Luo_2025_Chem.Biodivers__e02121

Eight dimeric flavanes were isolated from the plant Psychotria calocarpa (Rubiaceae), including four stereoisomeric flavan-flavan-3-ol dimers (1-4) and four stereoisomeric flavan-3-ol-flavan-3-ol dimers (5-8). Among them, compounds 1-3 are newly identified flavan-(48)-flavan-3-ol dimers, named psychodiflavanols A-C, respectively. Their structures were elucidated by a comprehensive spectroscopic analysis combined with the quantum chemical calculations of electronic circular dichroism spectra. Compounds 4-8 were determined to be known flavan- (48)-flavan-3-ol dimer or flavan-3-ol-(48)-flavan-3-ol dimers based on comparison with literature data. All isolates were evaluated for their inhibitory activities against acetylcholinesterase, butyrylcholinesterase (BChE), alpha-glucosidase, and alpha-amylase. The results demonstrated that psychodiflavanol A (1) had potent and selective inhibition of BChE, with a half-maximal inhibitory concentration (IC(50)) value of 11.47 +/- 2.12 microM. In addition, psychodiflavanol B showed a notable alpha-glucosidase inhibitory effect with an IC(50) value of 10.15 +/- 1.17 microM. These findings suggest that the flavane dimers from P. calocarpa might possess promising potential as lead compounds for developing therapeutic agents that target neurodegenerative and metabolic disorders.