Preventive effects of protopanaxadiol and protopanaxatriol ginsenosides on liver inflammation and apoptosis in hyperlipidemic apoE KO mice

Folic acid protects against tuberculosis-drug-induced liver injury in rats and its potential mechanism by metabolomics

Observational study indicated that folic acid (FA) supplementation may protect against tuberculosis-drug-induced liver injury (TBLI). The aim is to investigate the effect and mechanism of FA on TBLI in rats. Liver injury was induced by a daily gavage of isoniazid (INH) and rifampicin (RIF) in the model and FA groups. Rats in the FA group were also treated with 2.5 mg/kg body weight FA. Rats in the control group were not treated. Eight rats were used in each group. The severity of liver injury was measured by the serum levels of hepatic enzymes and histological score. The metabolites in serum and liver tissues were analyzed by HPLC-Q-TOF-MS/MS. FA treatment significantly reduced alanine aminotransferase and liver necrosis. Seventy-nine differential metabolites in the serum and liver tissues were identified among the three groups. N-acylethanolamines, INH and RIF metabolites, phosphatidylcholines, lysophosphatidylcholines, monoglycerides, diglycerides and bile acids were regulated by FA treatment, involving key metabolic pathways, such as N-acylethanolamine metabolism, INH and RIF metabolism, liver regeneration, inflammation alleviation and bile acid metabolism. RT-PCR and western blotting results confirmed the altered N-acylethanolamine metabolism and improved drug metabolism by FA. In conclusion, FA was protective against TBLI, which may be related to the regulation of N-acylethanolamine metabolism and drug detoxification by FA.

The promising therapeutic potentials of ginsenosides mediated through p38 MAPK signaling inhibition

The p38 mitogen-activated protein kinases (p38 MAPK) is a 38kD polypeptide recognized as the target for many potential anti-inflammatory agents. Accumulating evidence indicates that p38 MAPK could perform many roles in human disease pathophysiology. Therefore, great therapeutic benefits can be attained from p38 MAPK inhibitors. Ginseng is an exceptionally valued medicinal plant of the family Araliaceae (Panax genus). Recently, several studies targeted the therapeutic effects of purified individual ginsenoside, the most significant active ingredient of ginseng, and studied its particular molecular mechanism(s) of action rather than whole-plant extracts. Interestingly, several ginsenosides: ginsenosides compound K, F1, Rb1, Rb3, Rc, Rd, Re, Rf, Rg1, Rg2, Rg3, Rg5, Rh1, Rh2, Ro, notoginsenoside R1, and protopanaxadiol have shown to possess great therapeutic potentials mediated by their ability to downregulate p38 MAPK signaling in different cell lines and experimental animal models. Our review compiles the research findings of various ginsenosides as potent anti-inflammatory agents, highlighting the crucial role of p38 MAPK suppression in their pharmacological actions. In addition, in silico studies were conducted to explore the probable binding of these ginsenosides to p38 MAPK. The results obtained proposed p38 MAPK involvement in the beneficial pharmacological activities of ginsenosides in different ailments.

•

p38 MAPK plays many roles in human disease pathophysiology. Therefore, great therapeutic benefits can be attained from p38 MAPK inhibitors.

•

Several ginsenosides showed to possess great therapeutic potentials mediated by its ability to downregulate p38 MAPK signaling.

•

in silico ​studies were conducted to explore the binding of these ginsenosides to p38 MAPK and evidenced the promising their inhibitory effect.

Enhancement of skin barrier and hydration-related molecules by protopanaxatriol in human keratinocytes

Background

Protopanaxatriol (PPT) is a secondary intestinal metabolite of ginsenoside in ginseng. Although the effects of PPT have been reported in various diseases including cancer, diabetes and inflammatory diseases, the skin protective effects of PPT are poorly understood.

Methods

HaCaT cells were treated with PPT in a dose-dependent manner. mRNA and protein levels which related to skin barrier and hydration were detected compared with retinol. Luciferase assay was performed to explore the relative signaling pathway. Western blot was conducted to confirm these pathways and excavated further signals.

Results

PPT enhanced the expression of filaggrin (FLG), transglutaminase (TGM)-1, claudin, occludin and hyaluronic acid synthase (HAS) −1, −2 and −3. The mRNA expression levels of FLG, TGM-1, HAS-1 and HAS-2 were suppressed under NF-κB inhibition. PPT significantly augmented NF-κB-luc activity and upregulated Src/AKT/NF-κB signaling. In addition, PPT also increased phosphorylation of the mitogen-activated protein kinases (MAPKs) ERK, JNK and p38 and upstream MAPK activators (MEK and MKK). Furthermore, transcriptional activity of AP-1 and CREB, which are downstream signaling targets of MAPK, was enhanced by PPT.

Conclusion

PPT improves skin barrier function and hydration through Src/AKT/NF-κB and MAPK signaling. Therefore, PPT may be a valuable component for cosmetics or treating skin disorders.

Potential Dissociative Glucocorticoid Receptor Activity for Protopanaxadiol and Protopanaxatriol

Glucocorticoids are steroid hormones that regulate inflammation, growth, metabolism, and apoptosis via their cognate receptor, the glucocorticoid receptor (GR). GR, acting mainly as a transcription factor, activates or represses the expression of a large number of target genes, among them, many genes of anti-inflammatory and pro-inflammatory molecules, respectively. Transrepression activity of glucocorticoids also accounts for their anti-inflammatory activity, rendering them the most widely prescribed drug in medicine. However, chronic and high-dose use of glucocorticoids is accompanied with many undesirable side effects, attributed predominantly to GR transactivation activity. Thus, there is a high need for selective GR agonist, capable of dissociating transrepression from transactivation activity. Protopanaxadiol and protopanaxatriol are triterpenoids that share structural and functional similarities with glucocorticoids. The molecular mechanism of their actions is unclear. In this study applying induced-fit docking analysis, luciferase assay, immunofluorescence, and Western blot analysis, we showed that protopanaxadiol and more effectively protopanaxatriol are capable of binding to GR to activate its nuclear translocation, and to suppress the nuclear factor-kappa beta activity in GR-positive HeLa and HEK293 cells, but not in GR-low level COS-7 cells. Interestingly, no transactivation activity was observed, whereas suppression of the dexamethasone-induced transactivation of GR and induction of apoptosis in HeLa and HepG2 cells were observed. Thus, our results indicate that protopanaxadiol and protopanaxatriol could be considered as potent and selective GR agonist.

Protective effects of protopanaxatriol on acute liver injury induced by concanavalin A

The purpose of this study was to explore the protective effect of protopanaxatriol (PPT) on acute liver injury induced by concanavalin A (ConA). In this study, mice were randomly separated into four groups. The first group received PBS (i.v.). The second group was given PPT (50 mg/kg body weight, i.p.) for 3 days before PBS (i.v.) injection. The third group received ConA (15 mg/kg body weight, i.v.). The fourth group was administered PPT (50 mg/kg body weight, i.p.) for 3 days before ConA (i.v.) injection. The serum levels of ALT and AST were detected after 20 h of ConA injection. The pathological changes of liver were observed by H/E staining. The expression of inflammatory factors was measured by ELISA and qRTPCR, and the changes of the signaling pathway were detected by western blot. Histopathological changes and blood transaminase elevation indicated significant liver injury after ConA injection. However, PPT pretreatment obviously reversed these changes. The ELISA and qRT-PCR results indicated that PPT preconditioning significantly inhibited the production of inflammatory factors. In addition, this inhibitory effect of PPT was mainly mediated by regulation of the nuclear factor-κB (NF-κB) signaling pathway. The active ingredient of ginseng, PPT, exerts an obvious protective effect on acute liver injury caused by ConA through inhibiting the inflammatory response.