Pressurized water extraction (PWE) of terpene trilactones from Ginkgo biloba leaves

As a simple and green chemistry procedure, pressurized water extraction (PWE) was developed for removing the terpene trilactones, ginkgolides and bilobalide, from leaves of Ginkgo biloba L. Compared with conventional boiling-solvent extraction methods, PWE is a more effective, selective, economical and environmentally benign technique for the extraction of intermediate to polar compounds from herbal plants. In contrast to high temperature extraction, PWE at low temperature can minimize undesirable reactions such as thermal decomposition or degradation and remove much smaller amounts of impurities from the herbal materials. The other important advantage of PWE is that the extraction efficiency can be quantitatively assessed using a kinetic extraction model. Experimental results were proven to be closely consistent with the predicted values. After PWE, the terpene trilactones could be easily enriched by a liquid-liquid extraction and the extracts readily determined with a GC-FID method.