f_2相似因子法评价银杏酮酯缓释微丸大类成分总黄酮和各类成分的体外释放相关性研究

目的引入f_2相似因子法对银杏酮酯(GBE)缓释微丸的大类成分总黄酮和各类成分(包括黄酮类和萜内酯类)的释放曲线进行分析,以能较全面地评价其体外释放。方法运用紫外分光光度法、高效液相-质谱联用(HPLC-MS)测定GBE缓释微丸中大类成分(总黄酮)和各类成分(槲皮苷、异鼠李素、芦丁、槲皮素、银杏内酯A、银杏内酯B、银杏内酯C、白果内酯)的体外释放率,并进行f_2相似因子计算;采用扫描电镜法观察微丸释药前后的微观结构,结合方程拟合分别对微丸中总黄酮和各类成分的释药机制解析,以验证f_2相似因子法的可靠性。结果优化工艺的GBE微丸黄酮类和内酯类的各成分与大类成分总黄酮的f_2均大于50,说明大类成分总黄酮与各类成分体外释放曲线具有较好的相关性。释药机制解析进一步验证了该结果的可靠性。结论 f_2相似因子法可运用于多组分中药缓释制剂大类成分和各类成分的体外释放评价。     

人工半合成槲皮素水溶性衍生物对重组人磷脂酰肌醇3—激酶p110β催化亚基的影响

目的:研究人工半合成槲皮素水溶性衍生物—槲皮素-7-硫酸酯钠盐(SQMS)和槲皮素-7,4′-二硫酸酯二钠(SQDS)对重组人磷脂酰肌醇3-激酶(PI3-K)p110β催化亚基的影响.方法:利用基因工程的方法获得PI3-K p110β催化亚基.用磷脂酰肌醇-4,5-二磷酸,[γ-~(32)P]ATP与重组PI3-K p110β催化亚基起保温的方法测定PI3-K的活性;~(32)P标记的磷脂用氯仿和甲醇抽提、板薄层层析和放射自显影来分析.结果:Wortmannin是PI3-K特异的抑制剂,Wortmannin(2.5-20nmol/L)对重组PI3-K p110β亚基有抑制作用;SQMS和SQDS(2.5-20μmol/L)对重组人PI3-K p110β催化亚基有抑制作用.结论:人工半合成槲皮素水溶性衍生物是一种类型的PI3-K抑制剂.重组人PI3-K p110β催化亚基可作为一种较为简便地筛选和开发有效的PI3-K抑制剂的分子靶点.     

罗布麻叶总黄酮类化合物的提取及含量测定

目的建立罗布麻叶总黄酮含量的测定方法,并用此方法优化罗布麻叶的提取方法.方法以槲皮素为标准品,采用紫外分光光度法对罗布麻叶提取物中主要成分黄酮类化合物的含量进行测定,并比较75%乙醇回流、超声、索氏以及水提,超声5种提取方法所得提取物中总黄酮的含量.结果槲皮素的线性范围为2.96-22.20 mg·L-1,回归方程为Y=11.54X+0.175(r=0.999 96),75%乙醇超声2 h所得提取物中黄酮类化合物含量最高(13.07%).结论紫外分光光度法可以作为罗布麻叶的质量控制方法之一,用75%乙醇超声2 h提取所得的提取物中黄酮类化合物的含量较高.     

Activation of Nrf2 signaling by sitagliptin and quercetin combination against β-amyloid induced Alzheimer's disease in rats

The objective of this study was to evaluate the neuroprotective effect of sitagliptin (Sita), quercetin (QCR) and its combination in β-amyloid (Aβ) induced Alzheimer's disease (AD). Male Sprague–Dawley rats, weighing between 220 and 280 g were used for experiment. Rats were divided into 5 groups (n = 10) and the groups were as follows: (a) Sham control; (b) Aβ injected; (c) Aβ injected + Sita 100; (d) Aβ injected + QCR 100; and (e) Aβ injected + Sita 100 + QCR 100. Cognitive performance was observed by the Morris water maze (MWM), biochemical markers, for example, MDA, SOD, CAT, GSH, Aβ1-42 level, Nrf2/HO-1 expression and histopathological study of rat brain were estimated. Pretreatment with Sita, QCR and their combination showed a significant increase in escape latency in particular MWM cognitive model. Further co-administration of sita and QCR significantly reduced Aβ1-42 level when compared with individual treatment. Biochemical markers, for example, increased SOD, CAT and GSH, decreased MDA were seen, and histopathological studies revealed the reversal of neuronal damage in the treatment group. Additionally, Nrf2/HO-1 pathway in rat's brain was significantly increased by Sita, QCR and their combination. Pretreatment with QCR potentiates the action of Sita in Aβ induced AD in rats. The improved cognitive memory could be because of the synergistic effect of the drugs by decreasing Aβ1-42 level, antioxidant activity and increased expression of Nrf2/HO-1 in rat brain.     

In vitro exposure to quercetin and genistein alters lipid peroxides and prevents the loss of glutathione in human progenitor mononuclear (U937) cells

The effects of flavonoids quercetin and genistein were investigated according to their potency to inhibit the oxidation of U937 cells via Fenton's pathway through the analysis of lipid peroxides and glutathione (GSH) levels. Human leukemia (U937) cells from the American Type Culture Collection were maintained at 37 degrees C for 24 h under 5% CO2 tension in RPMI-1640 medium containing 10% fetal bovine serum and 50 units ml(-1) each of penicillin and streptomycin. Cells were oxidized with iron 50 microM) or copper (50 microM) in H2O2 (0.01 mM) without or with a flavonoid sample (10 or 20 microM) for the lipid peroxidation studies. The GSH levels were measured (GSH Kit) before and after oxidation as above with different concentrations of flavonoids (0-40 microM). Lipid peroxide was measured by the thiobarbituric acid assay. Both quercetin and genistein at either the 10 or 20 microM level decreased lipid peroxidation significantly compared with their respective controls (P < 0.01). Lipid peroxides by Fe compared to the Cu-treated samples did not differ significantly from each other. However, the combination of flavonoids at the doses tested significantly (P < 0.001) decreased lipid peroxides, the effect being the same for both metal ions. The GSH levels increased significantly before exposure to the metal ions (for the different doses for the differences between the flavonoid samples and their respective untreated levels). For quercetin and genistein the increases in GSH above their untreated levels were 4.5, 8.3, 11.7 and 15 and 3.8, 7.9, 12.5 and 14.6 nmol 10(-6) cells, respectively, for the 5-40 microM levels tested for each flavonoid. Following the exposure to the metal ions, GSH levels remained almost the same for the different concentrations for each of the flavonoids tested but significantly above all of the controls and same for those of the untreated samples. The results indicate that both flavonoids inhibited lipid peroxides and the inhibition may be attributed to the prevention of loss of intracellular GSH levels in U937 cells.     

HSP70在经热应激预处理后减少大鼠肝脏缺血再灌注损伤过程中的作用

目的　探讨热应激预处理能够减少肝脏缺血再灌注损伤的机制,以期寻找减轻肝脏缺血再灌注损伤的有效措施。方法　建立大鼠肝脏缺血再灌注损伤模型。将42只大鼠随机分为6组:①正常对照组(N);②槲皮素组(Q):腹腔注射槲皮素(quercetin, 7mg·kg-1 );③肝脏缺血再灌注(ischemi areperfusion,I/R)组(I);④热应激预处理组(H+I):缺血再灌注前16h给予热应激预处理;⑤槲皮素+热应激预处理组(Q+H+I):缺血再灌注前16h先给予槲皮素腹腔注射(7mg·kg-1 )再给予热应激处理;⑥槲皮素+缺血组(Q+I):缺血再灌注前16h给予槲皮素腹腔注射(7mg·kg-1 )。观察以上各组大鼠在肝脏缺血再灌注6h后热休克蛋白70(Heatshockprotein70, HSP70 )的表达,血清谷丙转氨酶(ALT)、谷草转氨酶(AST)的活性及肝脏组织形态学改变。结果　大鼠肝脏HSP70表达由高到低依次为:H+I组、I组、Q+H+I组、I+Q组、Q组、N组;而检测血清ALT、AST含量由高到低依次为:Q+I组、I组、Q+H+I组、H+I组、Q组、N组;肝脏组织形态学的改变显示与上述血中ALT、AST含量变化相对应。结论　HSP70在经热应激预处理后减少肝脏缺血再灌注损伤的过程中起重要的作用。     

Bioavailability of plant pigment phytochemicals in Angelica keiskei in older adults: A pilot absorption kinetic study

BACKGROUND/OBJECTIVES

Angelica keiskei is a green leafy vegetable rich in plant pigment phytochemicals such as flavonoids and carotenoids. This study examined bioavailability of flavonoids and carotenoids in Angelica keiskei and the alteration of the antioxidant performance in vivo.

SUBJECTS AND MATERIALS

Absorption kinetics of phytochemicals in Angelica keiskei were determined in healthy older adults (> 60 y, n = 5) and subjects with metabolic syndrome (n = 5). Subjects consumed 5 g dry Angelica keiskei powder encapsulated in gelatin capsules with a low flavonoid and carotenoid liquid meal. Plasma samples were collected at baseline, 0.5, 1, 2, 3, 4, 5, 6, 7, and 8 h. Samples were analyzed for flavonoids and carotenoids using HPLC systems with electrochemical and UV detection, respectively, and for total antioxidant performance by fluorometry.

RESULTS

After ingestion of Angelica keiskei increases in plasma quercetin concentrations were observed at 1-3 and 6-8 hr in the healthy group and at all time points in the metabolic syndrome group compared to baseline (P < 0.05). Plasma lutein concentrations were significantly elevated in both the healthy and metabolic syndrome groups at 8 hr (P < 0.05). Significant increases in total antioxidant performance were also observed in both the healthy and the metabolic syndrome groups compared to baseline (P < 0.05).

CONCLUSIONS

Findings of this study clearly demonstrate the bioavailability of phytonutrients of Angelica keiskei and their ability to increase antioxidant status in humans.     

槲皮素对HeLa细胞P21、CDK4蛋白表达的影响

目的:探讨不同浓度的槲皮素对HeLa细胞P21、CDK4蛋白表达的影响及意义。方法:采用不同浓度槲皮素处理体外培养的HeLa细胞,培养48h后免疫组织化学法检测HeLa细胞P21、CDK4蛋白表达的变化。结果:不同浓度的槲皮素均能显著增高P21和降低CDK4蛋白在HeLa细胞中的表达,且与空白对照组相比均有显著性差异(P<0.01)。结论:槲皮素可能通过上调HeLa细胞P21蛋白表达和下调CDK4蛋白表达,促进HeLa细胞凋亡。     

Two new flavonols from Cudrania cochinchinensis

Two new flavonols, 6-p-hydroxybenzyl kaempferol (1) and 6-p-hydroxybenzyl quercetin (2), together with six known compounds were isolated from the roots of Cudrania cochinchinensis and their structures elucidated on the basis of spectroscopic methods. Their antioxidant capacities were evaluated by 1,1-diphenyl-2-picryl-hydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging assays. The results suggested that compounds 2, 4, and 7 showed significant radical-scavenging activities.     

甘肃省不同产地萱草花蕾中芦丁、槲皮素、山柰酚的测定

目的:建立HPLC法同时测定萱草花蕾中芦丁、槲皮素、山柰酚3个黄酮类化合物的含量,并比较不同产地萱草中这3个化合物的含量。方法:采用Agilent SB-C18(4.6 mm×250 mm,5μm)色谱柱,以甲醇(A)-pH 3磷酸水溶液(B)为流动相,梯度洗脱(0～10 min,20%A;10～10.5 min,20%A→45%A;10.5～27.5 min,45%A;27.5～28 min,45%A→60%A;28～45min,60%A→20%A),流速0.7 mL.min-1,检测波长360 nm,柱温33℃,进样量20μL。结果:芦丁、槲皮素及山柰酚浓度分别在32.6～326μg.mL-1(r=0.9999)、1.06～10.6μg.mL-1(r=0.9997)和0.32～3.2μg.mL-1(r=0.9997)范围内线性关系良好;平均加样回收率(n=6)分别为99.53%(RSD=1.8%),96.96%(RSD=1.7%),98.75%(RSD=1.9%)。结论:该方法简便,操作简单,结果准确,重复性好,为评价萱草药材的质量提供了可靠的分析方法,可作为萱草中黄酮类化合物的含量测定方法。