Extraction of Total Flavonoids from Ginkgo biloba by Decompressing Inner Ebullition

[Objective] To study the extraction methods of total flavonoids from Ginkgo biloba leaves. [Method] By using the decompressing inner ebullition, the Ginkgo biloba leaves powder was desorbed and extracted to investigate the effects of each factor on the extraction rate, the best desorption and extraction conditions were found out, and then compared with traditional extraction method. [Result] The optimal desorption conditions were: with 80% ethanol as the desorption solvent, 20 min desorption time and 15 ml solvent dose; the best extraction technology was 0.067 MPa extraction pressure, 60 ℃ extraction temperature, 30% ethanol as extraction solvent, twice of extraction, 5 min each time; under these conditions, the extraction rate of flavonoids could reach up to 2.55%. Compared with the traditional ethanol extraction method, the temperature was cut down by 20 ℃, the extraction was 12 times faster, ethanol dose was three times less, the extraction solution had little pigment and impurities, and could be purified with macroporous adsorbing resin directly, the purity of total flavonoids from Ginkgo biloba was 29.8%, the advantages were obvious. [Conclusion] The method was economical, rapid and efficient, therefore could be applied to the extractin of flavonoids from Ginkgo biloba leaves.