Determination of Ginkgolides from Leaves of Ginkgo Biloba L. in Nanxiong by HPLC

The ginkgolides from leaves of Ginkgo biloba L. were determined by high performance liquid chromatography. The leaves were collected from trees of different ages in Nanxiong on various months. The chromatographic separation was performed on Kromasil C18 column at 35 ℃ with an eluent consisting of methanol-tetrahydrofuran-water(37∶8∶55 by volume), and the eluate was monitored by a differential refractometer detector. The sample was purified by a polyamide column. The ginkgolides content was quantified by external standard method. The determined results showed that the total content of four ginkgolides of ginkgolide A, ginkgolide B, ginkgolide C and bilobolide was 0.23%(by dried leaves). The leaves are optimally collected from trees of 5～10 ages on July.