Grape Seed Proanthocyanidin Extract Alleviates Arsenic-induced Oxidative Reproductive Toxicity in Male Mice

Objective To determine the ability of grape seed proanthocyanidin extract （GSPE） in alleviating arsenic-induced reproductive toxicity. Methods Sixty male Kunming mice received the following treatments by gavage： normal saline solution （control）; arsenic trioxide （ATO; 4 mg/kg）; GSPE （400 mg/kg）; ATO＋GSPE （100 mg/kg）; ATO＋GSPE （200 mg/kg） and ATO＋GSPE （400 mg/kg）. Thereafter, the mice were sacrificed and weighed, and the testis was examined for pathological changes. Nuclear factor （erythroid-derived 2）-like 2 （Nrf2）, heme oxygenase 1 （HO1）, glutathione S-transferase （GST）, NAD（P）H dehydrogenase, and quinone 1 [NQO1） expression in the testis was detected by real-time PCR. Superoxide dismutase （SOD）, glutathione （GSH）, total antioxidative capability （T-AOC）, malondialdehyde （MDA）, 8-hydroxydeoxyguanosine （8-OHdG）, and reproductive indexes were analyzed. Results ATO-treated mice showed a significantly decreased sperm count and testis somatic index and activity levels of SOD, GSH, and T-AOC than control group. Compared to the ATO-treated group, ATO ＋GSPE group showed recovery of the measured parameters. Mice treated with ATO＋high-dose GSPE showed the highest level of mRNA expression of Nrf2, HO, NO.O1, and GST. Conclusion GSPE alleviates oxidative stress damage in mouse testis by activating Nrf2 signaling, thus counteracting arsenic-induced reproductive toxicity.

Inhibitory Effects of Grape Seed Proanthocyanidin Extract on Selenite-induced Cataract Formation and Possible Mechanism

This study investigated the inhibitory effect of grape seed proanthocyanidin extract(GSPE) on selenite-induced cataract formation in rats and the possible mechanism.Eighty 8-day-old Sprague-Dawley rats were divided randomly into 5 groups:control group,model group,three GSPE groups(low dose,medium dose and high dose).Control group received subcutaneous injection of physiological saline.Model group was given subcutaneous injection of sodium selenite(20 μmol/kg body weight) on the postpartum day 10,and once every other day for consecutive three times thereafter.GSPE treated groups were respectively administered GSPE at doses of 50,100,and 200 mg/kg body weight intragastrically 2 days prior to the selenite injection(that was,on the postpartum day 8),and once daily for fourteen consecutive days thereafter.The opacity of lenses was observed,graded and photographed under the slit lamp microscopy and the maximal diameter of the nuclear cataract plaques was measured.The lenses were analyzed for superoxide dismutase(SOD),catalase(CAT),glutathione peroxidase(GSH-PX),malondialdehyde(MDA),calcium(Ca 2+),nitric oxide(NO) and anti-hydroxyl radical ability(anti-OH).The histomorphology of lenses was observed with HE staining under a light microscope.The levels of calpainⅡ,and iNOS protein and mRNA expression in lenses were detected by using immunohistochemistry and real-time quantitative RT-PCR.The results showed subcutaneous injection of sodium selenite led to severe nuclear cataract in model group,and the achievement ratio of model group was 100%.As compared with model group,the degree of lenses opacity and the maximal diameter of nuclear cataract plaques were significantly reduced in GSPE-treated groups.Moreover,we observed selenite treatment caused a significant decrease in the activities of antioxidative enzymes(SOD,CAT,GSH-PX) and anti-OH ability,accompanied by a significant increase in the levels of MDA,NO,Ca 2+ as well as iNOS,and calpainⅡ protein and mRNA expression.Administration of GSPE could dose-dependently preserve the activities of these antioxidative enzymes and anti-OH ability,accompanied by a significant reduction in the levels of MDA,NO,Ca 2+ as well as iNOS,and calpainⅡ protein and mRNA expression.These results suggested that GSPE markedly prevented selenite-induced cataract formation probably by suppressing the generation of lipid peroxidation and free radicals as well as the activation of iNOS,and calpainⅡ in the lenses.

Anti-proteolytic capacity and bonding durability of proanthocyanidin-biomodified demineralized dentin matrix

Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin（PA） for a clinically practical duration improves the mechanical properties of the dentin matrix and the immediate resin–dentin bond strength. The present study sought to evaluate the ability of PA biomodification to reduce collagenase-induced biodegradation of demineralized dentin matrix and dentin/adhesive interfaces in a clinically relevant manner. The effects of collagenolytic and gelatinolytic activity on PA-biomodified demineralized dentin matrix were analysed by hydroxyproline assay and gelatin zymography. Then, resin-/dentin-bonded specimens were prepared and challenged with bacterial collagenases. Dentin treated with 2% chlorhexidine and untreated dentin were used as a positive and negative control, respectively. Collagen biodegradation, the microtensile bond strengths of bonded specimens and the micromorphologies of the fractured interfaces were assessed. The results revealed that both collagenolytic and gelatinolytic activity on demineralized dentin were notably inhibited in the PA-biomodified groups, irrespective of PA concentration and biomodification duration. When challenged with exogenous collagenases, PA-biomodified bonded specimens exhibited significantly less biodegradation and maintained higher bond strengths than the untreated control. These results suggest that PA biomodification was effective at inhibiting proteolytic activity on demineralized dentin matrix and at stabilizing the adhesive/dentin interface against enzymatic degradation, is a new concept that has the potential to improve bonding durability.

Quantitative Mitochondrial Proteomics Study on Protective Mechanism of Grape Seed Proanthocyanidin Extracts Against Ischemia/Reperfusion Heart Injury in Rat

Cardiac ischemia/reperfusion（I/R） injury is a critical condition,often associated with high morbidity and mortality.The cardioprotective effect of grape seed proanthocyanidin extracts（GSPE） against oxidant injury during I/R has been described in previous studies.However,the underlying molecular mechanisms have not been fully elucidated.This study investigated the effect of GSPE on reperfusion arrhythmias especially ventricular tachycardia（VT） and ventricular fibrillation（VF）,the lactic acid accumulation and the ultrastructure of ischemic cardiomyocytes as well as the global changes of mitochondria proteins in in vivo rat heart model against I/R injury.GSPE significantly reduced the incidence of VF and VT,lessened the lactic acid accumulation and attenuated the ultrastructure damage.Twenty differential proteins related to cardiac protection were revealed by isobaric tag for relative and absolute quantitation（iTRAQ） profiling.These proteins were mainly involved in energy metabolism.Besides,monoamine oxidase A（MAOA） was also identified.The differential expression of several proteins was validated by Western blot.Our study offered important information on the mechanism of GSPE treatment in ischemic heart disease.

Grape Seed Proanthocyanidin Extract Ameliorates Streptozotocin-induced Cognitive and Synaptic Plasticity Deficits by Inhibiting Oxidative Stress and Preserving AKT and ERK Activities

Progressive memory loss and cognitive impairment are the main clinical manifestations of Alzheimer’s disease(AD).Currently,there is no effective drug available for the treatment of AD.Previous studies have demonstrated that the cognitive impairment of AD is associated with oxidative stress and the inhibition of AKT and ERK phosphorylation.Grape seed proanthocyanidin extract(GSPE)has been shown to have strong antioxidant effect and can protect the nervous system from oxidative stress damage.This study aimed to investigate the protective effect of GSPE on the cognitive and synaptic impairments of AD using a sporadic AD rat model induced by intracerebroventricular(ICV)injection of streptozotocin(STZ)(ICV-STZ).Rats were treated with GSPE(50,100,or 200 mg/kg every day)by intragastrical(ig.)administration for continuous 7 weeks,and ICV-STZ(3 mg/kg)was performed on the first day and third day of week 5.Learning and memory abilities were assessed by the Morris water maze(MWM)test at week 8.After behavioral test,hippocampal long-term potentiation(LTP)was recorded,and the levels of malondialdehyde(MDA),superoxide dismutases(SOD),glutathione(GSH)and the protein expression of AKT and ERK were measured in the hippocampus and cerebral cortex of rats.Our study revealed that ICV-STZ significantly impaired the working learning ability and hippocampal LTP of rats,significantly increased the levels of MDA,and decreased the activity of SOD and GSH in the hippocampus and cerebral cortex.In contrast,GSPE treatment prevented the impairment of cognitive function and hippocampal LTP induced by ICV-STZ,decreased the level of MDA,and increased the level of SOD and GSH.Furthermore,Western blot results showed that GSPE treatment could prevent the loss of AKT and ERK activities in the hippocampus and cerebral cortex induced by ICV-STZ.Our findings demonstrate that GSPE treatment could ameliorate the impairment of cognitive ability and hippocampal synaptic plasticity in a rat model of sporadic AD by inhibiting oxidative stress and preserving AKT and ERK activities.Therefore,GSPE may be an effective agent for the treatment of cognitive deficits associated with sporadic AD.

Overexpression of the LoMYB29 gene of Larix olgensis contributes to the regulation of proanthocyanidin biosynthesis in Arabidopsis thaliana

Proanthocyanidins(PAs)are the most broadly distributed secondary metabolites that play important roles in various aspects of plant development and response to biotic and abiotic stresses.In this study,we cloned a R2R3 MYB gene LoMYB29,which has a full-length coding sequence of 921 bp identified in Larix olgensis.Quantitative real-time reverse transcription polymerase chain reaction analysis indicates that LoMYB29 is expressed under mechanical wounding,high light intensity,and NaCl,PEG6000,Methyl Jasmonate,and abscisic acid treatments.Subcellular localization analysis and yeast twohybrid assay localized LoMYB29 to the nucleus,acting as a transcriptional activator.Staining with 4-dimethylaminocinnamaldehyde showed a darker blue-purple color in LoMYB29-overexpressing Arabidopsis seeds compared to that of wild seeds.LoMYB29-overexpression resulted in a significant increase in leaf PA content.The expression of early flavonoid biosynthesis-related gene CHI and late flavonoid biosynthesis-related genes,including DFR,LDOX,and ANR(PA branch gene),were also activated in transgenic plants overexpressing LoMYB29.The results indicate that LoMYB29 plays a positive role in the regulation of PA biosynthesis by activating the expression of PA biosynthetic genes.

Grape seed proanthocyanidin protects liver against ischemia/reperfusion injury by attenuating endoplasmic reticulum stress

AIM: To explore the effect of grape seed proanthocyanidin(GSP) in liver ischemia/reperfusion(IR) injury and alleviation of endoplasmic reticulum stress.METHODS: Male Sprague-Dawley rats(220-250 g) were divided into three groups, namely, sham, IR, and GSP groups(n = 8 each). A liver IR(70%) model was established and reperfused for 6 h. Prior to reperfusion, the GSP group was administered with GSP(100 mg/kg) for 15 d, and liver histology was then investigated. Serum aminotransferase and inflammatory mediators coupled with superoxide dismutase and methane dicarboxylic aldehyde were detected. Western blot was conducted to analyze the expression of glucoseregulated protein 78, CCAAT/enhancer-binding protein homologous protein, activating transcription factor-4, inositol-requiring enzyme-1, procaspase-12, and nuclear factor-κb. Apoptotic cells were detected by TUNEL staining.RESULTS: The serum aminotransferase, apoptotic cells, and Suzuki scores decreased in the GSP group compared with the IR group(P s < 0.05). The methanedicarboxylic aldehyde level was decreased in the GSP group, but the superoxide dismutase level was reversed(P s < 0.05). Similarly, GSP downregulated the proinflammatory factors and upregulated the levels of anti-inflammatory factors(Ps < 0.05). Western blot data showed that GSP increased glucose-regulated protein 78 expression and suppressed expression of CCAAT/enhancer-binding protein homologous protein, activating transcription factor-4, inositol-requiring enzyme-1, procaspase-12, and nuclear factor-κb compared with the IR group.CONCLUSION: GSP possesses antioxidative, anti-inflammatory, and antiapoptotic effects by relieving endoplasmic reticulum stress through regulation of related signaling pathways to protect the liver against IR injury.

Beneficial clinical effects of grape seed proanthocyanidin extract on the progression of carotid atherosclerotic plaques

Background Atherosclerotic plaques indicate the occurrence of ischemia events and it is a difficult task for clinical physicians. Grape seed proanthocyanidin extract （GSPE） has been reported to exert an antiatherogenic effect by inducing regression of atherosclerotic plaques in animal experimental studies. In this study, the antiatherogenic effect of GSPE has been investigated in clinical use. Methods Consecu- tive 287 patients diagnosed with asymptomatic carotid plaques or abnormal plaque free carotid intima-media thickness （CIMT） were ran- domly assigned to the GSPE group （n = 146） or control group （n = 141）. The patients in the GSPE group received GSPE 200 mg per day orally, while patients in the control group were only enrolled in a lifestyle intervention program. Carotid ultrasound examination was per- formed at baseline and 6, 12, 24 months during follow-up. Mean maximum CIMT （MMCIMT）, plaque score, echogenicity of plaques and ischemic vascular events were recorded. Results As anticipated, after treatment, GSPE resulted in significant reduction in MMCIMT pro- gression （4.2% decrease after six months, 4.9% decrease after 12 months and 5.8% decrease after 24 months） and plaque score （10.9% de- crease after six months, 24.1% decrease after 12 months and 33.1% decrease after 24 months） for the primary outcome, while MMCIMT and plaque score were stable and even increased with the time going on in control group. The number of plaques and unstable plaques also de- creased after treatment of GSPE. Furthermore, the carotid plaque can disappear after treatment with GSPE. The incidence rate for transitory ischemic attack （TIA）, arterial revascularization procedure, and hospital readmission for unstable angina in GSPE group were statistically significant lower （P = 0.02, 0.08, 0.002, respectively） compared with the control group. Conclusions GSPE inhibited the progression of MMCIMT and reduced carotid plaque size in GSPE treated patients, and with extended treatment, the superior efficacy on MMCIMT and carotid plaque occurred. Furthermore, the GSPE group showed lower rates of clinical vascular events.

Protective effect of ginkgo proanthocyanidins against cerebral ischemia/reperfusion injury associated with its antioxidant effects

Proanthocyanidins have been shown to effectively protect ischemic neurons, but its mechanism remains poorly understood. Ginkgo proan-thocyanidins （20, 40, 80 mg/kg） were intraperitoneally administered 1, 24, 48 and 72 hours before reperfusion. Results showed that ginkgo proanthocyanidins could effectively mitigate neurological disorders, shorten infarct volume, increase superoxide dismutase activity, and de-crease malondialdehyde and nitric oxide contents. Simultaneously, the study on grape seed proanthocyanidins （40 mg/kg） confirmed that different sources of proanthocyanidins have a similar effect. The neurological outcomes of ginkgo proanthocyanidins were similar to that of nimodipine in the treatmen＇t of cerebral ischemia/reperfusion injury. （Sur results suggestthat-ginkgo proanthocyanidins can effectively lessen cerebral ischemia/reperfusion injury and protect ischemic brain tissue and these effects are associated with antioxidant properties.

Protective effects of proanthocyanidins on beta-amyloid peptide (25-35)-induced PC12 cell apoptosis by blocking S-phase and increasing p53 gene expression

BACKGROUND： Current studies related to the effects of proanthocyanidins on Alzheimer＇s disease have focused primarily on the signal transduction pathway of cellular apoptosis. However, the influence of p53 gene expression on cell cycle regulation, with regard to the protective mechanisms of proanthocyanidins, has not been reported. OBJECTIVE： To observe the effect of proanthocyanidins on cell cycle distribution, cellular apoptosis and p53 gene expression in β-amyloid peptide （25-35） （Aβ25-35）-induced PC12 cells cultured in serum-free media, and to investigate the molecular neuroprotective mechanisms of proanthocyanidins with regard to cell cycle regulation. DESIGN, TIME AND SETTING： A parallel, controlled, at the Institute of Biochemistry and Molecular Biology cellular, and molecular study was performed Guangdong Medical College from July 2006 to July 2008. MATERIALS： Proanthocyanidins were provided by Nanjing Xuezi Medical and Chemical Research Center, China; Aβ25-35 was provided by Sigma, USA; PC12 cells were provided by the Institute of Basic Medical Science, Academy of Military Medical Sciences; and rabbit anti-p53 polyclonal antibody was provided by Santa Cruz Biotechnology, USA. METHODS： PC12 cells were cultured in serum-free media for 24 hours. Cells from the model group were treated with 25 μmol/L Aβ25-35 for 24 hours. Cells in the drug protection group were pre-treated with 30 mg/L proanthocyanidins for 1 hour and then treated with 25 μmol/LAβ2^-35 for 24 hours. The control group was not treated. MAIN OUTCOME MEASURES： Flow cytometry was used to detect cell cycle distribution and rate of apoptosis; reverse-transcriptase polymerase chain reaction was used to detect p53 mRNA expression; and Western blot was used to detect p53 protein expression. RESULTS： After treating with 25 μmol/LAβ25-35 for 24 hours, the rate of apoptosis and the percentage of cells in S phase were significantly increased （P 〈 0.01 ）, and p53 mRNA and protein expressions were decreased. Pretreatment with proanthocyanidins for 1 hour blocked the increase in apoptosis and the percentage of cells in S phase in Aβ25-35-induced PC12 cells （P 〈 0.01 ） and increased p53 mRNA and protein expressions. CONCLUSION： Proanthocyanidins blocked apoptosis and S-phase arrest in Aβ25-35-induced PC12 cells cultured in serum-free media. The protective mechanism could be related to increased p53 mRNA and protein expressions.

Comparative Analysis of Proanthocyanidins and Polysaccharides on Wild Lycium ruthenicum

[Objectives] To compare content of proanthocyanidins and polysaccharides in wild Lycium ruthenicum. [Methods] The wild L. ruthenicum collected from different regions such as Qinghai, Inner Mongolia, Ningxia and Gansu Province were taken as the research objects. The conventional indicators such as proanthocyanidins and polysaccharides of the experimental materials were determined, and the proanthocyanidins and polysaccharides of the experimental materials in different regions were compared and analyzed. The difference in content and correlation, and the cluster analysis method were used to divide clusters of the experimental materials. [Results] The absorbance of proanthocyanidins in the fruit of wild L. ruthenicum was No.4>No.1>No.5>No.6>No.3>No.2, among which the absorbance of anthocyanin(2.43) of wild L. ruthenicum variety No.4 was significantly higher than other experimental materials(P<0.05), and proanthocyanidin of No.2 had the lowest absorbance value of 1.35. There was no significant difference between No.3 and No.6(P>0.05), and there were significant differences among other experimental materials(P<0.05). The content of polysaccharides was: No.3>No.7>No.2>No.4>No.5>No.6>No.1; there was no significant difference between No.3 and No.7(P>0.05), but significantly higher than other materials(P<0.05). Besides, proanthocyanidins and polysaccharides showed significant variability, but there was no consistency in the correlation between them. [Conclusions] In terms of the absorbance of proanthocyanidins, the experimental materials No.1 and No.4 can be classified into a cluster; experimental materials No.2, No.3, No.5 and No.6 can be classified into another cluster. This can provide a theoretical basis for the introduction and breeding of fine varieties.

Proanthocyanidins prevent tau protein aggregation and disintegrate tau filaments

Occurrence of neurofibrillary tangles of the tau protein is a hallmark of tau-related neurodegenerative diseases, i.e. Alzheimer's disease(AD) and frontotemporal dementia. The pathological mechanism underlying AD remains poorly understood, and effective treatments are still unavailable to mitigate the disease.Inhibiting of tau aggregation and disrupting the existing fibrils are key targets in drug discovery towards preventing or curing AD. In this study, grape seed proanthocyanidins(GSPs) was found to effectively inhibit the repeat domain of tau(tau-RD) aggregation and disaggregate tau-RD fibrils in a concentrationdependent manner by inhibiting β-sheet formation of tau-RD. In cells, GSPs relieved cytotoxicity induced by tau-RD aggregates. Molecular dynamics simulations indicated that strong hydrogen bonding,hydrophobic interaction and π-π stacking between GSPs and tau-RD protein were major reasons why GSPs had high inhibitory activity on tau-RD fibrillogenesis. These results provide preliminary data to develop GSPs into medicines, foodstuffs or nutritional supplements for AD patients, suggesting that GSPs could be a candidate molecule in the drug design for AD therapeutics.

Functional foods effective for hepatitis C: Identification of oligomeric proanthocyanidin and its action mechanism

Hepatitis C virus(HCV)is a major cause of viral hepatitis and currently infects approximately 170 million people worldwide.An infection by HCV causes high rates of chronic hepatitis(】75%)and progresses to liver cirrhosis and hepatocellular carcinoma ultimately.HCV can be eliminated by a combination of pegylatedα-interferon and the broad-spectrum antiviral drug ribavirin;however,this treatment is still associated with poor efficacy and tolerability and is often accompanied by serious side-effects.While some novel direct-actingantivirals against HCV have been developed recently,high medical costs limit the access to the therapy in cost-sensitive countries.To search for new natural anti-HCV agents,we screened local agricultural products for their suppressive activities against HCV replication using the HCV replicon cell system in vitro.We found a potent inhibitor of HCV RNA expression in the extracts of blueberry leaves and then identified oligomeric proanthocyanidin as the active ingredient.Further investigations into the action mechanism of oligomeric proanthocyanidin suggested that it is an inhibitor of heterogeneous nuclear ribonucleoproteins(hn RNPs)such as hn RNP A2/B1.In this review,we presented an overview of functional foods and ingredients efficient for HCV infection,the chemical structural characteristics of oligomeric proanthocyanidin,and its action mechanism.

Antioxidant activity of proanthocyanidins from adansonia digitata fruit

Besides（-）-epicatechin,epicatechin-（4β-8 ）-epicatechin（procyanidin B2）,epicatechin-（4β-6 ）-epicatechin （procyanidin B5）,epicatechin-（4β-8,2β-O-7）-epicatechin（proanthocyanidin A2） and epicatechin- （4β-8）-epicatechin-（4β-8）-epicatechin（procyanidin C1）,which were isolated before from Adansonia digitata, in this work an A-type proanthocyanidin trimer,i.e.epicatechin-（4β-8）-epicatechin-（4β-8,2β-0-7）- epicatechin,tetrameric procyanidin D1,i.e.epicatechin-（4β-8）-epicatechin-（4β-8）-epicatechin-（4β-8）- epicatechin and a polymeric compound were isolated from the pericarp（fruit wall） of the fruits for the first time from this plant.The antioxidant activity of different fractions and pure compounds was experimentally evaluated in the DPPH- assay.The ethyl acetate fraction,and most of the isolated compounds displayed a high activity(IC50 2.40-9.60μg/ml) compared with the reference antioxidant Trolox(IC50 12.18μg/ml) as a standard.

BnbHLH92a negatively regulates anthocyanin and proanthocyanidin biosynthesis in Brassica napus

Yellow seed trait is a desirable characteristic with potential for increasing seed quality and commercial value in rapeseed,and anthocyanin and proanthocyanidins(PAs)are major seed-coat pigments.Few transcription factors involved in the regulation of anthocyanin and PAs biosynthesis have been characterized in rapeseed.In this study,we identified a transcription factor gene BnbHLH92a(BnaA06T0441000ZS)in rapeseed.Overexpressing BnbHLH92a both in Arabidopsis and in rapeseed reduced levels of anthocyanin and PAs.Correspondingly,the expression profiles of anthocyanin and PA biosynthesis genes(TT3,BAN,TT8,TT18,and TTG1)were shown by quantitative real-time PCR to be inhibited in BnbHLH92a-overexpressing Arabidopsis seeds,indicating that BnbHLH92a represses the anthocyanin and PA biosynthesis pathway in Arabidopsis.BnbHLH92a physically interacts with the BnTTG1 protein and represses the biosynthesis of anthocyanins and PAs in rapeseed.BnbHLH92a also binds directly to the BnTT18 promoter and represses its expression.These results suggest that BnbHLH92a is a novel upstream regulator of flavonoid biosynthesis in B.napus.

Zebrafish as an in Vivo Screen for Early Black Cranberry Proanthocyanidin Biomolecular Activity

Antioxidants have been widely studied in various naturally occurring substances as a bioavailable cancer prevention treatment. Proanthocyanidins (PACs), which are abundant polyphenols in Early Black (EB) Cranberry (Vaccinium macrocarpon), are readily available and we have shown their anticancer activity in several cancer cell lines. This work focused on the activity of these compounds when incorporated into the zebrafish (Danio rerio) system. We began investigating the in vivo effect of these phytochemicals, the protective role of several other cranberry compounds, and the metabolic activity of the vertebrate model organism. Proanthocyanidin fractions were separated from fresh EB Cranberry fruit by chromatography on Sephadex LH-20 in order to acquire a workable stock solution in DMSO. Various concentrations of proanthocyanidins in solution were tested against fish ranging in age from 1-cell stage to adult level of growth. Acridine orange apoptosis indicator dye was incorporated into the treatment protocol, and it was observed that irregular epithelial cell death was occurring in treated embryos but not in the control group. Further apoptosis assays were carried out utilizing Dihydroethidium (DHE) superoxide sensitive dye in the treatment protocol. Fluorescing red nuclei were visible along the outer surface of the epithelium cell layer;an indication of superoxide release within cells leading to the nicking of DNA within the nucleus. It was also possible to screen for superoxide release in PACs treated CCD-CO18 and HT-29 cells using confocal microscopy and cell apoptosis was investigated by trypan blue cytotoxicity assay;cell apoptosis results were statistically significant as confirmed by ANOVA analysis. Results indicate that the phytochemicals may induce apoptosis in rapidly dividing cells.

Effect of grape seed proanthocyanidins on tumor vasculogenic mimicry in liver cancer xenograft model

Objective: As a novel blood supply pattern, vasculogenic mimicry(VM) has attracted increasingly attention in recent years, which may partly compensate for the absence of feeding and facilitate tumor perfusion. However, anti-angiogenic drugs have little effect on VM. The grape seed proanthocyanidins(GSPs), a kind of promising bioactive phytochemical, has shown anti-carcinogenesis and anti-angiogenic in several tumor models. However, GSPs regulation of VM and its possible mechanisms in a H22 hepatoma carcinoma model remain not clear. The aim of this study was to examine the effects of GSPs on proliferation and VM in a H22 hepatoma carcinoma model and to investigate the underlying mechanism. Methods: Seventy-five mice were divided into the control group and experimental groups treated with different concentration of GSPs. CD34-PAS dual staining was employed to identify the VM structure. The immunohistochemical staining for investigating the expression of VEGF, Eph A2 and MMP-2 protein was performed. Results: Treatment of the H22 model with Endostar(4 mg/kg), 50, 100, 200 mg/kg of the GSPs resulted in 6.87%, 17.81%, 27.43%, 53.52% inhibition in tumor growth, respectively. The mean weight of tumors were significantly lower in GSPs(100 mg/kg) and GSPs(200 mg/kg) groups than in the control group(all P < 0.01). Similarly, compared with the control group, the number of VM channels were significantly reduced in GSPs(100 mg/kg) and GSPs(200 mg/kg) groups(all P < 0.01). Immunohistochemistry showed significant decreases in the expression levels of VEGF, Eph A2 and MMP-2 protein in GSPs(100 mg/kg) and GSPs(200 mg/kg) groups when compared with control group(all P < 0.001). Conclusion: This is the first report providing evidence that GSPs inhibit the VM structure by regulation of the VEGF/Eph A2/MMPs signaling pathway. Therefore, we concluded that GSPs has the potential of being a clinical anti-VM inhibitor.

Effect of grape proanthocyanidins on tumor growth and angiogenesis in H22 liver cancer xenograft model

Objective: The aim of this study was to investigate the effect of grape proanthocyanidins(GPC) on the growth and angiogenesis of hepatocellular carcinoma H22 cells xenograft in mice. Methods: The xenograft model was established using injected subcutaneously H22 cells into the right axilla of the mice. Each group was treated with different doses of GPC and Endostar. All these treatments were maintained for 10 days, and mice were sacrificed. The xenograft tumors in mice were measured. The proliferation activity level of H22 cells was determined by MTT assay, and the levels of vascular endothelial growth factor(VEGF) protein were examined by immunohistochemistry. Results: When treated with 50, 100 and 200 mg/kg of GPC and Endostar, the tumor inhibition rates were 13.17%, 23.37%, 36.15% and 14.71%, respectively. The tumor weight of xenograft was significantly lighter in high GPC group than the control group(P < 0.05). The ODs in GPC groups were 0.835, 0.666 and 0.519, respectively. The absorbances in middle and high GPC groups were statistically significant, compared with control group(P < 0.01). Immunohistochemical technique showed the expression of VEGF of the GPC groups was downregulated significantly compared with the control group(P < 0.01). Conclusion: GPC can inhibit the growth of hepatocellular carcinoma H22 cell xenograft in mice. The inhibition of angiogenesis by the down-regulation of VEGF expression may play a key role in the anti-neoplastic effect of GPC.

New N-acetyl-L-cysteine derivatives synthesized by the degradation of proanthocyanidins as high biological activity antioxidants

A novel degradation method was investigated to synthesize highly biologically active flavan-3-ol derivatives in the presence of N-acetyl-L-cysteine(NAC)as a nucleophile under acidic conditions for polymerized proanthocyanidins degradation.The reaction conditions were optimized by the combination of single-factor test and central composite experimental design(CCD).Grape seed proanthocyanidins were reacted with NAC at a ratio of 1:3 with 0.3 M methanolic HC1,a temperature of 55°C,and a reaction time of 50 mins.Most of the degradation products were separated and prepared by one-step high-speed countercurrent chromatography(HSCCC)and preparative high-performance liquid chromatography(prep-HPLC).Three monomeric pro anthocyanidins and four new N-acetyl-L-cysteine derivatives were isolated from degradation products with total degradation yield of 55.44%and high purity over 95%.Furthermore,the neuroprotective abilities of these compounds to H2O2-treated PC-12 neuroblastoma cells were evaluated.NAC derivatives showed better antioxidant activity than their corresponding underivatized monomers and NAC,indicating that they had a better performance in protecting PC-12 cells from oxidative stress damage.

Structural composition of oligomeric and polymeric proanthocyanidins from diff erent parts of grape pomace

Grape pomace is one of the most abundant solid by-products generated during winemaking,rich in bioactive compounds,i.e.,proanthocyanidins.The major objective of this work was to characterize structurally oligomeric and polymeric proanthocyanidins of diff erent parts of grape pomace(seed,skin,and stem).Column chromatography techniques were used to isolate oligomeric and polymeric proanthocyanidins fractions from diff erent parts of grape pomace.The purifi ed grape seed proanthocyanidins were used to assess the effi ciency of the three most frequently-used acidic degradation methods,using benzyl mercaptan,phloroglucinol,and cysteamine as nucleophiles.The structural characterization of proanthocyanidins in the different parts of grape pomace was further performed by the phloroglucinolysis and ESI-MS analysis.The results showed signifi cant diff erences in the structural composition of proanthocyanidins among diff erent parts of pomace.A positive correlation was found between the mean degree of polymerization and percentage of galloylation,in both oligomeric and polymeric fractions.The results provided useful information for the preparation of diff erent proanthocyanidins products from grape pomace.