Ginkgo 24 Biloba Extract 120mg by Source Naturals Inc. 30 Tablet Ginkgo biloba extract 24 us a purified standardized concentration of prime quality ginkgo biloba leaves. The extraction yields 24 ginkgo flavone glycosides (the key nutrients) from a 50 to 1 concentration. The ginkgo biloba tree has survived for over 200 million years virtually unchanged - the earth's oldest living species of tree. Now ginkgo biloba extract 24 is the subject of extensive scientific research and is used worldwide as a nutritional supplement. The ginkgo biloba leaves used in ginkgo-24 are tested and found to be free of pesticides herbicides and synthetic fertilizers.