Proanthocyanidins and Flavan-3-ols in the Prevention and Treatment of Periodontitis—Immunomodulatory Effects,Animal and Clinical Studies

This paper continues the systematic review on proanthocyanidins and flavan-3-ols in the prevention and treatment of periodontal disease and covers the immunomodulatory effects, and animal- and clinical studies, while the other part discussed the direct antibacterial properties. Inflammation as a major response of the periodontal tissues attacked by pathogenic microbes can significantly exacerbate the condition. However, the bidirectional activity of phytochemicals that simultaneously inhibit bacterial proliferation and proinflammatory signaling can provide a substantial alleviation of both cause and symptoms. The modulatory effects on various aspects of inflammatory and overall immune response are covered, including confirmed and postulated mechanisms of action, structure activity relationships and molecular targets. Further, the clinical relevance of flavan-3-ols and available outcomes from clinical studies is analyzed and discussed. Among the numerous natural sources of flavan-3-ols and proanthocyanidins the most promising are, similarly to antibacterial properties, constituents of various foods, such as fruits of Vaccinium species, tea leaves, grape seeds, and tannin-rich medicinal herbs. Despite a vast amount of in vitro and cell-based evidence of immunomodulatory there are still only a few animal and clinical studies. Most of the reports, regardless of the used model, indicated the efficiency of these phytochemicals from cranberries and other Vaccinium species and tea extracts (green or black). Other sources such as grape seeds and traditional medicinal plants, were seldom. In conclusion, the potential of flavan-3-ols and their derivatives in prevention and alleviation of periodontal disease is remarkable but clinical evidence is urgently needed for issuing credible dietary recommendation and complementary treatments.     

Co‐operative suppression of inflammatory responses in human dendritic cells by plant proanthocyanidins and products from the parasitic nematode Trichuris suis

Interactions between dendritic cells (DCs) and environmental, dietary and pathogen antigens play a key role in immune homeostasis and regulation of inflammation. Dietary polyphenols such as proanthocyanidins (PAC) may reduce inflammation, and we therefore hypothesized that PAC may suppress lipopolysaccharide (LPS) ‐induced responses in human DCs and subsequent T helper type 1 (Th1) ‐type responses in naive T cells. Moreover, we proposed that, because DCs are likely to be exposed to multiple stimuli, the activity of PAC may synergise with other bioactive molecules that have anti‐inflammatory activity, e.g. soluble products from the helminth parasite Trichuris suis (TsSP). We show that PAC are endocytosed by monocyte‐derived DCs and selectively induce CD86 expression. Subsequently, PAC suppress the LPS‐induced secretion of interleukin‐6 (IL‐6) and IL‐12p70, while enhancing secretion of IL‐10. Incubation of DCs with PAC did not affect lymphocyte proliferation; however, subsequent interferon‐γ production was markedly suppressed, while IL‐4 production was unaffected. The activity of PAC was confined to oligomers (degree of polymerization ≥ 4). Co‐pulsing DCs with TsSP and PAC synergistically reduced secretion of tumour necrosis factor‐α, IL‐6 and IL‐12p70 while increasing IL‐10 secretion. Moreover, both TsSP and PAC alone induced Th2‐associated OX40L expression in DCs, and together synergized to up‐regulate OX40L. These data suggest that PAC induce an anti‐inflammatory phenotype in human DCs that selectively down‐regulates Th1 response in naive T cells, and that they also act cooperatively with TsSP. Our results indicate a novel interaction between dietary compounds and parasite products to influence immune function, and may suggest that combinations of PAC and TsSP can have therapeutic potential for inflammatory disorders.     

Oligomeric proanthocyanidins protect myocardium by mitigating left ventricular remodeling in isoproterenol‐induced postmyocardial infarction

Extracellular matrix (ECM) remodeling is a major pathophysiological process during post‐myocardial infarction (MI). The activation, differentiation, and proliferation of cardiac fibroblasts to myofibroblasts regulate the expression of ECM proteins. The signaling by bone morphogenetic protein (BMP‐4), an extracellular ligand of the TGF‐β family, has recently been identified as an essential pathway in regulating cardiovascular dysfunctions including myocardial fibrosis. Oligomeric proanthocyanidins (OPC) are well known for their cardioprotective activity. The primary aim of the study was to investigate BMP‐4‐mediated ECM turnover in cardiac fibrosis during isoproterenol‐induced post‐MI and its downregulation by OPC. Myocardial injury was evaluated by assaying serum markers LDH and CK. Oxidative stress and the enzymatic and nonenzymatic antioxidant levels were assessed to support the cardioprotective nature of OPC. The total collagen level was analyzed by measuring hydroxyproline levels. The ISO‐induced group showed a significant decrease in the levels of antioxidants due to severe oxidative stress and increased expression of BMP‐4 which reflects the increased expression of MMP 2 and 9 with a concomitant increase and deposition of fibrillary collagens type I and III responsible for the fibrotic scar formation as evidenced in the histological analysis.BMP‐4 activation, thus, is strongly associated with cardiac fibrosis which was downregulated upon OPC supplementation. This study provides an evidence supporting the antifibrotic effect of OPC via regulation of BMP‐4‐mediated ECM turnover and also substantiates the remarkable antioxidant efficacy of OPC against isoproterenol induced severe oxidative stress and subsequent post‐MI cardiac fibrosis.     

Methacrylate-functionalized proanthocyanidins as novel polymerizable collagen cross-linkers — Part 2: Effects on polymerization,microhardness and leaching of adhesives

ObjectiveThe aim of the study was to investigate the effects of a novel polymerizable collagen cross-linker methacrylate-functionalized proanthocyanidins (MAPA) on the polymerization, microhardness and leaching of a HEMA-based experimental dental adhesive system.MethodsThree MAPAs were synthesized using different methacrylate (MA) to proanthocyanidins (PA) feeding ratios of 1:2, 1:1, and 2:1 to obtain MAPA-1, MAPA-2, and MAPA-3, respectively. The resulting three MAPAs and PA were added to an experimental adhesive formulated with HEMA and a tri-component photoinitiator system (0.5 wt% CQ/EDMAB/DPIHP) at 1%, 5% and 10% MAPA or PA concentrations (wt%). The adhesive polymerization kinetics was measured continuously in real-time for 10 min using a Fourier-transform infrared spectroscopy (FTIR) with an attenuated total reflectance (ATR) accessory. Degree of conversion (DC) and Vickers microhardness (MH) of cured adhesives were measured at 72 h post-cure. The leaching of cured adhesives in DI water was monitored using UV–vis spectrophotometer. Statistical analysis was performed using one-way and two-way ANOVA, Tukey’s (p < 0.05).ResultsThe adhesive formulations with 1%, 5% and 10% MAPAs-1, -2, -3 all generated higher rate of polymerization and 10-min DC than the formulations with PA at the same concentrations. At 72 h post-cure, the adhesive formulation with 5% MAPA-2 exhibited significantly higher DC (99.40%) and more than doubled MH (18.93) values than the formulation with 5% PA (DC = 89.47%, MH = 8.41) and the control (DC = 95.46%, MH = 9.33). Moreover, the cured adhesive with 5% MAPA-2 demonstrated significantly reduced PA leaching in comparison with cured adhesive with 5% PA.SignificanceSynthesized MAPA is a novel class of polymerizable collagen cross-linker that not only stabilizes dentin collagen via its PA component, but also improves polymerization, mechanical properties and stability of HEMA-based adhesives via its MA component. By inheriting the benefit while overcoming the drawback of PA, MAPA offers a revolutionary solution for improved bond-strength and longevity of dental restorations.     

原花青素联合乙醇湿粘结技术对乳牙牙本质剪切粘结强度的影响

目的：观察原花青素（PA）联合乙醇湿粘结技术对树脂乳牙牙本质剪切粘结强度的影响。方法：选取乳磨牙35颗,沿近远中向劈开,制成70个样本。将实验牙随机分为5组,分别为PA＋乙醇溶液预处理60 s和120 s组;乙醇单独预处理60 s和120 s组;对照组的牙本质树脂粘结试件。电子万能试验机测定37℃水浴保存24 h和30 d的剪切粘结强度;扫描电镜观察断裂面形态。结果：PA＋乙醇预处理组剪切粘结强度值明显大于乙醇单独预处理组和对照组（P＜0．05）,FESEM观察结果显示PA＋乙醇预处理组断裂主要发生在混合层顶部。结论：原花青素和乙醇湿粘结技术联合使用可以提高树脂乳牙牙本质间的剪切粘结强度。     

低聚原花青素对葡聚糖硫酸钠诱导小鼠溃疡性结肠炎的保护作用

 目的 研究低聚原花青素(oligomeric proanthocyanidins,OPC)对葡聚糖硫酸钠(dextran sulfate sodium,DSS)诱导的溃疡性结肠炎(ulcerative colitis,UC)小鼠的治疗作用,并初步探讨其保护机制。方法 选取雄性C57小鼠40只,选取8只为正常对照组。其他32只用2.5%的DSS进行UC造模后,随机分为模型组、美沙拉嗪组(美沙拉嗪500 mg/kg)、低剂量组(OPC500 mg/kg)、高剂量组(OPC1000 mg/kg),每组8只。连续给药7 d后处死小鼠,评估疾病活动指数(DAI),观察结肠病理变化,评估结肠大体形态损伤指数(colon macroscopic damage index,CMDI),计算检测血清IL-10水平,测定髓过氧化物酶(myeloperoxidase,MPO)活性。结果 与正常对照组相比,造模后各组小鼠的DAI评分明显升高,结肠黏膜变薄、上皮脱落和炎性细胞浸润,CMDI评分明显升高,结肠长度和血清IL-10水平明显降低,组织MPO活性明显升高,差异有统计学意义(P<0.05);与模型组相比,美沙拉嗪组、低剂量组和高剂量组的DAI评分和CMDI评分显著降低,结肠长度延长,血清IL-10水平明显升高,MPO活性明显降低,差异有统计学意义(P<0.05)。且美沙拉嗪组与高剂量组接近,均优于低剂量组。结论 OPC可通过减少氧化应激,抑制炎性反应,降低DSS诱导UC小鼠的DAI,改善小鼠结肠组织病理形态,具有治疗作用。     

Consumption of cranberry beverage improved endogenous antioxidant status and protected against bacteria adhesion in healthy humans: a randomized controlled trial

Consumption of polyphenol-rich foods is associated with lower risk from many chronic diseases. We hypothesized that a single dose of cranberry beverage would improve indices of oxidative stress, inflammation, and urinary antibacterial adhesion activity in healthy humans. Six males and 6 females (18-35 years; body mass index, 19-25 kg/m²) consumed placebo, cranberry leaf extract beverage, or low-calorie cranberry juice cocktail (LCJC) once in a randomized, double-blind, placebo-controlled cross-over experimental design trial. The washout period between beverages was 1 week. Blood was collected 0, 2, 4, 8, and 24 hours after beverage consumption for measuring oxidative and inflammatory biomarkers. Urine was collected at 0, 0 to 3, 3 to 6, 6 to 9, 9 to 12, and 24 hours postintervention to assess antibacterial adhesion activity. Consumption of cranberry leaf extract beverage elevated (P < .05) blood glutathione peroxidase activity, whereas LCJC consumption increased (P < .05) glutathione concentrations and superoxide dismutase activity compared with placebo. Cranberry leaf extract beverage and LCJC consumption had no effect on the inflammatory biomarkers measured as compared with placebo. At 0 to 3 hours postconsumption, urine from participants who consumed cranberry beverages had higher (P < .05) ex vivo antiadhesion activity against P-fimbriated Escherichia coli compared with placebo. An acute dose of cranberry beverages improved biomarkers of antioxidant status and inhibition of bacterial adhesion in urine.     

Cranberry proanthocyanidins are cytotoxic to human cancer cells and sensitize platinum‐resistant ovarian cancer cells to paraplatin

Polyphenolic extracts of the principal flavonoid classes present in cranberry were screened in vitro for cytotoxicity against solid tumor cells lines, identifying two fractions composed principally of proanthocyanidins (PACs) with potential anticancer activity. Matrix‐Assisted Laser Desorption/Ionization Time‐Of‐Flight Mass Spectrometry (MALDI‐TOF‐MS) analysis of the proanthocyanidins (PACs) fractions indicated the presence of A‐type PACs with 1–4 linkages containing between 2–8 epicatechin units with a maximum of 1 epigallocatechin unit. PACs exhibited in vitro cytotoxicity against platinum‐resistant human ovarian, neuroblastoma and prostate cancer cell lines (IC₅₀ = 79–479 µg/mL) but were non‐cytotoxic to lung fibroblast cells (IC₅₀ > 1000 µg/ml). SKOV‐3 ovarian cancer cells treated with PACs exhibited classic apoptotic changes. PACs acted synergistically with paraplatin in SKOV‐3 cells. Pretreatment of SKOV‐3 cells with PACs (106 µg/ml) resulted in a significant reduction of the paraplatin IC₅₀ value. Similarly, in a BrdU incorporation assay, co‐treatment of SKOV‐3 cells with PACs and paraplatin revealed reduced cell proliferation at lower concentrations than with either individually. In SKOV‐3 cell cultures co‐treated with PAC‐1 and paraplatin, an HPLC analysis indicated differential quantitative presence of various PAC oligomers such as DP‐8, ‐9, ‐11 and ‐14 indicating either selective binding or uptake. Cranberry proanthocyanidins exhibit cell‐line specific cytotoxicity, induce apoptotic markers and augment cytotoxicity of paraplatin in platinum‐resistant SKOV‐3 ovarian cancer cells. Copyright © 2009 John Wiley & Sons, Ltd.     

不同产地罗布麻叶中原花色素的含量测定

目的:测定不同产地罗布麻叶中原花色素的含量,并对不同产地的罗布麻叶进行比较。方法:采用分光光度法测定氯化花色素,测定波长为545nm。结果:天津产罗布麻叶中原花色素含量最高,新疆的最低。天津、山东、山西、陕西和新疆5个不同产地罗布麻叶中原花色素含量依次为10.95%,7.96%,7.30%,6.56%,2.16%。结论:不同产地罗布麻叶中的原花色素含量差异明显,应选择使用。