Sweet tea leaves extract improves leptin resistance in diet-induced obese rats

Aim of the study

Dietary obesity is usually characterized by leptin resistance and abnormal lipid metabolism. Lithocarpus polystachyus Rehd.(Sweet Tea) leaf is a kind of Chinese folkloric medicine, and it has been widely used for obesity, diabetes, and hypertension in South China. The present study is aimed at investigating the pharmacological mechanism of the anti-hyperleptinaemia effects of Sweet Tea leaves extract in high fat diet-induced obese rats.

Materials and methods

We induced high fat diet obesity for 14weeks to test the corrective effects of three ST doses (75, 150 and 300 mg/kg per day) for 8 weeks. At the end of the experiment, body weight, fasting blood glucose and serum lipids, superoxide dismutase (SOD), malondialdehyde (MDA), fasting serum insulin and leptin, C-reactive protein, adiponectin and resistin levels were measured, Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) was also calculated. mRNA gene expression of PPARγ (peroxisome proliferator-activated receptor γ) and C/EBPα(CCAAT/enhancer-binding protein α) in epididymal adipose tissue of DIO control and experimental groups were evaluated.

Results

Sweet Tea leaves extract could significantly decrease the levels of serum lipids, attenuate body weight gain and lower circulatingleptin and insulin levels, ameliorate the state of oxidative stress, raise serum adiponectin, reduce circulating CRP and resistin levels, and depress the expression of PPARγ and C/EBPα in epididymal adipose tissue of obese rats.

Conclusion

The present findings suggest that ST can effectively attenuate the leptin resistance at least through anti-hyperlipidemic activity and thus has the therapeutic potential in treating hyperlipidemia and hyperleptinaemia related to dietary obesity.     

银杏叶干燥方法的优化及其机制探讨

为研究在不同干燥过程中银杏叶化学成分的变化规律,该文采用超高效液相色谱与三重四极杆质谱(UPLC-TQ/MS)联用技术,对银杏叶在自然晒干,阴干,35,45,60,80℃烘干过程中儿茶素类、黄酮及其苷类、双黄酮类、内酯类及酚酸类成分含量变化进行分析。结果表明80℃烘干条件下能起到"杀青"的作用,有利于银杏叶中儿茶素类、黄酮及其苷类、银杏内酯类等成分的转化积累,对双黄酮类成分含量影响不明显。可见80℃快速烘干法有利于银杏叶各类活性成分的保持,可为银杏叶药材的初加工工艺优化提供有益参考。     

Carotenoids retention and in vitro iron bioavailability of traditional cowpea leaf dishes of rural Tanzania

Food preparation methods play a role in micronutrient retention and ultimately intake. Analyses for carotenoids retention and in vitro iron bioavailability of five cowpea leaf dishes prepared according to the traditional methods of rural Tanzania were carried out. All the five dishes are commonly eaten as relishes for staple meals of maize or rice. Laboratory analyses were carried out at the Nutrition Laboratory of the World Vegetable Centre in Taiwan. Carotenoids were analysed by high-performance liquid chromatography while iron bioavailability was analysed by an in vitro method. Results showed that traditional cowpea leaf dish consisting of sunflower oil, onion, tomatoes and coconut milk cooked for 30 min had the highest retention of β-carotene (40.83 ± 7.00%) and lutein (34.60 ± 3.30%) compared to other traditional recipes (p < 0.05). The highest iron bioavailability (10.04 ± 0.49%) was observed in the traditional recipe which involved boiling fresh cowpea leaves for 15 min. Although recipe variation can affect carotenoids retention and iron bioavailability, simple practices such as reduced cooking time and avoiding direct sun drying also need to be promoted.     

超临界流体萃取枸骨叶中熊果酸的工艺研究

目的优化超临界CO2流体萃取枸骨叶中熊果酸的工艺。方法在单因素实验基础上通过响应面分析建立超临界CO2流体萃取枸骨叶中熊果酸的数学模型,确定优选萃取工艺条件。结果优选萃取工艺条件为萃取压力27．1 M Pa ,萃取温度50℃,夹带剂流量0．09 mL · min-1。在此条件下熊果酸得率可达到2．11 mg · g -1。结论优化的萃取工艺稳定可靠。     

罗布麻叶对大鼠尿液内源性物质代谢的影响

目的：采用代谢组学方法考察罗布麻叶对正常大鼠尿液内源性物质代谢的影响。方法：罗布麻叶用10倍量70%乙醇回流提取,将大鼠分为空白对照组、罗布麻叶高剂量组及低剂量3组,连续灌胃给药29 d,运用SIMCA-P软件中的PCA法与PLS-DA法对比分析。结果：罗布麻叶给药组与空白对照组得分点达到很好的区分效果,连续给药22 d时,尿液内源性物质代谢改变最为明显。相比于罗布麻叶低剂量组,高剂量组与空白对照组之间差距更大。结论：罗布麻叶提取物对正常大鼠机体内源性物质代谢产生了影响,为进一步阐释罗布麻叶的药性研究工作提供了依据。     

芒果叶汁对肾上腺素所致高血糖的影响

摘要：目的探讨芒果叶汁对肾上腺素所致高血糖模型的影响,并初步探讨其实用性。方法采用注射肾上腺素引起的高血糖小鼠动物模型及正常小鼠,分别以芒果叶汁不同剂量组进行灌胃,给药结束后测定血糖水平。结果腹腔注射肾上腺素1．5h后,阳性对照组和50％、33％、25％芒果叶汁剂量组能够能够对抗肾上腺素引起的升血糖作用（P〈0．05）。100％芒果叶汁剂量组对肾上腺素引起的高血糖无作用（P〉0．05）。结论芒果叶汁对多种动物模型具有较好的降血糖作用。     

桑叶化学成分及其药用保健功能的研究进展

桑叶作为药食两用的重要植物资源,近年来成为国内外学者关注和研究的热点。研究表明,桑叶中含有1-脱氧野霉素、多种黄酮类化合物、氨基酸、桑叶多糖等生物活性成分,具有降血糖、降血脂、抗氧化、保护心肌、延缓衰老、抗炎抑菌及改善便秘、养颜美容等药理作用。对桑叶的化学成分、药用价值以及保健功能的相关研究,将促进这一重要植物资源在饮食及医药保健等方面的开发和利用。     

山楂叶总黄酮对2型糖尿病大鼠肾脏IGF-1表达影响的实验研究

目的：研究山楂叶总黄酮对2型糖尿病大鼠肾脏IGF-1表达的影响,并探讨其对2型糖尿病肾病的治疗作用。方法：静脉给予链脲佐菌素（STZ）及高脂高糖饲养制备2型糖尿病肾病（STZ—DN）大鼠模型。分别给予高和低剂量山楂叶总黄酮（200、50mg／kg）,12周后测定血糖、尿蛋白（UPr）、尿素氮（BUN）、肌酐（BCr）等相关指标,并采用免疫组化方法检测大鼠肾脏IGF-1表达情况。结果：与STz—DN模型组比较,山楂叶总黄酮能显著降低糖尿病肾病大鼠的血糖、BUN、BCr和UPr（P〈0．01）,肾功能明显改善,肾脏IGF-1表达明显降低（P〈0．01）。结论：山楂叶总黄酮可通过下调IGF-1的表达,从而对2型糖尿病肾痛具有治疗作用。     

银杏叶提取物注射液对肺癌化疗患者血液高凝状态的影响

目的:观察银杏叶提取物注射液对肺癌化疗患者微循环和血液流变学的改善作用。方法:100例肺癌化疗患者通过分层随机按数字表法分组法分为银杏叶提取物注射液组与低分子肝素钠组各50例,另设25例健康对照组。肺癌患者均采用一线化疗方案进行治疗,低分子肝素钠组采用肝素钠注射液,70~80 U·kg-1,分2次静脉滴注。银杏叶提取物注射液组采用银杏叶提取物注射液,20 mL/次,静脉滴注,1次/d。两组1个疗程均为10 d,间隔2 d,进行下1个疗程,共2个疗程。检测治疗前后血浆纤维蛋白原(Fib),D-二聚体(D-D)、血小板计数(PLT)和血小板聚集率(MPAR);检测治疗前后血液流变学指标。结果:肺癌患者治疗前Fib,D-D,PLT水平均明显高于健康对照组(P<0.01);银杏提取物注射液组治疗后Fib,D-D,MPV,MPAR水平低于低分子肝素钠辅组(P<0.01);银杏提取物注射液组治疗后全血黏度(高切、低切)、全血还原黏度(高切、低切)、血浆黏度、红细胞压积和血沉的改善均优于低分子肝素钠组(P<0.01);性别和病理因素对疗效影响不大,肿瘤的转移对疗效的影响有统计学意义,未发生转移的疗效好于已经转移者(P<0.05);银杏提取物注射液组累计不良反应发生率为12%,低于低分子肝素钠组的40%(P<0.01)。结论:银杏叶提取物注射液对肺癌患者的血液高凝状态有明显改善作用,对未发生转移的肺癌更好,临床使用安全。     

黔产钩藤药材茎枝和叶的HPLC指纹图谱比较

目的:比较黔产钩藤带钩茎枝和叶的HPLC指纹图谱,分析二者化学成分的差异,为钩藤叶的后续研究提供实验依据。方法:采用《中药色谱指纹图谱相似度评价系统》2004A版计算钩藤带钩茎枝和叶各10批样品的HPLC指纹图谱的相似度,以钩藤碱和异钩藤碱为指标成分进行指纹图谱比较,色谱条件为Kromasil C18色谱柱(4.6 mm×250 mm,5μm),流动相甲醇(A)-0.02%氨水(B)梯度洗脱(0~45 min,30%~60%A;45~75 min,60%~64%A;75~90 min,64%~70%A;90~95 min,70%~70%A),流速1.0 mL·min-1,柱温30℃,检测波长245 nm,进样量10μL。结果:确定了16个共有峰构成10批钩藤茎枝药材的特征指纹图谱,各批样品的相似度均>0.87;16个共有峰构成10批钩藤叶特征指纹图谱,各批样品的相似度均>0.80。结论:钩藤叶中异钩藤碱含量高于钩藤茎枝,但二者含有的钩藤碱含量相差不大。建立的指纹图谱条件能用于比对钩藤茎枝和叶中主要化学成分,为钩藤叶的药用研究提供参考。