Schäfer Angelika, Högger Petra
Universität Würzburg, Institut für Pharmazie und Lebensmittelchemie, Am Hubland, Würzburg, Germany.
Diabetes Res Clin Pract. 2007 Jul;77(1):41-6. doi: 10.1016/j.diabres.2006.10.011. Epub 2006 Nov 13.
The standardized maritime pine bark extract (Pycnogenol) was reported to exert clinical anti-diabetic effects after peroral intake. However, an increased insulin secretion was not observed after administration of the extract to patients. Our aim was to elucidate whether the described clinical effects of Pycnogenol are related to inhibition of alpha-glucosidase. Therefore, we analyzed the inhibitory activity of Pycnogenol, green tea extract and acarbose towards alpha-glucosidase. Furthermore, we explored different fractions of Pycnogenol containing compounds of diverse molecular masses from polyphenolic monomers, dimers and higher oligomers to uncover which components exhibited the most pronounced inhibitory activity. We found that Pycnogenol exhibited the most potent inhibition (IC(50) about 5 microg/mL) on alpha-glucosidase compared to green tea extract (IC(50) about 20 microg/mL) and acarbose (IC(50) about 1mg/mL). The inhibitory action of Pycnogenol was stronger in extract fractions containing higher procyanidin oligomers. The results obtained assign a novel, local effect to oligomeric procyanidins and contribute to the explanation of glucose-lowering effects of Pycnogenol observed in clinical trials with diabetic patients.
据报道，标准化的海松树皮提取物（碧萝芷）经口服后具有临床抗糖尿病作用。然而，在给患者施用该提取物后，未观察到胰岛素分泌增加。我们的目的是阐明碧萝芷所描述的临床效果是否与α-葡萄糖苷酶的抑制作用有关。因此，我们分析了碧萝芷、绿茶提取物和阿卡波糖对α-葡萄糖苷酶的抑制活性。此外，我们探索了碧萝芷的不同级分，这些级分包含从多酚单体、二聚体到更高寡聚物的不同分子量的化合物，以揭示哪些成分表现出最显著的抑制活性。我们发现，与绿茶提取物（IC50约为20μg/mL）和阿卡波糖（IC50约为1mg/mL）相比，碧萝芷对α-葡萄糖苷酶表现出最有效的抑制作用（IC50约为5μg/mL）。在含有较高原花青素寡聚物的提取物级分中，碧萝芷的抑制作用更强。所获得的结果赋予了低聚原花青素一种新的局部作用，并有助于解释在糖尿病患者的临床试验中观察到的碧萝芷的降血糖作用。
