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.

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.

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.

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.

A review:anticancer activity of grape seed proanthocyanidins

For years,a great deal of work has been carried out on proanthocyanidins extracted from various kinds of plants,of which grape seed proanthocyanidins(GSPs)attract most attention due to their benefi cial roles in human health.Indeed,GSPs have demonstrated substantial health benefi ts for a variety of disorders such as cancer,atherosclerosis,and cardiovascular diseases,to just name a few.In particular,GSPs inhibit cell proliferation,migration and invasion,and induce apoptosis and cell cycle arrest in various human cancers,including head and neck carcinoma,gastrointestinal tumors,lung cancer,skin tumors,and reproductive tumors,which points them to be promising chemo-preventive and/or chemotherapeutic agents.In this setting,we summarized the eff ects of GSPs against various types of cancer with a focus on the detailed molecular mechanisms involving various signaling pathways of tumor cells,which may serve as a basis for development of improved chemo-preventive or therapeutic strategies for cancer.

Targeted mutations of BnPAP2 lead to a yellow seed coat in Brassica napus L.

The yellow seed trait is preferred by breeders for its potential to improve the seed quality and commercial value of Brassica napus.In the present study,we produced yellow seed mutants using a CRISPR/Cas9 system when the two BnPAP2 homologs were knocked out.Histochemical staining of the seed coat demonstrated that proanthocyanidin accumulation was significantly reduced in the pap2 double mutants and decreased specifically in the endothelial and palisade layer cells of the seed coat.Transcriptomic and metabolite profiling analysis suggested that disruption of the BnPAP2 genes could reduce the expression of structural and regulated genes in the phenylpropanoid and flavonoid biosynthetic pathways.The broad suppression of these genes might hinder proanthocyanidin accumulation during seed development,and thereby causing the yellow seed trait in B.napus.These results indicate that BnPAP2 might play a vital role in the regulatory network controlling proanthocyanidin accumulation.

Proanthocyanidins Inhibit Seed Germination by Maintaining a High Level of Abscisic Acid in Arabidopsis thaliana

Proanthocyanidins （PAs） are the main products of the flavonoid biosynthetic pathway in seeds, but their biological function during seed germination is still unclear. We observed that seed germination is delayed with the increase of exogenous PA concentration in Arabidopsis. A similar inhibitory effect occurred in peeled Brassica napus seeds, which was observed by measuring radicle elongation. Using abscisic acid （ABA）, a biosynthetic and metabolic inhibitor, and gene expression analysis by real-time polymerase chain reaction, we found that the inhibitory effect of PAs on seed germination is due to their promotion of ABA via de novo biogenesis, rather than by any inhibition of its degradation. Consistent with the relationship between PA content and ABA accumulation in seeds, PA-deficient mutants maintain a lower level of ABA compared with wild-types during germination. Our data suggest that PA distribution in the seed coat can act as a doorkeeper to seed germination. PA regulation of seed germination is mediated by the ABA signaling pathway.

Modulation of Anti-Oxidation Ability by Proanthocyanidins during Germination of Arabidopsis thaliana Seeds

Proanthocyanidins （PAs） as the end products of flavonoid biosynthetic pathway mainly accumulate in seed coat but their biological function is largely unknown. We studied the anti-oxidation ability in seed coat and germination changes under externally applied oxidative stresses in PAs-deficient mutants of Arabidopsis. Germination of PAs-deficient mutant seeds was faster than that of wild-type under low or no oxidative stress, suggesting a PAs-induced inhibition of germination. When the applied oxidative stress was high, germination of PAs-deficient mutants was lower than that of wild-type, suggesting a loss of PAs-related anti-oxidation ability in the mutants. Using ABA signaling mutants, our studies demonstrated that both ABA signaling pathway and PAs were important for the response to serve oxidative stress during seed germination. However, the discrepancy of the response between abi mutants and PAs mutants to oxidative stress suggests that ABA signaling pathway may not play a major role in PAs＂ action in alleviating oxidative stress. Under low or no oxidative stress, germination was mainly determined by the ABA content in seed and the PAs-deficient mutant seeds germinated faster due to their lower ABA content than wild-type. However, oxidative injury inhibited germination when PAs-deficient seeds germinated under high oxidative stress, Wild-type exhibited higher germination under the high ox- idative stress due to the PAs＇ anti-oxidation ability. Oxidative stress applied externally led to changes in endogenous PAs contents that coincided with the expression changes of PAs biogenesis genes. PAs modulated the activities of some key enzymes that controlled the levels of reactive oxygen species and the anti-oxidation capacity during the seed germination. This work suggests that PAs contribute to the adaptive mechanism that helps germination under environmental stresses by playing dual roles in both germination control and anti-oxidation reaction.

Proanthocyanidins extracted from grape seeds inhibit the growth of hepatocellular carcinoma cells and induce apoptosis through the MAPK/AKT pathway

Proanthocyanidins naturally occur in various fruits,some vegetables and beverages.Increasing evidence has shown that dietary intake of proanthocyanidins is a promising alternative to tumor chemoprevention or chemotherapy.Grape seeds are the most abundant source of proanthocyanidins,and grape seed proanthocyanidins(GSPs)show an anticancer effect on hepatocellular carcinoma(HCC),which accounts for approximately 85-90%of all primary liver malignancies.Although an increasing number of studies have investigated the effects of GSPs on HCC and the associated mechanisms,the precise mechanism of GSP therapy in HCC remains unclear.This study aimed to understand the cytotoxic effect of GSPs on HepG2 cells by investigating morphology and growth inhibition.Cell proliferation and apoptosis were estimated by an MTT assay and flow cytometry,and the protein expression of HepG2 cells was determined through Western blotting.The results indicated that GSPs could markedly inhibit HepG2 liver cancer cells and induce apoptosis,with the effects varying by dose and treatment time.Furthermore,GSPs inhibited the phosphorylation of extracellular regulated protein kinases(ERK),c-Jun NH2-terminal kinase(JNK),p38 mitogen-activated protein kinase(p38 MAPK),IκBα,pyruvate dehydrogenase kinase 1(PDK1),glycogen synthase kinase-3 beta(GSK3β)and protein kinase B(AKT),which accounted for the inactivation of mitogen-activated protein kinase/AKT(MAPK/AKT)pathways.These results indicate that GSPs are a potential source of natural chemopreventive agents for the treatment of HCC.

Inhibitive Effect of Proanthocyanidins on Cyclooxygenase-2 Expression in A549 Cells Induced by Cytokine Interleukin-1 Beta

Cyclooxygenase-2(COX-2),an important enzyme,plays a pathological role in diseases,which can be inhibited by proanthocyanidins(PCs) effectively.In this paper,we investigated the inhibitive mechanism of COX-2 performed by PCs.Reverse transcription-polymerase chain reaction(RT-PCR) was performed to identify the mRNA expression level of COX-2 in A549 cell,which was induced by interleukin-1 beta(IL-1β).The pGL3 luciferase reporter vector containing the COX-2 gene promoter fragment(pGL3/COX-2p) was transfected into A549 cell induced by IL-1β,the interference on the COX-2 promoter activity from PCs was analyzed using a dualluciferase reporter assay,and the expressions of the nuclear factor κB composed of subunit p65(NF-κB/p65) and the inhibitor-κB(I-κB) were measured by the Western blotting and immunocytochemistry.The results exhibited that PCs not only inhibited the transcript of COX-2 mRNA and the COX-2 promoter activity,but also suppressed the nuclear translocation of NF-κB/p65 protein and the degradation of I-κB protein.

Identification of novel bioactive proanthocyanidins with potent antioxidant and anti-proliferative activities from kiwifruit leaves

Agro-wastes contribute major social,economic,and environmental challenges for food production and circular economy systems.The current increasing demand for clean label food production and use of natural bioactive compounds could turn these challenges into opportunities providing avenues for proper utilization of agro-wastes to produce valuable products.This study aimed to investigate the potential use of kiwifruit(Actinidia chinensis)leaves as a source of proanthocyanidins(PAs)bioactive phenolic phytochemicals.Kiwifruit leaves PAs were extracted,purified,identified,and evaluated for their antioxidant and anti-proliferative activities.The structural composition of the purified PAs was characterized using HPLC-QTOF-MS/MS and MALDI-TOF-MS.The results showed that purified kiwifruit leaves PAs(PKLPs)comprised mainly procyanidins,propelargonidins,and prodelphindins ranging from dimers to hexamers with(epi)catechin as terminal units and(epi)afzelechin or(epi)gallocatechin as dominant extension units.This study reports the structure of novel PKLPs monomer fractions was unique compared to the PAs that extracted from the other plant sources.The PKLPs exhibited higher phenolic content than the skin and flesh of several kiwifruit cultivars.Moreover,the PKLPs exhibited higher in vitro antioxidant activity in chemical-based(DPPH,ABTS,and FRAP)assays and H2O2-induced injury cell model than ascorbic,Trolox,and catechin(p<0.01).A remarkable dose-dependent anti-proliferation activity(IC_(50)=186.04±2.61μg/mL)against HepG2 cells was observed.In conclusion,this study demonstrated that kiwifruit leaves waste could serve as a sustainable and low-cost source of PAs,a group of multi-functional bioactive compounds that plays a key role in the food and pharmaceutical industries.

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.

The contribution of different polyphenol compositions from chokeberry produced in China to cellular antioxidant and antiproliferative activities

Abundant polyphenols make chokeberry have beneficial antioxidant and antiproliferative activity. In order to explore the contribution of different polyphenols in chokeberry to these activities, this study was conducted to determine polyphenol composition from 7 chokeberry varieties produced in China. Totally, 11 kinds of main polyphenol monomers were identified and quantified by UPLC-Q-TOF-MS and UPLC-PDA. HepG2 cells were used to evaluate their cellular antioxidant and antiproliferative activities. Partial least squares method was utilized to analyze multivariate correlations between proportion of different composition and monomers in total polyphenols with these activities. The results showed that the highest proportion in chokeberry polyphenols was proanthocyanidins. In comparing the bioactivities of 7 varieties of chokeberry, ‘Viking' and purple chokeberry had the strongest antioxidant activity, while 'Fukangyuan 1#' had the strongest antiproliferative activity. In terms of the contribution sources of these bioactivities, the total antioxidant activity of chokeberry mainly depended on the contribution of free polyphenols. As the main source of cellular antioxidant activity, anthocyanins and neochlorogenic acid can provide more contribution. The antiproliferative activity mainly depended on the proportion of free polyphenols and proanthocyanidins in total polyphenols. The results may provide some new possibilities for the comprehensive utilization of polyphenols from chokeberry.

Transcriptome and weighted gene co-expression network analysis of jujube(Ziziphus jujuba Mill.)fruit reveal putative genes involved in proanthocyanin biosynthesis and regulation

Proanthocyanidin(PA)is an important bioactive compound with multiple physiological benefits in jujube(Ziziphus jujube Mill.).However,the molecular mechanisms underlying PA biosynthesis in jujube fruit have not been investigated.Here,the profiling of PA,(+)-catechin and(–)-epicatechin and transcriptome sequencing of three jujube cultivars from Xinjiang Uyghur Autonomous Region of China at five developmental stages were analyzed.The levels of total PAs and catechin exhibited a decreased trend over jujube ripening,and epicatechin content of two jujube cultivars increased first and then declined.Transcriptome analysis revealed that the differentially expressed genes(DEGs)were mainly enriched in ribosome,glycolysis/gluconeogenesis,fructose and mannose metabolism.17 DEGs encoding PAL,CHS,CHI,CHS,F3'H,LAR,ANR,C4Hs,4CLs,FLSs,DFRs and UFGTs involved in PA biosynthesis were relatively abundant.The highly transcribed LAR gene may greatly contribute to epicatechin accumulation.A weighted gene co-expression network analysis(WGCNA)was performed,and a network module including 1620 genes highly correlated with content of Pas and catechin was established.We identified 58 genes including 9 structural genes and 49 regulatory genes related to PA biosynthesis and regulation in the WGCNA module.Sixteen genes encoding 9 families of transcriptional factors(i.e.,MYB,bHLH,ERF,bZIP,NAC,SBP,MIKC,HB,WRKY)were considered as hub genes.The results of qRT-PCR analysis validating 10 genes were well consistent with the transcriptome data.These findings provide valuable knowledge to facilitate its genetic studies and molecular breeding.

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.

苹果露中多酚物质的含量测定

利用HPLC法对苹果露中的生理活性成分进行含量测定。HPLC法采用Kromasil C18(4.6 mm×150 mm)色谱柱,流动相采用甲醇(A)-水(B)梯度洗脱,流速为1 mL/min,柱温为25℃,检测波长为290 nm,测定苹果露中儿茶素和原花青素B2的含量,苹果多酚采用分光光度法测定;结果表明:苹果露中儿茶素和原花青素B2的平均含量分别为26.77mg/L和45.43 mg/L,苹果多酚为2.92 mg/mL;儿茶素、原花青素B2和苹果多酚在苹果露中均能检测到,且含量较高,为人们饮用苹果露对人体的保健作用提供了理论依据。

Phytochemical and biological activities of Crataegus sinaica growing in Egypt

Objective:To evaluate the cardiac activity and hepatoprotection of Crataegus sinaica (C.sinaica).Methods:All the isolated compounds were isolated by open-column liquid chromatography(CC) using sephadex LH-20 as stationary phase.Elution of the column was performed with EtOH or MeOH.The phytochemical investigation of the young stem of C.sinaica for the first time together with the leaves and flowers lead to the isolation and identification of quercetin,hyperoside,vitexin-2"-0-rhamnoside,epicatechin,procyanidin B2 and procyanidins CI.Results:Rats treated with the low and high dose of C.sinaica leaves with flowers extract showed 15%and 17%reduction in the heart rate,and reduction in the STsegment by 107%and 57%;respectively.The T-amplitude was decreased by 59%of the high dose extract.On the other hand,the young steins and leaves with flowers extracts of C.sinaica on primary culture of rat hepatocytes monolayer indicated a hepatoprotection for the total extract,ethyl acetate,butanol,and chlor of orm fractions at 100μg/mL,75μg/mL,50μg/mL,and 25μg/mL; respectively.Conclusions:The results of these chemical and biological studies suggest the use of C.sinaica growing in Egypt as a preventive drug against cardiovascular and hepatic diseases. The chemical studies suggest the use of woody young stems as a newly investigated bioactive organ.The extraction of unsaturated fatty acids from the seeds of the plant would serve as a good health and nutritive product.