Hot-melt extrusion microencapsulation of quercetin for taste-masking

Besides its poor dissolution rate, the bitterness of quercetin also poses a challenge for further development. Using carnauba wax, shellac or zein as the shell-forming excipient, this work aimed to microencapsulate quercetin by hot-melt extrusion for taste-masking. In comparison with non-encapsulated quercetin, the microencapsulated powders exhibited significantly reduced dissolution in the simulated salivary pH 6.8 medium indicative of their potentially good taste-masking efficiency in the order of zein?>?carnauba wax?>?shellac. In vitro bitterness analysis by electronic tongue confirmed the good taste-masking efficiency of the microencapsulated powders. In vitro digestion results showed that carnauba wax and shellac-microencapsulated powders presented comparable dissolution rate with the pure quercetin in pH 1.0 (gastric) and 6.8 (intestine) medium; while zein-microencapsulated powders exhibited a remarkably slower dissolution rate. Crystallinity of quercetin was slightly reduced after microencapsulation while its chemical structure remained unchanged. Hot-melt extrusion microencapsulation could thus be an attractive technique to produce taste-masked bioactive powders.     

Antibacterial synergy between quercetin and polyphenolic acids against bacterial pathogens of fish

ObjectiveTo evaluate combinations of quercetin with gallic acid, p-anisic acid and cinnamic acid in vitro for synergistic activity against common Gram-negative bacterial pathogens of fish viz., Aeromonas hydrophila, Aeromonas salmonicida and Edwardsiella tarda.MethodsAntibacterial activity of quercetin, gallic acid, p-anisic acid and cinnamic acid was determined against selected bacterial pathogens individually, followed by combination of quercetin with polyphenolic acids using serial microplate dilution method measuring minimum inhibitory concentrations. Fractional inhibitory concentration indices were calculated.ResultsQuercetin and other polyphenolic compounds exhibited antibacterial action against the selected fish pathogens with mean minimum inhibitory concentrations ranging from 0.83 to 2.5 mg/mL. It was observed that fractional inhibitory concentration indices for combination of quercetin with gallic acid, p-anisic acid or cinnamic acid against Aeromonas salmonicida were less than 0.5, indicating synergistic interaction. However, the above combinations produced additive antimicrobial activity against Aeromonas hydrophila and Edwardsiella tarda.ConclusionsPositive antibacterial interaction was evident between quercetin and selected polyphenolic acids in vitro.     

Chemotype and genotype combined analysis applied to tomato (Lycopersicon esculentum Mill.) analytical traceability

A large number of fresh fruits and vegetables are primary sources of antioxidants; tomato (Lycopersicon esculentum Mill.) is accepted worldwide as a significant source of antioxidant functional compounds (vitamin C, lycopene, rutin). Many cultivars and hybrids of tomato, having different chemical and nutritional characteristics, are available on the market. Tomato cultivars for industrial processing are very different, not only in fruit characteristics (size, shape), but also in lycopene and antioxidant contents. The aim of this study was the chemotyping and genotyping of the tomato varieties Heinz 3402, Leader and Perfectpeel, (1) to evaluate the genetic traceability of these varieties, and (2) to determine whether their functional antioxidants compounds are useful markers of traceability. Principal component analysis (PCA) was first applied to the Random Polymorphic DNA (RAPD) fingerprints, confirming that this approach is a powerful identification method at intra-specific level. Heinz 3402 showed the highest antioxidant activity, followed by Perfectpeel and Leader varieties. Perfectpeel showed the lower lycopene content, while Leader and Heinz 3402 showed significantly higher values (13.68 and 15.78 mg/100 g, fresh weight, respectively). The highest rutin content was observed in Heinz 3402 (12.46 ± 0.69, mg/100 g, fresh weight), followed by Leader (7.87 ± 0.72) and Perfectpeel (2.70 ± 0.68). Antioxidant capacity was significantly correlated with the lycopene and rutin content. Finally, PCA was applied to chemotype data-sets, confirming both mineral content and functional antioxidant compounds as useful markers to unambiguously identify these high-lycopene content varieties.     

8-Br-cAMP联合槲皮素对人食管癌Eca-109细胞的逆转化作用

目的探讨8-Br-cAMP与槲皮素联合用药对人食管癌Eca-109细胞逆转化的作用。方法将培养的Eca-109细胞随机分为4组:①8-Br-cAMP组(Br):加终浓度为2×10-5mol/L8-Br-cAMP;②槲皮素组(Q):加槲皮素终浓度为43μmol/L;③8-Br-cAMP和槲皮素共同作用组(Br+Q):加终浓度为2×10-5mol/L8-Br-cAMP和终浓度为43μmol/L的槲皮素;④对照组(C):仅加DMEM培养液(含10%胎牛血清)。同时培养48h后分别对以上4组细胞制备细胞滴片及硝酸纤维素膜滴膜两种标本,进行Caspase-3和PCNA的免疫组化和免疫斑点印迹实验;应用完整细胞原位斑点印迹杂交技术检测c-myc、野生型p53(wtp53)、p16和EGFR的基因表达;并进行分化细胞/增殖细胞计数。结果8-Br-cAMP与槲皮素联合或单独应用均可上调Caspase-3免疫反应信号的表达,下调PCNA免疫反应信号的表达;同时上调wtp53和p16基因的表达,下调c-myc和EGFR基因的表达;且分化细胞的比率显著提高。结论8-Br-cAMP与槲皮素联合用药或单独用药均可通过调控人食管癌Eca-109细胞癌基因和抑癌基因的表达对Eca-109细胞起到生长抑制和促分化的作用。     

高效液相色谱法测定复方银杏叶片中银杏总黄酮的含量

目的建立复方银杏叶片中银杏总黄酮含量测定方法。方法采用高效液相色谱法,用Symmetry-C18色谱柱(250mm×4.6 mm,5μm),以甲醇-0.4%磷酸溶液(52∶48)为流动相,流速为1.0 ml.min-1,检测波长360 nm,柱温35℃。结果该法线性关系良好,平均加样回收率为98.35%,RSD为1.17%(n=5)。结论该法操作简便,分离效果好,结果准确,专属性强,可作为复方银杏叶片的质量控制方法。     

槲皮素对人食管癌Eca-109细胞的分化诱导作用

目的探讨槲皮素对人食管癌Eca-109细胞的分化诱导作用。方法将培养的Eca-109细胞分为两组:①加槲皮素组(Q组);②不加药物对照组(C组)。同时培养48h,收集各组细胞制备成细胞硝酸纤维素膜(NCM)标本及提取RNA制备RNA硝酸纤维素膜标本。分别对细胞硝酸纤维素膜(NCM)标本进行PCNA,VEGF的免疫斑点印迹阵列;对RNA硝酸纤维素膜标本EGFR,c-myc及wtp53的RNA斑点印迹阵列。印迹阵列皆用岛津薄层色谱扫描仪(TLC)进行波长523nm的扫描数值比较。结果①免疫斑点印迹显示:Q组的PCNA-IR,VEGF-IR的TLC扫描数值分别比C组低5.5倍,3.5倍;②RNA斑点印迹阵列显示,与C组相比:Q组的EGFR,c-myc的RNA斑点TLC扫描数值分别下调了7倍,2.2倍。而wtp53的RNA斑点TLC扫描数值则上调了2.2倍。结论槲皮素可下调作为肿瘤细胞恶性程度生物学指标的PCNA,EGFR,VEGF,c-myc等的表达,上调抑癌基因wtp53的表达,表明对人食管癌Eca-109细胞具有一定的诱导分化效应。     

槲皮素抑制HSP70表达对紫外线C致DNA损伤的影响

目的研究热休克蛋白70(HSP70)在紫外线C致DNA损伤中的保护作用。方法用254 nm紫外线不同照射剂量(10,20,40,80 J/m2)照射槲皮素(quercetin)抑制HSP70表达的A549细胞株(A549/quercetin),用Western-blot检测HSP70的水平,用碱性单细胞凝胶电泳检测DNA损伤,用彗星细胞率和Olive尾矩评价DNA损伤情况。A549细胞作为正常对照组,DMSO处理作为溶剂对照组(A549/DMSO)。结果无论在A549组、A549/DMSO组,还是在A549/quercetin组,DNA损伤的彗星细胞率随着紫外照射的剂量增加而逐渐增加,在10 J/m2时,未观察到HSP70的保护作用,3组的彗星细胞率差异无统计学意义;在20 J/m2照射时,可以观察到HSP70的保护作用,但不明显;40 J/m2照射时,观察到HSP70对DNA有很明显的保护作用;80 J/m2照射时,HSP70的保护作用又逐渐地消失了。进一步分析40 J/m2照射的Olive尾矩显示,与A549组或A549/DMSO组相比,A549/quercetin组Olive尾矩明显增加,差异有统计学意义(P<0.01)。结论HSP70能保护细胞免受一定剂量范围内的紫外线C照射引起的DNA损伤。     

Protective effect of quercetin on experimental chronic cadmium nephrotoxicity in rats is based on its antioxidant properties

Oxidative stress can play a key role in Cd-induced dysfunctions. Quercetin is a potent oxygen free radicals scavenger and a metal chelator. Our aim was to study the effect of quercetin on Cd-induced kidney damage and oxidative stress as well as its mechanism of action. Wistar rats were distributed in four experimental groups: control rats; Cd; quercetin and Cd + quercetin. Renal toxicity was evaluated by measuring urinary excretion of proteins, albumin, glucose and enzymes markers of tubular necrosis, as well as plasma concentration of creatinine. Plasma TBARS concentration and activity of antioxidant enzymes in kidney were also measured. Renal cell damage was assessed by electron microscopy. Animals that received both Cd and quercetin showed a better renal function than those receiving Cd alone. Cd-induced tubular lesions were markedly reduced in rats that also received quercetin. Cd-induced increase in plasma TBARS was prevented by the administration of quercetin. Total plasma antioxidants and renal superoxide dismutase and glutathione-reductase activities were higher in the group that received Cd and quercetin than in rats that received Cd alone. Quercetin administration does not modify the renal content or the urinary excretion of Cd. In conclusion, quercetin treatment prevents renal tubular damage and increased oxidative stress induced by chronic Cd administration, most probably throughout its antioxidant properties.     

银杏叶提取物对心肌细胞肥大的防治作用及其量效关系的研究

目的：在原代培养的新生大鼠心肌细胞上，观察银杏叶提取物(extract of ginkgo biloba．EGb)及其单体槲皮素(quercetin，Que)对血管紧张素11(AngiotensinⅡ，AngⅡ)诱导的心肌细胞肥大的防治作用。方法：采用改良Lowry法测定心肌细胞总蛋白含量，相差显微镜测量细胞大小作为心肌细胞肥大的指标。结果：EGb和Que能抑制AngⅡ引起的心肌细胞总蛋白含量及直径的增加，其效果与血管紧张素转换酶抑制剂(ACEI)卡托普利(captopril，Cap)相似。结论：EGb和Que能有效地防治心肌细胞肥大的发生和发展。     

紫外分光光度法测定水红花子中槲皮素的含量

目的采用紫外分光光度法测定水红花子中槲皮素的含量。方法在25℃、最大吸收波长为370 nm处测吸光度。结果此法线性范围0.004~0.011 9 g/L内,r=0.999 2,平均回收率为96.55%,RSD为0.78%(n=5)。结论用此方法可测量水红花子中槲皮素的含量。方法简便,灵敏度和准确度较高,结果满意。