圆穗蓼化学成分研究

从圆穗蓼全草的70%丙酮提取物中分得6个化合物,确定结构分别为(-)-表儿茶素-5-0-β-D-吡喃葡萄糖苷(Ⅰ),( )-儿茶素7-0-β-D-吡喃葡萄糖苷(Ⅱ),1-(3-0-β-D-吡喃葡萄糖基-4,5-二羟基-苯基)-乙酮(Ⅲ),(-)-表儿茶素(Ⅳ),绿原酸(Ⅴ),没食子酸(Ⅵ).Ⅰ～Ⅵ均为首次从该植物中分得.     

栽培鸡血藤藤茎次生代谢产物的动态积累变化研究

【目的】研究栽培鸡血藤藤茎中次生代谢产物在不同生长期的动态积累变化趋势,为其采收期的合理制定提供科学依据。【方法】参照《中国药典》（2010年版一部）附录XA测定醇溶性浸出物的含量;采用紫外分光光度法测定总黄酮的含量,采用高效液相色谱法同时测定原儿茶酸、儿茶素及表儿茶素的含量。【结果】鸡血藤藤茎中醇溶性浸出物、总黄酮及指标性成分原儿茶酸、儿茶素和表儿茶素的含量均随着生长年限的增加呈递增的趋势;而1年中不同月份样品的醇溶性浸出物、总黄酮、表儿茶素的含量变化均呈抛物线状,7～9月含量达到峰值;儿茶素的含量则一直呈上升状态;7～9月采收的4～6年生鸡血藤样品中醇溶性浸出物已达到现行版《中国药典》的要求。【结论】初步建议栽培鸡血藤藤茎以7年生以上采收为宜,其最佳采收年限与采收月份有待进一步研究确定。     

Molecular interaction of tea catechin with bovine β-lactoglobulin: A spectroscopic and in silico studies

Polyphenols has attained pronounced attention due to their beneficial values of health and found to prevent several chronic diseases. Here, we elucidated binding mechanism between frequently consumed polyphenol “tea catechin” and milk protein bovine beta-lactoglobulin (β-Lg). We investigated the conformational changes of β-Lg due to interaction with catechin using spectroscopic and in silico studies. Fluorescence quenching data (Stern-Volmer quenching constant) revealed that β-Lg interacted with catechin via dynamic quenching. Thermodynamic data revealed that the interaction between β-Lg and catechin is endothermic and spontaneously interacted mainly through hydrophobic interactions. The UV-Vis absorption and far-UV circular dichroism (CD) spectroscopy exhibited that the tertiary as well as secondary structure of β-Lg distorted after interaction with catechin. Molecular docking and simulation studies also confirm that catechin binds at the central cavity of β-Lg with high affinity (~10⁵ M⁻¹) and hydrophobic interactions play significant role in the formation of a stable β-Lg-catechin complex.     

Cryptostrobin and catechin isolated from Eugenia mattosii D. Legrand leaves induce endothelium-dependent and independent relaxation in spontaneously hypertensive rat aorta

BackgroundConsidering the therapeutic potential of phenolic compounds, the purpose of the present study was to investigate the mechanisms involved in the relaxation induced by cryptostrobin and catechin, isolated from Eugenia mattosii D. Legrand leaves, in the aorta of spontaneously hypertensive rats (SHR).MethodsThe thoracic aorta was isolated from SHR and kept in the organ bath system by recording contractile or relaxant responses.ResultsThe addition of cumulative concentrations of cryptostrobin and catechin induced endothelium-dependent and-independent relaxation in aorta rings from SHR, as well as both compounds were effective in reducing phenylephrine-induced contraction. Pretreatment of aortic rings with N_ω-nitro-l-arginine methylester (L-NAME, an inhibitor of nitric oxide synthase) or 1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, an inhibitor of soluble guanylate cyclase), resulted in a significant change of relaxant effect induced by catechin, and a slight influence on cryptostrobin-induced relaxation. Muscarinic receptor and potassium channels are involved in catechin-induced relaxation as assessed using atropine (a muscarinic receptor antagonist), tetraethylammonium (a non-selective K⁺ channel blocker) and glibenclamide (an ATP-sensitive K⁺ channel blocker). Conversely, cryptostrobin, but not catechin, blunted the contraction induced by the addition of phenylephrine in a calcium-free solution. Besides that, cryptostrobin attenuated the contraction of rat aorta rings induced by internal Ca²⁺ release and external Ca²⁺ influx.ConclusionsThese findings indicated that cryptostrobin and catechin alter vascular smooth muscle reactivity, and this effect may be involved, at least in part, by enhancing the endothelium NO/cGMP pathway and potassium channels activation. In addition, cryptostrobin reduced the phenylephrine, KCl and CaCl₂-induced contractions in a calcium-free solution.     

Attenuation of Cyclosporine-Induced Renal Dysfunction by Catechin: Possible Antioxidant Mechanism

One of great use of immunosuppressant, Cyclosporine-A (CsA) is in the solid organ transplantation; however the extensive use of this is cautionable due to its toxic effect in renal tissue, characterized by the tubular atrophy, interstitial fibrosis, and progressive renal impairment. However, there are many mediators are associated with pathogenesis of nephrotoxicity of CsA, the exact mechanism is still in debate. Recent studies indicate that Reactive Oxygen Species (ROS) induced oxidative stress and lipid peroxidations are the important mechanisms implicated in the pathophysiology of nephrotoxicity with CsA. In the present study we examined effect of dietary flavonoid catechin on oxidative damage in cyclosporine-A induced nephrotoxicity. Chronic administration of CsA (20 mg/kg/day) subcutaneously for 21 days significantly decreased the body weight as compared with vehicle treated rats. CsA (20 mg/kg/day) administration for 21 days significantly decreased the renal function by increase in the serum creatinine, blood urea nitrogen, and decrease in the creatinine and urea clearance as compared with vehicle treated rats. Catechin (100 mg/kg/day) for 21 days along with CsA significantly reversed the changed renal parameters, however lower dose of catechin (50 mg/kg/day) restored only increased serum creatinine levels as compared with CsA alone treated group. Biochemical analysis revealed that chronic administration of CsA (20 mg/kg/day) for 21 days significantly induced lipid peroxidation and decreased the glutathione levels in the kidney homogenate of rats. It is also observed that chronic CsA administered rats showed decrease in antioxidant defense enzyme superoxide dismutase and increase in the catalase activity as compared with vehicle treated rats. Co-administration of catechin (100 mg/kg/day) orally along with CsA for 21 days significantly reduced the lipid peroxidation and restored the decreased glutathione levels as compared with CsA alone group, but lower dose of catechin (50 mg/kg/day) restored only decreased glutathione levels induced by CsA. Co-administration of only higher dose of catechin (100 mg/kg/day) along with CsA significantly increased the superoxide dismutase (SOD) levels as compared with CsA alone treated group. It is also observed that catechin (100 mg/kg/day) along with CsA further increased the catalase levels as compared with CsA alone treated group, but not with lower dose of catechin. Animals administered with catechin (100 mg/kg/day) alone for 21 days showed significant increase in the catalase levels as compared with vehicle treated group. The major findings of the present study suggest that oxidative stress might play a significant role in CsA-induced nephrotoxicity. In conclusion, dietary administration of flavonoid catechin could be a useful component for the prevention/treatment of CsA-induced nephrotoxicity.     

生肌散质控方法的研究

目的 建立生肌散的质量标准。方法 采用TLC法对处方中血竭、冰片进行鉴别,用HPLC法测定方中君药儿茶中儿茶素的含量。结果 在TLC色谱中,能检出血竭、冰片。儿茶素在0．1762～3．524μg范围内,浓度与峰面积线性关系良好（r=0．9994）,样品的平均加样回收率为103．06％,RSD为0．39％（n=6）。结论 本文建立的方法对方中3味药材能准确、快速地进行定性、定量检测,可用于生肌散的质量控制。     

正交实验法优选三叶委陵菜渗漉提取的工艺条件

［摘要］目的优选三叶委陵菜的渗漉提取工艺条件。方法分别用紫外分光光度法和高效液相色谱法测定样品中的鞣质和儿茶素含量，采用正交实验设计对提取的条件进行优选。结果以乙醇浓度60%、浸泡时间24 h、乙醇用量10倍、流速0.3 mL·min 1为渗漉提取条件效果最好。结论该含量测定方法对鞣质和儿茶素定量准确，优选工艺稳定可行。     

高效液相色谱法测定子宫锭中儿茶素的含量

目的：建立子宫锭中儿茶素的含量测定方法。方法：色谱柱为Agilent HC C18（250mm×4．6mm，5μm），流动相为0．04mol·L^-1枸橼酸溶液-N，N-二甲基甲酰胺-四氢呋喃（THF）（45：8：2），检测波长280nm，柱温35℃，流速1．0ml·min^-1。结果：儿茶素在501．2～1754．2ng之间呈良好的线性关系。平均加样回收率为98．47％，RSD=1．92％（n=9）。结论：方法简便可靠，分离度好，可用于子宫锭的质量控制。     

儿茶药材中儿茶素和表儿茶素的高效液相色谱法分析研究

目的利用高效液相色谱法测定儿茶药材中儿茶素和表儿茶素的含量。方法色谱柱填料为十八烷基键合硅胶,流动相A:甲醇;流动相B:0.04 mol/L柠檬酸-N,N-甲基甲酰胺(45∶8,V/V)。A-B(15∶85,V/V),流速1m l/m in,柱温:35℃,检测波长280 nm。结果儿茶素在0.484~4.84μg、表儿茶素在0.184~1.84μg范围内呈良好的线性关系。两种成分的均回收率分别为98.11%和106.14%。结论该方法简便、准确、分离效果好,无干扰,可用于儿茶药材质量评价。