Flavonoid interactions during digestion,absorption, distribution and metabolism: a sequential structure–activity/property relationship-based approach in the study of bioavailability and bioactivity

Flavonoids are a group of polyphenols that provide health-promoting benefits upon consumption. However, poor bioavailability has been a major hurdle in their use as drugs or nutraceuticals. Low bioavailability has been associated with flavonoid interactions at various stages of the digestion, absorption and distribution process, which is strongly affected by their molecular structure. In this review, we use structure–activity/property relationship to discuss various flavonoid interactions with food matrices, digestive enzymes, intestinal transporters and blood proteins. This approach reveals specific bioactive properties of flavonoids in the gastrointestinal tract as well as various barriers for their bioavailability. In the last part of this review, we use these insights to determine the effect of different structural characteristics on the overall bioavailability of flavonoids. Such information is crucial when flavonoid or flavonoid derivatives are used as active ingredients in foods or drugs.     

Does Sulfation of Gastrin Influence Gastric Acid Secretion in Man?

To assess the physiologic significance of tyrosine o-sulfation of gastrin in humans, the gastric acid stimulatory potencies of sulfated and non-sulfated human gastrin-17 were compared in six normal young subjects. Sulfated and non-sulfated forms of synthetic human gastrin-17 were infused intravenously in doses from 12.7 to 478 pmol/ kg/h. Similar acid secretory responses were observed. The calculated maximal acid response for sulfated gastrin-17 was 35.7 ± 4.3mmol/h, and that for non-sulfated gastrin-17 was 39.8 ± 7.5 mmol/h (mean ± SEM, NS). The 50% effective dose of sulfated gastrin-17 was 22.2 ± 6.7pmol/kg/h, whereas it was 29.3 ± 5.8pmol/kg/h for non-sulfated gastrin-17 (NS). Finally, the 50% effective concentration of gastrin in serum was 34.7 ± 5.0 pmol sulfated gastrin-17/1 and 42.5 ± 11.8 pmol non-sulfated gastrin-17/1 (NS). The results show that tyrosine o-sulfation is without significant influence on the gastric acid secretory potency of gastrin in man. Moreover, the results also suggest that sulfated and non-sulfated gastrin-17 in man have similar rates of metabolism.     

构建携带人PAPS合成酶1(hpapss1)全长cDNA的重组腺病毒

目的 构建携带人PAPS合成酶1(hpapss1)全长cDNA的重组腺病毒,并感染巨噬细胞使PAPSS1过表达,为研究其在胆固醇代谢中的作用提供工具.方法 PCR扩增hpapss1全长cDNA,继而构建了真核表达载体pCDNA3.0-hpapss1,再将hpapss1片段亚克隆入腺病毒穿梭质粒pshuttle-CMV,得到转移质粒pshuttle-CMV-hpapss1,并将其转化含腺病毒基因组质粒pAdEasy-1的BJ5183感受态菌(AdEasier-1 cells).筛选并鉴定重组正确的腺病毒质粒pAdEasy-1-hpapss1,在阳离子脂质体介导下,转染腺病毒包装细胞(293细胞)进行包装和扩增.携带hpapss1全长cDNA的重组腺病毒感染THP-1来源的巨噬细胞48 h后,用Western blot方法测定蛋白水平来确定PAPSS1的过表达.结果 成功制备携带hpapss1全长cDNA的重组腺病毒,滴度为5.3×108 pfu/mL,实现了hpapss1基因在巨噬细胞中的过表达.结论 携带hpapss1全长cDNA的重组腺病毒的成功制备为进一步探讨PAPSS1及氧化固醇硫酸化在巨噬细胞胆固醇代谢平衡中的作用及机制建立了很好的模型和工具.     

The structural role of receptor tyrosine sulfation in chemokine recognition

Tyrosine sulfation is a post-translational modification of secreted and transmembrane proteins, including many GPCRs such as chemokine receptors. Most chemokine receptors contain several potentially sulfated tyrosine residues in their extracellular N-terminal regions, the initial binding site for chemokine ligands. Sulfation of these receptors increases chemokine binding affinity and potency. Although receptor sulfation is heterogeneous, insights into the molecular basis of sulfotyrosine (sTyr) recognition have been obtained using purified, homogeneous sulfopeptides corresponding to the N-termini of chemokine receptors. Receptor sTyr residues bind to a shallow cleft defined by the N-loop and β3-strand elements of cognate chemokines. Tyrosine sulfation enhances the affinity of receptor peptides for cognate chemokines in a manner dependent on the position of sulfation. Moreover, tyrosine sulfation can alter the selectivity of receptor peptides among several cognate chemokines for the same receptor. Finally, binding to receptor sulfopeptides can modulate the oligomerization state of chemokines, thereby influencing the ability of a chemokine to activate its receptor. These results increase the motivation to investigate the structural basis by which tyrosine sulfation modulates chemokine receptor activity and the biological consequences of this functional modulation.Linked ArticlesThis article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-5     

正交试验优选白芨多糖硫酸酯化工艺的研究

目的优选白芨多糖硫酸酯化的最佳工艺。方法采用氯磺酸-吡啶法合成白芨多糖硫酸酯。以取代度和产物量为指标,采用L9(34)正交设计对试剂比例、反应温度和反应时间进行优选。结果吡啶和氯磺酸比例6∶1,反应温度85℃,反应时间2h为比较适宜的工艺条件。结论白芨多糖硫酸酯化优化的工艺条件方法可行,为进一步扩大试验提供了有价值的参数。     

川芎中活性成分的提取工艺建立与综合评判

川芎,历来被誉为治疗头部疾病的圣药,广泛用于头痛、中风等疾病的治疗,具有显著疗效。川芎的活性成分有以藁本内酯、川芎内酯为主的苯酞类,以川芎嗪为代表的生物碱类,以阿魏酸为代表的有机酸类。其中苯酞类成分与川芎的镇静作用相关,川芎内酯有明显的强心、增加冠脉流量等作用,川芎嗪在临床上用于治疗脑血栓、偏头痛及脑外伤综合征,阿魏酸已作为治疗偏头痛的药物用于临床。因此,本实验在建立藁本内酯、川芎内酯定量基础上,本着中药“多靶点多部位有效部位群”理论,对川芎提取工艺进行了研究。1材料与仪器川芎购于四川都江堰市徐渡乡国家GA…     

CHENODEOXYCHOLIC ACID IN THE DISSOLUTION OF GALLSTONES

Chenodeoxycholic acid seems effective and safe in dissolving cholesterol gallstones of less than 1.5 cm in diameter, but it must be given continuously at doses of 12 to 15 mg per kilogram per day. Although liver toxicity appeared in several species of primates, man seems to avoid this because monohydroxy bile acids are sulfated and excreted more efficiently than in other primates.     

灵芝多糖硫酸酯对大鼠脑缺血再灌注损伤的保护作用及其机制

目的：对灵芝多糖（GLP）进行硫酸酯化分子修饰,观察灵芝多糖硫酸酯（GLPS）对大鼠脑缺血再灌注损伤的保护作用,初步探讨其作用机制。方法：硫酸酯化修饰GLP,得到GLPS;将100只SD大鼠随机分为假手术组、模型组、GLP组（40mg·kg^-1·d^-1）、GLPS组（40 mg·kg^-1·d^-1）和尼莫地平组（1 mg·kg^-1·d^-1）,每组20只。采用线栓法建立大鼠脑缺血再灌注模型,观察脑缺血再灌注损伤大鼠的神经功能缺损评分和脑组织含水量,检测大鼠脑组织中超氧化物歧化酶（SOD）活性和丙二醛（MDA）水平,ELISA法检测脑组织中匀浆中核因子kappa B（NF-κB）、肿瘤坏死因子α（TNF-α）、白细胞介素1（IL-1）和白细胞介素6（IL-6）水平,Western blotting法检测大鼠脑组织中热休克蛋白70（HSP-70）和磷酸化的丝氨酸/苏氨酸蛋白激酶（p-Akt）表达水平。结果：与模型组比较,GLP和GLPS组大鼠神经功能评分降低（P<0.01）,脑组织含水量减少（P<0.05或P<0.01）,SOD活性升高（P<0.05或P<0.01）,MDA水平降低（P<0.05或P<0.01）,NF-κB、TNF-α、IL-1和IL-6水平降低（P<0.05或P<0.01）,且GLPS组变化较GLP组明显（P<0.05）;Western blotting检测,与模型组比较,GLP组和GLPS组大鼠脑组织中p-Akt蛋白表达水平升高（P<0.05）,GLPS组大鼠脑组织中HSP-70蛋白表达水平升高（P<0.01）,而GLP组HSP-70蛋白表达水平升高效果不明显。结论：硫酸酯化修饰可以明显改善GLP对大鼠脑缺血再灌注损伤的保护作用,其作用机制可能通过调控HSP70/PI3K/Akt信号通路,抑制再灌注后继发的炎症反应,从而发挥对神经细胞的保护作用。