Dai-Hong Guo

Protection of SH-SY5Y neuronal cells from glutamate-induced apoptosis by 3,6'-disinapoyl sucrose, a bioactive compound isolated from Radix Polygala.

The neuroprotective effects of 3,6′-disinapoyl sucrose (DISS) from Radix Polygala against glutamate-induced SH-SY5Y neuronal cells injury were evaluated in the present study. SH-SY5Y neuronal cells were pretreated with glutamate (8 mM) for 30 min followed by cotreatment with DISS for 12 h. Cell viability was determined by (3,4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide (MTT) assay, and apoptosis was confirmed by cell morphology and flow cytometry assay, evaluated with propidium iodide dye. Treatment with DISS (0.6, 6, and 60 μmol/L) increased cell viability dose dependently, inhibited LDH release, and attenuated apoptosis. The mechanisms by which DISS protected neuron cells from glutamate-induced excitotoxicity included the downregulation of proapoptotic gene Bax and the upregulation of antiapoptotic gene Bcl-2. The present findings indicated that DISS exerts neuroprotective effects against glutamate toxicity, which might be of importance and contribute to its clinical efficacy for the treatment of neurodegenerative diseases.

Bioactive components from the tea polyphenols influence on endogenous antioxidant defense system and modulate inflammatory cytokines after total-body irradiation in mice

The present study aimed to evaluate the radioprotective efficacy of green tea polyphenols and the component ingredients against irradiated-induced damage in mice and elucidate the underlying mechanisms. Green tea polyphenols (GTP 50, 50 and 100 mg/kg, p.o. daily) and its four individual components (25 and 50 mg/kg, p.o. daily) were administrated to the irradiated-injured mice for 21 days. The radioprotective effect on the hematopoietic system, serum cytokines, and endogenous antioxidant enzymes was studied. GTP 50 significant revert the irradiated-induced decline in hematological parameters (RBCs, WBCs, Hb), meanwhile, protected antioxidant defense system, as evidenced by decreased of serum lipid peroxidation (malonyldialdehyde) and elevation the antioxidant enzyme superoxide dismutase (SOD). Among the GTP components, catechin showed the best effect on elevation of hematological parameters, and epigallocatechin gallate showed the best antioxidant activity. Moreover GTP and its bioactive components (catechin, epigallocatechin and epigallocatechin-3-gallate) assisted in decreasing the leukocytopenia seen after whole mice irradiation and significantly reduced the elevated serum inflammatory cytokines (TNF-α, IL-1β, and IL-6). Green tea polyphenols have a potential to be developed as radioprotective agents against irradiated-induced toxicity. Furthermore the antioxidant and anti-inflammatory activities of GTP can be attributed to the interaction of the different components through multiple and synergistic mechanisms.

Possible mechanism of the antidepressant effect of 3,6'-disinapoyl sucrose from Polygala tenuifolia Willd.

Objective  The present study was designed to observe the effects of 3,6′‐disinapoyl sucrose (DISS), an active oligosaccharide ester component obtained from the roots of Polygala tenuifolia Willd., on behavioral and biochemical aspects of depression induced by chronic mild stress (CMS) in rats. It is the first exploration of the possible association between DISSs antidepressant‐like effects and biochemical markers of depression, and involved measuring monoamine oxidase (MAO) activity, cortisol levels, superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels.

Synthesis and inhibitory effect of piperine derivates on monoamine oxidase.

A series of piperine derivates (1-19) have been designed, synthesized and evaluated in vitro for their monoamine oxidase (MAO) A and B inhibitory activity and selectivity. It is worth noting that most of the small amine moieties substituted on the piperidine ring proved to be potent and selective inhibitors of MAO-B rather than of MAO-A. 5-(3,4-methylenedioxyphenyl)-2E,4E-pentadienoic acid n-propyl amide (3) showed the greatest MAO-B inhibitory activity (IC(50)(MAO-B)=0.045 μM) and good selectivity (IC(50)(MAO-A)=3.66 μM). The conjugated double bond and carbonyl group of piperine are proved to be an essential feature for piperine and related alkylamides to exhibit MAO-inhibitory activity. Binding mode of the titled compounds was predicted using FlexX algorithm. The design and optimization of novel small molecule monoamine oxidase inhibitors will be guided by the results of this report.

Protective Role of Tea Polyphenols in Combination against Radiation-induced Haematopoietic and Biochemical Alterations in Mice

The purpose of this study was to investigate the radioprotective effects of tea polyphenols (TPs) in various combinations against radiation‐induced damage in mice. Mice were divided into different groups: non‐irradiated control, irradiated control, amifostine (43.6 mg/kg, i.v. 30 min before irradiation; positive control) and various combinations of tea polyphenols in different doses. The radioprotective effect on the haematopoietic system, serum cytokines and endogenous antioxidant enzymes were studied. TP50, containing approximately 50% of (‐)‐epigallochatechin‐3‐gallate in addition to other catechins, showed the greatest radioprotective effect against radiation‐induced changes in haematological parameters (red blood cell count, white blood cell count and haemoglobin), and maintained the spleen and thymus indices unchanged (spleen or thymus weight/body weight × 1000). Tea polyphenols also significantly decreased radiation‐induced lipid peroxidation (malondialdehyde levels), elevated endogenous antioxidant enzymes (superoxide dismutase) and reduced the serum cytokines which were elevated in radiation‐induced toxicity. This evidence shows the potential of tea polyphenols, particularly in the combination found in TP50, as radioprotectors in mice, especially regarding recovery of the haematopoietic system, antioxidant potential activity and reduction of inflammatory cytokines. Copyright

Antidepressant effects of the extract YZ-50 from Polygala tenuifolia in chronic mild stress treated rats and its possible mechanisms.

YZ-50 is an active fraction obtained from the root of Polygala tenuifolia Willd. (Polygalaceae) extract and it has been reported previously to exert beneficial effects on mental health in depressed sufferers, however, its mechanism of action remains unresolved. This study utilized the chronic mild stress (CMS) model of depression in Sprague-Dawley rats to evaluate the effects of YZ-50 on depressive behaviors. Furthermore, we tested the hypothesis that the capacity of YZ-50 to reverse the harmful effects of CMS is relative to the hypothalamo-pituitary-adrenal (HPA) system and brain-derived neurotrophic factor (BDNF) in the hippocampus. Repeated administration of YZ-50 for 28 days at the doses of 140 and 280 mg/kg in CMS, YZ-50 reversed the CMS-induced changes in sucrose consumption, plasma corticosterone levels and open field activity. In addition, CMS significantly decreased hippocampal BDNF mRNA levels. However, YZ-50 counteracted a decrease in hippocampal BDNF mRNA caused by CMS. In conclusion, YZ-50 reversed the harmful effects of CMS on mood and behaviors in rats and it possesses an antidepressant property that is at least in part mediated by the neuroendocrine and neuropropective systems, and it is likely that the HPA system plays an important role in this process.

Antioxidant activity of oligosaccharide ester extracted from Polygala tenuifolia roots in senescence-accelerated mice

The constituents of the ethanol extract from the root of Polygala tenuifolia Willd. (Polygalaceae) were investigated for antioxidant activity in senescence-accelerated mice. Consequently, two relevant samples were obtained, a fraction separated by macroporous resin (YZ-OE), and a major pure crystal of 3,6′-disinapoyl sucrose (DISS). Based on HPLC-ESI-MS analysis, the most constituents in the YZ-OE fraction from the extract of P. tenuifolia were oligosaccharide esters. The antioxidant activities of these two samples were evaluated using the accelerated senescence-prone, short-lived mice (SAMP) in vivo. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were increased significantly in SAMP mice fed oligosaccharide esters (YZ-OE 50 mg/kg) and its constituents (DISS 50 mg/kg). However, the content of malondialdehyde (MDA) was increased in the blood and liver of SAMP mice. But when given YZ-OE, it could be decreased, by 44.3% and 47.5%, respectively, compared with the SAMP model. Results from the analyses indicated that the oligosaccharide esters (YZ-OE) from roots of P. tenuifolia had a high in vivo antioxidant activity.

Methanolysis of triterpenoid saponin from Ardisia gigantifolia stapf. and structure–activity relationship study against cancer cells

Thirteen 13,28-epoxy triterpenoid saponins were isolated from Ardisia gigantifolia stapf. and one potential anti-tumor saponin was methanolysised by H2SO4 to afford four new compounds. The seventeen compounds were evaluated for their anti-proliferative activity on A549, HCT-8 and Bel-7402 cells. The structure-activity relationship analysis indicated that the incorporation of =O group at C-16, L-rhamnose at R(5) and acetyl group at OH-6 of the D-glucose lead to a significant increase of the cytotoxic activity on A549 and HCT-8 but significant reduction of the cytotoxic activity on Bel-7402 cells. The synthesized saponins losing 13,28-epoxy and CHO at C-30, losed their cytotoxicities on A549 and HCT-8 cells, suggesting that the two moieties play an essential role for activity. 3β-O-α-L-rhamnopyranosyl-(1→3)-[β-D-xylopyranosyl-(1→2)]-β-D-glucopyranosyl-(1→4)-[β-D-glucopyranosyl-(1→2)]-α-l-arabinopyranoside-16α-hydroxy-13,28-epoxy-oleanane (2) showed better inhibitory activity to Bel-7402 (IC50 0.86 μM) than that of 5-FU (IC50 8.30 μM), which indicate that five saccharide and methyl moiety at C-30 are important for anti-proliferative activity. The activities of saponins 15>14, 17>16, suggested that the configuration of 28,30-epoxy is preferable to be 30(R) rather than 30(S) on Bel-7402 cells. Further molecular mechanism studies of saponins 1 and 2 were carried out on the cell cycle distribution of Bel-7402 cells.

A comparison study of metformin only therapy and metformin combined with Chinese medicine jianyutangkang therapy in patients with type 2 diabetes: A randomized placebo-controlled double-blind study

The aim of this 26-week, double-blind, controlled clinical trial, was to compare the efficacy of monotherapy (metformin only) with combination therapy (Chinese medicine prescription JianYuTangKang [JYTK] plus metformin) on type 2 diabetes. All patients on metformin were randomized to receive authenticated JYTK (59 patients) or placebo JYTK (53 patients), 4.5g daily, for 26 weeks. Patients also received information regarding diet and exercise. Fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1C) level, and a lipid profile were measured before, during, and after the treatment. The results of the treatment group (JYTK plus metformin) were noninferior to those of the control group (metformin plus placebo) at 8 and 18 weeks. After 26 weeks of treatment, FPG levels decreased to 6.1±1.0mmol/L in the treatment group and 7.0±1.5mmol/L in the control group (p<0.01). HbA1C levels after 26 weeks were also significantly decreased in the treatment group compared with the control group (p<0.01). In addition, lipid profiles were also significantly different between the two groups. Integrated traditional Chinese and Western medicine therapy (JYTK plus metformin) for patients with type 2 diabetes mellitus may not only help improve glycemia and insulin sensitivity, but also help to modify the diabetes related lipid equilibrium. And thereby provides a basis for a novel, effective, and safe approach, to treat type 2 diabetic patients.

Effect of JYTK on Antioxidant Status and Inflammation in Patients With Type 2 Diabetes: A Randomized Double-Blind Clinical Trial

Background Diabetes is a metabolic disorder caused by oxidative stress and inflammation. JianYuTangKang (JYTK), as a potential Chinese integrative medicine, is an antioxidant used in Chinese medicine with potential anti-inflammatory properties. Objectives The present randomized clinical trial was carried out to evaluate the effects of JYTK on oxidative stress and inflammation in patients with type 2 diabetes mellitus (T2DM). Patients and Methods The parallel, randomized, double-blinded, placebo-controlled clinical trial included 150 newly diagnosed T2DM patients receiving metformin treatment (1.5 g/day), some of whom also received JYTK (4.5 g/day) in tablet form. The control group received 4.5 g/day placebo plus 1.5 g/day metformin. Body mass index (BMI), fasting plasma glucose, urinary albumin-to-creatinine ratio, and complete blood count as well as antioxidant and inflammation indices such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, superoxide dismutase (SOD), malonaldehyde (MDA), glutathione peroxidase (GPX), and high sensitivity C-reactive protein (hs-CRP) levels were assessed at baseline and at different time points during the treatment. Results All 112 patients, including 59 in the treatment group (JYTK + metformin) and 52 controls (metformin only) completed the 26-week clinical trial. JYKT plus metformin treatment increased IL-6 (36.4 ± 11.5 ng/L; P < 0.05), TNF-α (17.5 ± 11.3 vs. 22.5 ± 12.9 ng/L; P < 0.05), and MDA (1.9 ± 0.9; P < 0.05) levels compared to the control (2.2 ± 0.6 mM/mL), whereas total SOD level decreased (98.1 ± 30.4 vs. 78.5 ± 29.3 U/mL; P < 0.05). There were no changes in GPX and hs-CRP levels. There were no adverse effects associated with JYTK treatment. Conclusions JYTK combined with metformin improves some antioxidant indices (SOD and MDA), and decreases inflammation in patients with T2DM, suggesting that it can reduce the risk of diabetic complications.