Ginkgo Biloba Extract. Supports Mental Acuity. Suitable for Vegetarians. Ginkgo-24™ is a standardized concentration of prime quality Ginkgo biloba leaves. The extraction yields 24% ginkgo flavoneglycosides (the key nutrients) from a 50 to 1 concentration. The Gingko biloba tree has survived for over 200 million years virtually unchanged- the Earth's oldest living species of tree. Gingko biloba is the subject of extensive scientific research and is used worldwide as an herbal supplement.