Inhibitory effect of polyphenolic–rich extract from Cola nitida (Kolanut) seed on key enzyme linked to type 2 diabetes and Fe2+ induced lipid peroxidation in rat pancreas in vitro

• Published in: Asian Pacific Journal of Tropical Biomedicine
• Main Authors: Ganiyu Oboh, Kate E. Nwokocha, Ayodele J. Akinyemi, Adedayo O. Ademiluyi
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wolters Kluwer Medknow Publications 2014
• Subjects: α-Amylase; α-Glucosidase; Oxidative stress; Phenolic compounds; Arctic medicine. Tropical medicine; RC955-962; Biology (General); QH301-705.5; Arctic
• Online Access: https://doi.org/10.12980/APJTB.4.2014C75; https://doaj.org/article/54a66641d8504a38998808c3e73309bc

Objective: To investigate the inhibitory effect of phenolic-rich extracts from Cola nitida (C. nitida) seeds on key enzymes linked with type-2 diabetes and Fe2+ induced oxidative stress in rat pancreas. Methods: The phenolic extract was prepared with 80% acetone (v/v). Subsequently, the antioxidant properties and inhibitory effect of the extract on α – amylase and α – glucosidase as well as on Fe2+ induced lipid peroxidation in rat pancreas were determined in vitro. Results: The result revealed that C. nitida extract inhibited α-amylase (EC50=0.34 mg/mL) and α-glucosidase (EC50=0.32 mg/mL) activities as well as Fe2+ induced lipid peroxidation in rat pancreas in a dose dependent manner. In addition, the extract had high DPPH radical scavenging ability (EC50=2.2 mg/mL) and reducing power (8.2 mg AAE/g). Characterization of the main phenolic compounds of the extract using gas chromatography analysis revealed catechin (6.6 mg/100 g), epicatechin (3.6 mg/100 g), apigenin (5.1 mg/100 g) and naringenin (3.6 mg/100 g) were the main compounds in the extract. Conclusions: This antioxidant and enzyme inhibition could be some of the possible mechanism by which C. nitida is use in folklore for the management/treatment of type-2 diabetes. However, the enzyme inhibitory properties of the extract could be attributed to the presence of catechin, epicatechin, apigenin and naringenin.