一测多评法同时测定扶正固本颗粒中6种成分的含量

目的:建立扶正固本颗粒中2,3,5,4′-四羟基二苯乙烯基葡萄糖苷、黄芩苷、淫羊藿苷、汉黄芩苷、黄芩素、汉黄芩素等6种成分含量的测定方法.方法:采用高效液相色谱法.色谱柱为Dikma Diamonsil C18,流动相为乙腈-0.1％磷酸水溶液(梯度洗脱),检测波长为275 nm(0～8 min)、320 nm(8～9...     

黄芩素对多发性骨髓瘤细胞株RPMI8226和U266细胞增殖和迁移的影响

目的 探讨黄芩素对多发性骨髓瘤(MM)细胞增殖和迁移能力的影响及分子机制.方法 以不同浓度黄芩素处理MM细胞株RPMI 8226和U266细胞不同时间后,应用四甲基偶氮唑盐(MTT)比色实验检测黄芩素对MM细胞增殖的影响;用黄芩素和(或)IL-6处理RPMI 8226、U266细胞,激光共聚焦及Western blot检测处理前后细胞中β连环素(β-catenin)蛋白表达;Transwell小室实验检测不同浓度黄芩素处理前后RPMI 8226和U266细胞的迁移能力;RT-PCR检测不同浓度黄芩素处理前后细胞内β-catenin、c-myc、细胞周期素D1(Cyclin D1)和细胞迁移相关基因整联蛋白β7(integrin β7)基因mRNA表达.结果 黄芩素呈浓度和时间依赖性抑制RPMI 8226和U266细胞的增殖;激光共聚焦及Westem blot结果显示黄芩素能够抑制β-catenin的表达从而抵抗IL-6对MM细胞的促增殖作用;RT-PCR检测显示黄芩素能够抑制β-catenin、c-myc、cyclin D1和integrin β7的mRNA表达;Transwell小室迁移实验表明,在基质细胞衍生因子(SDF-1)的趋化下,黄芩素以浓度依赖的方式降低MM细胞的迁移能力.结论 黄芩素具有抑制MM细胞增殖和迁移的作用,其分子机制与抑制增殖相关基因β-catenin、c-myc、cyclin D1和integrin β7的表达有关.     

p12-LOX抑制剂对人胃癌SGC-7901细胞的作用

目的 观察血小板型12-脂氧合酶(p12-LOX)在人胃癌SGC-7901细胞(中分化胃腺癌细胞)中的表达及黄芩素(baicalein,Bai)对其生长的作用.方法 用四氮唑蓝(MTT)染色法及流式细胞仪(FCM)检测Bai对SGC-7901细胞增殖及周期的影响;逆转录-聚合酶链式反应(RT-PCR)法检测SGC-7901细胞中p12-LOX mRNA的表达及Bai对血管内皮生长因子(VEGF) mRNA表达的影响.结果 Bai能抑制SGC -7901细胞的增殖,并呈一定的时间、浓度依赖性.FCM结果表明,随着Bai浓度的增高,G0/G1期细胞比例从(62.27±3.20)%降低到(29.36±1.37)%,而S期细胞比例从(23.18±1.39)%升高到(68.21±1.64)% .SGC-7901细胞中存在p12-LOX mRNA表达;Bai降低VEGF mRNA的表达,且呈一定的浓度依赖性.结论 Bai可抑制SGC-7901细胞增殖,影响细胞周期的分布.     

Synergistic effects of baicalein with ciprofloxacin against NorA over-expressed methicillin-resistant Staphylococcus aureus (MRSA) and inhibition of MRSA pyruvate kinase

Ethnopharmacological relevance

Baicalein, the active constituent derived from Scutellaria baicalensis Georgi., has previously been shown to significantly restore the effectiveness of β-lactam antibiotics and tetracycline against methicillin-resistant Staphylococcus aureus (MRSA). With multiple therapeutic benefits, the antibacterial actions of baicalein may also be involved in overcoming other bacterial resistance mechanisms. The aim of the present study was to further investigate antibacterial activities of baicalein in association with various antibiotics against selected Staphylococcus aureus strains with known specific drug resistance mechanisms.

Material and methods

A panel of clinical MRSA strains was used for further confirmation of the antibacterial activities of baicalein. The effect of baicalein on inhibiting the enzymatic activity of a newly discovered MRSA-specific pyruvate kinase (PK), which is essential for Staphylococcus aureus growth and survival was also examined.

Results

In the checkerboard dilution test and time-kill assay, baicalein at 16 μg/ml could synergistically restore the antibacterial actions of ciprofloxacin against the NorA efflux pump overexpressed SA-1199B, but not with the poor NorA substrate, pefloxacin. Moreover, synergistic effects were observed when baicalein was combined with ciprofloxacin against 12 out of 20 clinical ciprofloxacin resistant strains. For MRSA PK studies, baicalein alone could inhibit the enzymatic activity of MRSA PK in a dose-dependent manner.

Conclusion

Our results demonstrated that baicalein could significantly reverse the ciprofloxacin resistance of MRSA possibly by inhibiting the NorA efflux pump in vitro. The inhibition of MRSA PK by baicalein could lead to a deficiency of ATP which might further contribute to the antibacterial actions of baicalein against MRSA.     

黄芩素对肝癌H22荷瘤小鼠的抑瘤作用研究

目的:研究黄芩素对肝癌H22荷瘤小鼠的抑瘤作用。方法:以H22肝癌细胞接种于正常小鼠左前肢腋窝皮下复制肝癌H22荷瘤模型。实验分为模型对照、环磷酰胺(30mg·kg-1)和黄芩素高、中、低剂量(80、40、20mg·kg-1)组。灌胃给药,每天1次,连续15d。末次给药后处死小鼠,剥离完整的肿瘤组织称重,并计算肿瘤抑制率;流式细胞仪分析细胞周期分布和凋亡率;按试剂盒说明书测定肿瘤组织中半胱氨酸蛋白酶(Caspase)-3的活性;RT-PCR测定瘤组织中B细胞淋巴瘤/白血病-2(Bcl-2)、Bcl-2相关X蛋白(Bax)的mRNA表达水平。结果:高、中剂量黄芩素可显著抑制模型小鼠体内肿瘤生长(P<0.01或P<0.05),抑制率分别为61.63%和44.65%;可显著提高G0/G1期细胞百分比(P<0.05),并减少S期细胞(P<0.01或P<0.05)。与模型对照组比较,黄芩素高、中、低剂量组细胞凋亡率显著提高(P<0.01或P<0.05)。高、中剂量黄芩素可显著增强肿瘤组织中Capcase-3活性(P<0.01或P<0.05),抑制Bcl-2mRNA表达(P<0.01或P<0.05);高剂量黄芩素可显著提高肿瘤组织中BaxmRNA表达(P<0.05)。结论:黄芩素可促进肝癌H22荷瘤小鼠肿瘤细胞的凋亡,其机制可能与增强Capcase-3活性、提高Bax表达,并抑制Bcl-2表达有关。     

创伤性脑损伤后大鼠脑组织12/15-脂氧合酶的表达及作用研究

目的 12/15-脂氧合酶(12/15-lipoxygenase,12/15-LOX)参与多种中枢神经系统疾病病理过程,与神经系统氧化应激、神经细胞炎症和凋亡密切相关,但对12/15-LOX代谢途径在创伤性脑损伤(traum atic brain in jury,TB I)病理机制中的研究尚少见报道。文中探讨12/15-LOX在TB I后的表达及其对TB I后皮层凋亡和炎症中的调节作用。方法探讨TB I后12/15-LOX的表达时相变化,选择12/15-LOX表达最高的时间点,观察应用其抑制剂黄芩素对神经细胞炎症及凋亡的影响。结果 12/15-LOX在TB I后表达显着增加,TB I后6 h甚至更早即开始升高,第2天达到高峰,第7天恢复至正常水平。与TB I组相比,应用黄芩素抑制12/15-LOX能显著减少神经细胞凋亡,降低脑组织IL-6和TNF-α的表达。皮层神经细胞凋亡指数从(57.97±5.08)%下降至(47.70±4.63)%,脑组织中炎症因子IL-6含量从(0.65±0.08)ng/g降至(0.56±0.05)ng/g,TNF-α含量从(2.55±0.32)ng/g降至(2.10±0.20)ng/g。结论 12/15-LOX在TB I后炎症及凋亡的病理过程中起重要作用。12/15-LOX抑制剂可能成为有效的治疗TB I的神经保护剂。     

黄芩素抑制皮肤鳞癌细胞株A431增殖的体外研究

目的 研究黄芩素(BAI)对鳞状细胞癌A431细胞的增殖、集落形成及细胞周期的影响,探索BAI抗肿瘤的作用机制.方法 以体外培养的人表皮鳞癌A431细胞株为研究对象,MTT法观察BAI对A431细胞的生长抑制作用,光镜和电镜观察细胞形态,集落形成实验观察BAI对瘤细胞的生长抑制,流式细胞仪检测细胞周期中各期细胞比例和凋亡率.结果 MTT法显示,随着BAI作用时间延长及剂量增加对A431细胞增殖的抑制作用增强,有明显的时间和剂量依赖性,与对照组比较差异有显著性(P<0.01);光镜显示,随黄芩素浓度的增大细胞生长速度明显受到抑制,形态变圆;电镜显示,A431细胞伪足明显缩短,数量减少;流式细胞仪检测显示,随BAI浓度及作用时间的延长,细胞周期被明显阻断在S期,凋亡率增高,与对照组比较差异有显著性(P<0.05).结论 (1)BAI处理48h后,抑制A431细胞增殖而无细胞毒性的最适剂量范围为10～30μM;②BAI能明显地抑制皮肤鳞癌A431细胞增殖、细胞周期的进程、瘤细胞集落及伪足形成.     

Comparative studies on interactions of baicalein, baicalin and scutellarin with lysozyme

The interactions of baicalein, baicalin and scutellarin with lysozyme (LYSO) were studied by fluorescence and UV spectroscopy. The results showed that all the three flavones can quench the fluorescence of LYSO via static quenching with the distance between the donor and acceptor less than 7 nm. The hydroxyl at B-ring gave flavones an advantage to binding with LYSO. Electrostatic forces played a major role in stabilizing baicalein–LYSO complex and baicalin–LYSO complex, whereas hydrophobic interactions in scutellarin–LYSO. Furthermore, the presence of pantothenic acid can increase the binding constant and the number of binding sites between flavones and LYSO.     

Enhanced bioavailability after oral and pulmonary administration of baicalein nanocrystal

The aim of the study was to investigate the potential of oral and pulmonary nanocrystal to enhance the bioavailability of baicalein, a bioactive flavonoid isolated from the root of Scutellaria baicalensis Georgi. So far, the nano-sized delivery system of baicalein and its pulmonary delivery have received no exploration. In the present investigation, the baicalein nanocrystal was prepared by anti-solvent recrystallization followed by high pressure homogenization. In vitro characterization was performed including particle size and distribution, Zeta potential, dissolution, scanning electron microscopy, differential scanning calorimetry and X-ray powder diffractometry. It was indicated that no crystalline change was observed after nanocrystal preparation. The baicalein nanocrystal containing only trace of stabilizer exhibited a significantly enhanced dissolution of baicalein. In vivo test was also carried out in rats and pharmacokinetic parameters of the baicalein crystal and the baicalein nanocrystal after gavage and pulmonary administration were compared, based on the simultaneous determination of baicalein and baicalin by high performance liquid chromatography. The mean relative bioavailability of oral baicalein nanocrystal was 1.67-fold that of oral baicalein crystal. The pulmonary baicalein nanocrystal had rapid and extensive absorption and had almost identical pharmacokinetic parameters to intravenous baicalein injection.