Lan Sun

Neuroprotective effects of tetramethylpyrazine on hydrogen peroxide-induced apoptosis in PC12 cells.

In the present study, we investigated the effects of tetramethylpyrazine (TMP) on hydrogen peroxide (H2O2)‐induced apoptosis in PC12 cells. The apoptosis in H2O2‐induced PC12 cells was accompanied by a decrease in Bcl‐2/Bax protein ratio, release of cytochrome c to cytosol and the activation of caspase‐3. TMP not only suppressed the down‐regulation of Bcl‐2, up‐regulation of Bax and the release of mitochondrial cytochrome c to cytosol, but also attenuated caspase‐3 activation and eventually protected against H2O2‐induced apoptosis. These results indicated that TMP blocked H2O2‐induced apoptosis by the regulation of Bcl‐2 family members, suppression of cytochrome c release, and caspase cascade activation in PC12 cells.

Anti-Inflammatory Activity of Methyl Salicylate Glycosides Isolated from Gaultheria yunnanensis (Franch.) Rehder

Gaultheria yunnanensis (Franch.) Rehder is a kind of traditional Chinese herbal medicine used for the treatments of rheumatoid arthritis, swelling and pain. Two methyl salicylate glycosides, namely methyl benzoate-2-O-β-D-xylopyranosyl(1-6)-O-β-D-gluco-pyranoside (J12122) and methyl benzoate-2-O-β-D-xylopyranosyl(1-2)[O-β-D-xylopyranosyl(1-6)]-O-β-D-glucopyranoside (J12123), are natural salicylic derivatives isolated from Gaultheria yunnanensis. In this study, we investigated the anti-inflammatory activity of J12122 and J12123 on LPS-induced RAW264.7 macrophage cells by measuring the production of pro-inflammatory cytokines, accumulation of nitric oxide (NO), and level of reactive oxygen species (ROS). The results showed that both methyl salicylate glycosides dose-dependently inhibited the production of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6, respectively. Consistent with these observations, J12122 and J12123 significantly suppressed the accumulation of NO, with an inhibitory rate of 56.20% and 51.72% at 3.0 μg/mL concentration, respectively. Furthermore, the two methyl salicylate glycosides reduced the level of ROS induced by LPS. These results showed that the isolated compounds possess anti-inflammatory properties through inhibition the production pro-inflammatory cytokines, NO, and ROS.

A Novel Naturally Occurring Salicylic Acid Analogue Acts as an Anti-Inflammatory Agent by Inhibiting Nuclear Factor-kappaB Activity in RAW264.7 Macrophages

Methyl salicylate 2-O-β-D-lactoside (DL0309), is a molecule chemically related to salicylic acid that is isolated from Gaultheria yunnanensis (FRANCH.) REHDER (G. yunnanensis). G. yunnanensis, a traditional Chinese herbal medicine, is widely used for treating rheumatoid arthritis, swelling, pain, trauma, and chronic tracheitis. In the present study, we explored the mechanism whereby DL0309 exerts anti-inflammatory effects, using the model of lipopolysaccharide (LPS)-treated RAW264.7 cells. We examined the effects of DL0309 on LPS-induced nuclear factor-kappaB (NF-κB) activity by Western blot analysis, cell imaging analysis and an electrophoretic mobility shift assay (EMSA). Production of pro-inflammatory cytokines was also measured. Our observations indicate that DL0309 suppressed production of nitric oxide (NO), reactive oxygen species (ROS) and the pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β), in a concentration-dependent manner. The phosphorylation of IKK-β and degradation of IκB-α by LPS were both inhibited by DL0309 in the cytoplasm. The increased protein level of NF-κB by LPS in the nucleus was also reduced by DL0309. Consistent with these results, we found that DL0309 prevents the nuclear translocation and DNA binding activity of NF-κB. Finally, our results demonstrate that DL0309 exerts anti-inflammatory effects, by inhibiting the production of pro-inflammatory cytokines and suppressing of the activation of the NF-κB signaling pathway in LPS-treated macrophage cells. Therefore, DL0309 may have therapeutic potential for treating inflammatory diseases by regulating the NF-κB pathway and pro-inflammatory cytokine production.

Protective effect of stilbenes containing extract-fraction from Cajanus cajan L. on Aβ25―35-induced cognitive deficits in mice

Cajanus cajan (L.) is a traditional Chinese herb medicine which contains a lot of potential active components. In the present study, we identified the effects of the stilbenes containing extract-fraction from C. cajan L. (sECC) on Abeta(25-35)-induced cognitive deficits, oxidative stress and cholinergic dysfunction in mice. Mice were treated with sECC (100 and 200mg/kg/d) for 1-week, and then received a single intracerebroventricular (i.c.v.) injection of Abeta(25-35) (5mug/mice). Behavioral changes and neuron apoptosis in mice were evaluated using Morris water maze and TUNEL tests. Furthermore, superoxide dismutase (SOD), choline acetyl transferase (ChAT) and acetylcholine esterase (AchE) activity in hippocampus and cortex were analyzed by spectrophotometric method. The data showed that consumption of sECC (200mg/kg) significantly ameliorated the cognitive deficits and neuron apoptosis caused by i.c.v. injection of Abeta(25-35). At the same time, the decreased SOD and ChAT activity in hippocampus and cortex were markedly increased by sECC (200mg/kg). sECC has no effect on AchE activity in hippocampus and cortex. These findings suggest that sECC may be a potential candidate for the development of therapeutic agents to manage cognitive impairment associated with Alzheimers disease (AD) through increasing the activity of ChAT and anti-oxidative mechanism.

Salvianolic acid A protects against vascular endothelial dysfunction in high-fat diet fed and streptozotocin-induced diabetic rats

Salvianolic acid A (SalA) is one of the main active ingredients of Salvia miltiorrhizae. The objective of this study was to evaluate the effect of SalA on the diabetic vascular endothelial dysfunction (VED). The rats were given a high-fat and high-sucrose diet for 1 month followed by intraperitoneal injection of streptozotocin (30 mg/kg). The diabetic rats were treated with SalA (1 mg/kg, 90% purity) orally for 10 weeks after modeling, and were given a high-fat diet. Contractile and relaxant responses of aorta rings as well as the serum indications were measured. Our results indicated that SalA treatment decreased the level of serum Von Willebrand factor and ameliorated acetylcholine-induced relaxation and KCl-induced contraction in aorta rings of the diabetic rats. SalA treatment also reduced the serum malondialdehyde, the content of aortic advanced glycation end products (AGEs), and the nitric oxide synthase (NOS) activity as well as the expression of endothelial NOS protein in the rat aorta. Exposure of EA.hy926 cells to AGEs decreased the cell viability and changed the cell morphology, whereas SalA had protective effect on AGEs-induced cellular vitality. Our data suggested that SalA could protect against vascular VED in diabetes, which might attribute to its suppressive effect on oxidative stress and AGEs-induced endothelial dysfunction.

Effects of salvianolic scid A on plantar microcirculation and peripheral nerve function in diabetic rats

Salvianolic acid A (SalA) is the main efficacious, water-soluble constituent of Salvia miltiorrhiza Bunge. This study evaluated the effects of SalA on plantar microcirculation and peripheral nerve dysfunction in streptozotocin (STZ )-induced type 2 diabetic rats. The rats were given a high-fat and high-sucrose diet for a month followed by intraperitoneal injection of STZ (30 mg/kg). Oral administration of SalA (1 and 3mg/kg, respectively) was performed daily for 10 weeks after modeling. Diabetic rats were given a high-fat diet, while age-matched healthy rats were given a standard chow. Plantar microcirculation was measured by Laser Doppler flowmetry, and peripheral nerve function was measured with regard to pain withdrawal latency and motor nerve conduction velocity. The results show that the plantar blood perfusion and vasodilation reactivities decreased significantly, and latency of pain withdrawal and motor nerve conduction velocity rose in diabetic rats compared with the normal control group. SalA increased peripheral blood perfusion and vascular activities; improved peripheral nerve function; and decreased AGEs levels, vascular eNOS expression, and blood glucose, lipid, vWF and malondialdehyde levels in diabetic rats. The beneficial effects of SalA on plantar microcirculation and peripheral nerve function in diabetic rats might be attributed to improvements in lipid and glucose metabolism in diabetic rats, the inhibition of AGEs formation and the development of oxidative stress-related nervous and vascular damage. Based on these findings, we proposed that therapeutic use of SalA to prevent the development of diabetic foot problems.

Protective effects of trans-2, 4-dimethoxystibene on cognitive, impairments induced by Aβ25–35 in, hypercholesterolemic rats

Trans-2, 4-dimethoxystibene (S3) is a synthetic stilbenes. In the present study, S3 was investigated to assess its neuroprotective effect against the toxicity induced by Abeta(25-35) in hypercholesterolemic rats. Rats were fed with hypercholesterolemic chow for six weeks, and then received a single intracerebroventricular (i.c.v.) injection of Abeta(25-35) and a treatment with S3 or estradiol (E2). Behavioral changes and neuron apoptosis in rats were evaluated using Morris water maze, step-down test and TUNEL tests. To further explore the mechanism of S3, the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), choline acetyl transferase (ChAT), acetylcholine esterase (AchE) and the contents of malondialdehyde (MDA) in hippocampus were analyzed by spectrophotometric method. At the same time, the releases of cytochrome C were analyzed by Western Blot, and the contents of acetylcholine (Ach) were analyzed by Elisa. The data showed that consumption of S3 (50mg/kg/d) significantly ameliorated the cognitive deficits and neuron apoptosis caused by i.c.v. injection of Abeta(25-35). Meanwhile, S3 reversed the decreased activity of ChAT, SOD, GSH-Px and contents of Ach, as well as the increased activity of AchE, MDA contents and the release of cytochrome C in hippocampus. These findings suggest that S3 may be a potential candidate for development as therapeutic agent to treat AD through regulating cholinergic nerve system and anti-oxidative mechanism.

Salvianolic Acid A Inhibits PDGF-BB Induced Vascular Smooth Muscle Cell Migration and Proliferation While Does Not Constrain Endothelial Cell Proliferation and Nitric Oxide Biosynthesis

Proliferation and migration of vascular smooth muscle cells (VSMCs) are critical events in the initiation and development of restenosis upon percutaneous transluminal coronary angioplasty (PTCA). Polyphenols have been suggested to ameliorate post-angioplasty restenosis. Salvianolic A (SalA) is one of the most abundant polyphenols extracted from salvia. In this study, we investigated the effect of salvianolic A (SalA) on the migration and proliferation of VSMCs. We found a preferential interaction of SalA with cellular systems that rely on the PDGF signal, but not on the EGF and bFGF signal. SalA inhibits PDGF-BB induced VSMC proliferation and migration in the concentration range from 0.01 to 0.1 μM. The inhibition of SalA on VSMC proliferation is associated with cell cycle arrest. We also found that SalA inhibits the PDGFRβ-ERK1/2 signaling cascade activated by PDGF-BB in VSMCs. In addition, SalA does not influence the proliferation of endothelial cells, the synthesis of NO and eNOS protein expression. Our results suggest that SalA inhibits migration and proliferation of VSMCs induced by PDGF-BB via the inhibition of the PDGFRβ-ERK1/2 cascade, but that it does not constrain endothelial cell proliferation and nitric oxide biosynthesis. Thus, the present study suggests a novel adjunct pharmacological strategy to prevent angioplasty-related restenosis.

Effects of trans-2,4-dimethoxystibene against the neurotoxicity induced by Aβ25―35 both in vitro and in vivo

Trans-2,4-dimethoxystibene (S(3)) is a synthetic stilbene. In this study, S(3) was investigated in terms of its neuroprotective effect against the toxicity induced by beta-amyloid(25-35) (Abeta(25-35)) both in vitro and in vivo. Protection by S(3) was studied at the in vivo level using a model of intracerebroventricular (i.c.v.) injection of Abeta(25-35) in mice. The consumption of S(3) (50mg/kg) significantly ameliorated the cognitive deficits and neuron apoptosis caused by i.c.v. injection of Abeta(25-35). At the same time, the decreased superoxide dismutase (SOD) and choline acetyl transferase (ChAT) were markedly increased, and the increased acetylcholine esterase (AchE) activity was significantly decreased in hippocampus and cortex. In vitro, SHY-SY5Y cells were co-cultured with Abeta(25-35), and then treated with S(3) immediately. Neuronal survival rates were increased, and this protection was associated with reduction of reactive oxygen species (ROS) and stabilization of mitochondrial membrane potential.

Polyphenols: Potential source of drugs for the treatment of ischaemic heart disease.

Polyphenols, which are naturally present in plants, have been studied for their chemical and pharmacological properties. Polyphenols have been found to exhibit various bioactivities such as antioxidant, free radical scavenging and anti-inflammatory effects, in addition to regulating the intracellular free calcium levels. These bioactivities are related to the underlying mechanisms of ischaemic heart diseases. Pharmacological studies have proven polyphenols to be effective in treating cardiovascular diseases in various ways, particularly ischaemic heart diseases. Based on their mode of action, we propose that some polyphenols can be developed as drugs to treat ischaemic heart diseases. For this purpose, a strategy to evaluate the therapeutic value of drugs for ischaemic heart diseases is needed. Despite several advances in percutaneous coronary intervention (PCI), the incidence of myocardial infarction and deaths due to cardiovascular diseases has not decreased markedly in China. Due to their pleiotropic properties and structural diversity, polyphenols have been of great interest in pharmacology. In the present review, we summarize the pharmacological effects and mechanisms of polyphenols reported after 2000, and we analyse the benefits or druggability of these compounds for ischaemic heart diseases.