环糊精对黄酮的包合作用及其在银杏黄酮提取中的应用

对β-环糊精(-βCD)进行甲基化修饰和表征,并通过相溶解度法研究了β-CD以及甲基化β-环糊精(M-β-CD)对银杏黄酮的替代品———芦丁的包合作用。实验表明,两种环糊精都能有效增加芦丁在水中的溶解度,尤其是M--βCD可使溶解度增加30倍。以此为依据,该研究用含有β-CD和M-β-CD的水溶液来提取银杏叶中的黄酮,探讨了环糊精与黄酮的摩尔比、提取温度和提取时间对提取效果的影响,结果发现:当n(M--βCD)∶n(黄酮)=3∶1,60℃下提取3 h后,黄酮的提取率达72%,w(黄酮)=12.4%,较传统的水浸法〔提取率42%,w(黄酮)=4.5%〕和醇提法〔提取率63%,w(黄酮)=6.1%〕有明显的提高。这表明通过-βCD及M--βCD对银杏黄酮的溶解和包合作用,可有效地提高黄酮的提取率以及提取物纯度。

Inclusion of Flavonoids in Cyclodextrin and Its Application in the Extraction of Flavonoids from Ginkgo Biloba Leaves

Partly methylated β-cyclodextrin(M-β-CD) was synthesized from β-cyclodextrin(β-CD) and identified.The inclusion interactions between rutin,a substitute for flavonoids,and β-CD as well as M-β-CD were investigated by phase solubility method.The results showed that both inclusion interactions could effectively enhance the solubility of rutin in water,which could be even increased 30 times by M-β-CD.Based on above results,experiments were carried out to extract flavonoids from Ginkgo biloba leaves with these two cyclodextrin aqueous solutions.The effects of mole ratio of cyclodextrin to flavonoids,extraction temperature and extraction time on the separation performance were investigated in detail.The results showed that by an extraction operation of 3 h at 60 ℃ with n(M-β-CD)∶n(flavonoids) =3∶1,the extraction ratio of flavonoids could reach 72%,and the mass fraction w(flavonoids)=12.4%.By comparison,the extraction ratio of flavonoids was 42% and w(flavonoids)=4.5% by extraction with water,and the extraction ratio of flavonoids was 63% and w(flavonoids)=6.1% with ethanol,which were much lower than those by extraction with M-β-CD solution.This indicated that by the inclusion and dissolution of flavonoids in β-CD and M-β-CD,the extraction rate and purity of flavonoids could be extraordinarily improved.