Structure-activity relationship analysis of Panax ginseng glycoproteins with cytoprotective effects using LC-MS/MS and bioinformatics

Panax ginseng glycoproteins (PGG) has been shown biological activity, but researches in this field are rarely reported. In this paper, PGG were prepared by reflux and then purified with macroporous resin column. Further separation and purification of PGG using high performance liquid chromatography (HPLC) and two major components (PGG-1, PGG-2) were obtained. The molecular weights were calculated by gel permeation chromatography (GPC), and the results are 1.5 KDa and 8.2 KDa respectively. The MTT assay was used to study the cytoprotective effects of PGG, the results exhibited that PGG had significant effect (P < 0.01), and showed an obvious dose-effect relationship. Anti-apoptosis experiment results showed that PGG and PGG-2 can inhibit Aβ-induced apoptosis in SH-SY5Y cells (P < 0.05), and PGG-2 displayed better activity. The structures of N- and O-glycan were determined by combination of LC-MS/MS and methylation analysis. The computed parameters of PGG determined by MS including the theoretical isoelectric point (pI), instability index, aliphatic index and grand average of hydropathicity (GRAVY) were summarized systematically. The distinct differences between two parts would affect the behavior of PGG in vivo. The results of activity test and bioinformatics analysis would guide the study of PGG in pharmacokinetics and mechanism.