银杏叶丙酮提取物对动物脂肪酸合酶的抑制

Inhibitory Activity of Acetonic Extraction of Ginkgo Leaf on Animal Fatty Acid Synthase

银杏叶丙酮提取物（AEGL）对动物脂肪酸合酶（FAS）有强抑制作用。选定的萃取条件是室温下用60％丙酮搅拌萃取30—60min。该萃取液IC50值为4．66μg／mL，抑制能力明显强于已知的FAS抑制剂，有效物的初步分离显示，对FAS有抑制作用的成分可能存在于黄酮组分中。酶学动力学研究表明，抑制包含可逆抑制和不可逆抑制两部分。推测酮酰还原功能域（KR）的NADPH结合部位是其作用部位之一。标准银杏叶提取物EGb761对FAS的可逆抑制和不可逆抑制都明显比银杏叶的60％丙酮萃取液弱，后者对NADPH呈现比较明显的竞争性，不同于EGb761，这表明银杏叶还具有新的应用开发领域。

The acetonic extract of Ginkgo leaf （AEGL）had strong inhibitiory activity on fatty acid synthase. The extract was prepared by extracting Ginkgo leaf with 60% acetone for 30 -60 min at room temperature. Its IC50 value was 4.66 μg/mL. Its inhibitory ability is stronger than that of inhibitors which have been published. Primary isolation of Ginkgo leaf extract showed that the effective components of Ginkgo leaf are flavonoids. It was showed that the inhibition consisted of both reversible inhibition and irreversible inhibition through kinetics studies. AEGL may be associated with the NAD- PH binding site of ketoacyl reductase of FAS. Inhibitory ability of EGb761, a commercial extract from Ginkgo leaf, also involves reversible and irreversible inhibition, but is weaker than that of AEGL. It was also showed that the AEGL inhibited FAS in a competitive pattern .against NADPH whereas the EGb761 had a different pattern. It should have some new fields for Ginkgo leaf medical application.