Chemical characterization, multivariate analysis and in vitro bioactivity evaluation of the roots of Fraxinus mandshurica

Fraxinus mandshurica is widely used in folk medicine to treat various diseases and has significant pharmacological effects. To make full use of this resource, its roots were studied. Twelve lignans were first obtained by natural product extraction, selective separation and identification, and were identified and quantified by high performance liquid chromatography-photodiode array (HPLC-DAD). The results of quantitative analysis showed that the highest lignin content in F. mandshurica roots was compound 9 with 102.02 mg/g, while the overall lignin content in Shanxi was low. The results of methodological validation showed that the RSD values of intra-day precision ranged from 0.35% to 1.38%, while the RSD values of inter-day precision were within 1.97%; the RSD values of reproducibility experiments ranged from 0.35% to 1.96%, while the RSD values of stability experiments were less than 2.97%; the spiked recovey of samples were within 102.84%, and the RSD values ranged from 0.39% to 1.77%, which fully confirmed the high precision and good reproducibility of the analytical method. In addition, fingerprinting and heatmap were established for 40 batches of samples from 8 origins. Next, multivariate analysis, including principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), was performed to investigate the differences in lignin content in the roots of F. mandshurica from different origins, and four lignins that could be used to distinguish F. mandshurica from different origins were screened. Finally, 12 lignans were evaluated for enzyme activity inhibition with α-glucosidase, tyrosinase and acetylcholinesterase, and the results showed that all 12 lignans exhibited enzyme activity inhibition to different degrees, which have potential applications in anti-diabetic, whitening and light spot and anti-Alzheimer's disease, and become a new source of natural enzyme activity inhibitors. This study established an identification and evaluation method applicable to plants of different origins, which provides a certain theoretical basis for the comprehensive exploitation of F. mandshurica.