Transformation of multi-component ginkgolide into ginkgolide B by Coprinus comatus.

Background: As the strongest antagonist of the platelet activating factor, ginkgolide B (GB) possesses anti-ischemic, anti-oxidant and anti-convulsant properties, and it is used for the treatment of thrombosis in clinical practice. Till now, GB is usually obtained from extraction of Ginkgo biloba leaves through column chromatography with an extremely low yield and high cost, which can not meet clinical requirement. Therefore, it is urgent to find a new method to prepare GB.

Results: In the current study, we studied the ability and mechanism to transform multi-component ginkgolide into GB by Coprinus comatus in order to enhance the GB yield. Except for ginkgolide A (GA) and GB, all the other ginkgolides in the extract were transformed by the strain. In the case of culture medium containing 20 g/L glucose, the transformation product was identified as 12% GA and 88% GB by high performance liquid chromatography-Mass spectrometry (HPLC-MS), two stage mass spectrometry (MS/MS) and nuclear magnetic resonance (NMR). Partial GA was also transformed into GB according to the yield (76%) and the content of GA in the raw ginkgolide (28.5%). Glucose was the key factor to transform ginkgolides. When glucose concentration in medium was higher than 40 g/L, all ginkgolides were transformed into the GB. Proteomic analysis showed that C. comatus transformed ginkgolide into GB by producing 5 aldo/keto reductases and catalases, and enhancing the metabolism of glucose, including Embden-Meyerhof pathway (EMP), hexose monophophate pathway (HMP) and tricarboxylic acid (TCA).

Conclusions: C. comatus could transform ginkgolides into GB when the medium contained 40 g/L glucose. When the strain transformed ginkgolides, the glucose metabolism was enhanced and the strain synthesized more aldo/keto reductases and catalases. Our current study laid the groundwork for industrial production of GB.