盐知母降血糖活性部位对胰岛素抵抗作用的影响

目的：探讨盐知母降血糖活性部位对胰岛素抵抗作用的影响及其作用机制。方法：采用地塞米松诱导3T3-L1脂肪细胞胰岛素抵抗模型,比较盐知母降血糖活性部位对培养基中葡萄糖消耗的影响;采用STZ （链脲佐菌素）诱导大鼠胰岛素抵抗模型,给药14 d后测定大鼠空腹血糖值（FBG）,并用试剂盒测定胰岛素、血浆瘦素、血浆抵抗素等水平。比较盐知母不同降血糖活性部位对2型糖尿病大鼠胰岛素抵抗作用的影响。结果：盐知母降血糖活性部位均能显著增加胰岛素抵抗3T3-L1脂肪细胞培养基中的葡萄糖消耗量,且盐知母三氯甲烷层萃取组作用最佳;与模型组相比,各给药组均显著改善糖尿病大鼠FBG、OGTT、HbAlc、Homa-IR等水平及LEP、ADPN等胰岛素抵抗水平。结论：盐知母降血糖活性部位能够改善胰岛素抵抗作用,且三氯甲烷萃取层作用显著。     

盐知母化学成分α-葡萄糖苷酶抑制作用研究

目的对盐知母化学成分α-葡萄糖苷酶抑制作用进行比较研究,以探讨盐知母降血糖作用的增效原理,为后期研发提供科学依据。方法采用高效液相色谱法,以PNPG(对硝基苯基α-D-吡喃葡萄糖苷)为底物比较盐知母化学成分对α-葡萄糖苷酶的抑制作用。结果从盐知母氯仿层中分离得到的顺-扁柏树脂酚,对α-葡萄糖苷酶具有良好的抑制作用,且优于阿卡波糖的作用。同时芒果苷、知母皂苷AⅢ等盐知母的增量成分对α-葡萄糖苷酶抑制作用也相对较强。结论盐知母活性部位氯仿层分离物,顺-扁柏树脂酚对α-葡萄糖苷酶具有较高的抑制活性,提示盐知母活性部位分离物顺-扁柏树脂酚在抗糖尿病产品开发方面具有很好的应用前景。     

盐知母不同有效部位改善链脲佐菌素诱导2型糖尿病大鼠糖代谢的研究

目的探究盐知母不同溶剂萃取物对2型糖尿病大鼠糖代谢的影响,旨在寻找盐知母降血糖作用的有效部位。方法 SD雄性大鼠ig脂肪乳10 g/kg,1次/d。4周后,ip链脲佐菌素35 mg/kg,建立2型糖尿病模型。造模成功的大鼠按血糖值随机分为模型组、阿卡波糖(0.2 g/kg)组以及石油醚萃取物、氯仿萃取物、醋酸乙酯萃取物、正丁醇萃取和萃余物组,连续ig给药14 d。于给药7、14 d后测定空腹血糖值(FBG),末次给药后测定口服葡萄糖耐量(OGTT),眼眶取血测定糖化血红蛋白(HbAlc)、血清胰岛素(FINS),计算胰岛敏感指数(ISI)和Homa胰岛素抵抗(HOMA-IR)指数。结果与模型组比较,盐知母氯仿萃取物能够明显降低FBG、HbA1c、FINS、HOMA-IR指数,升高ISI,改善OGTT;盐知母醋酸乙酯萃取物能够显著降低HbAlc、HOMA-IR指数,改善OGTT;盐知母正丁醇萃取物能够显著降低FINS;盐知母萃余物能够显著降低FBG、FINS、HOMA-IR指数,升高ISI。结论盐知母不同溶剂萃取物对2糖尿病大鼠糖代谢具有较好的改善作用,其中氯仿萃取物的作用最强。     

苦瓜根提取物对α-葡萄糖苷酶抑制作用研究

目的:通过α-葡萄糖苷酶活性抑制实验研究苦瓜根提取物对α-葡萄糖苷酶的抑制活性,筛选其活性部位。方法:采用乙醇回流提取,有机溶剂萃取,得到石油醚、乙酸乙酯、正丁醇等不同萃取部位,检测醇提物和各萃取部位对α-葡萄糖苷酶活性的抑制作用。结果:苦瓜根醇提物不同萃取部位对α-葡萄糖苷酶均有一定的抑制作用,与空白对照组对比,差异具有显著性（P<0.01）;其中水部位的抑制作用最强,当浓度为100μg·ml^-1时,抑制率达到61%。结论:苦瓜根醇提物不同萃取部位对α-葡萄糖苷酶均有抑制作用,其中水部位的抑制作用最强。     

知母提取物的降血糖作用

目的对知母进行系统提取分离,筛选提取物的降血糖作用活性组分。方法用四氧嘧啶及链脲佐菌素诱导的糖尿病小鼠和大鼠模型,以空腹血糖值为指标研究知母各提取物的降糖作用;从其活性部位知母总酚中继续分离得3个化合物(拔契皂苷元、芒果苷、新芒果苷),并探讨知母总酚及其成分对α-葡萄糖苷酶活性的影响。结果知母总酚能显著降低四氧嘧啶和链脲佐菌素引起的糖尿病动物的空腹血糖,从中分离得到的芒果苷体外有较好的抑制α-葡萄糖苷酶活性的作用。结论知母总酚对糖尿病动物有较好的降糖作用,其中芒果苷对α-葡萄糖苷酶活性的抑制可能是其降糖作用机制之一。     

甲壳低聚糖对α-葡萄糖苷酶活性的影响及降血糖作用

目的探讨甲壳低聚糖对α-葡萄糖苷酶活性的影响及降糖效果。方法在体外建立标准酶反应体系,分别加入6%甲壳低聚糖50,100,150,200,250,300μl,用4-硝基酚-α-D呋喃葡萄糖苷法测定酶活性;再建立加有6%阿卡波糖200μl的酶反应体系,测定酶活性;以250 mg/(kg.d)剂量灌胃,观察其对实验性糖尿病大鼠空腹及餐后血糖的影响。结果甲壳低聚糖对α-葡萄糖苷酶具有明显抑制作用,抑制效果接近于阿卡波糖;甲壳低聚糖能显著降低糖尿病大鼠空腹及餐后血糖。结论甲壳低聚糖可能具有阿卡波糖样的降血糖作用。     

桐花树根多酚提取物体外α-糖苷酶抑制活性与抗氧化能力

目的:研究桐花树根多酚提取物对α-糖苷酶的抑制作用与抗氧化活性。方法:采用PNPG法测定α-葡萄糖苷酶抑制活性,采用羟基自由基清除体系、DPPH·自由基清除体系、对脂质体过氧化活性测定评价桐花树根多酚的抗氧化活性。结果:桐花树根多酚提取物对α-葡萄糖苷酶有一定的抑制活性,IC₅₀为37.75μg·ml^-1。桐花树根多酚提取物表现出较强的抗氧化性能,清除DPPH的IC₅₀为0.618 mg·ml^-1,清除羟自由基的IC₅₀为0.0002 mg·ml^-1,对脂质体过氧抑制能力的IC₅₀约为0.585 mg·ml^-1。结论:桐花树根多酚提取物具有作为新型α-葡萄糖苷酶抑制剂与抗氧化剂的药用开发价值。     

知母盐炙前后体外降血糖作用的研究

目的利用Caco-2细胞模型比较知母盐炙前后的降血糖作用,并考察其作用机制,为盐知母炮制原理的阐明提供依据。方法建立Caco-2单层细胞模型,采用CCK-8细胞活力试剂盒检测5 000、2 500、500、250、50、25、5、2.5、0.5、0.25μg/m L生、盐知母水煎液细胞毒性,来确定药物最大毒性剂量。以蔗糖酶和麦芽糖酶底物,葡萄糖氧化酶法测定葡萄糖质量浓度,计算抑制率,比较其对Caco-2单层细胞上蔗糖酶和麦芽糖酶活力的影响。葡萄糖吸收实验测定剩余葡萄糖的质量浓度,比较生、盐知母对Caco-2细胞吸收和转运葡萄糖的影响。结果当生、盐知母质量浓度≤250μg/m L时,Caco-2细胞可进行细胞实验。实验选取了50、250μg/m L两个质量浓度。生、盐知母水煎液50、250μg/m L对蔗糖酶、麦芽糖酶活性均有抑制作用,且盐知母水煎液对蔗糖酶、麦芽糖酶的抑制作用均优于生知母。生、盐知母水煎液均有降低细胞对葡萄糖吸收的趋势,且呈现剂量相关性,但效果不显著。盐知母水煎液对葡萄糖吸收的抑制作用略好于生知母(P0.05)。结论盐知母对Caco-2细胞的降糖作用优于生知母,其降糖机制可能主要体现在α-葡萄糖苷酶上,而对葡萄糖吸收作用影响较小。     

蒺藜皂苷对正常和2型糖尿病大鼠餐后血糖水平的影响

目的研究蒺藜皂苷（STT）对正常和2型糖尿病大鼠餐后血糖水平的影响及可能机理。方法正常和2型糖尿病大鼠灌胃蔗糖或葡萄糖,同时灌胃STT,60 min后,尾静脉采血,测定血糖浓度;提取大鼠小肠α-葡萄糖苷酶,体外测定STT对酶活性的抑制作用。结果正常和2型糖尿病大鼠灌胃蔗糖同时灌胃STT 60min后,血糖水平显著低于对照,分别为对照的70.19%（P〈0.001）和68.05%（P〈0.001）,但STT对灌胃葡萄糖后血糖水平的变化无显著性影响;0.1、1、10 mg/mL的STT能够显著抑制α-葡萄糖苷酶的体外活性（P〈0.001）,抑制率分别为20.83%、43.73%和52.62%。结论STT能够显著降低正常和2型糖尿病大鼠餐后血糖水平的升高,其可能机理为对小肠α-葡萄糖苷酶的抑制作用。     

红葱萃取物对离体大鼠主动脉血管环的影响研究

目的:研究红葱萃取物(氯仿和乙酸乙酯萃取物)对离体大鼠胸主动脉血管环的影响作用。方法:将大鼠分为3组,即空白和氯仿、乙酸乙酯萃取物组,用Powerlab生物信号采集与分析系统测定离体主动脉血管环张力的变化。结果:与空白组比较,氯仿和乙酸乙酯萃取物组的血管环明显舒张,对苯肾上腺素(PE)和KCl引发的预收缩有显著抑制作用(P<0.05或P<0.01)。氯仿部位较乙酸乙酯部位萃取效果好(P<0.05或P<0.01)。结论:红葱的氯仿和乙酸乙酯萃取部位既能直接舒张血管环,亦能抑制PE和KCl对血管环的预收缩作用。     

Effect of an isolated active compound (Cg-1) of Cassia glauca leaf on blood glucose, lipid profile, and atherogenic index in diabetic rats

Objectives:

The objective of present study was to evaluate the effect of active principle (Cg-1) from Cassia glauca leaf on serum glucose and lipid profile in normal and diabetic rats.

Materials and Methods:

Diabetes was induced by streptozotocin in neonates. Oral administration of petroleum ether, chloroform, acetone, and methanol of C. glauca leaf (100 mg/kg, p.o.) for 21 days caused a decrease in fasting blood glucose (FBG) in diabetic rats. Among all the extracts, acetone extract was found to lower the FBG level significantly in diabetic rats. Glibenclamide was used as standard antidiabetic drug (5 mg/kg, p.o). Acetone extract was subjected to column chromatography that led to isolation of an active principle, which was given trivial name Cg-1. Cg-1 (50 mg/kg, p.o.) was studied for its hypoglycemic and hypolipidemic potential. The unpaired t-test and analysis of variance (ANOVA) followed by post hoc test was used for statistical analysis.

Results:

Cg-1 caused a significant reduction in FBG level. It also caused reduction in cholesterol, triglycerides, and LDL levels and improvement in the atherogenic index and HDL level in diabetic rats.

Conclusion:

Improvement in the FBG and the atherogenic index by Cg-1 indicates that Cg-1 has cardioprotective potential along with antidiabetic activity and provides a scientific rationale for the use as an antidiabetic agent.     

Antihyperglycemic and antihyperlipidemic activity of plectranthus amboinicus on normal and alloxan-induced diabetic rats

The present study was undertaken to investigate the antihyperglycemic and antihyperlipidemic effects of ethanol extract of Plectranthus amboinicus in normal and alloxan-induced diabetic rats. Diabetes was induced in Wistar rats by single intraperitoneal administration of alloxan monohydrate (150 mg/kg). Normal as well as diabetic rats were divided into groups (n=6) receiving different treatments. Graded doses (200 mg/kg and 400 mg/kg) of ethanol extract of Plectranthus amboinicus were studied in both normal and alloxan-induced diabetic rats for a period of 15 days. Glibenclamide (600 μg/kg) was used as a reference drug. Oral administration with graded doses of ethanol extract of Plectranthus amboinicus exhibited hypoglycemic effect in normal rats and significantly reduced the peak glucose levels after 120 min of glucose loading. In alloxan-induced diabetic rats, the daily oral treatment with ethanol extract of Plectranthus amboinicus showed a significant reduction in blood glucose. Besides, administration of ethanol extract of Plectranthus amboinicus for 15 days significantly decreased serum contents of total cholesterol, triglycerides whereas HDL-cholesterol, total proteins and calcium were effectively increased. Furthermore, effect of ethanol extract of Plectranthus amboinicus showed profound elevation of serum amylase and reduction of serum lipase. Histology examination showed ethanol extract of Plectranthus amboinicus exhibited almost normalization of damaged pancreatic architecture in rats with diabetes mellitus. Studies clearly demonstrated that ethanol extract of Plectranthus amboinicus leaves possesses hypoglycemic and antihyperlipidemic effects mediated through the restoration of the functions of pancreatic tissues and insulinotropic effect.     

Antidiabetic activity of Cassia occidentalis (Linn) in normal and alloxan-induced diabetic rats

Objective:

To evaluate the hypoglycemic activity of various extracts, petroleum ether, chloroform and aqueous extract of Cassia occidentalis in normal and alloxan-induced diabetic rats.

Materials and Methods:

Petroleum ether, chloroform and aqueous extract of whole plant of Cassia occidentalis were orally tested at the dose of 200 mg/kg for hypoglycemic effect in normal and alloxan-induced diabetic rats. In addition, changes in body weight, serum cholesterol, triglyceride and total protein levels, assessed in the ethanol extract-treated diabetic rats, were compared with diabetic control and normal animals. Histopathological observations during 21 days treatment were also evaluated.

Results:

Aqueous extract of C. occidentalis produced a significant reduction in fasting blood glucose levels in the normal and alloxan-induced diabetic rats. Apart from aqueous extract, petroleum ether extract showed activity from day 14 and chloroform extract showed activity from 7 days. Significant differences were observed in serum lipid profiles (cholesterol and triglyceride), serum protein, and changes in body weight by aqueous extract treated-diabetic animals, when compared with the diabetic control and normal animals. Concurrent histopathological studies of the pancreas of these animals showed comparable regeneration by extract which were earlier necrosed by alloxan.

Conclusion:

Aqueous extract of C. occidentalis exhibited significant antihyperglycemic activity in normal and alloxan-induced diabetic rats. They also showed improvement in parameters like body weight and serum lipid profiles as well as histopathological studies showed regeneration of β-cells of pancreas and so might be of value in diabetes treatment.     

Phytochemical analysis and anti-diabetic,anti-inflammatory and antioxidant activities of Loranthus acaciae Zucc. Grown in Saudi Arabia

The Loranthus genus has been demonstrated to be used in the treatment of wide range of diseases e.g. diabetes, inflammations and cancers. Many species of Loranthus represent a major source of biologically active constituents. Therefore, our study was carried out to investigate the anti-diabetic, anti-inflammatory and antioxidant effects of Loranthus acaciae Zucc. (Loranthaceae) grown in Saudi Arabia. Moreover, our research concerned the guided-fractionation and isolation of possible active compounds from this species. The crude ethanolic extract and its n-hexane, chloroform and n-butanol fractions were investigated for antidiabetic activity utilizing two methods namely, in alloxan-induced diabetic rats and glucose tolerance test in normal rats. Additionally, the anti-inflammatory activity was studied by the carrageenan-induced rat paw oedema method while DPPH free radical scavenging and β-carotene bleaching assays were utilized to determine the antioxidant activity. Various chromatographic and spectroscopic techniques were utilized for the isolation and characterization of the active compounds. Our results exhibited that the crude extract and chloroform fraction has the greatest hypoglycemic and antidiabetic effects. The chloroform fraction and crude extract produced at a dose of 500 mg/kg a significant hypoglycemic effect in diabetic rats with 47.0 and 33.6% reduction in blood sugar levels and in normoglycemic rats 35.6 and 35.4% respectively. A potent anti-inflammatory effect (67.2% at 500 mg/kg) was detected for the chloroform fraction. In addition, the chloroform fraction exhibited a high antioxidative and DPPH-radical inhibitory activity (85.4 and 88.3% respectively). The phytochemical analysis of L. acaciae led to the isolation and characterization of four compounds namely, quercetin 3-O-β-D-glucopyranoside (compound 1), quercetin 3-O-β-(6-O-galloyl)-glucopyranoside (compound 2), (-) catechin (compound 3), and catechin 7-O-gallate (compound 4). Among these compounds quercetin 3-O-β-D- glucopyranoside, quercetin 3-O-β-(6-O-galloyl)-glucopyranoside and catechin 7-O-gallate, are isolated for the first time from this plant.     

Biochemical Evaluation of the Hypoglycemic Effects of Extract and Fraction of Cassia fistula Linn. in Alloxan-induced Diabetic Rats

Various extracts of flowers of Cassia fistula Linn (Leguminosae) such as petroleum ether (60-80°), chloroform, acetone, ethanol, aqueous, and crude aqueous extracts and two fractions of ethanol extract were tested for antihyperglycemic activity in glucose-overloaded hyperglycemic rats. The effective antihyperglycemic extracts and fraction were tested for their hypoglycemic activity at two dose levels, 200 and 400 mg/kg, respectively. To confirm their utility in higher models, the effective extracts and fraction of C. fistula were subjected to antidiabetic study in an alloxan-induced diabetic model at two dose levels, 200 and 400 mg/kg, respectively. Biochemical parameters like glucose, urea, creatinine, serum cholesterol, serum triglyceride, high-density lipoprotein, low-density lipoprotein, hemoglobin, and glycosylated hemoglobin were also assessed in experimental animals. The petroleum ether and ethanol extracts of C. fistula and the water-soluble fraction of ethanol extract were found to exhibit significant antihyperglycemic activity. The extracts, at the given doses, did not produce hypoglycemia in fasted normal rats, and the fraction exhibited weak hypoglycemic effect after 2 h of the treatment. Treatment of diabetic rats with ethanol extract and water-soluble fraction of this plant restored the elevated biochemical parameters significantly (P<0.05) to the normal level. No activity was found in the petroleum ether extract of the plant. Comparatively, the water-soluble fraction of ethanol extract was found to be more effective than the ethanol extract, and the activity was comparable with that of the standard, glibenclamide (5 mg/kg).     

Antidiabetic Activity of Clerodendron phlomoidis Leaf Extract in Alloxan-Induced Diabetic Rats

Ethanol extract of leaves of Clerodendron phlomoidis L. subjected to preliminary qualitative phytochemical investigations showed the presence of alkaloids, phytosterols, glycosides, saponins, phenolic compounds, proteins and flavonoids. The extract was screened for hypoglycemic activity in alloxan-induced diabetic rats (120 mg/kg, i.p.) at two dose levels, viz., 100 and 200 mg/kg. The ethanol extract at 200 mg/kg dose level exhibited significant (p<0.05) hypoglycemic activity and also correction of altered biochemical parameters viz., cholesterol and triglycerides (p<0.05).     

Hypoglycemic and hypolipidemic effects of flavonoid rich extract from Eugenia jambolana seeds on streptozotocin induced diabetic rats

The hypoglycemic and hypolipidemic effects of flavonoid rich extract obtained from seeds of Eugenia jambolana (EJ) was analyzed in streptozotocin induced diabetic rats. Hypoglycemic activity was assessed by reduction in fasting blood glucose (FBG) and peak blood glucose level within 60 min of glucose tolerance test (GTT) in mild and severe diabetic (MD and SD respectively) rats. Different biochemical parameters like glycogen biosynthesis, glucose homeostatic enzyme (glucose-6-phosphatase, hexokinase) activities demonstrated significant (p<0.05) improvement as compared to diabetic counter parts. Further, the flavonoids also stimulated 16% increase in insulin release in vitro from pancreatic islets. The hypolipidemic action after this extract supplementation was confirmed by significant (p<0.05) decrease in the levels of LDL (27% MD, 29% SD), triglycerides (about 35% MD, 37% SD) and increase in HDL (21% MD, 34% SD) over untreated diabetic rats. The above mentioned action of this plant extract was found to be through dual up regulation of both the peroxisome proliferators-activated receptors (PPARalpha and PPARgamma) up to about 3-4 folds (over control) and their capacity to differentiate 3T3-L1 preadipocytes. The present data suggests that the flavonoid rich extract from EJ plant has both hypoglycemic and hypolipidemic effects which can help the cure and management of diabetes.