Chemical characterization and 5α-reductase inhibitory activity of phenolic compounds in goji berries

Lycium fruits have a high content of phenolics as bioactive constituents with various pharmacological effects, but there is a lack of comparative analysis and chemical profiling of phenolics in Lycium fruit varieties. An ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MSE) combined with chemometrics was developed to characterize the phenolics in fruits from four Lycium species, including Lycium barbarum L. (LBL), L. chinense Mill. (LCM), L. barbarum var. auranticarpum (LBA) and L. ruthenicun Murr. (LRM). 63 phenolics were identified according to reported tandem mass fragmentation patterns and the UNIFI scientific informatics platform. Nine phenolics (5, 18, 20, 29, 31, 37, 41, 43, 60) were common and predominant components among four types of Lycium fruit. The partial least squares discriminant analysis (PLS-DA) and the orthogonal partial least squares discriminant analysis (OPLS-DA) were analyzed on the basis of a matrix created from 653 sets of data, and 20 Lycium fruits were classified into four groups. Further analysis identified that phenolics profiles were characteristic for each Lycium species, and five markers (13, 29, 31, 35, 99) could be utilized for fruit identification. Subsequently, inhibitory activity against 5α-reductase of phenolic extracts of Lycium fruits showed that LBL extract was the relative better effective, followed by LCM, whereas LBA and LRM showed no activity, which might be associated with the high contents of marker compounds (29, 31, 35, 43, 71, 99) in LBL. These findings will provide guidance for the development of Lycium phenolics with beneficial properties for the prevention and treatment of Benign prostatic hyperplasia (BPH).