The influence of the vegetation period on the content of bilobalide and ginkgolides in ginkgo biloba (Ginkgo biloba L.) leaf extracts

Background. At present ginkgo biloba (Ginkgo biloba L.) is being widely researched. Its multi­directional impact on the nervous and cardiovascular system was proved by numerous pharmacological investigations and clinical trials. The ginkgo green leaf extract, which is produced in a strictly defined manner, is widely used in pharmacology. The aim of the study was to assess the influence of different extractants on the content of bilobalide and ginkgolides in extracts made from dried yellow and green ginkgo tree leaves. Material and methods. Dried green and yellow ginkgo tree leaves were chemically analysed. This material was extracted with water, acetone and ethyl alcohol. The content of ginkgolides and bilobalide in the extracts was measured by means of High Performance Liquid Chromatography (HPLC Agilent 1100 with Diode Array Detector). The compounds under analysis were identified by comparison with the reference substance. Results. The analysis revealed that the content of bilobalide and ginkgolides in the maidenhair tree extracts depended on the extraction method and type of leaves. There was higher overall content of terpenoids in ethanol extracts from green leaves. Bilobalide was the predominant terpen­oid in the yellow leaf extracts, whereas ginkgolides A and B were predominant in the green leaf extract. There was no ginkgolide C in the ginkgo extracts under analysis. Conclusions. The research proved the influence of the vegetation period and the extraction conditions on the content of bilobalide and ginkgolides in the ginkgo tree leaf extracts.