The fruits of the maidenhair tree, Ginkgo biloba (Ginkgoaceae)(see photo to the left) resembles that of the persimon in colour (pale orange), size and character, with one exception: its flesh stinks. The reason is an abundant production of butyric acid, the same compound that occurs in rancid butter. However, when the hulls fall off the nuts can be collected and dried. When cracked open, the odour-less contents can be eaten.
Ginkgo is possibly the oldest surviving plant in the world. Its origin is in the Permian era, some 200-225 million years ago. The present form of the ginkgo leaf has been essentially unchanged since Jurassic times, about 100 million years ago. Thus, Ginkgo biloba is a fascinating living fossil that can reach an age of over 500 year.
In Chinese herbal medicine ginkgo leaves have been used for more than 5,000 years against ailments ranging from asthma to impotence. Nowadays, the most common preparation is a standardised extract (containing 24 % flavoglycosides). Also the nuts have been used as a kidney yang tonic, which would imply such remarkable and diverse properties as increasing sexual energy, stopping bed-wetting and restoring hearing loss.
Ginkgo nuts can also be roasted and eaten simply because they are delicious. In Japan they are eaten in an egg custard like dish calles chawanmushi. Canned ginkgo nuts are available in Japan and China, and are also imported into some Western countries.
They contain very small quantities of a group of remarkable chemicals called ginkgolides; higher concentrations are found in the leaves and in the wood. The ginkgolides are highly modified diterpenes containing a tertiary butyl group and a lactone ring system that is stable towards strong acids but readily hydrolysed by weak bases. Just guess what that could do to improve your sex life!