Abstract: Dynamic changes of mass fraction of ginkgolides (ginkgolides A, B, C) and the total amount of ginkgoides obtained by supercritical CO₂ extraction in different timeframe were studied using Ginkgo biloba Linn. leaves as material. HPLC method combined with evaporative light scattering detector was applied to deter mine the mass fraction of ginkgolides. The results showed that the total amount of ginkgolides decreased with time. In the first 40 min, the amount of ginkgolides obtained by supercritical CO₂ extraction was 55.9% of total. But the trends of the dynamic changes of mass fraction of ginkgolides were increased first and then decreased. Ginkgolide A has the highest value in 60-80 min period of time and the mass fraction was 0.403%. Real-time mass fraction of ginkgolides B, C have the highest value in 40-60 min period of time and the mass fraction were 0.289% and 0.246%, respectively. The total amount of ginkgolides A,B,C decreased with the extension of time, and reached the highest in 0-20 min about 33.6%,33.3% and 35.4%, respectively.

Key words: supercritical CO₂ extraction, Ginkgo biloba Linn., ginkgolide