Structural features and bioavailability of four flavonoids and their implications for lifespan-extending and antioxidant actions in C. elegans

► All tested flavonoids are bioavailable to C. elegans and undergo extensive conjugation. ► Hydroxyl groups at the flavonoids B-ring and a double-bond at the C-ring promote lifespan extension. ► Hydroxyl groups at the flavonoids B-ring and a double-bond at the C-ring also reduce mtROS production and protein damage in vivo. But a causal relationship to lifespan-extension is questionable. ► The lifespan extension and mtROS reduction induced by the flavonols is DAF-16-independent.