Ginkgo BilobavsPiracetam

Ginkgo biloba extract (EGb 761) contains flavonoids (quercetin, kaempferol, isorhamnetin) and terpenoids (ginkgolides A, B, C, J and bilobalide). The flavonoids are potent antioxidants that scavenge superoxide, hydroxyl radicals, and peroxynitrite, and protect neurons from oxidative damage; they may also chelate iron. The terpenoids (ginkgolides and bilobalide) improve blood flow by antagonizing platelet-activating factor (PAF) at the PAF receptor, which reduces platelet aggregation, blood viscosity, and improves microcirculation in the brain. Bilobalide protects mitochondria and reduces apoptosis. Ginkgo modulates nitric oxide (NO) availability via endothelial nitric oxide synthase (eNOS) for vasodilation. It inhibits monoamine oxidase A and B (MAO-A, MAO-B), mildly elevating dopamine and serotonin. It may enhance cholinergic transmission and reduce amyloid aggregation.

Piracetam modulates AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) and NMDA (N-methyl-D-aspartate) glutamate receptors through positive allosteric modulation, enhancing excitatory neurotransmission without direct agonism. It increases membrane fluidity of neuronal phospholipid bilayers by reducing membrane microviscosity, which improves ion channel function and signal transmission. Piracetam enhances acetylcholine receptor density and turnover in the hippocampus, upregulating both muscarinic (M1) and nicotinic receptor expression. It potentiates the cholinergic system through increased high-affinity choline uptake. Additionally, piracetam improves cerebral blood flow via nitric oxide-dependent vasodilation and enhances oxygen utilization (glucose metabolism) in aged or hypoxic brain tissue, supporting mitochondrial function.