Evaluation of in vitro anti‐hyperglycemic effect of Cinnamon cassia derived phenolic phytochemicals

Abstract

Cinnamon cassia (Cinnamon) proanthocyanidins (PACs) are shown to have anti‐hyperglycemia potential. The present study investigates the carbohydrate hydrolysis enzyme inhibition of cinnamon PACs. Five grams of cinnamon bark powder were extracted in 100 mL acetone solution (CAE) (acetone: water: hydrochloric acid, 70:29.9:0.01) for 2 hours at room temperature and in 100 mL deionized water for 30 min at 90 □ (CWE). PACs were purified from CAE using LH‐20 (CAE‐PAC) to be further evaluated. PAC contents were evaluated by 4‐ Dimethylaminocinnamaldehyde (DMAC) assay and yielded 795, 177 and 123 mg/g, for CAE‐PAC, CAE and CWE respectively. The total phenolic contents of CAE and CWE were determined to be 152 and 134 mg/g respectively. All extracts were adjusted to the same PAC content (180, 90, 45 and 20 μg) and the inhibitory activity against rat α‐glucosidase was determined. The CAE‐PAC fraction had very low rat α‐glucosidase inhibitory activity, CAE had the highest (IC50 3.13 mg/mL DW) followed by CWE (IC50 5.21 mg/mL DW). The specific maltase and sucrase inhibitory activities were determined and CAE (IC50 2.47 and 0.63 mg/mL DW) had higher inhibition than CWE (IC50 5.56 and 2.79 mg/mL DW). Results suggest that the observed bioactivity is not PAC dependent and that CAE has higher anti‐hyperglycemic potential than CWE via inhibition of carbohydrate hydrolysis enzymes.This research was supported by US Army Natick Soldier Research Engineering Center