect of sorghum phenolic extracts depended on the phenolic concentration and composition. Sorghum with higher phenolic contents generally had higher inhibitory activity. Among the tested extracts, the brown sorghum (IS131C)-bran-free extract (BR-bran-free, half-maximal inhibitory concentration (IC50) = 18 ± 11 mg sorghum/mL) showed the strongest inhibition against α-glucosidase which was comparable to that of acarbose (IC50 = 1.39 ± 0.23 mg acarbose/mL). The red sorghum (Mr-Buster)-kernel-bound extract (RM-kernel-bound, IC50 = 160 ± 12 mg sorghum/mL) was the most potent in inhibiting α-amylase but was much weaker compared to acarbose (IC50 = 0.50 ± 0.03 mg acarbose/mL).

Linking the Phytochemicals and the α-Glucosidase and α-Amylase Enzyme Inhibitory Effects of Nigella sativa Seed Extracts

“…However, these drugs often induce serious gastrointestinal side effects including stomach pain, flatulence, and diarrhea [4]. As a result, natural α-glucosidase and α-amylase inhibitors, mostly from food products, have emerged as promising therapeutic options to supplement or even substitute existing drugs [2,[5][6][7]. Several types of natural plant products have emerged as promising α-glucosidase and α-amylase inhibitors in recent decades [8][9][10][11][12][13][14][15][16].…”

in vitro α amylase and amyloglucosidase inhibitory activities of selected underutilized cereals, yams and root crops

“…In vitro α amylase activity was measures using the method described in Xiong et al, (2020) [14] with some modifications as mentioned in Mel et al (2020) [15] and Janarny and Gunathilake, (2020) [16] . A sample of 1.00 mg from each yam, roots and cereal flours were weighed and 100 μl of the αamylase enzyme was added which was prepared by adding 27.5 mg of enzyme in 100 mL of 20 mmol sodium phosphate buffer containing 6.7 mmol of sodium chloride was added (pH 6.9).…”

Influence of In Vitro Human Digestion Simulation on the Phenolics Contents and Biological Activities of the Aqueous Extracts from Turkish Cistus Species

“…[ 19 ]. Aminoguanidine, pimagedine and metformin are examples of synthetic inhibitors for AGEs and acarbose, miglitol and voglibose are synthetic inhibitors for digestive enzymes and have been in use for the past decades [ 20 , 21 ]. However, clinical trials and in vivo experiments demonstrated the side effects of these synthetic inhibitors, such as hepatotoxicity, abdominal distention, flatulence, meteorism, anaemia, vomiting, heart failure, etc.…”