Investigations on the anti-inflammatory and anti-allergic activities of the leaves of Uncaria guianensis (Aublet) J. F. Gmelin

Uncaria guianensis (Aublet) J. F. Gmelin is an herbal medicine from tropical areas of South and Central America. We investigated the anti-inflammatory and anti-allergic properties of an ethanolic extract of U. guianensis leaves, containing alkaloids, flavonoids and phenol carboxylic acids, as revealed by thin layer chromatography (TLC). Oral pre-treatment with U. guianensis inhibited zymosan-induced paw oedema (500 mg/paw) and pleural exudation (100 mg/kg) within 4 h (25–200 mg/kg). U. guianensis (100 mg/ kg) inhibited total leukocyte and neutrophil numbers in the pleural cavity 4 h after zymosan stimulation. Pre-treatment with U. guianensis (100 mg/kg, p.o.) inhibited total leukocyte, neutrophil and eosinophil recruitment into the pleural cavity 24 h after LPS (250 ng/cavity, i.t.). Pre-treatment with U. guianensis inhibited paw oedema (25–200 mg/kg) induced by ovalbumin (OVA) within 1 h, and neutrophil and eosinophil recruitment into the mice pleural cavity 24 h after OVA (100 mg/kg). In vitro data revealed that U. guianensis impaired LPS-induced nitric oxide and CXCL8 generation by murine peritoneal macrophages, as well as OVA-induced interleukin-5 synthesis by previously sensitized spleen cells. These results demonstrate that U. guianensis leaves provide effective anti-inflammatory and anti-allergic activities.     

Oxindole alkaloids from Uncaria tomentosa induce apoptosis in proliferating, G0/G1-arrested and bcl-2-expressing acute lymphoblastic leukaemia cells

Natural products are still an untapped source of promising lead compounds for the generation of antineoplastic drugs. Here, we investigated for the first time the antiproliferative and apoptotic effects of highly purified oxindole alkaloids, namely isopteropodine (A1), pteropodine (A2), isomitraphylline (A3), uncarine F (A4) and mitraphylline (A5) obtained from Uncaria tomentosa, a South American Rubiaceae, on human lymphoblastic leukaemia T cells (CCRF-CEM-C7H2). Four of the five tested alkaloids inhibited proliferation of acute lymphoblastic leukaemia cells. Furthermore, the antiproliferative effect of the most potent alkaloids pteropodine (A2) and uncarine F (A4) correlated with induction of apoptosis. After 48 h, 100 micromol/l A2 or A4 increased apoptotic cells by 57%. CEM-C7H2 sublines with tetracycline-regulated expression of bcl-2, p16ink4A or constitutively expressing the cowpox virus protein crm-A were used for further studies of the apoptosis-inducing properties of these alkaloids. Neither overexpression of bcl-2 or crm-A nor cell-cycle arrest in G0/G1 phase by tetracycline-regulated expression of p16INK4A could prevent alkaloid-induced apoptosis. Our results show the strong apoptotic effects of pteropodine and uncarine F on acute leukaemic lymphoblasts and recommend the alkaloids for further studies in xenograft models.     

大叶钩藤的化学成分研究

目的：研究中药大叶钩藤非生物碱部 分的化学成分。方法：柱色谱等方法进行分离,NMR等波谱学方法进 行结构鉴定。结果与结论：分离得到6个化合物,乌索酸、3β-6β-23-trihydroxyurs-12-en-28-oic acid、3β,6β,19α-trihydroxyurs-12- en-28-oic acid、表儿茶素、β-谷甾醇、胡萝卜苷,均为首次从该植物中获得。     

Evaluation of the in vitro antioxidant activity in extracts of Uncaria tomentosa (Willd.) DC.

Different extracts of U. tomentosa were tested in vitro for their antioxidant activity utilizing tert -butyl-hydroperoxide-initiated chemiluminescence in rat liver homogenates. Methanol fractions of both stem-bark and roots were capable of exerting antioxidant activity by this technique. The presence of different concentrations of bark and root methanol extracts also prevented TBARS production and free radical-mediated DNA-sugar damage. © 1997 John Wiley & Sons, Ltd.     

Antitumoral and antioxidant effects of a hydroalcoholic extract of cat's claw (Uncaria tomentosa) (Willd. Ex Roem. & Schult) in an in vivo carcinosarcoma model

Aim of the study

The present work intended to study the antitumoral and antioxidant effects of Uncaria tomentosa (UT) hydroalcoholic extract in the Walker-256 cancer model.

Methods and materials

Walker-256 cells were subcutaneously inoculated in the pelvic limb of male Wistar rats. Daily gavage with UT extract (10, 50 or 100 mg kg⁻¹, Groups UT) or saline solution (Control, Group C) was subsequently initiated, until 14 days afterwards. For some parameters, a group of healthy rats (Baseline, Group B) was added. At the end of treatment the following parameters were evaluated: (a) tumor volume and mass; (b) plasmatic concentration of urea, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT) and lactate dehydrogenase (LDH); (c) hepatic and tumoral activity of catalase (CAT) and superoxide dismutase (SOD), as well as the rate of lipid peroxidation (LPO) and gluthatione (GSH); and (d) hepatic glutathione-S-transferase (GST) activity. The reactivity of UT extract with the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) was assessed in parallel.

Results

UT hydroalcoholic extract successfully reduced the tumor growth. In addition, treatment with UT reduced the activity of AST, which had been increased as a result of tumor inoculation, thus attempting to return it to normal levels. UT did not reverse the increase of LDH and GGT plasma levels, although all doses were remarkably effective in reducing urea plasma levels. An important in vitro free radical-scavenging activity was detected at various concentrations of UT extract (1–300 μg mL⁻¹). Treatment also resulted in increased CAT activity in liver, while decreasing it in tumor tissue. SOD activity was reduced in liver as well as in tumor, compared to Group C. No statistical significance concerning ALT, GST, LPO or GSH were observed.

Conclusions

This data represent an in vivo demonstration of both antitumoral and antioxidant effects of UT hydroalcoholic extract. The antineoplastic activity may result, partially at least, from the ability of UT to regulate redox and metabolism homeostasis.     

6种不同基源钩藤药材的显微鉴别

目的:研究6种不同基源钩藤药材的显微特征,对钩藤药材进行分种鉴别。方法:研究光镜下6种钩藤属植物的茎、钩、叶横切面特征和粉末显微特征。结果:不同种的钩藤在组织构造方面有基本相同之处,由外到内均由表皮、皮层、韧皮部、木质部及髓部组成。大多数钩藤的皮层、韧皮部及髓部薄壁细胞中均含棕色内含物。但各种之间又有不同特征,如主脉在叶的腹背面突出的形状、栅栏组织的列数、维管束的个数以及薄壁细胞中可见的草酸钙晶体类型。6种钩藤药材的显微特征比较研究表明,茎的横切面观轮廓、表皮毛的有无、韧皮部与木质部比例、形成层是否明显成环、射线宽窄和导管散在或径向相连以及髓部所占比例;叶主脉在叶的腹、背面凸出的形状、栅栏组织的列数和薄壁细胞中所含晶体种类;钩的形状等可作为钩藤属分种鉴别依据。粉末鉴定主要依据表皮细胞的形状、表皮细胞内是否存在油滴状物以及有无梯纹、环纹和网纹导管加以区别。结论:以上特征可以作为不同基源钩藤药材鉴别依据。     

毛钩藤叶的生药学鉴定

目的建立毛钩藤叶的生药鉴定方法。方法采用生药性状鉴别、显微鉴别及薄层层析色谱法对毛钩藤叶进行生药学研究。结果毛钩藤叶含众多多细胞非腺毛,栅栏组织细胞2列,叶片薄璧细胞含草酸钙簇晶,于上表面的表皮下层细胞沿网脉成列分布,气孔直轴式,薄层层析显示与对照药材至少有2种相同的生物碱成分。结论本实验为毛钩藤叶的鉴定、质量标准的制定及进一步开发利用提供了科学依据。     

RP-HPLC检测大鼠大血管中异钩藤碱的含量

目的: 建立测定大鼠大血管中异钩藤碱含量的方法。 方法: Wista大鼠灌胃钩藤水煎液后取出大血管,液氮研磨,用乙醇沉淀组织匀浆中的蛋白质,取上清液用氮气吹干,加甲醇复溶后取上清液直接进样,用高效液相色谱仪测定。RP18 Waters^TM 色谱柱（4.6 mm×250 mm,5 μm）,流动相甲醇-水（70∶30）,三乙胺调pH 8.0,流速 0.8 mL·min^-1,检测波长254 nm,异钩藤碱保留时间约为12 min,柱温 30℃。 结果: 大血管中异钩藤碱的质量浓度在0.04~20.0 mg·L^-1,大鼠峰面积之比Y与异钩藤碱的质量浓度X具有较好的线性关系,回归方程为Y=4.644 1X+0.161 2（R²=0.999 2）;平均提取回收率为99.34%,RSD<8.0%。 结论: 方法简便、稳定、易行,可以用于测定大鼠大血管中异钩藤碱的含量。     

鬼箭羽钩藤复方液对心肌肥大大鼠L型钙电流的影响

 目的 探讨鬼箭羽钩藤复方液对高血压性心肌肥大的影响.方法 利用腹主动脉缩窄法建立高血压性心肌肥大模型,利用灌胃法给予中药治疗,采用离体大鼠心脏 Langendorff 灌注法急性分离心肌细胞,利用膜片钳全细胞技术记录L型钙电流,比较正常对照组、高血压模型组及中药治疗组之间的区别.结果 高血压模型组的L型钙电流密度显著高于正常对照组(P＜0.05);中药治疗组的L型钙电流密度显著小于高血压模型组(P＜0.05),与正常对照组相比无显著性差异(P＞0.05).结论 鬼箭羽钩藤复方液具有逆转高血压性心肌肥大的作用.