Anti-hyperglycaemic effect of labdane diterpenes isolated from the rhizome of Amomum maximum Roxb., an edible plant in Southwest China

Abstract

Amomum maximum Roxb. rhizome is a fork medicine mainly used in South and Southeast Asia. In present study, the hypoglycaemic effects of the ethanolic extract of A. maximum rhizome were demonstrated both on α-glucosidase assay in vitro and streptozotocin (STZ)-induced postprandial hyperglycaemia in mice. Furthermore, six labdane diterpenes, amoxanthin A (1), ottensinin (2), coronarin D (3), coronarin D methyl ether (4), isocoronarin D (5), and zerumin (6), were isolated from its ethyl acetate sub-fraction with the guidance of α-glucosidase inhibitory activity. Among these compounds, 2 and 6 exhibited significant inhibitory effect on α-glucosidase, as well as on STZ-induced high postprandial blood glucose levels in mice. Additionally, molecular docking analysis revealed that 2 and 6 could firmly bind to the active sites of α-glucosidase. These results suggest that compounds 2 and 6 are the main anti-hyperglycaemic agents present in A. maximum, which may demonstrate potential beneficial effects in diabetes management.

Graphical Abstract

Keywords:

• Amomum maximum
• α-glucosidase
• anti-hyperglycaemic activity
• labdane diterpenes
• molecular docking

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

This study was supported by the National Natural Science Foundation of China (No. 81602991) and GDAS' Project of Science and Technology Development (No. 2019GDASYL-0103039).