Hepatoprotective effects of salidroside on fulminant hepatic failure induced by d-galactosamine and lipopolysaccharide in mice

Salidroside in the Treatment of NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) is the commonest reason for chronic liver diseases in the world and is commonly related to the hepatic manifestation of the metabolic syndrome. Non-alcoholic steatohepatitis (NASH) is a deteriorating form of NAFLD, which can eventually develop into fibrosis, cirrhosis, and liver cancer. The reason for NAFLD/NASH development is complicated, such as liver lipid metabolism, oxidative stress, inflammatory response, apoptosis and autophagy, liver fibrosis and gut microbiota. Apart from bariatric surgery and lifestyle changes, officially approved drug therapy for NAFLD/NASH treatment is lacking. Salidroside (SDS) is a phenolic compound extensively distributed in the tubers of Rhodiola plants, which possesses many significant biological activities. This review summarized the related targets regulated by SDS in treating NAFLD/NASH. It is indicated that SDS could improve the status of NAFLD/NASH by ameliorating abnormal lipid metabolism, inhibiting oxidative stress, regulating apoptosis and autophagy, reducing inflammatory response, alleviating fibrosis and regulating gut microbiota. In conclusion, although the multiple bioactivities of SDS have been confirmed, the clinical data are inadequate and need to become the focus of attention in the later study.

Dietary Supplementation of Salidroside Alleviates Liver Lipid Metabolism Disorder and Inflammatory Response to Promote Hepatocyte Regeneration via PI3K/AKT/Gsk3-β Pathway

Fatty liver hemorrhagic syndrome (FLHS) is a chronic hepatic disease which occurs when there is a disorder in lipid metabolism. FLHS is often observed in caged laying hens and characterized by a decrease in egg production and dramatic increase of mortality. Salidroside (SDS) is an herbal drug which has shown numerous pharmacological activities, such as protecting mitochondrial function, attenuating cell apoptosis and inflammation, and promoting antioxidant defense system. We aimed to determine the therapeutic effects of SDS on FLHS in laying hens and investigate the underlying mechanisms through which SDS operates these functions. We constructed oleic acid (OA)-induced fatty liver model in vitro and high-fat diet-induced FLHS of laying hens in vivo. The results indicated that SDS inhibited OA-induced lipid accumulation in chicken primary hepatocytes, increased hepatocyte activity, elevated the mRNA expression of proliferation related genes PCNA, CDK2, and cyclinD1 and increased the protein levels of PCNA and CDK2 (P < 0.05), as well as decreased the cleavage levels of Caspase-9, Caspase-8, and Caspase-3 and apoptosis in hepatocytes (P < 0.05). Moreover, SDS promoted the phosphorylation levels of PDK1, AKT, and Gsk3-β, while inhibited the PI3K inhibitor (P < 0.05). Additionally, we found that high-fat diet-induced FLHS hens had heavier body weight, liver weight, and abdominal fat weight, and severe steatosis in histology, compared with the control group (Con). However, hens fed with SDS maintained lighter body weight, liver weight, and abdominal fat weight, as well as normal liver without hepatic steatosis. In addition, high-fat diet-induced FLHS hens had high levels of serum total cholesterol (TC), triglyceride (TG), alanine transaminase (ALT), and aspartate aminotransferase (AST) compared to the Con group, however, in the Model+SDS group, the levels of TC, TG, ALT, and AST decreased significantly, whereas the level of superoxide dismutase (SOD) increased significantly (P < 0.05). We also found that SDS significantly decreased the mRNA expression abundance of PPARγ, SCD, and FAS in the liver, as well as increased levels of PPARα and MTTP, and decreased the mRNA expression of TNF-α, IL-1β, IL-6, and IL-8 in the Model+SDS group (P < 0.05). In summary, this study showed that 0.3 mg/mL SDS attenuated ROS generation, inhibited lipid accumulation and hepatocyte apoptosis, and promoted hepatocyte proliferation by targeting the PI3K/AKT/Gsk3-β pathway in OA-induced fatty liver model in vitro, and 20 mg/kg SDS alleviated high-fat-diet-induced hepatic steatosis, oxidative stress, and inflammatory response in laying hens in vivo.

Efficient Enzymatic Synthesis of Lipophilic Phenolic Glycoside Azelaic Acid Esters and Their Depigmenting Activity

In this paper, an enzymatic route for synthesizing phenolic glycoside azelaic acid esters was successfully set up via lipase-catalyzed esterification and transesterification. Among the lipases tested, Candida antarctica lipase B (Novozyme 435) showed the highest activity in catalyzing esterification and Thermomyces lanuginosus (Lipozyme TLIM) gave the highest substrate conversion in catalyzing transesterification for the synthesis of ester. The addition of 4A molecular sieves into the reaction system is found to be an effective method for in situ absorption of the byproduct water and methanol, with which the substrate conversions of the enzymatic esterification and transesterification were 98.7 and 95.1%, respectively. Also, the main product ratios in transesterification were above 99.0% with lipozyme TLIM as a catalyst because the hydrolysis reaction was hindered. The results of the physical and biological properties indicate that all esters had higher Clog p values than their parent compounds. Also, the esters showed higher intracellular tyrosinase inhibitory and depigmentating activities than phenolic glycosides, azelaic acid (AA), and their physical mixtures due to their higher membrane penetration and tyrosinase inhibitory effects. In particular, piceid 6″-O-azelaic acid ester (PIA) showed the strongest inhibitory effect against melanin production. Its inhibitory rate was 77.4% at a concentration of 0.25 mM, about 4.2 times higher than that of arbutin (18.5%).

Protective Effects of Taraxacum officinale L. (Dandelion) Root Extract in Experimental Acute on Chronic Liver Failure

BACKGROUND

Taraxacum officinale (TO) or dandelion has been frequently used to prevent or treat different liver diseases because of its rich composition in phytochemicals with demonstrated effect against hepatic injuries. This study aimed to investigate the possible preventing effect of ethanolic TO root extract (TOERE) on a rat experimental acute on chronic liver failure (ACLF) model.

METHODS

Chronic liver failure (CLF) was induced by human serum albumin, and ACLF was induced in CLF by D-galactosamine and lipopolysaccharide (D-Gal-LPS). Five groups (n = 5) of male Wistar rats (200-250 g) were used: ACLF, ACLF-silymarin (200 mg/kg b.w./day), three ACLF-TO administered in three doses (200 mg, 100 mg, 50 mg/kg b.w./day).

RESULTS

The in vivo results showed that treatment with TOERE administered in three chosen doses before ACLF induction reduced serum liver injury markers (AST, ALT, ALP, GGT, total bilirubin), renal tests (creatinine, urea), and oxidative stress tests (TOS, OSI, MDA, NO, 3NT). Histopathologically, TOERE diminished the level of liver tissue injury and 3NT immunoexpression.

CONCLUSIONS

This paper indicated oxidative stress reduction as possible mechanisms for the hepatoprotective effect of TOERE in ACLF and provided evidence for the preventive treatment.

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.

Transrutinosylation of tyrosol by flower buds of Sophora japonica

Dried flower buds of Japanese sophora (Sophora japonica) comprising rutinosidase activity were tested in rutinosylation of tyrosol via transglycosylation process from rutin. Optimal conditions for transrutinosylation of tyrosol were 49 mM rutin and 290 mM tyrosol, giving maximum conversion up to 66.4% and 24% yield of isolated and purified rutinoside. The rutinosylation proceeded exclusively on the primary hydroxyl of tyrosol, thus forming rhamnosylated derivative of salidroside. This strict regioselectivity differentiates the sophora biocatalyst from microbial rutinosidases.

Comparative study of relationship between structure of phenylethanoid glycopyranosides and their activities using cell-free assays and human cells cultured in vitro

The study focused on protective potential of phytochemicals applicable in prevention and health protection is of great importance. Various structures of these compounds and a wide range of their biological activities have inspired organic chemists to sythesize their effective analogues in order to further increase their efficacy. The aims of our study were (i) to synthesize phenylethanoid glycopyranosides: salidroside (SALI - tyrosol β-d-glucopyranoside), tyrosol β-d-galactopyranoside (TYBGAL), tyrosol α-d-galactopyranoside (TYAGAL), tyrosol α-d-mannopyranoside (TYAMAN), hydroxytyrosol α-d-mannopyranoside (HOTAMA), homosyringyl β-d-glucopyranoside (HSYGLU), hydroxytyrosol β-d-xylopyranoside (HOTXYL) and hydroxysalidroside (HOSALI); (ii) to determine their antioxidant capacities (cell-free approaches); (iii) to evaluate their cytotoxicity (MTT test), protectivity against hydrogen peroxide (H₂O₂; comet assay) and effect on the intracellular glutathione level (iGSH; flow cytometry) in experimental system utilizing human hepatoma HepG2 cells. HOSALI, HOTAMA, HOTXYL and HSYGLU manifested the highest antioxidant capacity in cell-free assays and they were most active in protection of HepG2 cells against H₂O₂. On the other hand, pre-treatment of HepG2 cells with SALI had protective effects even though SALI displayed almost no activity in cell-free assays. Differences in the efficacy of the analogues revealed that structures of their molecules in terms of aglycone combined with sugar moiety affect their activities.

Salidroside promotes rat spinal cord injury recovery by inhibiting inflammatory cytokine expression and NF-κB and MAPK signaling pathways

Spinal cord injury (SCI) is a public health problem in the world. The SCI usually triggers an excessive inflammatory response that brings about a secondary tissue wreck leading to further cellular and organ dysfunction. Hence, there is great potential of reducing inflammation for therapeutic strategies of SCI. In this study, we aim to investigate if Salidroside (SAD) exerts an anti-inflammatory effect and promotes recovery of motor function on SCI through suppressing nuclear factor-κB (NF-κB) and the mitogen-activated protein kinase (MAPK) pathways. In vitro, real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) were used to examine the inhibitory effect of SAD on the expression and release of interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) activated by lipopolysaccharide (LPS) in astrocytes. In addition, SAD was found to inhibit NF-κB, p38 and extracellular-regulated protein kinases (ERK) signaling pathways by western blot analysis. Further, in vivo study showed that SAD was able to improve hind limb motor function and reduce tissue damage accompanied by the suppressed expression of inflammatory cytokines IL-1β, IL-6, and TNF-α. Overall, SAD could reduce the inflammatory response and promote motor function recovery in rats after SCI by inhibiting NF-κB, p38, and ERK signaling pathways.

Protective Effects of Salidroside against Carbon Tetrachloride (CCl4)-Induced Liver Injury by Initiating Mitochondria to Resist Oxidative Stress in Mice

The antioxidant effect of salidroside has been proven, but its role in liver injury is poorly understood. In this study, we aimed to evaluate the protective effects and mechanism of salidroside on liver injury induced by carbon tetrachloride (CCl4) in vivo. Mice were pretreated with salidroside (60 mg/kg, intraperitoneally injected, i.p.) once per day for 14 consecutive days and then administered with CCl4 (15.95 g/kg, i.p.) for 24 h to produce a liver injury model. Salidroside attenuated hepatic transaminase elevation in serum and ameliorated liver steatosis and necrosis, thereby suggesting its protective effect on the liver. Salidroside antagonized CCl4-induced toxicity by equilibrating antioxidation system, thereby inhibiting reactive oxygen species accumulation, and restoring mitochondrial structure and function. Salidroside exerts antioxidant and liver-protective effects by selectively inhibiting the activation of genes, including growth arrest and DNA -damage-inducible 45 α (Gadd45a), mitogen-activated protein kinase 7 (Mapk7), and related RAS viral oncogene homolog 2 (Rras2), which induce oxidative stress in the mitogen-activated protein kinase pathway. These results revealed that salidroside can protect the liver from CCl4-induced injury by resisting oxidative stress and protecting mitochondrial function.

Evaluation of antileishmanial efficacy of Salidroside against the SSG-sensitive and resistant strain of Leishmania donovani

The successful control and eradication of leishmaniasis are still challenging in view of the lack of adequate chemotherapy and potential prophylaxis. Research is going on for finding an appropriate anti-leishmanial drug which should be acceptable in terms of cost and safety. In view of this, the current study investigated the anti-leishmanial efficacy of salidroside (SAL) which is a phenylpropanoid glycoside. The leishmanicidal capacity of SAL was verified in vitro as well as in vivo. The SAL exhibited leishmanicidal activity against the promastigotes of L. donovani which was further validated by propidium iodide staining and its ability to arrest the promastigotes at the sub G₀/G₁ stage. SAL decreased and controlled the VL infection in mice as estimated by real-time PCR. Active immunomodulation was exhibited upon SAL treatment in BALB/c mice. The characteristic features like pronounced DTH reaction, polarization of immune status to Th1 type of immune response, increased the production of CD4⁺ and CD8⁺ T cells indicated the immune-stimulatory property of SAL. In addition to this the expression of NF-ĸB, iNOS genes along with the levels of leishmanicidal species, NO and ROS were found to be augmented in SAL treated infected animals. Moreover, SAL exhibited minimal toxicity to the THP-1 cells and it revealed no toxicity against liver and kidney. The capability of SAL in promoting the immune status in favor of host during VL infection without causing any side-effects may be used as an effective strategy to fight the disease.

Salidroside alleviates ischemic brain injury in mice with ischemic stroke through regulating BDNK mediated PI3K/Akt pathway

There is evidence suggesting that inhibition of apoptosis plays a critical role in preventing neurons from damage and even death, after brain ischemia/reperfusion, which shows therapeutic potential for clinical treatment of brain injury. In this study, We preformed MCAO model in C57BL/6J wild-type (BDNK+/+) and BDNK knockout (BDNF-/-) mice respectively, and investigated the neuroprotective effect of Salidroside (Sal) and its underlying mechanisms. The results showed that Sal reversed brain infarct size, reduced cerebral edema, decreased the neurological deficit score and diminished TUNEL positive cells significantly. However, BDNK deficiency inhibited the neuroprotective effect of Sal. In addition, Sal increased cell viability, ameliorated neuron cell injury by decreasing LDH activity, and inhibited cell apoptotic rate. Sal suppressed apoptotic signaling via DNA-binding-dependent and -independent mechanisms. Furthermore, the neuroprotective effect of Sal on BDNK was mediated by PI3K/Akt pathway, which was proved by the use of PI3K knockout (PI3K-/-) mice and siRNA-PI3K. In summary, these data strongly suggested that Sal could be used as an effective neuroprotective agent to protect against ischemic stroke after cerebral I/R injury through regulating BDNK-mediated PI3K/Akt apoptotic pathway in DNA-binding-dependent and -independent manners.

Mixing ratio optimization for functional complex extracts of Rhodiola crenulata, Panax quinquefolius, and Astragalus membranaceus using mixture design and verification of immune functional efficacy in animal models

We aimed to identify the optimum mixing ratio for various ingredients to obtain complex extracts with high extract yields and immune-enhancing activity in animals. The extract yield and amounts of nitric oxide (NO) and interleukin (IL)-6 were set to maximum for modeling predictions. The predicted optimum values for the mixing ratio were 49.5% for Rhodiola crenulata, 26.1% for Astragalus membranaceus, and 24.4% for Panax quinquefolius, and the predicted response values were 31.5% yield, 13.4% NO production, and 6.1% IL-6 production; actual values were 35.3% yield, 14.7% NO, and 6.6% IL-6. The optimum mixing ratio extract (OMRE) was used for the animal experiments. Treating mice with OMRE at 200 mg/kg produced significant increases in spleen indexes and T-cell/B-cell proliferation. OMRE treatment increased IL-10 and IL-6 production in concanavalin A- and lipopolysaccharide-induced T- and B- lymphocytes, respectively. These results provide a basis for the development of functional extracts and drinks.

Salidroside alleviates high glucose-induced oxidative stress and extracellular matrix accumulation in rat glomerular mesangial cells by the TXNIP-NLRP3 inflammasome pathway

Diabetic nephropathy (DN) is a metabolic disease characterized by mesangial cell proliferation and extracellular matrix (ECM) accumulation. Salidroside (SAL) is the major ingredient in Rhodiola rosea and possesses beneficial effects on DN. This study aimed to evaluate the effect of SAL on high glucose (HG)-induced oxidative stress and ECM accumulation and the underlying mechanism. Rat glomerular mesangial cells HBZY-1 were induced by high glucose (HG) in the presence or absence of SAL. Cell proliferation was measured by CCK-8 assay. The reactive oxygen species (ROS) level, malondialdehyde (MDA) level and superoxide dismutase (SOD) activity were detected to evaluate oxidative stress. The expression levels of ECM proteins including fibronectin (FN) and type IV collagen (Coll IV) were detected by qRT-PCR and western blot analysis. The expressions of thioredoxin-interacting protein (TXNIP), nod-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing CARD (ASC), and caspase-1 were assessed by western blot. Si-TXNIP or si-NC was transfected into HBZY-1 cells to inhibit TXNIP-NLRP3 inflammasome pathway. The results showed that SAL treatment alleviated HG-induced cell proliferation. SAL reduced the levels of ROS and MDA, and induced the SOD activity. Besides, the mRNA and protein expressions of FN and Coll IV were decreased by SAL. The expression levels of TXNIP, NLRP3, ASC, and caspase-1 were reduced in the SAL treated cells. In addition, TXNIP knockdown inhibited TXNIP-NLRP3 inflammasome activation and suppressed HG-induced cell proliferation, oxidative stress, and ECM accumulation. In conclusion, SAL alleviated HG-induced oxidative stress and ECM accumulation in rat glomerular mesangial cells by the TXNIP-NLRP3 inflammasome pathway.

Salidroside ameliorates sepsis-induced acute lung injury and mortality via downregulating NF-κB and HMGB1 pathways through the upregulation of SIRT1

Sepsis is a life-threatening medical condition. Salidroside, a substance isolated from Rhodiola rosea, possesses antioxidant and anti-inflammatory properties. The effect and mechanism of salidroside on sepsis-induced acute lung injury still remains to be well clarified. Here, we investigated the effect and mechanism of salidroside on septic mouse models and explored the role of salidroside-upregulated SIRT1. Salidroside inhibited the inflammatory responses and HMGB1 productions in bacterial lipopolysaccharide (LPS)-treated macrophages and mice. Salidroside could also reverse the decreased SIRT1 protein expression in LPS-treated macrophages and mice. Salidroside also alleviated the sepsis-induced lung edema, lipid peroxidation, and histopathological changes and the mortality, and improved the lung PaO₂/FiO₂ ratio in cecal ligation and puncture (CLP)-induced septic mice. Salidroside significantly decreased the serum TNF-α, IL-6, NO, and HMGB1 productions, pulmonary inducible NO synthase (iNOS) and phosphorylated NF-κB-p65 protein expressions, and pulmonary HMGB1 nuclear translocation in CLP septic mice. Moreover, sepsis decreased the SIRT1 protein expression in the lungs of CLP septic mice. Salidroside significantly upregulated the SIRT1 expression and inhibited the inflammatory responses in CLP septic mouse lungs. These results suggest that salidroside protects against sepsis-induced acute lung injury and mortality, which might be through the SIRT1-mediated repression of NF-κB activation and HMGB1 nucleocytoplasmic translocation.

Polysaccharide Encrusted Multilayered Nano-Colloidal System of Andrographolide for Improved Hepatoprotection

Andrographolide (AP), a phytoconstituent of Andrographis paniculata is reported as a potent hepatoprotective agent. However, utility of this molecule is restricted due to its low aqueous solubility, gastric instability and hence low bioavailability. It was aimed to formulate and characterize AP-loaded, natural biopolymer stabilized, multilayered nano-hydrocolloid delivery system. Nanoemulsion (NE) was formulated using layer-by-layer (LbL) technology via electrostatic deposition of chitosan over alginate encrusted o/w NE by ultra-sonication. Improved transparency and stability of NE were observed with increasing sonication time. Best stability was obtained after 20 min sonication and particle size of the multilayered NE was measured in the range of 90.8-167.8 nm. Transmission electron microscopy confirmed the progressive layering of nanosized NE. Higher magnitude of zeta potential (i.e., 22.9 to 31.01 mV) confirmed higher stability and coating of alginate layer over NE surface for the period of 3 months. NE showed strategic release pattern when assessed in vitro in various simulated biological fluids of GIT in timed pattern. Multilayered NE showed significant modulation in liver function test (ALT, ALP, AST, TBIL, DBIL, and liver glycogen) and serum cytokines (TNF-α, IL-6, IL-10, and IL-β) when assessed in vivo in galactosamine-lipopolysaccharide intoxicated mice. In conclusion, the andrographolide engrained multi-layered NE enhanced the solubility, stability and henceforth assured the increased availability in simulated biological fluids. The in vivo study exhibited the significantly improved hepatoprotection by andrographolide when delivered in stable multi-layered NE carrier systems.

Salidroside Regulates Inflammatory Response in Raw 264.7 Macrophages via TLR4/TAK1 and Ameliorates Inflammation in Alcohol Binge Drinking-Induced Liver Injury

The current study was designed to investigate the anti-inflammatory effect of salidroside (SDS) and the underlying mechanism by using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages in vitro and a mouse model of binge drinking-induced liver injury in vivo. SDS downregulated protein expression of toll-like receptor 4 (TLR4) and CD14. SDS inhibited LPS-triggered phosphorylation of LPS-activated kinase 1 (TAK1), p38, c-Jun terminal kinase (JNK), and extracellular signal-regulated kinase (ERK). Degradation of IκB-α and nuclear translocation of nuclear factor (NF)-κB were effectively blocked by SDS. SDS concentration-dependently suppressed LPS mediated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein levels, as well as their downstream products, NO. SDS significantly inhibited protein secretion and mRNA expression of of interleukin (IL)-1β and tumor necrosis factor (TNF)-α. Additionally C57BL/6 mice were orally administrated SDS for continuous 5 days, followed by three gavages of ethanol every 30 min. Alcohol binge drinking caused the increasing of hepatic lipid accumulation and serum transaminases levels. SDS pretreatment significantly alleviated liver inflammatory changes and serum transaminases levels. Further investigation indicated that SDS markedly decreased protein level of IL-1β in serum. Taken together, these data implied that SDS inhibits liver inflammation both in vitro and in vivo, and may be a promising candidate for the treatment of inflammatory liver injury.

Cardioprotective effects of salidroside on myocardial ischemia-reperfusion injury in coronary artery occlusion-induced rats and Langendorff-perfused rat hearts

BACKGROUND/OBJECTIVES

The current study was designed to investigate the protective role of salisroside on rats through the study of energy metabolism homeostasis and inflammation both in ex vivo and in vivo.

METHODS

Energy metabolism homeostasis and inflammation injury were respectively assessed in global ischemia of isolated hearts and coronary artery ligated rats.

RESULTS

Excessive release of cardiac enzymes and pro-inflammatory cytokines was inhibited by salidroside in coronary artery occlusion-induced rats. ST segment was also restored with the treatment of salidroside. Triphenyltetrazolium chloride staining (TTC) staining and pathological analysis showed that salidroside could significantly alleviate myocardial injury in vivo. Accumulated data in ex vivo indicated that salidroside improved heart function recovery, which was reflected by enhanced myocardial contractility and coronary flow in isolated hearts. The contents of ATP and glycogen both in ex vivo and in vivo were restored by salidroside compared with those in the model group. Besides, the expressions of p-AMPK, PPAR-α and PGC-1α in rats and isolated hearts subjected to salidroside were significantly elevated, while the levels of p-NF-κBp65, p-IκBα, p-IKKα and p-IKKβ were dramatically reduced by salidroside.

CONCLUSIONS

The present study comprehensively elaborated the protective effects of salidroside on myocardial injury and demonstrated that AMPK/PGC-1α and AMPK/NF-κB signaling cascades were implicated in the myocardial ischemia-reperfusion injury (I/R) model.

Salidroside alleviates oxidative stress in the liver with non- alcoholic steatohepatitis in rats

Background

Nonalcoholic steatohepatitis (NASH) is characterized by fat accumulation in the hepatocyte, inflammation, liver cell injury, and varying degrees of fibrosis, and can lead to oxidative stress in liver. Here, we investigated whether Salidroside, a natural phenolic antioxidant product, can protect rat from liver injury during NASH.

Methods

NASH model was established by feeding the male SD rats with high-fat and high-cholesterol diet for 14 weeks. Four groups of male SD rats including, normal diet control group, NASH model group, and Salidroside treatment group with150mg/kg and 300 mg/kg respectively, were studied. Salidroside was given by oral administration to NASH in rats from 9 weeks to 14 weeks. At the end of 14 weeks, liver and serum were harvested, and the liver injury, oxidative stress and histological features were evaluated.

Results

NASH rats exhibited significant increases in the following parameters as compared to normal diet control rats: fat droplets with foci of inflammatory cell infiltration in the liver. ALT, AST in serum and TG, TC in hepatocyte elevated. Oxidative responsive genes including CYP2E1 and Nox2 increased. Additionally, NASH model decreased antioxidant enzymes SOD, GSH, GPX, and CAT in the liver due to their rapid depletion after battling against oxidative stress. Compared to NASH model group, treatment rats with Salidroside effectively reduced lipid accumulation, inhibited liver injury in a does-dependent manner. Salidroside treatment restored antioxidant enzyme levels, inhibited expression of CYP2E1 and Nox2 mRNA in liver, which prevented the initial step of generating free radicals from NASH.

Conclusion

The data presented here show that oral administration of Salidroside prevented liver injury in the NASH model, likely through exerting antioxidant actions to suppress oxidative stress and the free radical–generating CYP2E1 enzyme, Nox2 in liver.

A novel mechanism of action for salidroside to alleviate diabetic albuminuria: effects on albumin transcytosis across glomerular endothelial cells

Salidroside (SAL) is a phenylethanoid glycoside isolated from the medicinal plant Rhodiola rosea. R. rosea has been reported to have beneficial effects on diabetic nephropathy (DN) and high-glucose (HG)-induced mesangial cell proliferation. Given the importance of caveolin-1 (Cav-1) in transcytosis of albumin across the endothelial barrier, the present study was designed to elucidate whether SAL could inhibit Cav-1 phosphorylation and reduce the albumin transcytosis across glomerular endothelial cells (GECs) to alleviate diabetic albuminuria as well as to explore its upstream signaling pathway. To assess the therapeutic potential of SAL and the mechanisms involved in DN albuminuria, we orally administered SAL to db/db mice, and the effect of SAL on the albuminuria was measured. The albumin transcytosis across GECs was explored in a newly established in vitro cellular model. The ratio of albumin to creatinine was significantly reduced upon SAL treatment in db/db mice. SAL decreased the albumin transcytosis across GECs in both normoglycemic and hyperglycemic conditions. SAL reversed the HG-induced downregulation of AMP-activated protein kinase and upregulation of Src kinase and blocked the upregulation Cav-1 phosphorylation. Meanwhile, SAL decreased mitochondrial superoxide anion production and moderately depolarized mitochondrial membrane potential. We conclude that SAL exerts its proteinuria-alleviating effects by downregulation of Cav-1 phosphorylation and inhibition of albumin transcytosis across GECs. These studies provide the first evidence of interference with albumin transcytosis across GECs as a novel approach to the treatment of diabetic albuminuria.

Protective activity of salidroside against ethanol-induced gastric ulcer via the MAPK/NF-κB pathway in vivo and in vitro

Salidroside (Sal) is a traditional Chinese medicine with various pharmacological effects. The present study aimed to investigate the protective effect of Sal on ethanol-induced acute gastric ulcer and H2O2-induced gastric epithelial cell damage. 0.2 ml ethanol and 400 μM H2O2 were applied to establish a gastric ulcer model in vivo and in vitro respectively. The production of interleukin (IL)-6, interleukin (IL)-1β and tumor necrosis factor (TNF)-α was analyzed, as well as myeloperoxidase (MPO), malondialdehyde (MDA) and superoxide dismutase (SOD). MTT assay was used to detect cell viability. In addition, MAPK/NF-κB signal pathway-related proteins p-ERK, p-JNK, p-p38, p-IκBα and p-NF-κBp65 were analyzed to determine the underlying protective mechanism. Downstream genes such as cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX) and leukotrienes B4 (LTB4) were also measured. Obtained data indicated that Sal inhibited the overproduction of pro-inflammatory cytokines and enhanced antioxidant activity. Collectively, it is assumed that Sal could alleviate ethanol-induced acute gastric ulcer and H2O2-induced gastric epithelial cell damage through the MAPK/NF-κB pathway.

Rhodiola plants: Chemistry and biological activity

Rhodiola is a genus of medicinal plants that originated in Asia and Europe and are used traditionally as adaptogens, antidepressants, and anti-inflammatory remedies. Rhodiola plants are rich in polyphenols, and salidroside and tyrosol are the primary bioactive marker compounds in the standardized extracts of Rhodiola rosea. This review article summarizes the bioactivities, including adaptogenic, antifatigue, antidepressant, antioxidant, anti-inflammatory, antinoception, and anticancer activities, and the modulation of immune function of Rhodiola plants and its two constituents, as well as their potential to prevent cardiovascular, neuronal, liver, and skin disorders.

Salidroside attenuates allergic airway inflammation through negative regulation of nuclear factor-kappa B and p38 mitogen-activated protein kinase

Salidroside is a biologically active ingredient of Rhodiola rosea, which has several interesting biological properties, including anti-oxidant and anti-inflammatory; however, its anti-allergic effects are poorly understood. The objective of this study is to determine whether salidroside attenuates the inflammatory response in an ovalbumin (OVA)-induced asthma model. OVA-sensitized/challenged mice show airway hyperresponsiveness (AHR) to inhaled methacholine and have an increased amount of T-helper2 type cytokines [interleukin (IL)-4, IL-5, and IL-13] and eosinophils in their bronchoalveolar lavage fluids and lung tissues. However, three successive intraperitoneal administrations of salidroside before the last OVA challenge result in significant inhibition of these asthmatic reactions. Moreover, OVA significantly increases the activation of nuclear factor-kappa B (NFκB) and p38 mitogen-activated protein kinase (MAPK) in lung tissues, whereas salidroside markedly suppresses NF-κB translocation and reduces phosphorylation of p38 MAPK. Furthermore, salidroside attenuates the expression of intercellular adhesion molecule 1 and IL-6 through modulating the activities of p38 MAPK and NF-κB in the BEAS-2B cells stimulated by proinflammatory cytokines. These findings indicate that salidroside protects against OVA-induced airway inflammation and AHR, at least in part via downregulation of NF-κB and p38 MAPK activities. Our data support the utility of salidroside as a potential medicine for the treatment of asthma.

Effects of Two Different Rhodiola rosea Extracts on Primary Human Visceral Adipocytes

Rhodiola rosea (Rro) has been reported to have various pharmacological properties, including anti-fatigue, anti-stress and anti-inflammatory activity. It is also known to improve glucose and lipid metabolism, but the effects of Rhodiola rosea on adipocyte differentiation and metabolism are not still elucidated. In this study the anti-adipogenic and lipolytic activity of two extracts of Rhodiola rosea, containing 3% salidroside (RS) or 1% salidroside and 3% rosavines (RR) on primary human visceral adipocytes was investigated. Pre-adipocytes were analyzed after 10 and 20 days of treatment during differentiation and after 7 days of treatment when they reached mature shape. The RS extract significantly induced higher apoptosis and lipolysis in comparison to control cells and to RR extract. In contrast, RR extract significantly reduced triglyceride incorporation during maturation. Differentiation of pre-adipocytes in the presence of RS and RR extracts showed a significant decrease in expression of genes involved in adipocyte function such as SLC2A4 and the adipogenic factor FGF2 and significant increase in expression of genes involved in inhibition of adipogenesis, such as GATA3, WNT3A, WNT10B. Furthermore RR extract, in contrast to RS, significantly down-regulates PPARG, the master regulator of adipogenesis and FABP4. These data support the lipolytic and anti-adipogenetic activity of two different commercial extracts of Rhodiola rosea in primary human visceral pre-adipocytes during differentiation.

Infrared-assisted extraction of salidroside from the root of Rhodiola crenulata with a novel ionic liquid that dissolves cellulose

Tetrabutylphosphonium hydroxide aqueous solution, a novel ionic liquid that could dissolve cellulose rapidly at ambient temperature, was used for the first time to develop an extraction method with infrared-assisted extraction.

Protective effect of total saponins of Aralia elata (Miq) Seem on lipopolysaccharide-induced cardiac dysfunction via down-regulation of inflammatory signaling in mice

TAS attenuates LPS-induced cardiomyocyte dysfunctionviadown-regulation of inflammatory signaling in mice.

Salidroside induces neuronal differentiation of mouse mesenchymal stem cells through Notch and BMP signaling pathways

Salidroside (p-hydroxyphenethyl-β-D-glucoside, SAL), a phenylpropanoid glycoside isolated from a popular traditional Chinese medicinal plant Rhodiola rosea L., possesses multiple pharmacological actions. Previous study showed that SAL could induce rat mesenchymal stem cells (MSCs) to differentiate into dopaminergic neurons and induce mouse MSCs D1 to differentiate into neuronal cells. However, the mechanisms of SAL-induced neuronal differentiation of MSCs still need investigation. In this study, we observed the effects of SAL on neuronal differentiation of D1 cells and the possible involvement of Notch and BMP signaling pathways. SAL inhibited the proliferation, induced neuronal phenotypes, and upregulated the expressions of neuronal-specific marker molecules, such as neuronal enolase 2 (Eno2/NSE), microtubule-associated protein 2 (MAP2), and beta 3 class III tubulin (Tubb3/β-tubulin III) in D1 cells. SAL not only downregulated the expressions of Notch1 and hairy enhancer of split 1 (Drosophila) (Hes1) but also upregulated the expression of Smad1/5/8 and its phosphorylation (p-Smad 1/5/8). The neuronal differentiation effects of SAL on D1 cells were promoted by a Notch signaling antagonist, DAPT, but attenuated by a BMP signaling pathway antagonist, Noggin. Our findings suggest that SAL might be promising in inducing neuronal differentiation of mouse MSCs mediated by both Notch signaling pathway and BMP signaling pathway.

Water extract of Acer tegmentosum reduces bone destruction by inhibiting osteoclast differentiation and function

The stem of Acer tegmentosum has been widely used in Korea for the treatment of hepatic disorders. In this study, we investigated the bone protective effect of water extract of the stem of Acer tegmentosum (WEAT). We found that WEAT inhibits osteoclast differentiation induced by receptor activator of nuclear factor-κB ligand (RANKL), an essential cytokine for osteoclast differentiation. In osteoclast precursor cells, WEAT inhibited RANKL-induced activation of JNK, NF-κB, and cAMP response element-binding protein, leading to suppression of the induction of c-Fos and nuclear factor of activated T cells cytoplasmic 1, key transcription factors for osteoclast differentiation. In addition, WEAT inhibited bone resorbing activity of mature osteoclasts. Furthermore, the oral administration of WEAT reduced RANKL-induced bone resorption and trabecular bone loss in mice. Taken together, our study demonstrates that WEAT possesses a protective effect on bone destruction by inhibiting osteoclast differentiation and function.

Melatonin treatment reduces endoplasmic reticulum stress and modulates the unfolded protein response in rabbits with lethal fulminant hepatitis of viral origin

Hepatocyte apoptosis plays an important role in the development of fulminant hepatic failure (FHF). The objective of this study was to investigate whether endoplasmic reticulum (ER) stress and unfolded protein response (UPR) inhibition is an underlying mechanism of melatonin anti-apoptotic effects in an animal model of FHF of viral origin induced by the rabbit hemorrhagic disease virus (RHDV). Rabbits were experimentally infected with 2 × 10(4) hemagglutination units of a RHDV isolate and received melatonin at two concentrations of 10 mg/kg and 20 mg/kg at 0 hr, 12 hr and 24 hr postinfection. RHDV infection induced increased expression of CCAAT/enhancer-binding protein homologous protein (CHOP), immunoglobulin heavy chain binding protein (BiP/GRP78), glucose-regulated protein 94 (GRP94), phospho-c-Jun N-terminal kinase (JNK) and caspase-12. These effects were attenuated by melatonin. Double immunofluorescence staining showed colocalization of CHOP and cleaved caspase-3 in liver sections of RHDV-infected rabbits, while immunostaining decreased markedly with melatonin treatment. RHDV infection resulted in significant increases in the mRNA levels of activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1 (IRE1), spliced X-box binding protein-1 (XBP1s) and tumor necrosis factor receptor-associated factor 2 (TRAF2). Melatonin attenuated the extent of the changes. Data obtained provide evidence that in rabbits with experimental infection by RHDV, reduction in apoptotic liver damage by melatonin is associated with attenuation of ER stress through a modulation of the three arms of UPR signaling and further support a potential hepatoprotective role of melatonin in FHF.

Salidroside stimulates osteoblast differentiation through BMP signaling pathway

Salidroside (SAL) is one of main active components of Rhodiola rosea L. and possesses diverse pharmacological effects. However, the direct role of SAL in bone metabolism remains elusive. In this study, effects of SAL on osteoblast differentiation of murine pluripotent mesenchymal cell line C3H10T1/2 and osteoblastic cell line MC3T3-E1 were examined. We first identified SAL as a potential BMP2 activator in a cell-based screening assay. SAL (0.5-10 μM) could slightly promote the proliferation and greatly increase the alkaline phosphatase (ALP) activity in both cells. Furthermore, SAL increased the mRNA expressions of osteoblast marker genes in either C3H10T1/2 or MC3T3-E1 cells after treatment for different time. Moreover, the mineralization of C3H10T1/2 cells assayed by Alizarin red S staining was dose-dependently increased by SAL. Mechanistically, SAL increased the mRNA level of genes involved in the regulation of BMP signaling pathway, including BMP2, BMP6 and BMP7 and enhanced the phosphorylation of Smad1/5/8 and ERK1/2. The osteogenic effect of SAL was abolished by BMP antagonist noggin or by BMP receptor kinase inhibitor dorsomorphin. Further in vivo study demonstrated that SAL reversed bone loss in ovariectomized rats. Collectively, our findings indicate that SAL regulates bone metabolism through BMP signaling pathway.

Salidroside attenuates LPS-stimulated activation of THP-1 cell-derived macrophages through down-regulation of MAPK/NF-kB signaling pathways

Excessive activation of macrophages is implicated in various inflammatory injuries. Salidroside (Sal), one of the main bioactive components of Rhodiola Sachalinensis, has been reported to possess anti-inflammatory activities. This study aimed to examine the effect of Sal on the activation of macrophages and the possible mechanism. The lipopolysaccharide (LPS)-stimulated phrobol 12-myristate 13-acetate (PMA)-differentiated THP-1 macrophage models were established. The changes in the inflammatory profiles of THP-1-derived macrophages were determined. The results showed that Sal significantly decreased the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), interleukin-1beta (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) at both mRNA and protein levels in THP-1-derived macrophages, and the effect was dose-depedent. Moreover, NF-κB activation was significantly suppressed and the phosphorylation of ERK, p38 and JNK was substantially down-regulated after Sal treatment. The findings suggested that Sal can suppress the activation of LPS-stimulated PMA-differetiated THP-1 cells, as evidenced by the decreased expression of iNOS, COX2, IL-1β, IL-6 and TNF-α, and the mechanism involves the inhibition of NF-κB activation and the phosphorylation of the MAPK signal pathway.

Effects of salidroside on exhaustive exercise‑induced oxidative stress in rats

Intense exercise increases oxygen consumption and may produce an imbalance between reactive oxygen species (ROS) and antioxidants, inducing oxidative stress as a result of increased ROS production. Exogenous antioxidants may prevent oxidative damages since they are able to detoxify certain peroxides by scavenging the ROS produced during exercise. The aim of this study was to evaluate the effects of salidroside on exhaustive exercise-induced oxidative stress in rats. A total of 40 animals were randomly divided into four groups of ten rats each: control (C), low-dose salidroside‑treated (LT), middle-dose salidroside-treated (MT) and high-dose salidroside-treated (HT) groups. The rats in the treated groups received salidroside (25, 50 and 100 mg/kg, respectively) intragastrically (ig) and the rats in the control group received drinking water ig for 4 weeks. After 4 weeks, the rats performed an exhaustive swimming exercise and exhaustive swimming times were recorded. The malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glycogen levels in the liver tissues of the rats were measured. The data revealed that salidroside was able to elevate the exercise tolerance and increase the liver glycogen levels of the rats following exhaustive exercise. Salidroside was also able to reduce MDA levels and enhance the activities of antioxidant enzymes (CAT, SOD and GSH-Px) in the liver tissues of the rats. The results from this study indicate that salidroside is effective in the prevention of oxidative stress following exhaustive exercise.

Protective effect of salidroside from Rhodiolae Radix on diabetes-induced oxidative stress in mice

It has been confirmed that diabetes mellitus (DM) carries increased oxidative stress. This study evaluated the effects of salidroside from Rhodiolae Radix on diabetes-induced oxidative stress in mice. After induction of diabetes, diabetic mice were administered daily doses of 50, 100 and 200 mg/kg salidroside for 28 days. Body weights, fasting blood glucose (FBG), serum insulin, TC (total cholesterol), TG (triglyceride), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) were measured. Results showed that salidroside possessed hypoglycemic activity and protective effects against diabetes-induced oxidative stress, which could significantly reduce FBG, TC, TG and MDA levels, and at same time increase serum insulin levels, SOD, GPx and CAT activities. Therefore, salidroside should be considered as a candidate for future studies on diabetes.

Melatonin attenuates apoptotic liver damage in fulminant hepatic failure induced by the rabbit hemorrhagic disease virus

Hepatocyte apoptosis plays an important role in the development of fulminant hepatic failure (FHF). The objective of this study was to investigate the antiapoptotic effect of melatonin in an animal model of FHF of viral origin induced by the rabbit hemorrhagic disease virus (RHDV). Rabbits were experimentally infected with 2 × 10(4) hemagglutination units of a RHDV isolate and received melatonin at two concentrations of 10 and 20 mg/kg at 0, 12, and 24 hr postinfection. RHDV infection induced liver apoptosis, with increased caspase-3 immunoexpression and activity and poly(ADP-ribose)polymerase-1 (PARP-1) proteolysis. These effects were attenuated by melatonin in a concentration-dependent manner. Antiapoptotic effects of melatonin were related to a reduced expression of Bax and cytosolic cytochrome c release, increased expression of Bcl-2 and Bcl-xL, and inhibition of caspase-9 activity. Increased thiobarbituric reactive acid substances concentration and oxidized-to-reduced glutathione ratio were significantly prevented by melatonin administration. Melatonin treatment also resulted in a reduction in caspase-8 activity, tumor necrosis factor receptor-1 (TNF-R1) expression, and phosphorylated Janus kinase (JNK) expression, and increased expression of cellular FLICE-inhibitory protein (c-FLIP). Our findings show that inhibition of apoptotic mechanisms contributes to the beneficial effects of melatonin in rabbits with experimental infection by RHDV and supports a potential hepatoprotective role of melatonin in FHF.

The protective effects of total saponins from Ornithogalum saundersiae (Liliaceae) on acute hepatic failure induced by lipopolysaccharide and D-galactosamine in mice

ETHNOPHARMACOLOGICAL RELEVANCE

This study examined the protective effects of total saponins from Ornithogalum saundersiae (Liliaceae) on D-galactosamine (D-GalN) and lipopolysaccharide (LPS)-induced fulminant hepatic failure.

MATERIALS AND METHODS

Total saponins of Ornithogalum saundersiae (Liliaceae) (OC) were prepared with ethyl alcohol extract from bulbs of the plant. Mice were given an intraperitoneal injection of D-GalN (700 mg/kg)/LPS (10 μg/kg). OC (100 mg/kg, 200 mg/kg and 300 mg/kg) was administered orally for 3 days continuously, and at the last day at 1 h before the D-GalN/LPS injection. Mice were sacrificed at 8 h after the D-GalN/LPS injection. The liver injury was assessed biochemically, investigating aspartate aminotransferase (AST), alanine aminotransferase (ALT), malondialdehyde (MDA), glutathione (GSH) activities, and the expressions of caspase-3 and hypoxia inducible factor-1α (HIF-1α) as well. Tumor necrosis factor (TNF-α) content was measured after D-GalN/LPS induced 1 h by ELISA assay. The survival rates after application of OC in 24 h also were observed.

RESULTS

D-GalN/LPS increased the serum aminotransferase levels and lipid peroxidation, while decreased the reduced glutathione level. The pretreatment with OC attenuated these changes in a dose-dependent manner. Elevation of TNF-α level and activation of caspase-3, HIF-1α were observed in the D-GalN/LPS group, which was attenuated by OC. The survival rate of the OC groups was significantly higher than that of the D-GalN/LPS group.

CONCLUSIONS

Protection afforded by OC against D-GalN/LPS-induced fulminant hepatic failure is the result of reduced oxidative stress, inhibited expression of caspase-3, HIF-1α, and anti-apoptotic activity.

Anti-apoptotic activity of gentiopicroside in D-galactosamine/lipopolysaccharide-induced murine fulminant hepatic failure

This study investigated the hepatoprotective effects of gentiopicroside on d-galactosamine (d-GalN) and lipopolysaccharide (LPS)-induced fulminant hepatic failure. Mice were administrated orally with gentiopicroside (40 or 80 mg/kg body weight) at 12h and 1h before d-GalN (700 mg/kg)/LPS (10 microg/kg) injection. Gentiopicroside markedly reduced the increases in serum aminotransferase activities and lipid peroxidation. The glutathione content decreased in d-GalN/LPS alone group, and this decrease was attenuated by gentiopicroside. Increases in serum tumor necrosis factor-alpha (TNF-alpha), which were observed in d-GalN/LPS alone group, were significantly reduced by gentiopicroside. Importantly, gentiopicroside attenuated d-GalN/LPS-induced apoptosis of hepatocytes, as estimated by the caspase-3 cleavage, poly(ADP-ribose) polymerase (PARP) cleavage, and DNA fragmentation. d-GalN/LPS-induced caspase-8 and -9 activation was significantly suppressed by gentiopicroside. Moreover, increased cytosolic cytochrome c protein was reduced by gentiopicroside. Also, the increased ratio of Bax and Bcl-2 protein was significantly attenuated by gentiopicroside. After 6h of d-GalN/LPS injection, phosphorylated c-jun N-terminal kinase (JNK) and extracellular signal regulated kinase (ERK) was significantly increased, whereas phosphorylation JNK and ERK were attenuated by gentiopicroside. Our results suggest that gentiopicroside offers remarkable hepatoprotection against damage induced by d-GalN/LPS related with its anti-apoptotic activities.