Blood glucose-lowering activity of protocatechuic acid is mediated by inhibiting a-glucosidase

α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in various plant foods but also as a major microbial metabolite of dietary anthocyanins in the large colon.The present study investigated the inhibitory mechanism of PCA on a-glucosidase in vitro and examined its effect on postprandial blood glucose levels in vivo.Results from in vitro experiments demonstrated that PCA was a mix-type inhibitor of a-glucosidase.Driven by hydrogen bonds and van der Waals interactions,PCA reversibly bound withα-glucosidase to form a stable a-glucosidase-PCA complex in a spontaneous manner.The computational simulation found that PCA could insert into the active cavity of a-glucosidase and establish hydrogen bonds with catalytic amino acid residues.PCA binding aroused the steric hindrance for substrates to enter active sites and caused the structural changes of interacted catalytic amino acid residues.PCA also exhibited postprandial hypoglycemic capacity in diabetic mice.This study may provide the theoretical basis for the application of PCA as an active ingredient of functional foods in dietary management of diabetes.

Patterns of alteration in boar semen quality from 9 to 37 months old and improvement by protocatechuic acid

Background Comprehending the patterns of alteration in boar semen quality and identifying effective nutritional interventions are crucial for enhancing the productivity of commercial pig systems.This study aimed to examine the alteration in semen quality in boars,and assess the impact of protocatechuic acid(PCA)on semen quality during the phase of declining semen quality.Methods In Exp.1,a total of 38 Pig Improvement Company(PIC)boars were selected and their semen quality data were recorded from the age of 9 to 37 months.In Exp.2,18 PIC boars(28 months old)were randomly assigned into three groups(n=6)and fed a basal diet,a basal diet containing 500 or 1,000 mg/kg PCA,respectively.The experiment lasted for 12 weeks.Results The semen volume,concentration,and total number of spermatozoa in boars exhibited an increase from 9 to 19 months old and showed a significant linear decreased trend in 28,24,and 22 months old.Sperm motility displayed an upward trajectory,reaching its peak at 20 months of age,and showed a significant linear decreased trend at 20 months old.Dietary supplementation of PCA demonstrated an effect to mitigate the decrease in semen volume,concentration of spermatozoa,total number of spermatozoa(P>0.05),and significantly increased the sperm motility(P<0.05).Moreover,supplementation of 1,000 mg/kg PCA significantly increased the sperm viability(P<0.05).Analysis on cellular signaling pathways revealed that PCA restored serum testosterone levels and alleviated oxidative damage by upregulating the expression of HO-1,SOD2,and NQO1 in testicular stromal cells.Notably,PCA can enhance phosphorylation by selectively binding to AMP-activated protein kinase(AMPK)protein,thereby improving sperm mitochondrial function and augmenting sperm motility via PGC-1/Nrf1.Conclusions These data elucidated the pattern of semen quality variation in boars within the age range of 9 to 37 months old,and PCA has the potential to be a natural antioxidant to enhance sperm quality through modulation of the AMPK/PGC-1/Nrf1 signaling pathway.

Protocatechuic acid and quercetin attenuate ETEC-caused IPEC-1 cell inflammation and injury associated with inhibition of necroptosis and pyroptosis signaling pathways

Background:Necroptosis and pyroptosis are newly identified forms of programmed cell death,which play a vital role in development of many gastrointestinal disorders.Although plant polyphenols have been reported to protect intestinal health,it is still unclear whether there is a beneficial role of plant polyphenols in modulating necroptosis and pyroptosis in intestinal porcine epithelial cell line(IPEC-1)infected with enterotoxigenic Escherichia coli(ETEC)K88.This research was conducted to explore whether plant polyphenols including protocatechuic acid(PCA)and quercetin(Que),attenuated inflammation and injury of IPEC-1 caused by ETEC K88 through regulating necroptosis and pyroptosis signaling pathways.Methods:IPEC-1 cells were treated with PCA(40μmol/L)or Que(10μmol/L)in the presence or absence of ETEC K88.Results:PCA and Que decreased ETEC K88 adhesion and endotoxin level(P<0.05)in cell supernatant.PCA and Que increased cell number(P<0.001)and decreased lactate dehydrogenases(LDH)activity(P<0.05)in cell supernatant after ETEC infection.PCA and Que improved transepithelial electrical resistance(TEER)(P<0.001)and reduced fluorescein isothiocyanate-labeled dextran(FD4)flux(P<0.001),and enhanced membrane protein abundance of occludin,claudin-1 and ZO-1(P<0.05),and rescued distribution of these tight junction proteins(P<0.05)after ETEC infection.PCA and Que also declined cell necrosis ratio(P<0.05).PCA and Que reduced mRNA abundance and concentration of tumor necrosis factor-α(TNF-α),interleukin(IL)-6 and IL-8(P<0.001),and down-regulated gene expression of toll-like receptors 4(TLR4)and its downstream signals(P<0.001)after ETEC infection.PCA and Que down-regulated protein abundance of total receptor interacting protein kinase 1(t-RIP1),phosphorylated-RIP1(p-RIP1),p-RIP1/t-RIP1,t-RIP3,p-RIP3,mixed lineage kinase domain-like protein(MLKL),p-MLKL,dynamin-related protein 1(DRP1),phosphoglycerate mutase 5(PGAM5)and high mobility group box 1(HMGB1)(P<0.05)after ETEC infection.Moreover,PCA and Que reduced protein abundance of nod-like receptor protein 3(NLRP3),nod-like receptors family CARD domain-containing protein 4(NLRC4),apoptosis-associated speck-like protein containing a CARD(ASC),gasdermin D(GSDMD)and caspase-1(P<0.05)after ETEC infection.Conclusions:In general,our data suggest that PCA and Que are capable of attenuating ETEC-caused intestinal inflammation and damage via inhibiting necroptosis and pyroptosis signaling pathways.

Beneficial effects of protocatechuic acid on diabetic retinopathy in streptozocin-induced diabetic rats

·AIM:To determine the effects of protocatechuic acid(PCA)on streptozocin-induced diabetic retinopathy(DR)in rats.·METHODS:Wistar rats were given a 50 mg/kg intraperitoneal injection of streptozocin to induce diabetes.Animals were assigned randomly one of four groups(8 rats per group):control,diabetic,diabetic plus PCA(25 mg/kg·d),and diabetic plus PCA(50 mg/kg·d).After inducing diabetes,treatments were started one week later and continued for eight weeks.After the experiment,the rats were sacrificed,and their retinas were taken for biochemical and molecular analysis.·RESULTS:PCA administration diminished the blood glucose and glycated haemoglobin levels relative to the diabetic group.In diabetic rats,PCA lowered elevated levels of advanced glycosylated end products(AGEs)and receptor for AGEs(RAGE).In the retina of diabetic rats,PCA effectively decreased inflammatory cytokine,nuclear factor-κB,tumour necrosis factor-α,interleukin-1β,and vascular endothelial growth factor,and increased antioxidant markers glutathione,superoxide dismutase,and catalase.·CONCLUSION:The protective benefits of PCA against DR may be attributable to its suppression of the AGEs and RAGE and its antioxidant and anti-inflammatory properties.

非共价/共价相互作用对明胶-PCA复合物功能特性和稳定性的影响

为探讨原儿茶酸(protocatechuic acid,PCA)与明胶之间的相互作用对明胶-PCA复合物功能特性和稳定性的影响,本文通过非共价和共价结合方式制备明胶-PCA复合物,采用紫外-可见光谱、荧光光谱和傅里叶红外光谱分析PCA与明胶之间的相互作用,并对复合物的抗氧化活性、抑菌活性和稳定性进行分析。结果表明,与非共价复合物相比,共价复合物具有更高的PCA结合率。PCA与明胶二者相互作用对明胶具有荧光淬灭作用,且共价作用引起的荧光淬灭程度更大。明胶-PCA复合物具有优异1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基和2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸(2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid,ABTS+)自由基清除能力。与共价复合物GPCA-2相比,非共价复合物GPCA-1对DPPH和ABTS+自由基清除能力更加显著(P<0.05),其清除率分别为49.71%±2.9%和38.39%±0.57%。明胶-PCA复合物还表现出对大肠杆菌、李斯特菌和沙门氏菌的抑菌作用。与GPCA-2相比,GPCA-1的抑菌效果更加显著(P<0.05),其大肠杆菌、李斯特菌和沙门氏菌的抑菌圈直径分别为11.31±0.91、12.57±0.93和8.83±0.35 mm。虽然PCA与明胶之间的相互作用在一定程度上降低了PCA的抗氧化活性和抑菌活性,却能显著(P<0.05)提高PCA的光稳定性和热稳定性。明胶-PCA共价复合物在紫外光和热处理80 min后,其PCA的保留率可达到92.58%±0.62%和90.30%±0.97%。实验结果为功能型明胶-PCA复合产品的开发与利用提供理论依据。

Dietary protocatechuic acid ameliorates inflammation and up-regulates intestinal tight junction proteins by modulating gut microbiota in LPS-challenged piglets

Background: Weaning is one of the major factors that cause stress and intestinal disease in piglets. Protocatechuic acid(PCA) is an active plant phenolic acid which exists in Chinese herb, Duzhong(Eucommia ulmoides Oliver), and is also considered as the main bioactive metabolite of polyphenol against oxidative stress and inflammation. This study aimed to investigate the effect of PCA on growth performance, intestinal barrier function, and gut microbiota in a weaned piglet model challenged with lipopolysaccharide(LPS).Methods: Thirty-six piglets(Pig Improvement Company line 337 × C48, 28 d of age, 8.87 kg ± 0.11 kg BW) were randomly allocated into 3 treatments and fed with a basal diet(CTL), a diet added 50 mg/kg of aureomycin(AUR), or a diet supplemented with 4000 mg/kg of PCA, respectively. The piglets were challenged with LPS(10 μg/kg BW) on d 14 and d 21 by intraperitoneal injection during the 21-d experiment. Animals(n = 6 from each group) were sacrificed after being anesthetized by sodium pentobarbital at 2 h after the last injection of LPS. The serum was collected for antioxidant indices and inflammatory cytokines analysis, the ileum was harvested for detecting mRNA and protein levels of tight junction proteins by PCR and immunohistochemical staining, and the cecum chyme was collected for intestinal flora analysis using 16 S rRNA gene sequencing.Results: Dietary supplementation of PCA or AUR significantly increased the expression of tight junction proteins including ZO-1 and claudin-1 in intestinal mucosa, and decreased the serum levels of thiobarbituric acid reactive substances(TBARS) and IL-6, as compared with CTL group. In addition, PCA also decreased the serum levels of IL-2 and TNF-α(P < 0.05). Analysis of gut microbiota indicated that PCA increased the Firmicutes/Bacteroidetes ratio(P < 0.05). Spearman's correlation analysis at the genus level revealed that PCA reduced the relative abundance of Prevotella 9, Prevotella 2, Holdemanella, and Ruminococcus torques group(P < 0.05), and increased the relative abundance of Roseburia and Desulfovibrio(P < 0.05), whereas AUR had no significant effect on these bacteria.Conclusions: These results demonstrated that both PCA and AUR had protective effect on oxidative stress, inflammation and intestinal barrier function in piglets challenged with LPS, and PCA potentially exerted the protective function by modulating intestinal flora in a way different from AUR.

Optimization of the Ultrasonic-assisted Extraction Process for Protocatechuic Acid from Emilia sonchifolia DC by Response Surface Methodology

[Objectives] This study was conducted to optimize the extraction process of protocatechuic acid from Emilia sonchifolia DC. [Methods] The optimal extraction conditions were determined by single factor,response surface analysis and variance analysis,and the content of protocatechuic acid was determined by HPLC. [Results] The protocatechuic acid standard curve equation was: y = 1 435 x + 8 403,R^2= 0. 999 8,indicating a good linear relationship. The optimal extraction conditions were as follows: a temperature at 80 ℃,an extraction time of 1 h,a material-to-liquid ratio at 1:10 and an ultrasonic power of 600 W,and the content of protocatechuic acid extracted was 1. 93 mg/g. The method showed a RSD of 0. 41%,less than 2%,and the detection limit was 0. 0000047261 g/ml.The experimental sample X1 was the low-level 0. 1 mg/ml standard solution,which showed recovery of protocatechuic acid between 100.8% and 105.2%,with a RSD of 0. 013%;and the sample X2 was the high-level 1. 0 mg/ml standard solution,which exhibited recovery between 100. 6% and 102. 2%,with a RSD of 0.076%. Thus,the recovery was high,and the requirements of the performance index were met. [Conclusions] The detection method is stable and reliable and can produce satisfactory results.

Caffeic acid and protocatechuic acid modulate Nrf2 and inhibit Ehrlich ascites carcinomas in mice

Objective:To assess the nuclear factor-erythroid 2-related factor-2(Nrf2)modulatory effect of caffeic acid and protocatechuic acid and determine the anti-tumor activity of these phenolic compounds against Ehrlich ascites carcinoma growth in mice.Methods:Antioxidant activity of protocatechuic acid and caffeic acid was assessed using ferric reducing antioxidant power(FRAP)and 2,2-diphenyl-1-picrylhydrazyl(DPPH).Nrf2 activation potential of phenolic compounds was tested by quantitative realtime polymerase chain reaction,and luciferase complementation reporter assays.In vivo efficacy was tested using the Ehrlich ascites carcinoma model.Results:FRAP and DPPH radical scavenging assays showed that caffeic acid and protocatechuic acid were more potent compared with cinnamic acid and benzoic acid.Luciferase complementation reporter assays identified caffeic acid and protocatechuic acid as the activators of Nrf2.Both caffeic acid and protocatechuic acid upregulated the expression of Nrf2 target genes heme oxygenase-1(HO-1),glutamate-cysteine ligase catalytic subunit(GCLC),and glutamate-cysteine ligase modifier subunit(GCLM)and the activity of NAD(P)H:quinone oxidoreductase 1(NQO1)when tested on HCT-116 cells using a cell-based assay system at 9 h.In addition,intraperitoneal administration of caffeic acid and protocatechuic acid to Ehrlich ascites carcinoma bearing mice suppressed tumor growth and angiogenesis.Conclusions:Caffeic acid and protocatechuic acid can modulate Nrf2 and inhibit Ehrlich ascites carcinoma cells.

Crystal Structure,Stability and Dissolution of a Drug-drug Molecular Salt Hydrate of Berberine with Protocatechuic Acid

A drug-drug molecular salt hydrate of berberine and protocatechuic acid has been prepared.Protocatechuic acid lost its carboxylic proton and turned to be protocatechuic anion to form a 1：1：1 organic salt hydrate with berberine,[C（20）H（18）NO4]＋[C7H5O4]^-·H2O（1）.Compound1 crystallizes in the triclinic system,space group P1 with a = 7.9849（5）,b =10.5437（5）,c = 14.3621（5）？,α = 77.983（4）,β = 82.900（4）,γ = 78.024（4）o,V = 1152.82（10） A^3,Mr= 507.48,Dc= 1.462 g/cm^3,μ = 0.929 mm^-1,F（000） = 532,Z = 2,the final R = 0.0488 and w R = 0.1322 for 3993 reflectionswith I 〉 2σ（I）.The hydrate exhibited good solid state stability against humidity,which may result from strong hydrogen-bonding interactions between water molecules and carboxylate groups.The hydrate also exhibited acceptable solubility and dissolution rate.

Protective and therapeutic effect of protocatechuic acid in assessment of letrozole- induced polycystic ovary syndrome in rats

Objective:To investigate the potential activity of protocatechuic acid in female Wistar rats with letrozole-induced polycystic ovary syndrome(PCOS).Methods:Thirty rats were divided into five groups of six each.Group 1 received 0.5%carboxy methyl cellulose orally and served as the normal control group;group 2 was treated orally with 1 mg/kg of letrozole daily for 21 days and served as the PCOS induced group;group 3 was orally administered with letrozole of 1 mg/kg for 21 days and further administered with standard drug of clomiphene citrate at a dose of 1 mg/kg body weight in 0.5%carboxy methyl cellulose per oral and served as the standard group;groups 4 and 5 were administered with letrozole of 1 mg/kg for 21 days and further treated with protocatechuic acid orally at low dose of 5 mg/kg body weight and high dose of 15 mg/kg body weight respectively for 15 days.At the end of the study period,rats were subjected for the estimation of invasive blood pressure and heart rate,biochemical estimations and antioxidant assay.In addition,ovarian histomorphology was examined.Results:The PCOS was confirmed in the letrozole induced rats with increased concentration of androgen,abnormal lipid levels,glucose,glycosylated haemoglobin and also depletion of antioxidants.After protocatechuic acid treatment,the increased levels of testosterone due to induction of PCOS were restored to normal levels.Additionally,there was a consistent decrease in luteinizing hormone and follicle stimulating hormone levels in the treatment groups,followed by decrease in the number of cysts after treatment with protocatechuic acid.Histopathological observations showed a remarkable recovery of the ovarian tissue and the presence of normalized structure of antral follicle.Protocatechuic acid treatment restored all the parameters to normalcy and abolished cysts formation in ovaries of female rats.Conclusions:Protocatechuic acid shows potential protective effects in letrozole-induced PCOS rats.The protective effect is comparable to that of clomiphene citrate and thus shows its potential in the treatment of PCOS.

基于脂肪酸组成结合主成分分析识别不同比例大豆油和菜籽油调配的调和油

结合脂肪酸组成和化学计量学方法,对大豆油、菜籽油及其不同比例的二元调和油的识别进行基础研究,并分析不同比例调和油中脂肪酸含量的变化。结果表明在大豆油和菜籽油中,共检出脂肪酸组分17种,主要以油酸、亚油酸、棕榈酸和亚麻酸为主。在以不同比例低芥酸菜籽油和大豆油调配的调和油中,脂肪酸含量随调和比例的改变而呈现一定趋势的增加或减小。结合脂肪酸组成,对所有的139个样品进行了主成分分析(PCA),结果表明大豆油和菜籽油可以互相实现区分,不同比例的调和油样品分布在调配的溯源样品之间,基本按照比例关系分布成一条直线。研究通过对菜籽油、大豆油及其不同比例调配的调和油的脂肪酸组成进行了定量分析,分析了它们之间脂肪酸组成的变化,并结合化学计量学手段进行一些识别分析,为规范调和油的生产和保障公平有序的调和油市场提供参考。

原儿茶酸促进铁循环强化Fenton体系降解避蚊胺

为了减少传统Fenton体系中Fe(Ⅱ)的投加量,提高H_(2)O_(2)的利用率,选择添加原儿茶酸(PCA)实现Fenton体系中的铁循环。以避蚊胺(DEET)为目标污染物,在最佳反应条件:c(DEET)0=0.2 mmol/L,c(H_(2)O_(2))=1.0 mmol/L,n(H_(2)O_(2))/n[Fe(Ⅱ)]=20∶1,n(PCA)/n[Fe(Ⅱ)]=1∶1,pH值=3.0下,DEET在20 min内降解率可达75%。对DEET降解过程中的总铁(TFe)和Fe(Ⅱ)浓度的变化进行记录,证明了PCA除了作为络合剂提高溶液中Fe离子的溶解度,也可作为还原剂促进体系中的Fe循环。利用叔丁醇(TBA)和对苯醌(PBQ)作为自由基淬灭剂鉴别反应体系中主要活性物质,得出PCA/Fe(Ⅱ)/H_(2)O_(2)体系中起主要氧化作用的是羟基自由基(·OH)。共存离子试验结果表明,SO^(2-)_(4)的存在对DEET的降解没有影响。对常见的污染物降解试验表明,Fe(Ⅱ)/PCA/H_(2)O_(2)体系普适性较好。

HPLC法测定广西不同产地八角茴香中4种有机酸的含量

[目的]建立八角茴香中莽草酸、原儿茶酸、对羟基苯甲酸、对甲氧基苯甲酸的含量测定方法。[方法]采用高效液相色谱法对八角茴香进行测定,色谱柱为Kromasil 100-5-C_(18)(250 mm×4.6 mm,5μm),流动相为乙腈-3%磷酸水溶液(梯度洗脱),流速为1.0 ml/min,进样量为10μl,检测波长为254 nm,柱温为40℃。[结果]广西11个不同产地的八角茴香中莽草酸含量为6.34%~7.41%,原儿茶酸含量为0.28%~0.98%,对羟基苯甲酸含量为0.73%~1.90%,对甲氧基苯甲酸含量为0.07%~0.23%。[结论]本研究建立的方法操作简单,稳定性强,重复性好,可用于八角茴香中有效成分的含量测定。

甘肃河西地区不同产地锁阳中4种活性成分与生态因子的相关性研究

目的:对甘肃河西地区不同产地锁阳中4种活性成分与生态因子的相关性进行研究。方法:收集甘肃河西地区9个不同产地锁阳的经纬度、海拔、温度、降水量等生态因子信息,采用高效液相色谱法测定不同产地锁阳中没食子酸、原儿茶酸、儿茶素、根皮苷4种活性成分的含量,分析活性成分与生态因子的相关性。结果:不同产地锁阳中4种活性成分含量差异较大,没食子酸含量在0.056~0.453mg/g之间,原儿茶含量在0.010~0.058mg/之间,儿茶素含量在2.813~6.751mg/g之间,根皮苷含量在0.056~0.178mg/g之间。结论:最暖季降水量、年均降水量、最湿月降水量、最湿季降水量、最湿季均温、最冷月最高温是影响锁阳中原儿茶酸含量的主要生态因子,降水量与其呈明显负相关,温度与其呈明显正相关,其他活性成分与生态因子相关性不显著。

诱变筛选荧光假单胞菌M18高产吩嗪-1-羧酸(PCA)菌株及发酵条件研究

研究了亚硝基胍 (NTG)的诱变剂量、处理时间以及氯化钠浓度对野生型荧光假单胞菌M 18存活率的影响 ,NTG的诱变剂量 2 5～ 2 0 0mg/L ,处理时间 10～ 30min范围内 ,随着诱变剂剂量增加和时间的延长 ,M 18的存活率不断下降。NTG的作用剂量 2 5mg/L ,处理时间 10min时 ,细菌存活率为 5 5 %左右。利用细菌存活率为 5 5 %时的诱变条件 ,经生物测定 ,初筛获得 2 0株抑菌效果明显的诱变株。经摇瓶发酵复筛 ,从这 2 0株诱变株中 ,获得PCA高产诱变株M 18N0 7。并对此菌株发酵条件进行调整 ,较理想的培养条件为 :蛋白胨 18g/L ,葡萄糖 16 g/L ,氯化钠 1g/L ,硝酸钾10 g/L。小瓶培养时间 17h ,大瓶 5 %接种量 ,2 8℃培养 5 4h。

HPLC法测定骨伤跌打康复凝胶贴膏剂中7种成分含量

目的 建立测定骨伤跌打康复凝胶贴膏剂中7种主要成分质量分数的HPLC法。方法 色谱柱为Agilent ZORBA×SB-C18S tableBond Analytical柱(4.6 mm×250 mm, 5μm);测定波长为290 nm,流动相为乙腈-0.1%甲酸水梯度洗脱;流速为1.0 mL/min;柱温为35℃;进样量为10μL。结果 骨伤跌打康复凝胶贴膏剂中的原儿茶酸、咖啡酸、阿魏酸、盐酸小檗碱、大黄酸、大黄素、大黄酚7种主要有效成分在浓度线性范围内与色谱峰面积的标准曲线线性关系良好;原儿茶酸、咖啡酸、阿魏酸、盐酸小檗碱、大黄酸、大黄素、大黄酚的平均回收率分别为93.79%、95.86%、96.12%、95.31%、96.58%、107.43%、97.12%,7种成分的平均回收率均在93.79%~107.43%范围内。结论 建立的方法适合作为骨伤跌打康复凝胶贴膏剂质量控制的方法。

多成分含量测定结合抗氧化活性的化学计量学分析筛选五味子标准汤剂质量标志物的研究

目的探究五味子标准汤剂抗氧化活性的质量标志物。方法采用基于一测多评法(QAMS)的超高效液相色谱法(UPLC)结合化学计量学评价15批五味子标准汤剂的质量;采用DPPH法和ABTS法测定15批样品的抗氧化活性,并借助灰色关联度(GRA)和偏最小二乘回归法(PLSR)分析8种成分含量与抗氧化活性的关联。采用分子对接技术探讨候选质量标志物与抗氧化核心靶点的结合性,同时对单体的体外抗氧化活性进行实验验证。结果QAMS法与外标法(ESM)的含量结果差异不显著(P>0.05),并推测原儿茶酸、五味子醇乙、五味子酯乙、五味子乙素为五味子标准汤剂的质量差异成分。根据GRA和PLSR结果,上述4个质量差异成分可作为抗氧化能力的备选标志物。分子对接结果显示4个候选质量标志物与抗氧化相关靶点具有良好的亲和力。研究认为五味子标准汤剂的抗氧化作用可能是多种成分综合作用的结果,其中,单体成分验证结果显示原儿茶酸具有明显的抗氧化活性并呈现剂量依赖关系,最符合作为质量标志物的特征,因而可能作为五味子标准汤剂抗氧化的质量标志物。结论基于UPLC含量测定法和体外抗氧化实验,预测了五味子标准汤剂中的潜在抗氧化活性物质,也为五味子其它相关制剂的质量评价提供合理依据。

HPLC法测定赤瓟不同药用部位中原儿茶醛和原儿茶酸的含量

[目的]建立中药材赤瓟不同药用部位(块根和果实)中原儿茶醛和原儿茶酸的含量测定方法。[方法]采用高效液相色谱法(HPLC)测定赤瓟(块根和果实)中原儿茶醛和原儿茶酸的含量。色谱条件:Discovery C_(18)柱(4.6 mm×250 mm,5μm),流动相为甲醇-5%磷酸水溶液进行梯度洗脱(0~40 min,甲醇:20%~100%),紫外检测波长:280 nm,流速:1 m L/min。[结果]原儿茶醛的含量在0.003~0.052 mg/m L范围内具有良好的线性关系(r=1.000 0),平均回收率为100.6%,RSD为1.27%;原儿茶酸的含量在0.002~0.042 mg/m L范围内具良好的线性关系(r=1.000 0),平均回收率为100.6%,RSD为1.76%。[结论]该测定方法操作简单、结果可靠、重复性好、定量准确,可用于赤瓟(块根和果实)中原儿茶醛和原儿茶酸的含量测定。

基于多光谱技术对原儿茶酸抑制低密度脂蛋白氧化及其与牛血清白蛋白相互作用的研究

植物多酚被称作人类健康的“第7类营养素”,在医药、食品和营养保健等多个领域受到广泛关注。红心猕猴桃果皮(RKP)中多酚含量丰富,是提取植物多酚的优良原料,但常被视为加工废料遭弃用。该研究拟通过脉冲超声(PU)辅助天然深共晶溶剂(NADES)提取RKP多酚,并通过荧光光谱和紫外-可见光谱探究RKP中重点多酚—原儿茶酸(PCA)抑制低密度脂蛋白(LDL)氧化功效及其与牛血清白蛋白(BSA)的相互作用机制。结果表明,NADES对RKP多酚的提取率显著高于常规溶剂(如水或乙醇)。在超声功率400 W、料液比1﹕40(g·mL^(-1))、温度70℃、提取20 min及含水率20%(ω/ω)条件下,所筛选的6种NADES溶剂中,氯化胆碱-乙二醇组合提取率最高(29.84 mg GAE/g DW)。光谱实验结果表明,PCA具有较强的DPPH自由基清除能力,清除率最高可达94.39%。PCA能够显著延长LDL氧化过程中共轭二烯(CD)生成的延滞时间及达到峰值时间,有效抑制脂质氧化过程中脂褐素及总荧光产物生成,减少LDL氧化过程中色氨酸(Trp)及赖氨酸(Lys)残基的氧化修饰,显示出对LDL氧化极强的抑制效果。多光谱法对PCA与BSA相互作用研究发现,两者之间存在相互作用,具有较强的亲和力,且只有一个结合位点,疏水作用力在相互作用过程中起主要作用;相互作用后酪氨酸(Tyr)周围微环境几乎不发生改变,而Trp周围微环境极性降低、疏水性增加;三维荧光光谱进一步证明二者之间存在相互作用,并由此引起蛋白质结构发生变化;综合荧光光谱和紫外-可见光谱的实验结果,PCA与BSA相互作用猝灭机理为静态猝灭。该研究为开发RKP及PCA提供参考。

高效液相色谱及红外光谱法分析鸡血藤提取物中儿茶素类成分

建立高效液相色谱结合红外光谱法检测鸡血藤提取物中儿茶素类成分原儿茶酸、儿茶素、表儿茶素。利用Design-Expert13.0.6设计响应面试验,优化甲醇体积分数、液料比、超声时间、超声温度交互的提取条件,确定最高提取率。采用高效液相色谱(HPLC)法与红外光谱法对鸡血藤提取物中儿茶素类成分进行定量和定性分析,确定儿茶素类成分含量和单体结构。样品经甲醇溶液超声提取,以0.2%(质量分数)H3PO4-乙腈作为流动相进行梯度洗脱,采用InertsilTM ODS-35μm色谱柱(150 mm×4.6 mm,5μm)进行分离,柱温为30℃,流量为1 mL/min,检测波长为260 nm,进样体积为10μL。红外光谱法采用KBr压片法测定成分含量。原儿茶酸、儿茶素、表儿茶素的质量浓度在100~1000μg/mL范围内与色谱峰面积线性关系良好,相关系数分别为0.9997、0.9992、0.9993。利用Design-Expert13.0.6确定超声波最优提取工艺为超声时间40 min,超声温度51℃,甲醇体积分数50%,液料比50∶1 mL/g,得到儿茶素类物质总质量分数为7.8837 mg/g。红外光谱法证明鸡血藤中具有儿茶素类物质的单体或聚合体成分,为鸡血藤中儿茶素类物质的开发和质量控制提供光谱学理论基础和依据。