Chemical characterization of Ginkgo biloba L. and antioxidant properties of its extracts and dietary supplements

Ginkgo biloba L. is the most commercialized medicinal plant worldwide, being its consumption related to prevention, and even decrease of the progression of degenerative neurological diseases. Considering the correlation between oxidative stress and the mentioned diseases, the antioxidant activity of different dietary supplements (syrup and several pills) was evaluated and compared to the leaves infusion, aqueous and methanolic extracts. Furthermore, G. biloba was chemically characterized in nutritional and bioactive components namely, fatty acids, sugars, organic acids, tocopherols, phenolics and flavonoids. Palmitic, α-linolenic and oleic acids were the main fatty acids found; fructose was the most abundant sugar; quinic acid was the most abundant organic acid and α-tocopherol was, by far, the most abundant vitamer. Dietary supplements showed higher antioxidant activity than G. biloba infusion and extracts due to their higher phenolics and flavonoids concentration. The pills with the highest concentration of plant extract (100 mg) allow the intake of the highest antioxidants concentration.Fundação para a Ciência e a Tecnologia (FCT, Portugal) for financial support to CIMO (strategic project PEst-OE/AGR/UI0690/2011) and to L. Barros (“compromisso para a Ciência 2008” contract). The authors are also grateful to Eugénia Batista for dietary supplements supply