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Evaluation of Ethnomedical Claim III: Anti-hyperglycemic activities of Gongronema latifolium root and stem (民族药物需求评估III:Gongronema latifolium根与茎的降糖活性)

Authors

  • Adeleke Clement Adebajo,

    Corresponding author
    1. Institute of Pharmaceutical Biology and Phytochemistry, Westfälische Wilhelms-Universität, Munster, Germany
    2. Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität, Munster, Germany
    • Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile Ife, Nigeria
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  • Marcus Durojaye Ayoola,

    1. Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile Ife, Nigeria
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  • Samuel Akintunde Odediran,

    1. Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile Ife, Nigeria
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  • Adetunji Joseph Aladesanmi,

    1. Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile Ife, Nigeria
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  • Thomas Jürgen Schmidt,

    1. Institute of Pharmaceutical Biology and Phytochemistry, Westfälische Wilhelms-Universität, Munster, Germany
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  • Eugene Joseph Verspohl

    1. Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität, Munster, Germany
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Correspondence

Adeleke Clement Adebajo, Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile Ife, Nigeria.

Tel: +234 8033679390

Email: caadebajo@yahoo.com

Abstract

Background

The insulinotropic activity of the combined root and stem of Gongronema latifolium (Asclepiadaceae) was evaluated to justify its African ethnomedicinal use in the management of diabetes.

Methods

A methanolic extract and its chromatographic fractions (A1A6) were tested for glucose-reducing and in vitro insulin-stimulating abilities using glucose-loaded rats and INS-1 cells, respectively. In vivo insulin-releasing activities for the significantly (P < 0.05) active antihyperglycemic A5 and A6 and in vitro insulinotropic activity of the C1 fraction and its isolated constituents were also similarly determined.

Results

The extract (100 mg/kg) had higher in vivo antihyperglycemic activity than the individual A1A6, indicating a synergistic effect of the plant constituents. Higher in vivo insulin release in response to A5 (100 mg/kg) than A6, agreed with their in vivo antihyperglycemic activities and confirmed insulin release as a mechanism of action of the plant. Compared with 5.6 mmol/L glucose (negative control), the extract and the A3, A6, and C1 (all at 100.0 μg/mL) elicited significantly higher in vitro insulin release that was similar to that of glibenclamide (1.0 μg/mL; P > 0.05). Fraction C1 yielded a 1:1 mixture of α-amyrin and β-amyrin cinnamates (1a:1b), lupenyl cinnamate (2), lupenyl acetate (3), and two unidentified triterpenoids, Y and Z. The 1a:1b mixture (100.0 μg/mL) demonstrated the highest insulinotropic activity that was comparable (P > 0.05) to that of glibenclamide (1.0 μg/mL).

Conclusions

The results confirm pancreatic activity as a mechanism underlying the antidiabetic action of G. latifolium and justify its ethnomedical use.

摘要

背景

为了证实非洲民族医药在糖尿病治疗中的作用,评估了Gongronema latifolium(萝藦科)的根与茎组合是否具有促胰岛素分泌的活性作用。

方法

检测其甲醇提取物以及它的色谱片段(A1A6)是否具有降糖作用,分别使用葡萄糖负荷大鼠以及INS-1细胞在体外测定其刺激胰岛素分泌的能力。在体内检测其促进胰岛素释放的活性,发现A5A6片段具有显著的降糖活性(P < 0.05),同样在体内还测定了C1片段以及它的分离成分的促胰岛素分泌作用。

结果

提取物(100 mg/kg)体内降糖活性比单个的A1A6高,这表明植物的各种成分具有协同作用。在体内使用A5(100 mg/kg)以后的胰岛素释放作用比A6强烈,这与它们在体内的降糖活性相一致,证实了这个植物的作用机制是促进胰岛素释放。与血糖为5.6 mmol/L相比较(阴性对照),提取物与A3A6以及C1(浓度都是100.0 ug/mL)在体外促进胰岛素释放作用显著增强,其强度与格列本脲(1.0 µg/mL;P < 0.05)所导致的相类似。C1片段可产生1:1混合的α-肉桂香树脂醇与β-肉桂香树脂醇(1a:1b),肉桂酸羽扇烯酯(2), 醋酸羽扇烯酯(3),以及两个未经确认的三萜类化合物,Y与Z。经证实1a:1b混合物(100.0 µg/mL)具有最高的促胰岛素分泌活性,与格列本脲(1.0 µg/mL)的促泌活性相似(P < 0.05)。

结论

研究结果证实了G. latifolium潜在的降糖作用机制是胰腺活性作用,证明了它作为民族药物的作用。

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