Jialin Duan

Antihyperglycemic, hypolipidemic and antioxidant activities of total saponins extracted from Aralia taibaiensis in experimental type 2 diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE As a well-known traditional Chinese medicine the root bark of Aralia taibaiensis has multiple pharmacological activities, including relieving rheumatism, promoting blood circulation to arrest pain, inducing diuresis to reduce edema, and antidiabetic action. It has long been used as a folk medicine for the treatment of traumatic injury, rheumatic arthralgia, nephritis, edema, hepatitis and diabetes mellitus in China. AIM OF STUDY To evaluate the antihyperglycemic, hypolipidemic and antioxidant activities of total saponins extracted from Aralia taibaiensis (SAT) in experimental type 2 diabetic mellitus (T2DM) rats. MATERIALS AND METHODS Acute toxicity was studied in rats to determine the safe oral dose of SAT. Then, SAT was given orally to normal and streptozotocin-nicotinamide induced T2DM rats at 80, 160 and 320 mg/kg doses for a series of 28 days to determine the antihyperglycemic activity. Glibenclamide (600 μg/kg), a standard antidiabetic drug, was used as a positive control drug. At the end of treatment, biochemical parameters and antioxidant levels were measured to evaluate the hypolipidemic and antioxidant activities of SAT. RESULTS Oral administration of SAT did not exhibit toxicity and death at a dose not more than 2000 mg/kg. SAT dose-dependently improved the symptoms of polydipsia, polyuria, polyphagia and weight loss in diabetic rats. Compared with diabetic control group, administration of 320 mg/kg SAT resulted in significant (P<0.05) fall in the levels of fasting blood glucose, glycosylated hemoglobin, creatinine, urea, alanine transarninase, aspartate aminotransferase, total cholesterol, triglycerides, low density lipoprotein cholesterol and malondialdehyde, but significant (P<0.05) increase in the levels of serum insulin, superoxide dismutase and reduced glutathione. However, SAT did not have any effect on the normal rats. CONCLUSIONS SAT had excellent antihyperglycemic, hypolipidemic and antioxidant activities in T2DM rats and might be a promising drug in the therapy of diabetes mellitus and its complications.

Dissection of Mechanisms of a Chinese Medicinal Formula: Danhong Injection Therapy for Myocardial Ischemia/Reperfusion Injury In Vivo and In Vitro

Traditional Chinese medicine uses a systemic treatment approach, targeting multiple etiological factors simultaneously. Danhong injection (DHI), a very popular Chinese medicine injection, is reported to be effective for many cardiovascular conditions. The primary active ingredients of DHI, and their systemic and interrelated mechanism have not been evaluated in an established myocardial ischemia/reperfusion (MI/R) model. We identified the main active constituents in DHI, including hydroxysafflor yellow A (A), salvianolic acid B (B), and danshensu (C), by HPLC fingerprint analysis and assessed their effect on MI/R rats and cardiomyocytes. These 3 compounds and DHI all decreased the levels of IL-1, TNF-α, and MDA, increased those of IL-10 and SOD activity in vivo and in vitro, and had antiapoptotic effects, as shown by flow cytometric analysis and TUNEL assay. Moreover, these compounds increased phosphorylation of Akt and ERK1/2 in cardiomyocytes. Interestingly, we found compound A exerted a more prominent anti-inflammatory effect than B and C, by decreasing NF-κB levels; compound B had more powerful antioxidative capacity than A and C, by increasing Nrf2 expression; compound C had stronger antiapoptotic ability than A and B, by lowering caspase-3 activity. Our results elucidate the mechanisms by which DHI protects against MI/R induced injury.

Protective effect of butin against ischemia/reperfusion-induced myocardial injury in diabetic mice: involvement of the AMPK/GSK-3β/Nrf2 signaling pathway.

Hyperglycemia-induced reactive oxygen species (ROS) generation contributes to development of diabetic cardiomyopathy (DCM). This study was designed to determine the effect of an antioxidant butin (BUT) on ischemia/reperfusion-induced myocardial injury in diabetic mice. Myocardial ischemia/reperfusion (MI/R) was induced in C57/BL6J diabetes mice. Infarct size and cardiac function were detected. For in vitro study, H9c2 cells were used. To clarify the mechanisms, proteases inhibitors or siRNA were used. Proteins levels were investigated by Western blotting. In diabetes MI/R model, BUT significantly alleviated myocardial infarction and improved heart function, together with prevented diabetes-induced cardiac oxidative damage. The expression of Nrf2, AMPK, AKT and GSK-3β were significantly increased by BUT. Furthermore, in cultured H9c2 cardiac cells silencing Nrf2 gene with its siRNA abolished the BUT’s prevention of I/R-induced myocardial injury. Inhibition of AMPK and AKT signaling by relative inhibitor or specific siRNA decreased the level of BUT-induced Nrf2 expression, and diminished the protective effects of BUT. The interplay relationship between GSK-3β and Nrf2 was also verified with relative overexpression and inhibitors. Our findings indicated that BUT protected against I/R-induced ROS-mediated apoptosis by upregulating the AMPK/Akt/GSK-3β pathway, which further activated Nrf2-regulated antioxidant enzymes in diabetic cardiomyocytes exposed to I/R.

Aralia taibaiensis Protects Cardiac Myocytes against High Glucose-Induced Oxidative Stress and Apoptosis.

Patients with type 2 diabetes have increased cardiovascular disease risk compared with those without diabetes. Hyperglycemia can induce reactive oxygen species (ROS) generation, which contributes to the development of diabetic cardiomyopathy. Our previous study has demonstrated that the total saponins of Aralia taibaiensis (sAT), a frequently-used antidiabetic medicine in traditional Chinese medicine (TCM), can scavenge free radicals in vitro and have good anti-oxidant ability on lipid peroxidation of rat liver microsomes. This work was designed to investigate whether sAT could protect the heart while it was used in the treatment of diabetes. Oxidative stress was induced in H9c2 cells by high glucose (33 mM) and glucose oxidase (15 mU, G/GO) and the protective effects of sAT were evaluated. Treatment of H9c2 cells with G/GO resulted in an increase in cell death, intracellular ROS level and cell oxidative injury, which were markedly reduced by sAT treatment. Further study revealed that sAT induced the nuclear translocation of Nrf2 and expression of its downstream targets. Moreover, Nrf2 siRNA markedly abolished the cytoprotective effects of sAT. sAT exerted cytoprotective effects against oxidative stress induced by hyperglycemia and the cardioprotective effects of sAT might be through the Nrf2/ARE pathway. Thus, sAT might be a promising candidate for the treatment of diabetic cardiomyopathy.

Safflor yellow A protects neonatal rat cardiomyocytes against anoxia/reoxygenation injury in vitro.

Aim:To investigate the effects of safflor yellow A (SYA), a flavonoid extracted from Carthamus tinctorius L, on cultured rat cardiomyocytes exposed to anoxia/reoxygenation (A/R).Methods:Primary cultured neonatal rat cardiomyocytes were exposed to anoxia for 3 h followed by reoxygenation for 6 h. The cell viability was measured using MTT assay. The releases of lactate dehydrogenase (LDH) and creatine kinase (CK), level of malondialdehyde (MDA), and activities of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were analyzed. Hoechst 33258 staining and changes in Bcl-2/Bax ratio and caspase 3 activity were used to examine A/R-induced apoptosis.Results:The A/R exposure markedly decreased the viability of cardiomyocytes, suppressed the activities of SOD, GSH, CAT and GSH-Px, and Bcl-2 protein expression. Meanwhile, the A/R exposure markedly increased the release of LDH and CK, and MDA production in the cardiomyocytes, and increased the rate of apoptosis, caspase 3 activity, Bax protein expression. Pretreatment with SYA (40, 60 and 80 nmol/L) concentration-dependently blocked the A/R-induced changes in the cardiomyocytes. Pretreatment of the cardiomyocytes with the antioxidant N-acetylcysteine (NAC, 200 μmol/L) produced protective effects that were comparable to those caused by SYA (80 nmol/L).Conclusion:SYA protects cultured rat cardiomyocytes against A/R injury, maybe via inhibiting cellular oxidative stress and apoptosis.

Antioxidant properties of magnesium lithospermate B contribute to the cardioprotection against myocardial ischemia/reperfusion injury in vivo and in vitro.

OBJECTIVE To determine the cardioprotective effect of magnesium lithospermate B (MLB) on myocardial ischemia/reperfusion (MI/R) injury and to investigate the antioxidant potential in vivo and in vitro. METHODS MI/R injury was induced by the occlusion of left anterior descending coronary artery for 30 min followed by reperfusion for 3 h in rats. After reperfusion, hearts were harvested to assess infarct size, histopathological damages, the levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH) and malondialdehyde (MDA). Blood samples were collected to determine serum levels of creatine kinase-MB (CK-MB), cardiac troponin (cTnl) and lactate dehydrogenase (LDH). Furthermore, simulated ischemia/reperfusion (SI/R) injury in vitro was established by oxygen and glucose deprivation (OGD) for 2 h followed by 24-hour recovery period in cardiomyocytes. The activity of LDH in the cultured supernatant and the levels of intracellular reactive oxygen species (ROS), SOD and MDA in cardiomyocytes were also measured. Finally, cardiomyocytes apoptosis was determined with flow cytometry. RESULTS MLB significantly limited infarct size, ameliorated histopathological damages and prevented leakage of CK-MB, cTnI and LDH. Additionally, SOD, CAT, GPx and GSH activities were notably increased by MLB, along with the MDA content decreased as compared with the model group in rats. In vitro study, MLB also decreased LDH activity in the cultured supernatant, increased SOD activity in cardiomyocytes, reduced intracellular ROS and MDA levels, and significantly suppressed cardiomyocytes apoptosis. CONCLUSION MLB possessed remarkably cardioprotective effects on MI/R injury in vivo and in vitro. The protection of MLB may contribute to its antioxidant properties.

Iridoid glycosides from the flowers of Gentiana macrophylla Pall. ameliorate collagen-induced arthritis in rats

BACKGROUND The flowers of Gentiana macrophylla have been usually applied to cure the joint inflammation and rheumatoid arthritis in Traditional Chinese Medicine. HYPOTHESIS/PURPOSE This work aimed to investigate the anti-rheumatoid arthritic effect and possible mechanism of iridoid glycosides from G. macrophylla (GMI) using an animal model of collagen-induced rheumatoid arthritis (CIA) in rats. STUDY DESIGN All rats were randomly divided into five groups: normal control, CIA, dexamethasone, 15mg/kg and 30mg/kg GMI. METHODS CIA was induced (day 0) in male Sprague-Dawley rats by intradermal injection of complete Bovine CII at the base of the tail. Dexamethasone was chosen as the positive drug. The administration of different drugs started from day 1 and continued for 28 days. Paw swelling, arthritis score and histopathological changes were examined to assess the severity of arthritis. In addition, the serum levels of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions in joint synovial tissues were detected. RESULTS GMI reduced paw edema, arthritis scores and the index of spleen and thymus from day 7 to 21 after CIA compared with those in the CIA group. Our data also demonstrated that GMI inhibited pro-inflammatory cytokines such as TNF-α, IL-1β and IL-6, regulated the expression of iNOS and COX-2 compared with those in the CIA group. We also obtained four major components from GMI, identified as loganic acid, swertamarin, gentiopicroside and sweroside, and the contents of them were also calculated respectively. CONCLUSION Taken together, our results shed light on the therapeutic efficacy of GMI in rats rheumatoid arthritis model by reducing the levels of IL-1β, IL-6 and TNF-α in serum as well as down-regulating the levels of iNOS and COX-2. Therefore, GMI may be an effective therapy for the treatment of rheumatoid arthritis.

Effects and Mechanism of Combination of Rhein and Danshensu in the Treatment of Chronic Kidney Disease

Traditional Chinese medicine (TCM) plays a systemic role in disease treatment, targeting multiple etiological factors simultaneously. Based on clinical experience, rhubarb and Salvia miltiorrhiza are commonly prescribed together for the treatment of chronic kidney disease (CKD) and have been proven to be very effective. However, the rationale of the combination remains unclear. The major active ingredients of these two herbs are rhein (RH) and danshensu (DSS), respectively. The aim of this paper is to investigate the renoprotective effects of RH and DSS in vitro and in vivo, and the underlying mechanism. A total of 5/6 nephrectomy rats and HK-2 cells were subjected to chronic renal injury. The combination of RH and DSS conferred a protective effect, as shown by a significant improvement in the renal function, blood supply, and fibrotic degree. Proinflammatory cytokines and adhesion molecules were suppressed by RH and DSS through NK-κB signaling. The combination also inhibited apoptosis by up-regulating Bcl-2 and down-regulating Bax. Inhibiting the TGF-β/Smad3 pathway was at least in part involved in the antifibrotic mechanism of the combination treatment of RH and DSS. This study demonstrates for the first time the renoprotective effect and the mechanism of RH and DSS combination on chronic renal injury. It could provide experimental evidence to support the rationality of the combinatorial use of TCM in clinical practices.

Insulin-secretagogue activity of eleven plant extracts and twelve pure compounds isolated from Aralia taibaiensis.

AIMS To investigate the insulinogenic activities of the eleven saponins enriched traditional Chinese medicine (TCM) extracts. MAIN METHODS Radioimmunoassay and trypan blue exclusion assay were used to investigate the insulinogenic activity and cytotoxic effects respectively. KEY FINDINGS The total saponin extract of Aralia taibaiensis (sAT) exhibited highest insulinogenic activity and no cytotoxicity was recorded. Twelve pure compounds from sAT stimulated insulin secretion from a mouse insulinoma βTC3 cells in a concentration-dependent manner. TA35 outperformed the other compounds which suggested that the active insulinogenic ingredient of sAT was probably TA35. In addition, both sAT and TA35 markedly potentiated glucose-induced insulin secretion. SIGNIFICANCE Our study is the first to show that sAT dramatically stimulated insulin secretion and its antidiabetic activity may be related to its high saponin content. These findings suggested that sAT and the compound TA35 isolated from sAT may provide novel therapeutic tools for the treatment of non-insulin dependent diabetes mellitus (NIDDM).

ShenKang injection suppresses kidney fibrosis and oxidative stress via transforming growth factor-β/Smad3 signalling pathway in vivo and in vitro

The purpose of this study is to investigate the antifibrosis and antioxidation of ShenKang injection (SKI) in vivo and in vitro and to evaluate potential mechanisms involved in the treatment of chronic kidney disease (CKD).