Mechanisms of endothelium-dependent vasorelaxation induced by procyanidin B2 in venous bypass graft

Cardioprotective abilities of procyanidins, might, at least in part, attribute to their vasodilator properties. The present study was undertaken to assess the vasorelaxant effect of procyanidin B2 on isolated human saphenous vein (HSV) and its underlying mechanisms. Procyanidin B2 relaxed phenylephrine-induced contraction of HSV rings in concentration-dependent manner. The relaxation was dependent on the presence of endothelium and was strongly affected by l-NAME, hydroxocobalamin or ODQ, the inhibitors of NO/cGMP pathway. Indomethacin significantly affected only the relaxation produced by the highest concentrations of procyanidin B2. Apamin and TRAM-34 combination, in the presence of l-NAME and indomethacin, did not additionally decreased procyanidin B2-induced relaxation. In the presence of K⁺ channel blockers, relaxation induced by procyanidin B2 was partially attenuated by 4-aminopyridine, significantly inhibited by glibenclamide and almost abolished by iberiotoxin. Procyanidin B2 also relaxed the contractions induced by phenylephrine or caffeine in Ca²⁺-free solution. Finally, nifedipine slightly, while thapsigargin strongly antagonized HSV relaxation. Our results indicate that procyanidin B2 induces endothelium-dependent relaxation of HSV, which results primarily from stimulation of NO production, as well K⁺ channels opening, especially BK_Ca, and partially K_ATP and K_V. Regulation of the intracellular Ca²⁺ release and inhibition of Ca²⁺ influx probably contribute to procyanidin B2-induced relaxation.     

原花青素对 2 型糖尿病局灶性脑缺血大鼠脑组织信号转导及转录激活因子 1 的影响

目的 探讨原花青素（PC）对2型糖尿病局灶性脑缺血大鼠脑信号转导及转录激活因子1 （STAT1）表达的影响.方法 75只SD大鼠随机分为假手术组,2型糖尿病合并脑缺血组,PC低、中、高剂量组,每组15只.制作2型糖尿病大鼠局灶性脑缺血模型,PC组在建立2型糖尿病模型后给予灌胃,1次/24 h,连续1周,于大脑中动脉缺血术前1h再灌胃1次.PC低、中、高剂量组分别以PC粉剂50、100、200 mg/（kg·次）灌胃.进行神经功能评分,免疫组化SABC染色法对STAT1蛋白进行定量分析,统计大鼠缺血侧大脑皮质缺血半暗带区每高倍镜视野STAT1蛋白的阳性细胞数.结果 与假手术组比较,2型糖尿病合并脑缺血组的神经行为学评分明显增高[0分比（3.42±1.00）分],缺血侧海马区神经细胞计数减少[（102.10±4.62）个/HP比（56.60±6.15）个/HP],缺血侧皮质STAT1阳性细胞数增多[（4.10±1.26）个/HP比（20.13±1.36）个/HP],差异均有高度统计学意义（均P＜0.01）;与2型糖尿病局灶性脑缺血组相比,PC低、中和高剂量组的神经行为学评分明显减少[（2.83±0.83）、（1.83±0.58）、（1.42±0.51）分]、缺血侧海马区神经细胞计数增多[（82.40±2.88）、（92.40±4.28）、（95.20±5.26）个/HP]、缺血侧皮质STAT1的表达均明显减少[（17.25±0.99）、（13.67±1.88）、（12.92±1.74）个/HP],差异均有统计学意义（P＜ 0.05或P＜0.01）;PC中、高剂量组的作用比PC低剂量组更明显（P＜ 0.01）,但PC中、高剂量组组间比较,差异无统计学意义（P＞0.05）.结论 原花青素可能通过降低STAT1蛋白的表达,影响Janus激酶/信号转导及转录激活因子信号转导途径,从而抑制细胞凋亡,减轻神经功能缺损,达到对2型糖尿病合并缺血性脑血管病的保护作用.     

HPLC法测定威麦宁胶囊中原花青素B2和表儿茶素的含量

目的:建立威麦宁胶囊中原花青素B2、表儿茶素的HPLC测定方法。方法:采用高效液相色谱法测定原花青素B2、表儿茶素的含量,其标准曲线、精密度、重复性、加样回收率均符合要求。色谱柱:Zorbax SB-C18柱,流动相为乙腈-0.04%磷酸水溶液,梯度洗脱,检测波长为280nm,柱温30℃,流速1.0 mL.min-1,进样量10μL。结果:原花青素B2、表儿茶素的标准曲线分别为A原花青素B2=7047.3C-1066(r=0.9998),A表儿茶素=7321.9C-601.43(r=0.9999),加样回收率分别为93.56%(RSD 4.36%)、99.34%(RSD 4.14%),3个批次威麦宁胶囊中原花青素B2、表儿茶素的平均含量分别为1.44mg/粒、0.96mg/粒。结论:威麦宁胶囊3个批次中2种主要成分的含量相近。该方法简便、准确、重复性好,可为威麦宁胶囊提供质量控制方法。     

Cinchonain Ib isolated from Eriobotrya japonica induces insulin secretion in vitro and in vivo

Aims of the study

Eriobotrya japonica leaves had been used traditionally for the treatment of diabetes mellitus by immersing the dried leaves in a hot water drink. Few studies have shown the hypoglycemic effect of Eriobotrya japonica using crude alcoholic extract and isolated methanolic compounds. These studies proposed that the mechanism of action could be by stimulating the β-islets of Langerhans to secrete insulin, however with no scientific evidence.

Methods

Eriobotrya japonica water extract (EJWE) and the compounds derived from it: cinchonain Ib, procyanidin B-2, chlorogenic acid and epicatechin, were tested for their effects on insulin secretion from INS-1 cells and following oral administration in rats.

Results

The present study showed that EJWE increased significantly (p < 0.05) insulin secretion from INS-1 cells in dose-dependent manner. Oral administration of EJWE at 230 mg/kg to rats, however, decreased plasma insulin level for as long as 240 min post-administration and caused a transient drop of blood glucose at 15 and 30 min post-administration. On the other hand, cinchonain Ib enhanced significantly (p < 0.05) insulin secretion from INS-1 cells, whereas epicatechin inhibited significantly (p < 0.05) insulin secretion from INS-1 cells. In addition, cinchonain Ib enhanced significantly (150%: p < 0.05) plasma insulin level in rats for as long as 240 min after 108 mg/kg oral administration but did not induce any change in blood glucose level.

Conclusion

These data indicate that cinchonain Ib has an insulinotropic effect and suggest the possible use of cinchonain Ib for managing type 2 diabetes.     

葡萄籽原花青素提取物对乙酸性结肠炎模型大鼠保护作用机制探讨

目的:研究葡萄籽原花青素提取物(GSPE)治疗乙酸性结肠炎的作用机制。方法:制备大鼠乙酸性结肠炎模型,分别设正常对照组、模型对照组、阳性对照组和GSPE低、中、高剂量组(灌胃);给药8d时分别检测结肠组织中髓过氧化物酶(MPO)、超氧化物歧化酶(SOD)、氧化型谷光甘肽过氧化物酶(GSH-Px)及丙二醛(MDA)的变化。结果:与正常对照组比较,模型对照组MPO含量明显升高(P<0.01);与模型对照组比较,GSPE各剂量组MPO活性、MDA含量明显降低(P<0.05),SOD和GSH-Px活性明显升高(P<0.05)。结论:GSPE治疗乙酸性结肠炎作用机制与其抗炎、抗氧化、提高组织抗氧化能力、减轻脂质过氧化损伤及促进损伤组织的修复有关。     

SPE-HPTLC of procyanidins from the barks of different species and clones of Salix

A SPE-HPTLC method was developed for the qualitative and quantitative analysis of procyanidin B(1) in willow barks. The chromatography was performed on HPTLC silica gel layer with the mobile phase chloroform-ethanol-formic acid (50:40:6 v/v/v), in the Automatic Developing Chamber-ADC 2. The methanol extracts from willow barks were purified by SPE method on RP-18 silica gel columns with methanol-water (7:93 v/v) as the eluent. The presence of procyanidin B(1) was revealed in the majority of investigated willow barks. The content of procyanidin B(1) varied from 0.26 mg/g in the extract of Salix purpurea clone 1067-2.24 mg/g in the extract of Salix alba clone 1100. The method was validated for linearity, precision, LOD, LOQ and repeatability.     

Procyanidin B2 protects rats from paraquat-induced acute lung injury by inhibiting NLRP3 inflammasome activation

Paraquat is a commonly used heterocyclic herbicide and has high toxicity by causing acute lung injury. There is no effective treatment for paraquat poisoning. We evaluated the effects of procyanidin B2, a natural dietary phytochemical, on paraquat-induced lung injury in rats. Paraquat was used to induce acute lung injury of rats, which were administered with procyanidin B2. The lung injury was evaluated by measuring the lung/body weight ratio, the histology and PMNs count. The oxidative stress was assessed by detecting ROS-mediated indices in the BALF. The expression of IL-1β and IL-18 were detected by RT-PCR and ELISA. The levels of NLRP3 inflammasome components including NLRP3, ASC and caspase-1 were detected by western blot. The lung injury in the paraquat-induced models in NLRP3 gene silenced animals was compared with the same lung injury model treated with procyanidin B2. Administration of procyanidin B2 significantly reduced paraquat-induced lung injury with lower BALF PMNs count, MPO activity, MDA level and elevated SOD activity. Procyanidin B2 suppressed expression of IL-1β and IL-18 at both RNA and protein levels, similar to the NLRP3 gene silenced rats. Compared to paraquat-induced group, procyanidin B2 showed remarkably decreased NLRP3, ASC and caspase-1 signals in the lung tissues in a dose-dependent manner. Procyanidin B2 significantly suppressed the activation of NLRP3 inflammasome in the lung tissue induced by paraquat in the rat model. This finding revealed a novel mechanism by which procyanidin B2 exerts anti-inflammatory effects and their clinical benefits in health.     

Procyanidin B2 protects against diet-induced obesity and non-alcoholic fatty liver disease via the modulation of the gut microbiota in rabbits

BACKGROUND Procyanidins have beneficial effects on metabolic syndrome and antimicrobial activity,but the mechanisms underlying these effects are unclear.AIM To investigate the effects of procyanidin B2(PB2)on non-alcoholic fatty liver disease and to explore the possible mechanism.METHODS Thirty male New Zealand white rabbits were randomized into three groups.All of them were fed either a high-fat-cholesterol diet(HCD)or chow diet.HCD-fed rabbits were treated with vehicle or PB2 daily for 12 wk.Body weight and food intake were evaluated once a week.Serum biomarkers,such as total cholesterols,triglycerides,and aspartate transaminase,were detected.All rabbits were sacrificed and histological parameters of liver were assessed by hematoxylin and eosin-stained sections.Moreover,several lipogenic genes and gut microbiota(by 16S rRNA sequencing)were investigated to explore the possible mechanism.RESULTS The HCD group had higher body weight,liver index,serum lipid profile,insulin resistance,serum glucose,and hepatic steatosis compared to the CHOW group.PB2 treatment prevented HCD-induced increases in body weight and hypertriglyceridemia in association with triglyceride accumulation in the liver.PB2 also ameliorated low-grade inflammation,which was reflected by serum lipopolysaccharides and improved insulin resistance.In rabbit liver,PB2 prevented the upregulation of steroid response element binding protein 1c and fatty acid synthase and the downregulation of carnitine palmitoyltransferase,compared to the HCD group.Moreover,HCD led to a decrease of Bacteroidetes in gut microbiota.PB2 significantly improved the proportions of Bacteroidetes at the phylum level and Akkermansia at the genus level.CONCLUSION Our results indicate the possible mechanism of PB2 to improve HCD-induced features of metabolic syndrome and provide a new dietary supplement.     

原花青素B2及黄曲霉毒素B1对人胚胎肝细胞细胞色素P450亚酶1A2、3A4活力及基因表达的影响

目的 探讨原花青素B2(PC-B2)与黄曲霉毒素B1(AFB1)对人胚胎肝细胞L-02细胞色素P450 (CYP)亚酶1A2、3A4活力及其基因表达的影响.方法 L-02细胞体外培养后分空白对照、溶剂对照、AFB1染毒、PC-B2处理和PC-B2干预共5组,其中PC-B2处理分为3个亚组,分别采用3、10、30 μg/ml PC-B2干预,PC-B2干预分为3各亚组,分别采用3、10、30 μg/ml PC-B2预处理12 h后,再加不同浓度PC-B2与AFB1干预24 h.测定各组细胞的CYP1 A2、CYP3A4酶活力以及CYP1 A2、CYP3A4基因的mRNA表达水平;测定细胞存活率,倒置荧光显微镜观察细胞形态.结果 与空白对照组相比,AFB1染毒组细胞存活率降低(P＜0.05),胞膜结构不清,漂浮细胞增多,CYP1 A2、CYP3A4酶活力及其mRNA表达水平明显升高(P＜0.05).与空白对照组相比,3、10μg/ml PC-B2处理组细胞相关指标无明显变化,但30 μg/ml PC-B2处理组的细胞存活率升高,CYP1A2、CYP3A4酶活力下降(P＜0.05).与AFB1染毒比较,30 μg/ml PC-B2干预组的细胞存活率升高(P＜0.05),各浓度PC-B2干预组的细胞CYP1A2、CYP3A4酶活力及基因表达均降低(P＜0.05),且干预浓度越高,CYP1A2、CYP3A4酶活力及基因表达越低(P＜0.05).结论 AFB1能明显诱导肝细胞CYP1A2、CYP3A4酶活力及其mRNA表达,促使肝细胞凋亡,PC-B2干预可促进肝细胞生长并抑制上述CYP二个亚酶的活力及其基因表达,提示PC-B2可能通过抑制Ⅰ相代谢酶CYP对AFB1的活化而对肝细胞有良好保护作用.