A cytochrome c-enhanced peroxidation reaction with potential use in screening dietary antioxidants

Reactive oxygen species (ROS) that result from events such as cellular respiration can cause damage to biological molecules and tissues. A variety of endogenous and dietary antioxidants function in moderating the extent of oxidative damage in the body. In this report, a pro-oxidant system is presented as an assay for screening possible antioxidant activities of dietary factors. The assay reaction involves peroxidatic oxidation of the redox indicator N,N,N′,N′-tetramethyl-1,4-phenylenediamine (TMPD). It is shown that the reaction rate is enhanced by up to 10-fold in the presence of cytochrome c (cyt c), a mitochondrial electron transport protein. The extent to which selected dietary antioxidant factors inhibit the cytochrome c-enhanced peroxidatic oxidation of TMPD is also reported. Considering the known pathological consequences of mitochondrial membrane disruption and cytochrome c release in the cell, this reaction and assay may be of pathological and therapeutic relevance.     

原花青素的抗炎作用及其作用机制探讨

目的研究原花青素的抗炎作用及其作用机制。方法以二甲苯致炎小鼠耳片肿胀及角叉菜胶诱发大鼠足爪肿胀模型,分别探讨原花青素对小鼠耳片肿胀及大鼠足爪肿胀的抑制作用。用紫外分光光度法测定足爪炎性渗出液中前列腺素E2（prostaglandin E2,PGE2）的含量。Westerm Blot法和免疫组化法（immunohistochemistry,IHC）检测大鼠足爪中环氧合酶-2（Cyclooxygenase-2,COX2）的表达情况。结果10mg／kg和20mg／kg的原花青素抑制二甲苯致炎小鼠耳片肿胀,原花青素5mg／kg和20．0mg／kgi p在2～5h抑制角叉菜胶诱导的大鼠足爪肿胀。原花青素5mg／kg和20．0mg／kgip能抑制大鼠炎症足爪组织PGE2的生物合成。原花青素5mg／kg和20．0mg／kgip能明显下调COX-2的表达。结论原花青素具有较强的抗炎作用,其抗炎作用可能与抑制COX-2的表达继而下调PGE2的生物合成有关。     

Food anthocyanins decrease concentrations of TNF-α in older adults with mild cognitive impairment: A randomized,controlled, double blind clinical trial

Background & aimsVascular function, blood pressure and inflammation are involved in the pathogenesis of major chronic diseases, including both cardiovascular disease (CVD) and mild cognitive impairment (MCI). This study investigated the effects of food anthocyanins on microvascular function, 24-h ambulatory blood pressure (ABP) and inflammatory biomarkers in older adults with MCI.Methods and resultsThirty-one participants with MCI [19 female, 12 male, mean age 75.3 (SD 6.9) years and body mass index 26.1 (SD 3.3) kg/m²], participated in a randomized, controlled, double-blind clinical trial (Australian New Zealand Clinical Trials Registry: ACTRN12618001184268). Participants consumed 250 mL fruit juice daily for 8 weeks, allocated into three groups: a) high dose anthocyanins (201 mg); b) low dose anthocyanins (47 mg); c) control. Microvascular function (Laser Speckle Contrast Imaging combined with a post-occlusive reactive hyperaemia test), 24h ABP and serum inflammatory biomarkers were assessed before and after the nutritional intervention.ResultsParticipants in the high anthocyanins group had a reduction in serum tumor necrosis factor alpha (TNF-α) (P = 0.002) compared to controls and the low anthocyanins group (all P's > 0.05). Serum IL-6, IL-1β, c-reactive protein, and parameters of microvascular function and 24h ABP were not altered by any treatment.ConclusionA daily high dose of fruit-based anthocyanins for 8 weeks reduced concentrations of TNF-α in older adults with MCI. Anthocyanins did not alter other inflammatory biomarkers, microvascular function or blood pressure parameters. Further studies with a larger sample size and longer period of follow-up are required to elucidate whether this change in the immune response will alter CVD risk and progression of cognitive decline.     

液相色谱-质谱结合网络药理学及实验验证新疆樱桃李花色苷改善动脉粥样硬化的作用机制

目的:研究新疆樱桃李花色苷（XJP-ACY）抗动脉粥样硬化（AS）作用的活性成分及作用机制。方法：通过液相色谱-质谱（LC-MS）鉴定的新疆樱桃李花色苷主要成分,从XJP-ACY主要成分和AS角度,应用网络药理学方法,筛选其潜在活性成分潜在靶点,构建“成分-疾病-靶点”网络,并预测XJP-ACY抗AS作用信号通路。观察XJP-ACY对氧化型低密度脂蛋白（ox-LDL）诱导EA.hy926内皮细胞损伤模型作用,分析内皮细胞活力、测定抗氧化酶活力,细胞凋亡以及内皮细胞黏附等的影响。蛋白质印迹检测相关蛋白表达,初步验证网络药理学的预测结果。结果：从新疆樱桃李花色苷中鉴定成分4个,预测得到其潜在抗AS作用靶点21个;聚类分析得到2个基因簇和2个核心基因,核心基因为FGF2、ADRA2C。基因本体（GO）分析结果表明筛选得到的靶点主要涉及炎症反应、MAPK的正调控等生物过程。京都基因和基因组百科全书（KEGG）通路富集分析得到28条信号通路,涉及PI3K-AKT信号通路、糖尿病并发症中的AGE-RAGE信号通路、C型凝集素受体信号通路等相关通路。细胞实验表明,ox-LDL诱导EA.hy926建立内皮细胞损伤模型：100 μmol/L ox-LDL作用24 h,为适合本研究的最优条件。XJP-ACY可提高ox-LDL诱导的EA.hy926细胞存活率,增加一氧化氮（NO）水平和超氧化物歧化酶（SOD）活力,降低乳酸脱氢酶(LDH)、丙二醛(MDA)含量和内皮素-1(ET-1)表达水平,降低细胞活性氧（ROS）水平,抑制细胞间黏附分子-1（ICAM-1）的表达,减少炎症介质分泌;XJP-ACY可抑制ox-LDL诱导的EA.hy926细胞凋亡,其机制与其提高B淋巴细胞瘤-2（Bcl-2）蛋白表达相关。结论：本研究初步阐释XJP-ACY治疗AS多成分、多靶点、多途径的作用特点在于参与抑制炎症反应、促进细胞凋亡。     

Anthocyanin-rich extract from Hibiscus sabdariffa calyx counteracts UVC-caused impairments in rats

Abstract

Context: Ultraviolet radiation (UV) was reported to cause oxidative stress. Hibiscus sabdariffa L. (Malvaceae) calyx is commonly used in traditional Asian and African medicines and possesses strong antioxidant capacity due to its anthocyanin (ANTH) content.

Objective: This study researched the possible protective role of Hibiscus sabdariffa calyx extract (HSCE) in UVC exposure of rats.

Material and methods: Levels of serum enzymes, renal function tests, and some oxidant/antioxidant biomarkers of skin, lens, and retina tissues were monitored. Rats were exposed to UVC 4?h daily for 40?d and simultaneously received HSCE containing 2.5, 5, and 10?mg doses of ANTH in drinking water.

Results: Significant (p?<?0.05) increases in the levels of serum aminotransferases, lactate dehydrogenase, urea, creatinine, and uric acid were noted after UVC exposure. In skin, lens, and retina tissues, total oxidant status, oxidative stress index, lipid peroxidation, and protein oxidation escalated markedly (p?<?0.05) whereas total antioxidant status, reduced glutathione, and superoxide dismutase decreased dramatically (p?<?0.05) related to UVC. Co-administration of HSCE with each ANTH dose significantly (p?<?0.05) reversed aforementioned parameters (except total oxidant status) almost in all tissues. The LD₅₀ of HSCE in rats was determined to be above 5000?mg/kg.

Discussion and conclusion: Our data revealed that HSCE has a remarkable potential to counteract UVC-caused impairments, probably through its antioxidant and free radical-defusing effects. Therefore, HSCE could be useful against some cutaneous and ocular diseases in which UV and oxidative stress have a role in the etiopathogenesis.     

An anthocyanin-enriched extract from strawberries delays disease onset and extends survival in the hSOD1G93A mouse model of amyotrophic lateral sclerosis

Objective: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease resulting from the death of motor neurons in the brain, brain stem, and spinal cord. Several processes such as oxidative stress, neuroinflammation, and neuronal apoptosis, contribute to disease progression. Anthocyanins are flavonoid compounds derived from fruits and vegetables that possess antioxidant, anti-inflammatory, and anti-apoptotic abilities. Thus, these unique compounds may provide therapeutic benefit for the treatment of ALS.

Methods: We used the G93A mutant human SOD1 (hSOD1^G93A) mouse model of ALS to assess the effects of an anthocyanin-enriched extract from strawberries (SAE) on disease onset and progression. Mice were administered SAE orally beginning at 60 days of age until end-stage such that mice received 2?mg/kg/day of the extract's primary anthocyanin constituent. Clinical indices of disease were assessed until mice were sacrificed at end-stage. Histopathological indices of disease progression were also evaluated at 105 days of age.

Results: hSOD1^G93A mice supplemented with SAE experienced a marked (～17 day) delay in disease onset and a statistically significant (～11 day) extension in survival in comparison to their untreated mutant counterparts. Additionally, SAE-treated hSOD1^G93A mice displayed significantly preserved grip strength throughout disease progression. Histopathological analysis demonstrated that SAE supplementation significantly reduced astrogliosis in spinal cord, and preserved neuromuscular junctions (NMJs) in gastrocnemius muscle.

Discussion: These data are the first to demonstrate that anthocyanins have significant potential as therapeutic agents in a preclinical model of ALS due to their ability to reduce astrogliosis in spinal cord and preserve NMJ integrity and muscle function. Therefore, further study of these compounds is warranted in additional preclinical models of ALS and other neurodegenerative diseases.     

Effect of Hibiscus sabdariffa on obesity in MSG mice

The aim of the present investigation was determine whether a standardized Hibiscus sabdariffa calyces aqueous extract has an effect on body weight in an obese animal model induced by the administration of monosodium glutamate. Hibiscus sabdariffa aqueous extract, containing 33.64 mg of total anthocyanins per each 120 mg of extract, was orally administered (120 mg/kg/day) for 60 days to healthy and obese mice, and body weight gain, food and liquid intake, aspartate aminotransferase (AST), alanine aminotransferase (ALT), cholesterol, and triglycerides levels were measured. Hibiscus sabdariffa administration significantly reduced body weight gain in obese mice and increased liquid intake in healthy and obese mice. ALT levels were significantly increased on the 15th and 45th days in obese mice, but AST levels did not show significant changes. Mortality was not observed in the Hibiscus sabdariffa treated groups. Triglycerides and cholesterol levels showed non-significant reductions in animals treated with Hibiscus sabdariffa. Our data confirm the anti-obesity effect of Hibiscus sabdariffa reported by the Mexican population.     

Anthocyanins from purple sweet potato attenuate dimethylnitrosamine-induced liver injury in rats by inducing Nrf2-mediated antioxidant enzymes and reducing COX-2 and iNOS expression

Anthocyanins of the purple sweet potato exhibit antioxidant and hepatoprotective activities via a multitude of biochemical mechanisms. However, the signaling pathways involved in the actions of anthocyanin-induced antioxidant enzymes against chronic liver injury are not fully understood. We examined whether an anthocyanin fraction (AF) from purple sweet potato may prevent dimethylnitrosamine (DMN)-induced liver injury by inducing antioxidants via nuclear erythroid 2-related factor 2 (Nrf2) pathways and by reducing inflammation. Treatment with AF attenuated the DMN-induced increased serum alanine aminotransferase and aspartate aminotransferase activities. It also prevented the formation of hepatic malondialdehyde and the depletion of glutathione and maintained normal glutathione-S-transferase (GST) activity in the livers of DMN-intoxicated rats. Furthermore, AF increased the expression of Nrf2, NADPH:quinine oxidoreductase-1, heme oxygenase-1, and GSTα, which were reduced by DMN, and decreased the expression of cyclooxygenase-2 and inducible nitric oxide synthase. An increase in the nuclear translocation of nuclear factor kappa B (NF-κB) was observed in the DMN-induced liver injury group, but AF inhibited this translocation. Taken together, these results demonstrate that AF increases the expression of antioxidant enzymes and Nrf2 and at the same time decreases the expression of inflammatory mediators in DMN-induced liver injury. These data imply that AF induces antioxidant defense via the Nrf2 pathway and reduces inflammation via NF-κB inhibition.     

Color and chemical stability of spray-dried blueberry extract using mesquite gum as wall material

Blueberry is an important source of anthocyanins, which are highly colored substances recognized for their antioxidant activity. One of the drawbacks of using anthocyanins as food colorant is their low stability. The objective of this study was to evaluate the variations found in color and concentration of the compounds (which produce the color) on spray-dried powders, obtained from blueberry extracts with added mesquite gum. Ethanolic blueberry extracts were concentrated until reaching 35% of soluble solids. They were then spray-dried using mesquite gum as an encapsulating agent at 140 and 160 °C of air inlet temperature and 8.5, 9.1 and 9.6 mL/min of feeding rates. The lowest losses in the content of total phenolics, total anthocyanins, and color of the samples were found in samples dried at 140 °C and 9.1 mL/min. The microencapsulates that were stored for 4 weeks at 4 °C in the absence of light presented low degradation of phenolics (10%), anthocyanins (7%) and antioxidant activity (15%). Final color values were L = 39.87, C = 47.83 and H° = 28.59, with a total color difference ΔE = 5.     

Photoprotective Potential of Anthocyanins Isolated from Acanthopanax divaricatus Var. albeofructus Fruits against UV Irradiation in Human Dermal Fibroblast Cells

Ultraviolet (UV) A penetrates deeply into the skin and induces the generation of reactive oxygen species (ROS) causing damage to fibroblasts, which leads to aging of the skin. However, the body has developed an antioxidant defence system against the harmful effects of ROS. Enzymes such as superoxide dismutase (SOD) and catalase (CAT) play critical roles on the removal of excess ROS in living organisms. In this study, the antioxidant activities of anthocyanins (cyanidin 3-galactoside and cyanidin 3-lathyroside) from Acanthopanax divaricatus var. albeofructus (ADA) fruits were investigated by xylenol orange, thiobarbituric acid reactive substances (TBARS), and antioxidant enzyme assay. As a result, generation of H₂O₂ and lipid peroxide induced by UVA-irradiation in human dermal fibroblast (HDF-N) cells was reduced by treatment of anthocyanins. Also, augmented enzyme (SOD and CAT) activities were observed in UVA-irradiated cells when treated with anthocyanin. In conclusion, the results obtained show that anthocyanins from ADA fruits are potential candidates for the protection of fibroblast against the damaging effects of UVA irradiation. Furthermore, anthocyanin may be a good candidate for antioxidant agent development.