Ellagic acid inhibits gastric cancer cells by modulating oxidative stress and inducing apoptosis

Objective:To evaluate the anticancer effect of ellagic acid on gastric cancer cells.Methods:MTT assay was used to evaluate the effect of ellagic acid at different concentrations(0.5-100μg/mL)on gastric cancer AGS cells.RT-qPCR and Western blot analyses were applied to assess apoptosis(BCL-2,CASP-3,and BAX)and autophagy(LC3,ATG5,and BECN1)in AGS cells treated with ellagic acid.The expression of invasion-related markers including TP53,CDKN2A,and PTEN was determined.In addition,cell cycle markers including cyclin A,B,D,and E were measured by ELISA.Oxidative stress markers were evaluated using spectrophotometry.Results:Ellagic acid inhibited the proliferation of AGS cells in a concentration-and time-dependent manner.The expression of BCL-2 was significantly decreased(P<0.05)and CASP-3 and BAX were markedly increased(P<0.01)in AGS cells treated with ellagic acid.However,this compound induced no significant changes in the expression levels of LC3,ATG5,and BECN1(P>0.05).Moreover,the oxidative stress markers including SOD,TAC,and MDA were increased by ellagic acid(P<0.01).Conclusions:Ellagic acid can inhibit cell proliferation,induce apoptosis,and modulate oxidative stress in AGS cells.However,further in vivo and molecular studies are needed to verify its anticancer efficacy.

Ellagic Acid Enhances Antioxidant System Activity and Maintains the Quality of Strawberry Fruit during Storage

Ellagic acid(EA)is a natural antioxidant,widely present in a lot of forms’soft fruits,nuts,and other plant tissues,and helpful for promoting human health;however,its protective effect on postharvest fruit and improving the quality index of postharvest fruit have rarely been studied.In this experiment,the strawberries were soaked in 0,100,200,300,400,and 500 mg L^(−1) EA,respectively,and the influential EA on fruit quality and the antioxidant system of strawberries were studied.Compared with the control,EA treatment can reduce the browning degree and rotting rate of strawberry fruit during storage and augment the soluble solid content(SSC).EA treatment can also increase the content of related stuff and enzyme activity in antioxidant systems;the gene expression level of polyphenol oxidase(PPO)in strawberries treated with EA was always down-regulated,correspondingly,the expression of other antioxidant enzyme genes was enhanced.Among the strawberry fruits treated with EA of different concentrations,300 mg L^(−1) EA had the best effect in the process of strawberry preservation.The results suggested that the proper concentration of exogenous EA at 300 mg L−1 could maintain strawberries’quality and enhance the antioxidant system by improving the activities of antioxidative enzymes and the ascorbateglutathione(AsA-GSH)cycle during storage.

Ellagic acid ameliorates cisplatin-induced acute kidney injury by regulating inflammation and SIRT6/TNF-α signaling

De spite cisplatin has been widely used in the treatment of various cancers,the noteworthy nephrotoxicity greatly constrained its clinical value.For this reason,finding novel targeted therapies to attenuate the nephrotoxicity of cisplatin should be pretty significant.Our previous study found that histone deacetylase sirtuin 6(SIRT6)could be an ideal target for the treatment of cisplatin-induced acute kidney injury.In this study,we explored the protective effects of ellagic acid,a natural polyphenol compound that activates SIRT6,on cisplatin-induced nephrotoxicity.Pre-treatment of ellagic acid attenuated cytotoxicity of cisplatin in primary renal cells and TCMK-1 cells.Moreover,ellagic acid ameliorated renal dysfunction,apoptosis and fibrosis induced by cisplatin in mice.Furthermore,ellagic acid reduced nephrotoxicity-associated inflammatory factor interleukin(IL)-1βand IL-6 expression both in vitro and in vivo.Mechanistically,ellagic acid reversed cisplatin-reduced SIRT6 expression and diminished cisplatin-induced tumor necrosis factor(TNF)-αexpression.And SIRT6 knockdown abrogated the protective effects of ellagic acid on cisplatin-induced cell apoptosis,indicating the renal-protective effects of ellagic acid are mainly dependent on ellagic acid-mediated SIRT6 activation.Our results provide preclinical rationale for using ellagic acid as a feasible and promising agent to ameliorate cisplatin-induced acute kidney injury,and support ellagic acid as a potential adjunctive therapy for future cancer treatment.

Influence of ellagic acid on prostate cancer cell proliferation:A caspase-dependent pathway

Objective:To evaluate the effect of allagic acid treatment on the cell viability of human prostate cancer cells.Methods:Ellagic acid(10-100 mol/L) treatment(48 h) of human prostate carcinoma PC3 cells was found to result in a dose-dependent inhibition of cell growth and apoptosis of PC3 cells as assessed by MTT assay,western blotting.flow cytometry and confocal microscopy.Results:We observed that ellagic acid treatment of PC3 cells resulted in a dose dependent inhibition of cell growth/cell viability.This ellagic acid caused cell growth inhibition was found to be accompanied by induction of apoptosis,as assessed by the cleavage of poly (ADP-ribose) polymerase(PARP) and morphological changes.Further,induction of apoptosis accompanied a decrease in the levels of antiapoptotic protein Bcl-2 and increase in proapoptotic protein Bax.thus shifting the Bax:Bcl-2 ratio in favor of apoptosis.Ellagic acid treatment of PC3 cells was also found to result in significant activation of caspases,as shown by the dose dependent decrease in the protein expression of procaspase-3,-6.-8 and -9.This ellagic acid-mediated induction of apoptosis was significantly(80%-90%) inhibited by the caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethylketone(Z-VAD-FMK).Thus these data suggested an essential role of caspases in ellagic acid-mediated apoptosis of PC3 cells.Conclusions:It is tempting to suggest that consumption of tropical pigmented fruits and vegetables could be an effective strategy to combat prostate cancer.

In vitro and in vivo antioxidant activities of three major polyphenolic compounds in pomegranate peel: Ellagic acid, punicalin, and punicalagin

Pomegranates is abundant in polyphenols and is well-known for its antioxidant activity. Punicalagin （PG） is a major poly- phenolic compound in the pomegranate peel. In certain conditions, PG can be hydrolyzed to punicallin （PL） and ellagic acid （EA）, and PL can be further hydrolyzed to EA. PG, PL, and EA all play important roles in the antioxidant activity of pomegranate peels. This study was conducted to compare the in vitro antioxidant activity and in vivo anti-oxidative stress effects of PG, PL, and EA. For the in vitro test, 2,2-diphenyl-l-picrylhydrazyl radical （DPPH.） and superoxide anion （O2~） scavenging capacities, ferric-reducing antioxidant power （FRAP）, and lipid peroxidation （LPO） inhibition capacities of PG, PL, and EA were tested. For the in vivo test, oxidatively stressed mice, which were induced by oxidized fish oil, were administrated PG, PL or EA （10 mg kg-1 d-1） for 21 days. The results showed that the in vitro antioxidant activity trends were EA〉PG〉PL〉Trolox in scavenging DPPH., PG〉PL〉EA=Trolox in scavenging O2~, EA〉PG=PL〉Trolox in FRAP, and Trolox〉PG〉EA〉PL in LPO inhibition. In the in vivo test, the EAt＇reatment increased the average daily weight gain and total antioxidant capacity （T-AOC） in the plasma （P〈0.05）, liver （P〈0.05）, and intestine （P〈0.05） in oxidatively stressed mice. It increased the superoxide dismutase （SOD） activity in the liver （P〈0.05） and intestine （P〈0.05）. It increased the glutathi- one peroxidase （GSH-Px） activity in the intestine （P〈0.05） and the intestinal villus height to crypt depth ratio （P〈0.05）. EA treatment decreased the malondialdehyde （MDA） content in the plasma （P〈0.05）, liver （P〈0.05）, and intestine （P〈0.05） and the mRNA expressions of the pro-inflammatory factors, TNF-a （P〈0.05）, IFN-y （P〈0.05） and IL-6 （P〈0.05）. PL increased the SOD （P〈0.05） and GSH-Px activities （P〈0.05） in the intestine and decreased the MDA content （P〈0.05） and the mRNA expressions of TNF-a （P〈0.05） and IL-6 （P〈0.05） in the intestine. PG increased the SOD activity （P〈0.05） and GSH-Px activity （P〈0.05） in the intestine and decreased the MDA content in the intestine （P〈0.05） and IL-6 mRNA expression in the intestine （P〈0.05）. In summary, EA, PL, and PG all had powerful in vitro antioxidant capacities, and they had different antioxidant advantages in acting against different types of radicals; EA was more effective than PL and PG in protecting against oxidative injury in vivo, especially for intestinal injury. These findings suggest that multiple polyphenol compounds in pomegranate peel may exert superior antioxidant activity than single purified polyphenols; when using pomegranate peels as health-promoting additive in animal feed, raising EA content by methods of hydrolysis or fermentation in advance could achieve better effects.

Ellagic acid induces apoptosis through inhibition of nuclear factor κB in pancreatic cancer cells

AIM:To determine the effect of ellagic acid on apop-tosis and proliferation in pancreatic cancer cells and to determine the mechanism of the pro-survival effects of ellagic acid. METHODS:The effect of ellagic acid on apoptosis was assessed by measuring Phosphatidylserine externalization,caspase activity,mitochondrial membrane potential and DNA fragmentation;and proliferation by measuring DNA thymidine incorporation. Mitochondrial membrane potential was measured in permeabilized cells,and in isolated mitochondria. Nuclear factor kB(NF-kB) activity was measured by electromobility shift assay(EMSA) . RESULTS:We show that ellagic acid,a polyphenolic compound in fruits and berries,at concentrations 10 to 50 mmol/L stimulates apoptosis in human pancreatic adenocarcinoma cells. Further,ellagic acid decreases proliferation by up to 20-fold at 50 mmol/L. Ellagic acid stimulates the mitochondrial pathway of apoptosis associated with mitochondrial depolarization,cytochrome C release,and the downstream caspaseactivation. Ellagic acid does not directly affect mitochondria. Ellagic acid dose-dependently decreased NF-kB binding activity. Furthermore,inhibition of NF-kB activity using IkB wild type plasmid prevented the effect of ellagic acid on apoptosis. CONCLUSION:Our data indicate that ellagic acid stimulates apoptosis through inhibition of the prosu-rvival transcription factor NF-kB.

Aceclofenac-induced hepatotoxicity:An ameliorative effect of Terminalia bellirica fruit and ellagic acid

BACKGROUND Aceclofenac(ACF),a widely used nonsteroidal anti-inflammatory drug,has been associated with a number of severe cases of clinical hepatotoxicity.Terminalia bellirica,an evergreen tree,is known to have several ethnomedicinal uses including antioxidant and hepatoprotective effects.Hence T.bellirica fruit extracts and its phytoconstituent ellagic acid(EA)are expected to provide protection against oxidative stress and liver damage produced by long-term use of ACF.AIM To evaluate the antioxidant and hepatoprotective activities of T.bellirica fruit extracts and EA against ACF-induced toxicity in albino Wistar rats.METHODS The in vitro antioxidant activities of T.bellirica fruit ethyl acetate and aqueous extracts were measured by metal ion chelation and nitric oxide radical scavenging assays.The in vivo antioxidant and hepatoprotective effects of T.bellirica extracts(200 mg/kg)and EA(40 mg/kg)in ACF-induced hepatotoxic rats were assessed in serum and liver tissue after oral administration for 21 d.Silymarin(40 mg/kg)was used as a standard control.Oxidative stress markers in the blood(ferric reducing ability of plasma and lipid peroxidation inhibition)and liver tissues(superoxide dismutase,catalase and malondialdehyde)were analyzed using standard protocols.Liver function markers such as alkaline phosphatase,glutamic pyruvic transaminase,glutamic oxaloacetic transaminase,lactate dehydrogenase,γ-glutamyl transferase,creatinine,total protein,and uric acid were evaluated in rat serum.RESULTS The T.bellirica fruit ethyl acetate extract exhibited superior metal ion chelating and nitric oxide radical scavenging abilities during in vitro antioxidant assays as compared to aqueous extracts.Oral administration of ACF in rats(15 mg/kg)for 21 d produced oxidative stress and adversely affected liver function suggesting liver injury.Treatment with extracts(ethyl acetate and aqueous),EA and silymarin accounted for a significant reduction in the adverse effects of ACF on oxidative stress and liver function markers in serum and hepatic tissue in rats.Histopathological evaluation of the liver indicated that the extracts and EA significantly decreased the degree of liver damage.The in vivo efficacy of EA was higher than T.bellirica fruit extracts.Of these extracts,ethyl acetate extract revealed comparatively better antioxidant and hepatoprotective activity.CONCLUSION Ellagic acid and T.bellirica fruit extracts exhibited considerable hepatoprotective and antioxidant activities in long-term ACF-treated rats.

Dietary ellagic acid ameliorated Clostridium perfringens-induced subclinical necrotic enteritis in broilers via regulating inflammation and cecal microbiota

Background: Subclinical necrotic enteritis(SNE), a common intestinal disease of broiler caused by Clostridium perfringens, could reduce production performance of broilers by chronic intestinal damage and poor absorption of nutrients. Ellagic acid(EA) has been reported to present antioxidant and anti-inflammatory properties on human and animals in many aspects. This study was conducted to evaluate the effect and mechanism of EA in relieving SNE in broilers induced by C. perfringens.Results: C. perfringens challenge decreased body weight(BW), average daily gain(ADG), jejunal villi height/crypt depth(V/C) ratio, the activity of catalase(CAT) and the mRNA expression of zonula occludens 1(ZO-1) in jejunal mucosa of broilers. While feed conversion ratios(FCR), jejunal crypt depth(CD), the activities of myeloperoxidase(MPO) and diamine oxidase(DAO), as well as the concentrations of interleukin 6(IL-6), C-reactive protein(CRP) and procalcitonin(PCT) in serum, the activities of inducible nitric oxide synthase(iNOS) and lysozyme(LZM), the concentration of malondialdehyde(MDA), and the mRNA expressions of claudin-2, TNF-α, IL-1β, TLR-4, TLR-2, NF-κB,JAK3, STAT6 and iNOS in jejunal mucosa of broilers were increased by C. perfringens challenge. Dietary EA supplement relieved these adverse effects, and heightened jejunal villi height(VH), the concentration of D-xylose in plasma, activity of superoxide dismutase(SOD), and the mRNA expression of occludin in jejunal mucosa of broilers.The alpha diversity of cecal microbiota indicated that dietary EA supplement increased observed species and Shannon index. C. perfringens challenge increased the relative abundance of Firmicutes and decreased the relative abundance of Desulfobacterota in cecal microbiota. EA increased the relative abundance of Firmicutes in cecal microbiota. LEfSe analysis showed that C. perfringens challenge triggered the imbalance of cecal microbiota in broilers, dietary EA supplementation led to a small beneficial effect on microbiota, while the simultaneous effect of them seemed to stimulate the immune function of broilers by improving the microbiota balance.Conclusions: Dietary EA ameliorated C. perfringens-induced SNE in broilers via regulating jejunal inflammation signaling pathways TLR/NF-κB and JAK3/STAT6, relieving jejunal oxidative stress and balancing cecal microbiota to inhibit intestinal barrier damage, prevent systemic inflammatory response and improve nutrient absorption capacity,finally protect and enhance growth performance of broilers.

Comparison of the impact of epigallocatechin gallate and ellagic acid in an experimental cataract model induced by sodium selenite

AIM：To compare the potential protective effects of epigallocatechin gallate（EGCG） and ellagic acid（EA） in an experimental cataract model.●METHODS：Twenty-eight Spraque-Dawley rat pups were assigned into four groups.All the rats,except for those in the control group,were injected subcutaneously sodium selenite to induce experimental cataract on the postpartum ninth day,and between 10 th and 14 th days.Rats in the sham,EGCG,and EA groups were intraperitoneally administered 50 mg/（kg·d） saline solution,50 mg/（kg·d） EGCG and 200 mg/（kg·d） EA,respectively.The reduced glutathione（GSH） and malondialdehyde（MDA） levels,total antioxidant status（TAS） and total oxidant status（TOS） in lens supernatants were measured.RESULTS：The mean cataract gradings in EGCG and EA groups were found to be significantly lower than that in sham group（P〈0.001）.The mean GSH levels and TASs in EGCG and EA groups were significantly higher than that in sham group while mean MDA levels and TOSs in EGCG and EA groups were significantly lower than that in the sham group（P〈0.001）.CONCLUSION：EGCG and EA have protective effects on cataract development via the inhibition of oxidative stress.

Research progress on the anticarcinogenic actions and mechanisms of ellagic acid

Cancer is a leading cause of death worldwide. Cancer treatments by chemotherapeutic agents, surgery, and radiation have not been highly effective in reducing the incidence of cancers and increasing the survival rate of cancer patients. In recent years, plant-derived compounds have attracted considerable attention as alternative cancer remedies for enhancing cancer prevention and treatment because of their low toxicities, low costs, and low side effects. Ellagic acid(EA) is a natural phenolic constituent. Recent in vitro and in vivo experiments have revealed that EA elicits anticarcinogenic effects by inhibiting tumor cell proliferation, inducing apoptosis, breaking DNA binding to carcinogens, blocking virus infection, and disturbing inflammation, angiogenesis, and drug-resistance processes required for tumor growth and metastasis. This review enumerates the anticarcinogenic actions and mechanisms of EA. It also discusses future directions on the applications of EA.

Influence of chemical penetration enhancers on skin permeability of ellagic acid-loaded niosomes

This study aimed to develop niosomes of ellagic acid(EA),a potent antioxidant phytochemical substance,for dermal delivery and to investigate the influence of chemical penetration enhancers on the physicochemical properties of EA-loaded niosomes.The EA niosomes were prepared by reverse phase evaporation method using Span 60,Tween 60 and cholesterol as vesicle forming agents and Solulan C24 as a steric stabilizer.Polyethylene glycol 400(PEG)was used as a solubilizer while dimethylsulfoxide(DMSO)or Nmethyl-2-pyrrolidone(NMP)was used as a skin penetration enhancer.It was found that the mean particle sizes of EA-loaded niosomes were in the range of 312e402 nm with PI values of lower than 0.4.The niosomes were determined to be spherical multilamellar vesicles as observed by transmission electron microscope and optical microscopy.All niosomes were stable after 4 months storage at 4
C.In vitro skin permeation through human epidermis revealed that the skin enhancers affected the penetration of EA from the niosomes at 24 h.The DMSO niosomes showed the highest EA amount in epidermis;whereas the NMP niosomes had the highest EA amount in the acceptor medium.Concomitantly,the skin distribution by confocal laser scanning microscopy showed the high fluorescence intensity of the DMSO niosomes and NMP niosomes at a penetration depth of between 30e90 mm(the epidermis layer)and 90e120 mm(the dermis layer)under the skin,respectively.From the results,it can be concluded that the DMSO niosomes are suitable for epidermis delivery of EA while the NMP niosomes can be used for dermis delivery of EA.

Ellagic Acid-induced Hypercoagulable State in Animals:a Potentially Useful Animal Hypercoagulable Model for Evaluation of Anticoagulants

Objective To establish and evaluate a hypercoagulable animal model for the assessment of anticoagulants. Methods Forty mice, thirty-two rats, and twenty-four rabbits were randomly and equally divided into control group (saline) and three ellagic acid (EA)-treated groups (low, middle, and high doses). In the mice, bleeding time (BT) was estimated with tail transaction, and clotting time (CT) with template method. Prothrombin time (PT) and the activated partial thromboplastin time (APTT) in rats and rabbits were measured by means of Quick's one-stage assay and modified APTT assay respectively. In addition, thrombin activity was estimated in rats with PT assay using a hemagglutination analyzer. The circulating platelet aggregates were de- tected in rabbits through platelet counting and presented as the circulating platelet aggregate ratio (CPAR). Results EA shortened BT and CT in mice, PT and APTT in rats, and increased thrombin activity and CPAR, all in a dose-dependent manner. EA also brought reduction of PT and APTT in rabbits in dose- and time-dependent manners. Conclusion EA could induce hypercoagulable state through activating coagulation system and platelets in mice, rats, and rabbits.

Ellagic acid supports neurons by regulating astroglia nuclear factor erythroid 2-related factor 2

OBJECTIVE Astroglia support neurons by providing substrates for neuronal metabolism, glutamate clearance and anti-oxidant protection. Nuclear factor erythroid 2-related factor 2(Nrf2) is the main switch of intracellular antioxidant defense system. Also, Nrf2 signaling is recognized to activate the neurotrophic pathway to replace/protect damaged organelles. Ellagic acid(EA), an excretion component of fruits and nuts, displays anti-oxidant, cardioprotective and antiinflammatory activities. However, few studies have been focused on the neurotrophic properties of EA. Our study investigated whether EA could enhance astroglia neurotrophic effects to support neurons and the underlying mechanisms as well. METHODS Primary neuron-enriched cultures, primary astroglia-enriched cultures and primary neuron-astroglia co-cultures were applied to detect whether pharmacological regulation of astroglia function by EA could be utilized to overcome neuronal death. RESULTS This study indicated that EA promoted neuronal survival. Furtherly, astroglia Nrf2 participate in EA-elicited neuronal survival with the following scenarios. First, EA induced astroglia proliferation, neurotrophic factors release and Nrf2 activation. Second, astroglia-targeted Nrf2 si RNA inhibited EA-mediated astrogliosis,neurotrophic factors excretion and neuronal survival. CONCLUSION EA mediated astroglia Nrf2 activation to enhanced neurotrophic effects on neurons, and these findings might provide new strategies for neurotrophic factor-based treatment of neurodegenerative disease.

Development and validation of a RP-HPLC method for the simultaneous determination of Embelin,Rottlerin and Ellagic acid in Vidangadi churna

Vidangadi churna is a popular Ayurvedic formulation described in the chapter Krimicikitsa of the Ayurvedic literature Cakradatta for the treatment of Krimiroga. The preparation is a composite mixture of the fine powder of fruits of Vidang （Embelia ribs）, glandular trichomes of the fruits of Kamala （Mallotus philippensis）, mature fruits of Harde （Terminalia chehula）, Saindhava and Yavakshara. The use of reversed phase C18 column eluted with gradient mobile phase of acetonitrile and water enabled the efficient separation of the chemical markers in 22 rain. Validation of the method was performed in order to demonstrate its selectivity, accuracy, precision, repeatability and recovery. All calibration curves showed good linear correlation coefficients （r2〉0.995） within the tested ranges. Three markers in Vidangadi churna were quantitied with respect to Embelin （0.647%, w/w）, Rottlerin （4.419%, w/w）, and Ellagic acid （0.459%, w/w）. lntraand inter-day RSDs of retention times and peak areas were less than 3.12%. The recoveries were between 99.66% and 102.33%. In conclusion, a method has been developed for the simultaneous quantification of three markers in Vidangadi churna. The RP-HPLC method was simple, precise and accurate and can be used for the quality control of the raw materials as well as formulations.

漆酶催化没食子酸染色阳离子改性棉织物的性能

利用漆酶催化没食子酸,并对聚二甲基二烯丙基氯化铵改性棉织物进行染色。结果表明:漆酶可催化没食子酸聚合,采用一浴一步法和一浴二步法工艺对改性棉织物染色,二者的染色特征值相接近,染色改性棉织物的UPF≥40,亲水性能明显提升,力学性能也有所改善。

基于PI3K/AKT/GSK-3β信号通路探讨EA改善APP/PS1双转基因小鼠认知功能障碍的内在机制

目的探讨鞣花酸(ellagicacid,EA)对APP/PS1双转基因小鼠认知功能的影响,并基于磷脂酰肌醇3-激酶/蛋白激酶B/糖原合成酶激酶-3(PI3K/AKT/GSK-3β)信号通路探讨鞣花酸对双转基因小鼠海马氧化应激水平的调节机制。方法将32只SPF级6月龄APP/PS1双转基因小鼠随机分为4组,即APP/PS1组、APP/PS1+EA组、APP/PS1+LY294002组、APP/PS1+EA+LY294002组,每组8只,另外选取8只SPF级C57BL/6J野生型小鼠(Wildtype)作为空白对照组,即WT组。APP/PS1+EA组给予50mg·kg^(-1)·d^(-1)灌胃EA;APP/PS1+LY294002组予以1.5mg·kg^(-1)·d^(-1)腹腔注射PI3K抑制剂LY294002;APP/PS1+EA+LY294002组予以50mg·kg^(-1)·d^(-1)灌胃EA,同时按1.5mg·kg^(-1)·d^(-1)腹腔注射LY294002;WT组和APP/PS1组于相同时间点灌胃等体积10%二甲基亚砜(DMSO)。每日给药1次,连续给药60天。Morris水迷宫检测小鼠学习和记忆能力,免疫组化、蛋白免疫印迹法检测PI3K、AKT、GSK-3β相关蛋白的表达,透射电镜观察小鼠海马组织超微结构变化。结果与WT组相比,其他四组的逃避潜伏期均增长(P<0.05),穿越平台次数明显减少(P<0.01);APP/PS1组、APP/PS1+LY294002组和APP/PS1+EA+LY294002组中的PI3K、AKT蛋白表达量显著降低(P<0.01),GSK-3β表达量显著升高(P<0.01);APP/PS1+EA组的PI3K表达量降低(P<0.05),AKT表达量显著降低(P<0.01),GSK-3β表达量升高(P<0.05);与WT组相比,APP/PS1组海马神经元细胞数目较少,线粒体结构破坏,大部分线粒体出现肿胀,线粒体的内膜和外模不完整,部分线粒体嵴消失,微管、微丝缠结,排列紊乱,而APP/PS1+EA组神经元细胞数较APP/PS1组增多,线粒体结构较清晰,可见清楚的线粒体嵴,线粒体轻度水肿。微管、微丝排列较整齐有序。结论鞣花酸改善AD模型小鼠的学习和记忆能力、减少海马神经元细胞损伤和凋亡,其作用机制可能是通过调节PI3K、AKT、GSK-3β等相关蛋白降低AD模型小鼠海马氧化应激水平。

鞣花酸抑制酪氨酸酶的动力学、荧光光谱分析及分子对接

以蘑菇酪氨酸酶为靶点,采用抑制动力学、荧光光谱分析结合分子对接模拟技术,系统研究鞣花酸(ellagic acid,EA)对酪氨酸酶的抑制作用及机理。体外研究与动力学结果表明,EA以可逆的混合型抑制方式显著抑制酪氨酸酶活性(IC_(50)=0.05mg/mL),其结合常数K_(I)<K_(IS),表明EA与游离酶的结合比与酶-底物复合物的结合更紧密。荧光光谱猝灭分析表明,EA与酪氨酸酶存在静态猝灭作用,两者通过自发的吸热过程结合生成复合物,主要作用力为疏水作用力,只有1个或1类结合位点。同步和三维荧光光谱分析表明,EA使酪氨酸酶的微环境极性增大,疏水能力减弱,酪氨酸酶的Trp残基更靠近结合位点。分子对接模拟分析进一步印证上述实验结果,形象地表明EA对酪氨酸酶为混合型抑制,EA主要通过疏水作用力和氢键与游离酶或酶-底物复合物进行结合,最终导致酶活性降低。本研究对EA在食品工业中作为保鲜剂的各种应用具有一定参考意义。

没食子酸稳定‘户太八号’桃红葡萄酒香气与色泽

[目的]针对‘户太八号’桃红葡萄酒贮藏期色泽和香气损失的问题,研究酿造过程中没食子酸处理对色泽与香气的提升效果,以优化桃红葡萄酒的护色增香工艺。[方法]以‘户太八号’葡萄为试材,酿酒过程中分别在发酵前(Pr)、中(M)、后(Po)3个时期添加200和300 mg·L^(-1)的没食子酸,发酵结束后贮藏6个月,然后利用HS-SPME-GC-MS对酒样香气物质进行分析,通过CIELab颜色空间参数(L^(*)、a^(*)、b^(*)、C^(*)ab、Hab、ΔE^(*)ab)和紫外分光光度计进行色泽指标的测定,再结合感官品评分析不同处理对供试酒样香气特征的影响。[结果]在发酵后添加没食子酸处理的发酵香气物质含量显著高于对照组,增加约16%,但两种添加浓度处理造成的差异不显著。发酵前添加没食子酸处理对供试酒样香气的保留起到积极作用,相比于对照组增加约65%-73%,而发酵中添加没食子酸对葡萄酒香气物质的稳定作用较小。感官品评结果显示,对于整体香气的影响,发酵后添加没食子酸有最优的葡萄酒香气改善效果,发酵前处理的添加效果优于发酵中处理。偏最小二乘回归(PLSR)模型揭示萜烯、脂肪酸、高级醇、乙酸酯和脂肪酸乙酯(回归系数>0.1)是‘户太八号’桃红葡萄酒花香和柑橘香气(R2c>0.80且R2v>0.70)的重要贡献成分,其中脂肪酸乙酯和乙酸酯这两类果香酯类物质对其贡献更突出。色泽分析结果显示,发酵前添加没食子酸处理具有显著的护色作用,且200 mg·L^(-1)处理(Pr1)效果优于300mg·L^(-1)(Pr2),Pr1处理组酒样L^(*)值比对照降低0.58%,a^(*)值提高45.38%。另外,颜色表征结果显示,发酵前添加没食子酸处理增强了‘户太八号’桃红葡萄酒的紫红色调,且200 mg·L^(-1)处理效果优于300 mg·L^(-1)。[结论]发酵前添加没食子酸处理对‘户太八号’桃红葡萄酒色泽稳定具有显著作用,且添加量为200 mg·L^(-1)的效果更好,而发酵后没食子酸添加处理对葡萄酒香气稳定性具有显著作用。

复配转锈液中各组分对锈转化行为的影响

[目的]针对锈蚀的固定钢铁结构无法进行返厂除锈涂装的现状,绿色转锈液的开发对锈蚀结构件的腐蚀防护及延寿具有重要意义。[方法]通过开路电位、电化学阻抗谱、极化曲线等测试方法研究了带锈Q235钢在质量分数为3%的酸性转锈液中的电化学行为,采用扫描电镜、能谱仪和红外光谱仪考察了不同转锈液对锈层的反应状态和转化膜的组成,根据接触角分析了有机树脂在转锈表面的润湿情况。[结果]在由质量分数均为1%的植酸、单宁酸和没食子酸组成的复配体系中,酸性较强的植酸能够快速溶解锈层,产生大量铁离子,铁离子再与植酸、单宁酸和没食子酸发生螯合,形成致密的锈转化膜。[结论]复配酸转锈液能够获得比单一酸转锈液性能更加良好的转化膜,与有机树脂能够较好地相容。

没食子酸改性酶解-糖基化胶原蛋白-壳聚糖复合膜的制备及表征

为改善猪皮胶原蛋白(PC)可食性膜的机械性能、耐热性和疏水性较差等问题,本研究将猪皮胶原蛋白进行酶解-糖基化改性处理制备出糖基化胶原蛋白(HG-PC)可食性膜,然后通过没食子酸(GA)对糖基化胶原蛋白膜改性制备复合膜(GA-HG-PC膜)。对比分析PC膜、HG-PC膜和GA-HG-PC膜的机械性能、持水性、水蒸气透过率、颜色、热稳定性及抗氧化性,并通过傅里叶变换红外光谱和扫描电子显微镜表征薄膜结构、纳米粒度及Zeta电位仪测定膜液的粒径和电位。结果表明,GA-HG-PC膜的抗拉强度、断裂伸长率分别较PC膜和HG-PC膜提高121.57%、19.00个百分点和91.52%、14.16个百分点;其水蒸气透过率较PC膜和HG-PC膜下降,耐水性显著改善(P<0.05);GA-HG-PC膜的颜色比PC膜和HG-PC膜更深,透明度下降,热稳定性提高;此外,GA-HG-PC膜的内部结构更加稳定,氢键作用力较强,成膜溶液稳定性提高,其1,1-二苯基-2-苦基肼(DPPH)自由基清除率分别较HG-PC膜和PC膜增加10.49和18.26个百分点(P<0.05)。本研究可为改善PC膜的功能特性提供新思路,拓展其在果蔬、水产品、肉制品及烘焙食品等领域的应用,对开发新型可食性蛋白膜具有一定意义。