Protective effects of Forsythia suspensa extract against oxidative stress induced by diquat in rats

Forsythia suspensa extract has been proved as a potential antioxidant in the recent years. The present study was undertaken to obtain the optimal antioxidant fraction in vitro and examine its antioxidative potential against diquat-induced oxidative stress in male Sprague Dawley rats in vivo. In vitro, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging experiment indicated that the CH₂Cl₂ fraction of F. suspensa (FSC) exerted the strongest scavenging activities; forsythoside A, forythialan A and phillygenin from it might be the major antioxidant constituents. In vivo, pretreatment of rats with different doses of FSC (25, 50 and 100 mg/kg bw) and vitamin C (100 mg/kg bw, positive control) for 15 days significantly lowered the tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in plasma compared to the negative control group. Also, FSC significantly increased the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and the levels of glutathione (GSH) in plasma, liver and kidney whereas it decreased the levels of malondialdehyde (MDA) in plasma and kidney. Moreover, the protective effect of FSC (100 mg/kg bw) was better than vitamin C. These results revealed that FSC exerted a protective effect against diquat-induced oxidative stress and is worthy of becoming a potential dietary antioxidant.     

Pycnogenol modulates apoptosis by suppressing oxidative stress and inflammation in high glucose-treated renal tubular cells

Compelling evidence indicates that polyphenolic antioxidants protect against diabetic nephropathy. Pycnogenol is made up of flavonoids, mainly procyanidins and phenolic compounds, and is a known powerful antioxidant. Hyperglycemia is characteristic of diabetic nephropathy and induces renal tubular cell apoptosis. Thus, in this study, we used high glucose-treated renal tubular cells to investigate the protective action of pycnogenol against high glucose-induced apoptosis and diabetic nephropathy. We also sought to further delineate the underlying mechanisms elicited by oxidative stress and inflammation and suppressed by pycnogenol. Results show that pycnogenol significantly suppressed the high glucose-induced morphological changes and the reduction in cell viability associated with cytotoxicity. Bcl2/Bax protein levels indicated pycnogenol’s anti-apoptotic effect against high glucose-induced apoptotic cell death. In addition, several key markers of oxidative stress and inflammation were measured for pycnogenol’s beneficial effects. Results indicate pycnogenol’s anti-oxidative and anti-inflammatory efficacy in suppressing lipid peroxidation, total reactive species (RS), superoxide (O₂), nitric oxide (NO), peroxynitrite (ONOO⁻), pro-inflammatory inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and nuclear factor-kappa B (NF-κB) nuclear translocation. Based on these results, we conclude that pycnogenol’s anti-oxidative and anti-inflammatory properties underlie its anti-apoptotic effects, suggesting further investigation of pycnogenol as a promising treatment against diabetic nephropathy.     

Ethylacetate extract from DraconisResina inhibits LPS-induced inflammatory responses in vascular smooth muscle cells and macrophages via suppression of ROS production

DraconisResina (DR) is a type of dragon’s blood resin obtained from Daemomoropsdraco BL. (Palmae). DR has long been used as a traditional Korean herbal medicine, and is currently used in traditional clinics to treat wounds, tumors, diarrhea, and rheumatism, insect bites and other conditions. In this study, we evaluated fractionated extracts of DR to determine if they inhibited the production of interleukin-1β (IL-1β) and the expression of cyclooxygenase (COX)-2. The results of this analysis revealed that the ethylacetate extract of DraconisResina (DREA) was more potent than that of other extracts. Moreover, DREA inhibited the production of nitric oxide (NO), reactive oxygen species (ROS), prostaglandin E₂ (PGE₂), tumor necrosis factor-α (TNF-α), IL-8 and IL-6 in lipopolysaccharide (LPS)-treated human aortic smooth muscle cells (HASMC) and RAW 264.7 macrophages. Furthermore, treatment with an NADPH oxidase assembly inhibitor, AEBSF, efficiently blocked LPS-induced mitogen-activated protein kinases (MAPKs) activation, as did DREA. These findings indicate that DREA inhibits the production of NO, PGE₂, TNF-α, IL-8, and IL-6 by LPS via the inhibition of ROS production, which demonstrates that DREA inhibits LPS-induced inflammatory responses via the suppression of ROS production. Taken together, these results indicate that DREA has the potential for use as an anti-atherosclerosis agent.     

Protective effect of Chrysanthemum indicum Linne against 1-methyl-4-phenylpridinium ion and lipopolysaccharide-induced cytotoxicity in cellular model of Parkinson’s disease

Chrysanthemum indicum Linn. (CI) has been used in Oriental medicine for several centuries. In the present study, the effect of CI extract was evaluated against 1-methyl-4-phenylpridinium ion (MPP⁺)-induced damage in SH-SY5Y cells and lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. Cell viability, oxidative damage, reactive oxygen species, expression of Bcl-2/Bax, and poly (ADP-ribose) polymerase (PARP) proteolysis were evaluated using SH-SY5Y cells. Production of iNOS, prostaglandin E₂, and pro-inflammatory cytokines like tumor necrosis factor (TNF)-α, interleukin (IL)-1β, interleukin (IL)-6, expression of cyclooxygenase type-2 (COX-2) and type-1 (COX-1) were examined in activated BV-2 microglia. At 1, 10 and 100 μg, CI inhibited cell loss, decreased the reactive oxygen species production, regulated the Bax/Bcl-2 ratio and inhibited PARP proteolysis in MPP⁺-induced SH-SY5Y cells. Furthermore, CI suppressed the production of prostaglandin E_2, expression of cyclooxygenase type-2 (COX-2), blocked IκB-α degradation and activation of NF-κB p65 in BV-2 cells in a dose-dependent manner. The molecular mechanisms involved by CI might involve its inhibitory actions both on neuronal apoptosis and neuroinflammatory NF-κB/IκB-α signaling pathway. The present investigation scientifically supports the long history and safe usage of CI as an important functional food with potential benefits in ameliorating deleterious conditions seen in PD.     

Suppression of oxidative stress and pro-inflammatory mediators by Cymbopogon citratus D. Stapf extract in lipopolysaccharide stimulated murine alveolar macrophages

Exploration of antioxidants of plant origin and their scientific validation for their immense pharmacological potential is emerging as an issue of intense research now-a-days.The effect of Cymbopogon citratus extract was seen on cell viability, oxidative stress markers i.e. ROS production, SOD activity, lipid peroxidation and GSH content of murine alveolar macrophages stressed with lipopolysaccharide. Modulation in release of NO and pro-inflammatory cytokine TNF-α along with alterations in mitochondrial membrane potential under stress were compared with known plant derived antioxidant quercetin. The extract was not found to be cytotoxic at any of the selected doses. At 5 and 10 μg the extract showed significant increase in SOD activity, GSH content (p < 0.001), decrease in ROS production as seen by fluorescent dye DCFH-DA and also MDA formation (lipid peroxidation marker) significantly. The extract also showed reduction in the release of pro-inflammatory mediators TNF-α and NO significantly indicating an anti-inflammatory effect. The extract was able to restore mitochondrial membrane potential as estimated by spectrofluorimetry using the fluorescent dye Rhodamine 123. The results suggest potential use of the cytoprotective, antioxidant and anti-inflammatory property of C. citratus in the form of dietary component and also in formulations against lung inflammatory diseases where oxidative stress plays an important role.     

The methanolic fraction of Centratherum anthelminticum seed downregulates pro-inflammatory cytokines,oxidative stress,and hyperglycemia in STZ-nicotinamide-induced type 2 diabetic rats

This study aimed to ascertain the potential of Centratherum anthelminticum seeds methanolic fraction (CAMFs) for the management of type 2 diabetes and its associated complications. CAMFs was initially tested on β-TC6 cells for H₂O₂-induced nuclear factor-κB (NF-κB) translocation effects. The result displayed that CAMFs significantly inhibited NF-κB translocation from cytoplasm into the nucleus, dose-dependently. Furthermore, a 12-week sub-chronic CAMFs study was carried out on streptozotocin (STZ)-nicotinamide–induced type 2 diabetic rat model to evaluate glycemia, essential biochemical parameters, lipid levels, oxidative stress markers, and pro-inflammatory cytokines level. Our study result showed that CAMFs reduced hyperglycemia by increasing serum insulin, C-peptide, total protein, and albumin levels, significantly. Whereas, elevated blood glucose, glycated hemoglobin, lipids and enzyme activities were restored to near normal. CAMFs confirmed antioxidant potential by elevating glutathione (GSH) and reducing malondialdehyde (MDA) levels in diabetic rats. Interestingly, CAMFs down-regulated elevated tumor necrosis factor α (TNF-α), interleukin (IL)-1β and IL-6 in the tissues and serum of the diabetic rats. We conclude that CAMFs exerted apparent antidiabetic effects and demonstrated as a valuable candidate nutraceutical for insulin-resistant type 2 diabetes and its associated complications such as dyslipidemia, oxidative stress, and inflammation.     

Modulation of human neutrophil oxidative metabolism and degranulation by extract of Tamarindus indica L. fruit pulp

The tamarind (Tamarindus indica L.) is indigenous to Asian countries and widely cultivated in the American continents. The tamarind fruit pulp extract (ExT), traditionally used in spices, food components and juices, is rich in polyphenols that have demonstrated anti-atherosclerotic, antioxidant and immunomodulatory activities. This study evaluated the modulator effect of a crude hydroalcoholic ExT on some peripheral human neutrophil functions. The neutrophil reactive oxygen species generation, triggered by opsonized zymosan (OZ), n-formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol myristate acetate (PMA), and assessed by luminol- and lucigenin-enhanced chemiluminescence (LumCL and LucCL, respectively), was inhibited by ExT in a concentration-dependent manner. ExT was a more effective inhibitor of the PMA-stimulated neutrophil function [IC₅₀ (in μg/10⁶cells) = 115.7 ± 9.7 (LumCL) and 174.5 ± 25.9 (LucCL)], than the OZ- [IC₅₀ = 248.5 ± 23.1 (LumCL) and 324.1 ± 34.6 (LucCL)] or fMLP-stimulated cells [IC₅₀ = 178.5 ± 12.2 (LumCL)]. The ExT also inhibited neutrophil NADPH oxidase activity (evaluated by O₂ consumption), degranulation and elastase activity (evaluated by spectrophotometric methods) at concentrations higher than 200 μg/10⁶ cells, without being toxic to the cells, under the conditions assessed. Together, these results indicate the potential of ExT as a source of compounds that can modulate the neutrophil-mediated inflammatory diseases.     

Preventive effect of Coptis chinensis and berberine on intestinal injury in rats challenged with lipopolysaccharides

Coptis chinensis has been used in traditional Chinese medicine to treat inflammatory symptoms. Berberine is the main alkaloid compound of C. chinensis. This study utilized a typical lipopolysaccharide (LPS) injured model to investigate the effects of C. chinensis aqueous extract (CCAE) and berberine (major active ingredient in CCAE) in the gut-derived sepsis. In rats, pretreatment with different doses of berberine (30 or 120 mg/kg bw, i.g.; BBR30 or BBR120) or CCAE (containing 9.9% berberine; 300 mg/kg bw, i.g.; CCAE300) prior to the administration of LPS (20 mg/kg bw, i.p.) significantly suppressed the increased tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and nitrite oxide (NO) in plasma as well as the activation of toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) in ileum. In addition, CCAE300 and BBR30 markedly elevated the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px); significantly prevented the increased malondialdehyde (MDA), NO and villi injury in ileum compared with the negative control. Collectively, CCAE300 and BBR30 reduced the LPS-induced intestinal damage by elevating the activities of SOD and GSH-Px and by suppressing the activation of TLR4 and NF-κB in ileum. These results indicate that CCAE and berberine are promising agents for preventing sepsis and its complications.     

Exposure to ZnO nanoparticles induces oxidative stress and cytotoxicity in human colon carcinoma cells

Engineered nanoparticles offer great promise in many industrial and biomedical applications, however little information is available about gastrointestinal toxicity. The purpose of this study was to assess the cytotoxicity, oxidative stress, apoptosis and proinflammatory mediator release induced by ZnO nanoparticles on human colon carcinoma LoVo cells. The biological activity of these particles was related to their physico-chemical characteristics. The physico-chemical characteristics were evaluated by analytical electron microscopy. The cytotoxicity was determined by growth curves and water-soluble tetrazolium assay. The reactive oxygen species production, cellular glutathione content, changes of mitochondrial membrane potential and apoptosis cell death were quantified by flow cytometry. The inflammatory cytokines were evaluated by enzyme-linked immunoadsorbent assay. Treatment with ZnO (5 μg/cm² corresponding to 11.5 μg/ml) for 24 h induced on LoVo cells a significant decrease of cell viability, H₂O₂/OH increase, O2⁻ and GSH decrease, depolarization of inner mitochondrial membranes, apoptosis and IL-8 release. Higher doses induced about 98% of cytotoxicity already after 24 h of treatment. The experimental data show that oxidative stress may be a key route in inducing the cytotoxicity of ZnO nanoparticles in colon carcinoma cells. Moreover, the study of the relationship between toxicological effects and physico-chemical characteristics of particles suggests that surface area does not play a primary role in the cytotoxicity.     

Anti-inflammatory activity of Korean thistle Cirsium maackii and its major flavonoid,luteolin 5-O-glucoside

The anti-inflammatory activity of whole Cirsium maackii (family Compositae) plants and of its major flavonoid, luteolin 5-O-glucoside, was evaluated for their ability to inhibit lipopolysaccharide (LPS)-induced nitric oxide (NO) production, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) protein expression, and tert-butylhydroperoxide (t-BHP)-induced reactive oxygen species (ROS) generation in RAW 264.7 murine macrophage cells. The methanolic extract of C. maackii showed strong anti-inflammatory activity, and was thus fractionated with several solvents. The ethyl acetate-soluble fraction, exhibiting the highest anti-inflammatory activity potential, was further to yield a major flavonoid, luteolin 5-O-glucoside. We found that luteolin 5-O-glucoside, at a non-toxic concentration, inhibited LPS-induced NO production and t-BHP-induced ROS generation in a dose-dependent manner in RAW 264.7 cells. It also suppressed the expression of iNOS and COX-2 in LPS-stimulated macrophages. Furthermore, the efficacies of the methanolic extract of C. maackii in inhibiting both NO and ROS were attributed to its flavonoid content by HPLC analysis. These results indicated that C. maackii whole plants and its flavonoids inhibit the expression of iNOS and COX-2 in through the inhibition of ROS generation, and therefore can be considered as a useful therapeutic and preventive approach for the treatment of various inflammatory and oxidative stress-related diseases.     

Combined treatment with capsaicin and resveratrol enhances neuroprotection against glutamate-induced toxicity in mouse cerebral cortical neurons

Capsaicin and resveratrol as natural products have a variety of beneficial effects. However, capsaicin is also a neurotoxic agent, rendering its effect on the nervous system confusing. The aim of this study was to investigate whether capsaicin and/or resveratrol have a protective effect against glutamate (Glu)-induced neurotoxicity. After exposure to glutamate for 15 min, cerebral cortical neurons of ICR mouse fetuses on embryonic days 15–16 were post-treated with capsaicin and/or resveratrol for 24 h. Glu induced a significant reduction in cell viability, but the cell viability increased significantly with capsaicin or resveratrol treatment and further was highest in the neurons co-treated with both phytochemicals. Glu-induced reactive oxygen species generation and apoptotic neuronal death also significantly decreased by a combined treatment with both phytochemicals. Due to Glu insults, the reduced mRNA levels of cytoplasmic glutathione peroxidase, copper/zinc and manganese superoxide dismutases, and Bcl-x_L and the overexpressed mRNA levels of interleukin-1β and tumor necrosis factor-α were significantly restored by post-treatment of capsaicin and/or resveratrol. These findings indicate that capsaicin and resveratrol are neuroprotective against Glu-induced toxicity and that the combined treatment of both phytochemicals can enhance the neuroprotection, suggesting a useful therapeutic application in the treatment of neurodegenerative disorders.     

Increased apoptotic efficacy of lonidamine plus arsenic trioxide combination in human leukemia cells. Reactive oxygen species generation and defensive protein kinase (MEK/ERK, Akt/mTOR) modulation

Lonidamine is a safe, clinically useful anti-tumor drug, but its efficacy is generally low when used in monotherapy. We here demonstrate that lonidamine efficaciously cooperates with the anti-leukemic agent arsenic trioxide (ATO, Trisenox™) to induce apoptosis in HL-60 and other human leukemia cell lines, with low toxicity in non-tumor peripheral blood lymphocytes. Apoptosis induction by lonidamine/ATO involves mitochondrial dysfunction, as indicated by early mitochondrial permeability transition pore opening and late mitochondrial transmembrane potential dissipation, as well as activation of the intrinsic apoptotic pathway, as indicated by Bcl-X_L and Mcl-1 down-regulation, Bax translocation to mitochondria, cytochrome c and Omi/HtrA2 release to the cytosol, XIAP down-regulation, and caspase-9 and -3 cleavage/activation, with secondary (Bcl-2-inhibitable) activation of the caspase-8/Bid axis. Lonidamine stimulates reactive oxygen species production, and lonidamine/ATO toxicity is attenuated by antioxidants. Lonidamine/ATO stimulates JNK phosphorylation/activation, and apoptosis is attenuated by the JNK inhibitor SP600125. In addition, lonidamine elicits ERK and Akt/mTOR pathway activation, as indicated by increased ERK, Akt, p70S6K and rpS6 phosphorylation, and these effects are reduced by co-treatment with ATO. Importantly, co-treatment with MEK/ERK inhibitor (U0126) and PI3K/Akt (LY294002) or mTOR (rapamycin) inhibitors, instead of ATO, also potentiates lonidamine-provoked apoptosis. These results indicate that: (i) lonidamine efficacy is restrained by drug-provoked activation of MEK/ERK and Akt/mTOR defensive pathways, which therefore represent potential therapeutic targets. (ii) Co-treatment with ATO efficaciously potentiates lonidamine toxicity via defensive pathway inhibition and JNK activation. And (iii) conversely, the pro-oxidant action of lonidamine potentiates the apoptotic efficacy of ATO as an anti-leukemic agent.