Coptis chinensis inflorescence ameliorates hyperglycaemia in 3T3-L1 preadipocyte and streptozotocin-induced diabetic mice

• Coptis chinensis inflorescence extract (CE) inhibits α-amylase and α-glucosidase.
• CE increases the glucose consumption of 3T3-L1 preadipocyte dose-dependently.
• CE and its main alkaloids facilitate insulin secretion in diabetic mice.
• CE and its main alkaloids have a glucose-lowering effect in diabetic mice.
• CE and its main alkaloids relieve liver injury and lipid metabolic disturbance.

Coptis chinensis inflorescence is rich in isoquinoline alkaloids, especially berberine; these alkaloids comprise a chemical group with anti-hyperglycaemic effect. This study mainly investigated the α-amylase and α-glucosidase inhibitory activities of C. chinensis inflorescence extract (CE). The effect of CE was similar to that of acarbose. Results of 3T3-L1 preadipocyte assay showed that CE can increase glucose consumption. In addition, CE and its main alkaloids (jatrorrhizine, columbamine, epiberberine, coptisine, palmatine, and berberine) were used to ameliorate streptozotocin-induced diabetic mice. Anti-hyperglycaemic activity was realised by reducing the blood glucose level and increasing the insulin content. Furthermore, CE and its main alkaloids can relieve liver injury and lipid metabolic disturbance. Therefore, CE exerts anti-hyperglycaemic activity, and alkaloids may be an active compound group. Overall, the results provide scientific foundation for C. chinensis inflorescence as functional food to ameliorate hyperglycaemia.