Department of Pharmacology and Toxicology, Madonna University, Elele Rivers State, Nigeria.
Asian Pac J Trop Med. 2011 Jun;4(6):475-7. doi: 10.1016/S1995-7645(11)60129-6.
To investigate the interacting effects of co-administration of methanol leaf extract of Catharanthus roseus (C. roseus) on the hypoglycemic activity of metformin as well as glibenclamide using experimental rats.
Phytochemical analysis as well as acute toxicity and lethality (LD(50)) test were carried out on its methanol leaf extract. The alloxan model for experimental induction of diabetes in rats was employed. Six groups comprising five rats each were used. Groups II, III and IV received 250 mg/kg of extract, 100 mg/kg of metformin and 1 mg/kg of glibenclamide respectively, while V and VI were administered metformin-extract and glibenclamide-extract combinations respectively at doses as above. Group I served as negative control and received only distilled water. All administration was done once daily for seven days. Fasting blood glucose was determined at 2, 12, 24, 72 and 168 h using a glucometer. One-way ANOVA with post-hoc tests was used to assess for significant difference due to administration of drug alone and with co-administration of drug and extract.
The LD(50) was 2 121.32 mg/kg. The phytochemical studies indicated the presence of saponins, tannins, alkaloids, phlotatannins, flavonoids, triterpenoids, reducing sugars, anthraquinones and glycosides. All medicaments significantly reduced blood glucose levels when compared with control alone (P<0.05) with the highest percentage reduction in blood glucose (64.86%) exhibited by metformin-extract combination.
The leaf extract of C. roseus significantly increases the hypoglycemic effect of metformin.
研究长春花甲醇叶提取物（C. roseus）与二甲双胍和格列本脲联合给药对实验大鼠降血糖活性的相互作用影响。
对其甲醇叶提取物进行了植物化学分析以及急性毒性和致死（LD 50 ）测试。采用链脲佐菌素诱导实验性糖尿病大鼠模型。使用包含五只大鼠的六组，每组 5 只。第 II、III 和 IV 组分别给予 250 mg/kg 的提取物、100 mg/kg 的二甲双胍和 1 mg/kg 的格列本脲，而 V 和 VI 组则分别以相同剂量给予二甲双胍-提取物和格列本脲-提取物组合。第 I 组作为阴性对照，仅给予蒸馏水。所有药物均每日一次连续给药 7 天。使用血糖仪在 2、12、24、72 和 168 h 测定空腹血糖。采用单因素方差分析和事后检验评估药物单独给药和药物与提取物联合给药的差异。
LD 50 为 2121.32 mg/kg。植物化学研究表明存在皂苷、单宁、生物碱、黄酮、三萜、还原糖、蒽醌和糖苷。与单独对照相比，所有药物均显著降低血糖水平（P<0.05），其中二甲双胍-提取物组合使血糖降低的百分比最高（64.86%）。
长春花的叶提取物显著增强了二甲双胍的降血糖作用。
