Objective To determine the best extraction process of ginkgo leaves with the total transfer rate of total flavonol glycosides and terpene lactones as the index.Methods The effects of ethanol concentration, solid-liquid ratio and extraction time on extraction process were investigated by orthogonal design method, and the contents of total flavonol glycosides and terpene lactones were detected by HPLC to calculate transfer rate.Results The optimum extraction conditions were as follows:85% ethanol refluxing and extracting for three times;the first time extracting with five-fold amount of solvent (V/W) for 3 hours;the last two times with three-fold solvent (V/W) for 2 hours.Conclusion This extraction process has the advantages of simplicity of operator, reason, energy conservation, high efficiency, and is suitable for industrial production.

Objective To prepare the phmaceutical reference materials of total lactones extract from ginkgo leaf for quantitative analysis.Methods A HPLC determination method was developed to investigate the uniformity and stability of the reference extract of ginkgo leaf total lactones using with bilobalide, ginkgolide A, ginkgolide B and ginkgolide C as the indexes.Three laboratories participated in the collaborative calibration test.Results The four components in reference extract had good uniformity and stability with RSD less than 2.0%;the marked values of the four components had been determined through statistical data analysis which provided by assigned traceability values.The values of bilobalide, ginkgolide A, ginkgolide B, and ginkgolide C were 39.54%, 29.03%, 15.96% and 11.69%, respectively.Conclusion The reference extract of ginkgo leaf total lactones can be prepared for quality control in future quantitative analysis.