Cytosolic β-glucosidase inhibition and renal blood flow suppression are leading causes for the enhanced systemic exposure of salidroside in hypoxic rats

Pharmacokinetic-Pharmacodynamic Correlation Analysis of Rhodiola crenulata in Rats with Myocardial Ischemia

The pharmacokinetics (PK) of Rhodiola crenulata in rats were studied, and pharmacokinetic-pharmacodynamic (PK-PD) correlation analysis was performed to elucidate their time-concentration-effect relationship. The myocardial ischemia model was made with pituitrin. Rats were divided into sham operation, sham operation administration, model, and model administration groups (SG, SDG, MG, and MDG, respectively; n = 6). Blood was collected from the fundus venous plexus at different time points after oral administration. The HPLC-QQQ-MS/MS method was established for the quantification of five components of Rhodiola crenulata. CK, HBDH, SOD, LDH, and AST at different time points were detected via an automatic biochemical analyzer. DAS software was used to analyze PK parameters and PK-PD correlation. The myocardial ischemia model was established successfully. There were significant differences in the PK parameters (AUC0-t, AUC0-∞, Cmax) in MDG when compared with SDG. Two PD indicators, CK and HBDH, conforming to the sigmoid-Emax model, had high correlation with the five components, which indicated a delay in the pharmacological effect relative to the drug concentration in plasma. The difference in the PK parameters between modeled and normal rats was studied, and the time-concentration-effect of composition and effect indicators were investigated. This study can provide reference for the rational clinical application of Rhodiola crenulata and for related studies of other anti-myocardial ischemia drugs.

Reduction of emodin-8-O-ß-D-glucoside content participates in processing-based detoxification of polygoni multiflori radix

BACKGROUND

The occurrence of severe liver injury by the herbal medicine Polygoni Multiflori Radix (PMR) has drawn significant attention. The fact that processing attenuates PMR-induced hepatotoxicity has been well accepted, but the mechanisms are still ambiguous.

PURPOSE

This study aimed to illuminate the mechanism of processing-based attenuation of PMR hepatotoxicity.

METHODS

The contents of emodin-8-O-β-d-glucoside (EG) and emodin (EMD) in raw and processed PMR were quantified. The difference in toxicokinetic behaviors of EG and EMD was determined in vivo, and the disposition properties of EG were investigated in vitro and in vivo.

RESULTS

Decreased EG content was found in processed (black bean) PMR. Processed PMR showed reduced adverse effects relative to raw PMR. In addition, less hepatic protein adduction derived from EMD was produced in mice after exposure to processed PMR than that in animals receiving raw PMR. Glucose transporters SGLT1 and GLUT2 participated in the absorption of EG, and effective hydrolysis of EG to EMD took place in the intestinal epithelial cells during the process of absorption. Cytosolic broad-specificity β-glucosidase and lactase phlorizin hydrolase, as well as intestinal flora, participated in the hydrolysis of EG. The circulated EMD resulting from the deglycosylation of EG executed the hepatotoxic action.

CONCLUSION

EG is a pre-toxin and can be metabolically activated to EMD participating in the hepatotoxic event. The reduction of EG content due to processing is a key mechanistic factor that initiates the detoxification of PMR.

Salidroside protects mice from high-fat diet-induced obesity by modulating the gut microbiota

Obesity is a systemic disease with multisystem inflammation associated with gut dysbiosis. Salidroside (SAL) which is a major glycoside extracted from Rhodiola rosea L. has a wide range of pharmacological effects, but the role of gut microbiota in the protective effects of SAL on obesity has not been studied. Herein, we aim to explore whether SAL could ameliorate high-fat diet (HFD)-induced obesity in mice by modulating microbiota. Results showed that oral treatment with SAL alleviated HFD-induced obesity in mice as evidenced by body weight and fat weight. SAL supplementation effectively attenuated fat accumulation, lipid synthesis genes expression, liver inflammation, and metabolic endotoxemia. In addition, SAL treatment alleviated intestinal damage and increased the expression of mucin protein (Mucin-2) and tight junction (TJ) proteins (Occludin and Zonula Occludens-1). 16S rRNA sequencing analysis revealed that the gut microbiota of obese mice was also partly improved by SAL via restoring the microbial community structure and diversity. A fecal microbiota transplantation (FMT) study was designed to verify the causality. Compared with fecal transplantation (FM) from the HFD-treated mice, FM from the SAL-treated mice significantly mitigate the symptoms of obese mice, including decreasing body weight, fat accumulation, and attenuating pathological damage in the gut. Thus, SAL could be a remarkable candidate to prevent obesity.

Salidroside alleviates ulcerative colitis via inhibiting macrophage pyroptosis and repairing the dysbacteriosis-associated Th17/Treg imbalance

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by flora disequilibrium and mucosal immunity disorder. Here, we report that salidroside effectively restricts experimental colitis from two aspects of intestinal macrophage pyroptosis and dysbacteriosis-derived colonic Th17/Treg imbalance. In innate immunity, the upregulated TREM1 and pyroptosis-related proteins in inflamed colons were inhibited by salidroside administration and further experiments in vitro showed that salidroside suppressed LPS/ATP-induced bone marrow-derived macrophages (BMDMs) pyroptosis evident by the decline of LDH and IL-1β release as well as the protein level of NLRP3, caspase-1, and GSDMD p30. Moreover, the TREM1 inhibitor weakened the effect of salidroside on BMDMs pyroptosis, whereas salidroside still could downregulate TREM1 when NLRP3 was inhibited. In adaptive immunity, salidroside improved the gut microflora diversity and Th17/Treg ratio in DSS-induced mice, especially promoting the abundance of Firmicutes. Clearance of the gut flora blocked the benefit of salidroside on colonic inflammation and Th17/Treg adaptive immunity, but transplanting salidroside-treated foecal bacterium into flora-depleted wild mice reproduced the resistance of salidroside to gut inflammation. Taken together, our data demonstrated that salidroside protected experimental colitis via skewing macrophage pyroptosis and Th17/Treg balance, indicating its potential effect on UC and other immune disorders.

Metabolic Activation of Militarine In Vitro and In Vivo

Bletilla striata is consumed as food and herbal medicine. Militarine (MLT) is a major ingredient in B. striata. Previous studies demonstrated that MLT showed teratogenic toxicity to zebrafish embryos. The present study aimed to identify reactive metabolites possibly involved in the cytotoxicity of MLT and determine the metabolic pathways involved. MLT was found to be hydrolyzed to p-hydroxybenzyl alcohol (HBA) by β-glucosidase and esterases. The resulting HBA further underwent spontaneous dehydration to form quinone methide. HBA was also metabolized to the corresponding sulfate, followed by departure of the sulfate to generate a quinone methide. The resultant quinone methide reacted with hepatic glutathione (GSH) and protein to form the corresponding GSH conjugate and protein adduction. Additionally, inhibition of sulfotransferases (SULTs) attenuated the susceptibility of hepatocytes to the toxicity of MLT. This study provides that the hydrolytic enzymes β-glucosidase, esterases, and SULTs participate in the metabolic activation of MLT.

The bioinformatics and metabolomics research on anti-hypoxic molecular mechanisms of Salidroside via regulating the PTEN mediated PI3K/Akt/NF-κB signaling pathway

Salidroside (SAL), a major bioactive compound of Rhodiola crenulata, has significant anti-hypoxia effect, however, its underlying molecular mechanism has not been elucidated. In order to explore the protective mechanism of SAL, the lactate dehydrogenase (LDH), reactive oxygen species (ROS), superoxide dismutase (SOD) and hypoxia-induced factor 1α (HIF-1α) were measured to establish the PC12 cell hypoxic model. Cell staining and cell viability analyses were performed to evaluate the protective effects of SAL. The metabolomics and bioinformatics methods were used to explore the protective effects of salidroside under hypoxia condition. The metabolite-protein interaction networks were further established and the protein expression level was examined by Western blotting. The results showed that 59 endogenous metabolites changed and the expression of the hub proteins of CK2, p-PTEN/PTEN, PI3K, p-Akt/Akt, NF-κB p65 and Bcl-2 were increased, suggesting that SAL could increase the expression of CK2, which induced the phosphorylation and inactivation of PTEN, reduced the inhibitory effect on PI3K signaling pathways and activated the PI3K/Akt/NF-κB survival signaling pathway. Our study provided an important insight to reveal the protective molecular mechanism of SAL as a novel drug candidate.

Salidroside: A review of its recent advances in synthetic pathways and pharmacological properties

Salidroside has been identified as one of the most potent compounds isolated from various Rhodiola plants, which have been used for a long time as adaptogens in traditional Chinese medicine. However, due to the severe growing environment of herbal medicine and large-scale excavation, the content of natural salidroside is extremely small. Most of the previous studies focused on herbal medicine, and there were few reviews on the synthesis of its main active ingredient salidroside. This paper presents different synthetic routes of salidroside to resolve the contradiction between supply and demand and lays the foundation for new drug research and development. Furthermore, emerging evidence indicates that salidroside, a promising environmentally-adapted drug with low toxicity and few side effects, possesses a wide spectrum of pharmacological properties, including activities on the cardiovascular system and central nervous system, anti-hypoxia, anti-fatigue and anti-aging activities, anticancer activity, anti-inflammatory activity, antioxidant activity, antivirus and immune stimulation activities, antidiabetic activity, anti-osteoporotic activity, and so on. Although the former researches have summarized the pharmacological effects of salidroside, focusing on the central nervous system, diabetes, and cancer, the overall pharmacological aspects of it have not been analyzed. This review highlights biological characteristics and mechanisms of action from 2009 to now as well as toxicological and pharmacokinetic data of the analyzed compound reported so far, with a view to providing a reference for further development and utilization of salidroside.

Salidroside as a potential neuroprotective agent for ischemic stroke: a review of sources, pharmacokinetics, mechanism and safety

Salidroside (Sal) is a bioactive extract principally from traditional herbal medicine such as Rhodiola rosea L., which has been commonly used for hundreds of years in Asia countries. The excellent neuroprotective capacity of Sal has been illuminated in recent studies. This work focused on the source, pharmacokinetics, safety and anti-ischemic stroke (IS) effect of Sal, especially emphasizing its mechanism of action and BBB permeability. Extensive databases, including Pubmed, Web of science (WOS), Google Scholar and China National Knowledge Infrastructure (CNKI), were applied to obtain relevant online literatures. Sal exerts powerful therapeutic effects on IS in experimental models either in vitro or in vivo due to its neuroprotection, with significantly diminishing infarct size, preventing cerebral edema and improving neurological function. Also, the findings suggest the underlying mechanisms involve anti-oxidation, anti-inflammation and anti-apoptosis by regulating multiple signaling pathways and key molecules, such as NF-κB, TNF-α and PI3K/Akt pathway. In pharmacokinetics, although showing a rapid absorption and elimination, bioavailability of Sal is elevated under some non-physiological conditions. The component and its metabolite (tyrosol) are capable of distributing to brain tissue and the later keeps a higher level of concentration. Moreover, Sal scarcely has obvious toxicity or side effects in a variety of animal experiments and clinical trials, but combination of drugs and perinatal use of medicine should be taken more attentions. Finally, as an active ingredient, not only is Sal isolated from diverse plants with limited yield, but also large batches of the products can be harvested by biological and chemical synthesis. With higher efficacy and better safety profiles, Sal could sever as a promising neuroprotectant for preventing and treating IS. Nevertheless, further investigations are still required to explore the pharmacodynamic and pharmacokinetic properties of Sal in the treatment of IS.