Metabolic Profile and Quantification of Terpene Trilactones and Flavonoids in Ginkgo biloba L. Buds Depending on Physiological Stages

Abstract

The phytochemical profiles of extracts from closed, semi-opened and opened leaf buds and the summer leaves of Ginkgo biloba were studied. The extraction and purification of bilobalide and ginkgolides, using andrographolide as an internal standard, were optimised. The terpene trilactone concentrations increased with bud development, from 1.07 mg/g dry wt in closed buds to a maximum of 3.75 mg/g dry wt in summer leaves. The major terpene trilactone was bilobalide at all developmental stages. The concentration of flavonol aglycones in hydrolysed extracts was also analysed. The flavonol glycoside concentration increased from the closed bud stage (0.21 ± 0.01% dry wt) to the summer leaf stage (1.15 ± 0.01% dry wt). A linear correlation was observed between the terpene trilactone and flavonoid content during gingko leaf development.