Chen_2023_J.Agric.Food.Chem_71_11080

A total of nine new phenolic amides (1-9), including four pairs of enantiomeric mixtures (3-5 and 8), along with ten known analogues (10-19) were identified from the fruits of Lycium barbarum using bioassay-guided chromatographic fractionation. Their structures were elucidated by comprehensive spectroscopic and spectrometric analyses, chiral HPLC analyses, and quantum NMR, and electronic circular dichroism calculations. Compounds 5-7 are the first example of feruloyl tyramine dimers fused through a cyclobutane ring. The activity results indicated that compounds 1, 11, and 13-17 exhibited remarkable inhibition against alpha-glucosidase with IC(50) of 1.11-33.53 microM, 5-150 times stronger than acarbose (IC(50) = 169.78 microM). Meanwhile, compounds 4a, 4b, 5a, 5b, 13, and 14 exerted moderate agonistic activities for peroxisome proliferator-activated receptor (PPAR-gamma), with EC(50) values of 10.09-44.26 microM. Especially,compound 14 also presented inhibitory activity on dipeptidyl peptidase-4 (DPPIV), with an IC(50) value of 47.13 microM. Furthermore, the banding manner of compounds 14 and 17 with the active site of alpha-glucosidase, DPPIV, and PPAR-gamma was explored by employing molecular docking analysis.