BDNF and Cognitive impairment: For instance, OligonolR, a flavanol-rich extract from lychee fruit, may improve cognitive impairment [168], while icariin, a flavanol contained in the medicinal herb Epimedium sagittatum, may attenuate synaptic plasticity and cognitive deficits through the activation of the BDNF/tropomycin receptor kinase B (TrkB)/Akt pathway [169], and cocoa extract administration may reduce Aβ oligomer formation [170].