Cinnamaldehyde Prevents Endothelial Dysfunction Induced by High Glucose by Activating Nrf2

Background/Aims: Ginsenoside Rb1 (Rb1) has been reported to have varieties of neuroprotective effects. This study aimed to evaluate the effects of Rb1 on pentylenetetrazol (PTZ)-induced rat brain injury and Mg²⁺ free-induced neuron injury and analyzed the detailed molecular mechanisms in vivo and in vitro. Methods: Seizure duration and latency were measured in epilepsy kindled rat. The cognitive impairment was assessed by Morris water maze (MWM) test. Oxidative stress parameters, malondialdehyde (MDA) and glutathione (GSH) were measured by the 2-thiobarbituric acid methods and the DTNB-GSSG reductase recycling methods. Neuronal damage was assessed by hematoxylin and eosin (H&E) and Nissl staining. Neuronal apoptosis was measured by Annexin V-FITC and propidium iodide (PI) staining. Immunohistochemistry and immunofluorescence staining were performed to evaluate Nrf2 and HO-1 expressions. Expression of Nrf2, HO-1, Bcl-2, iNOS and LC3 were evaluated by western blot. Results: The PTZ-injured rats presented longer seizure duration and shorter seizure latency. Rb1 ameliorated these effects, as well as the cognitive deficits caused by PTZ exposure. Besides, Rb1 dose-dependently increased GSH levels, decreased MDA levels and alleviated neuronal damage in PTZ-treated rats. In vitro, Rb1 increased cell viability and decreased neuronal apoptosis in a dose-dependent manner under Mg²⁺ free condition. Moreover, in vivo and in vitro, Rb1 enhanced both the Nrf2 and HO-1 expressions. Furthermore, upregulation of the expression of Bcl-2 and downregulation of the expression of iNOS and LC3 were observed. However, knockdown of Nrf2 adversely affected the protective effects of Rb1 in epileptic hippocampal neurons. Conclusion: Rb1 conferred neuroprotective effects against PTZ-induced brain damage and Mg²⁺ free-induced neuron injury by activating Nrf2/ARE signaling.

Section: Discussionmentioning

confidence: 99%

Ginsenoside Rb1 Protects the Brain from Damage Induced by Epileptic Seizure via Nrf2/ARE Signaling

Shi

Wang

Teng

et al. 2018

“…Cinnamon, which is used as an herbal drug and spice, has been employed to treat obesity and diabetes for thousands of years in traditional Chinese medicine [20]. CA, the main volatile oil constituent of cinnamon, exhibits glucose-lowering activity [21]. Furthermore, CA positively alters body composition in vivo [22, 23] and regulates adipocyte differentiation in vitro [24].…”

Section: Discussionmentioning

confidence: 99%

Cinnamaldehyde Ameliorates Diet-Induced Obesity in Mice by Inducing Browning of White Adipose Tissue

Zuo

Zhao

et al. 2017

Background/Aims: Obesity has become a major health concern with few effective medications. Cinnamaldehyde (CA) has been reported to exhibit anti-diabetic and anti-inflammatory properties. However, whether CA shows anti-obesity activity remains unknown. Therefore, the present study aimed to investigate the potential anti-obesity effects of CA on mice fed a high-fat diet (HFD) and to explore the possible mechanisms involved. Methods: Male C57BL/6J mice fed an HFD for 12 weeks were supplemented with CA (40 mg/kg/day) via gavage for an additional 8 weeks. Mice fed a standard diet were used as normal controls. Results: The results revealed that CA treatment decreased body weight, fat mass, food intake, and serum lipid, free fatty acid and leptin levels. CA administration also improved insulin sensitivity in HFD-induced obese mice. Additionally, CA inhibited the hypertrophy of adipose tissue and induced browning of white adipose tissue. Uncoupling protein 1 (UCP1) was expressed in white adipose tissue after the oral administration of CA. Furthermore, CA enhanced the expression of the peroxisome proliferator-activated receptor γ (PPARγ), PR domain-containing 16 (PRDM16) and PPARγ coactivator 1α (PGC-1α) proteins in both brown and white adipose tissues. Conclusions: The results suggest that CA exhibits therapeutic potency against obesity by inducing the browning of white adipose tissue in HFD-fed mice.

“…Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key regulator of oxidative stress and the inflammatory response in endothelial cells [16, 17]. Nrf2 binds to the antioxidant response element (ARE) and triggers the expression of ARE-regulated genes, including heme oxygenase-1 (HO-1).…”

Section: Introductionmentioning

confidence: 99%

Allicin Decreases Lipopolysaccharide-Induced Oxidative Stress and Inflammation in Human Umbilical Vein Endothelial Cells through Suppression of Mitochondrial Dysfunction and Activation of Nrf2

Zhang¹,

Pan²,

Xu³

et al. 2017

104

Background: Allicin, a major component of garlic, is regarded as a cardioprotective agent and is associated with increased endothelial function. Methods: The effects of allicin on lipopolysaccharide (LPS)-induced vascular oxidative stress and inflammation in cultured human umbilical vein endothelial cells (HUVECs) and the mechanisms underlying these effects were studied. The protective effects were measured using cell viability, a lactate dehydrogenase (LDH) assay and cell apoptosis as indicators, and the anti-oxidative activity was determined by measuring reactive oxygen species (ROS) generation, oxidative products and endogenous antioxidant enzyme activities. HUVEC mitochondrial function was assessed by determining mitochondrial membrane potential (MMP) collapse, cytochrome c production and mitochondrial ATP release. To investigate the potential underlying mechanisms, we also measured the expression of dynamic mitochondrial proteins using western blotting. Furthermore, we evaluated the Nrf2 antioxidant signaling pathway using an enzyme-linked immunosorbent assay (ELISA). Results: Our results demonstrated that allicin enhanced HUVEC proliferation, which was suppressed by LPS exposure, and LDH release. Allicin ameliorated LPS-induced apoptosis, suppressed ROS overproduction, reduced lipid peroxidation and decreased the endogenous antioxidant enzyme activities in HUVECs. These protective effects were associated with the inhibition of mitochondrial dysfunction as indicated by decreases in the MMP collapse, cytochrome c synthesis and mitochondrial ATP release. In addition, allicin attenuated the LPS-induced inflammatory responses, including endothelial cell adhesion and TNF-α and IL-8 production. Furthermore, allicin increased the expression of LXRα in a dose-dependent manner. Allicin-induced attenuation of inflammation was inhibited by LXRα siRNA treatment. Finally, allicin activated NF-E2-related factor 2 (Nrf2), which controls the defense against oxidative stress and inflammation. Conclusions: Taken together, the present data suggest that allicin attenuated the LPS-induced vascular injury process, which may be closely related to the oxidative stress and inflammatory response in HUVECs. Allicin modulated Nrf2 activation and protected the cells against LPS-induced vascular injury. Our findings suggest that allicin attenuated the LPS-induced inflammatory response in blood vessels.