A new cafestol-type diterpenoid, 5β-hydroxy-2-oxocafestol named coffecanepholide C (1) along with three known diterpenoids including cafestol (2), tricalysiolide A (3) and atractyligenin (4) were identified from the Coffea canephora trunks collected at Lam Dong province, Vietnam. Their structures were elucidated by HRESIMS and NMR spectroscopic analysis (1H, 13C, COSY, HSQC, HMBC, and NOESY NMR) as well as compared with data in the literature. Upon evaluation of the α-glucosidase inhibitory activity, compound 1 (IC50 = 142.0 ± 0.2 µM) and compound 3 (IC50 = 286.2 ± 1.2 µM) exhibited activity against α-glucosidase, while structures 2 and 4 showed no activity. Furthermore, the docking simulations revealed that the carbonyl groups of compounds 1 and 3 formed hydrogen bonds with Lys506 residue at the enzyme pocket, which may induce the α-glucosidase inhibitory activity.
Keywords: Coffea canephora; NMR; cafestol; diterpene; molecular docking; α-glucosidase inhibition.