Ginsenoside C-K

Ginsenoside CK (CK) is a metabolite of natural diol ginsenoside in the intestine, which has a unique chemical structure and pharmacological activity. CK has great potential in the treatment of neurologic dysfunction diseases. However, the therapeutic effect and potential mechanism of CK on Parkinson's disease (PD) have not been studied. Accordingly, this study used microbiome analysis to correlate behavioral, physiological and biochemical indices, and combined with WB to elucidate the mechanism of CK's improvement on PD. CK showed significant therapeutic effects on PD mice, which improved behavioral abnormalities such as spatial memory ability and motor coordination in PD mice, increased the activities of T-AOC and GSH-Px, decreased the MDA content, thus alleviating oxidative stress injury, suppressed the levels of pro-inflammatory factors IL-1β, IL-6, and TNF-α, and activated the expression of anti-inflammatory factor IL-2, which then exerted against neuroinflammation, inhibited the apoptosis of dopaminergic neurons in the substantia nigra of PD mice, increased the expression of TH, and prevented the aggregation of α-Syn in the substantia nigra. Microbiomics analysis showed that CK treatment could reshape the gut microbiota of PD mice by increasing the abundance of probiotics (Bacteroides anomalies) and decreasing the number of pathogenic bacteria (Actinomycetes). Correlation analysis showed that gut microbiota had potential correlation with behavioral, physiological and biochemical indexes. Western blot results showed that CK inhibited the expression levels of apoptotic proteins Bax, caspase-3, and Bcl-2, which revealed that CK treatment could improve the dysfunction of MPTP-induced PD mice from the molecular level. Collectively, these findings will provide a basis for further development of CK as an anti-PD drug.

Ginsenosides R2 and F2 are key active components of Panax japonicus var. major which exhibit a wide range of pharmacological effects. However, few UDP-glycosyltransferases (UGTs) involved in Rh2 and F2 biosynthesis have been identified. In this study, 12 UGTs from Panax japonicus var. major were predicted and characterized. Among them, one UGT (PjvmUGT45) exhibited superior catalytic activities by catalyzing the C3 hydroxyl glycosylation of protopanaxadiol (PPD) and compound K to form Rh2 and F2, respectively. Especially, PjvmUGT45 showed certain substrate specificity and regional specificity at the C-3 sites of PPD-type ginsenosides. Site-directed mutagenesis showed that Gln334, His349, Ser354, and Asp373 were key residues for PjvmUGT45, and the K280A mutant highly improved its activity. Our results revealed the biosynthetic mechanism of ginsenosides in Panax japonicus var. major, providing a novel alternative UGT for ginsenoside Rh2 production by synthetic biological methods.