7,8-Dihydroxyflavone (7,8-DHF, tropoflavin) is a naturally occurring flavone found in Godmania aesculifolia, Tridax procumbens, and primula tree leaves. It has been found to act as a potent and selective small-molecule agonist of the tropomyosin receptor kinase B (TrkB) (Kd ≈ 320 nM), the main signaling receptor of the neurotrophin brain-derived neurotrophic factor (BDNF). 7,8-DHF is both orally bioavailable and able to penetrate the blood–brain barrier. A prodrug of 7,8-DHF with greatly improved potency and pharmacokinetics, R13 (and, formerly, R7), is under development for the treatment of Alzheimer's disease.