From Waste to Resource: Valorization of Yellow Ginkgo Leaves as a Source of Pharmacologically Relevant Biflavonoids

Ginko (Ginkgo biloba L.) is a widely distributed ornamental tree that produces large quantities of leaves annually, turning golden yellow in autumn due to chlorophyll degradation and carotenoid retention. While green ginkgo leaves and standardized extracts have been extensively studied, senescent and naturally fallen leaves remain only scarcely investigated, despite representing a substantial biomass resource. In this study, we analyzed yellow ginkgo leaves collected directly from trees and those naturally shed at four time points during autumn. We determined pigment composition, total polyphenols, flavonoids, phenolic acids, and the concentrations of five major biflavonoids. Chlorophylls decreased progressively in tree-collected leaves, whereas carotenoid levels remained stable or slightly elevated. Polyphenolic compounds were more abundant in fallen leaves. Biflavonoid profiling revealed the presence of amentoflavone, bilobetin, ginkgetin, isoginkgetin, and sciadopitysin, with sciadopitysin as the most abundant. Total biflavonoid content reached up to 8 mg/g dw, with higher levels in fallen leaves compared to those collected from the tree. These findings highlight yellow ginkgo leaves, particularly fallen ones, as a sustainable and non-invasive source of pharmacologically relevant biflavonoids. However, further research is needed to optimize eco-friendly extraction strategies and to evaluate safety aspects.