GABAvsGotu Kola

GABA binds to GABA-A receptors (ligand-gated Cl- channels with alpha1-6, beta1-3, gamma1-3 subunits) and GABA-B receptors (G-protein coupled, Gi/o mediated), reducing neuronal excitability through hyperpolarization. However, supplemental GABA has limited blood-brain barrier penetration due to absence of a dedicated transporter and rapid metabolism by GABA-transaminase and succinate semialdehyde dehydrogenase in periphery. The calming effects may be mediated through: (1) GABA-A and GABA-B receptors in the enteric nervous system (gut-brain axis) — vagal afferents project to the nucleus tractus solitarius and influence limbic regions; (2) small amounts crossing the BBB via paracellular leakage or in individuals with compromised barrier integrity; (3) peripheral effects reducing systemic stress markers (cortisol, heart rate variability). PharmaGABA (Lactobacillus fermentation product) may have better absorption via peptide-like transport or different pharmacokinetics.

Triterpene saponins (asiaticoside, madecassoside, asiatic acid, madecassic acid) are the primary bioactives. They increase BDNF expression in the hippocampus via CREB and ERK/MAPK pathways, promoting neuroplasticity, synaptogenesis, and memory formation. They enhance collagen type I synthesis through stimulation of fibroblasts and improve microcirculation via VEGF and angiopoietin modulation. Anxiolytic effects occur through positive allosteric modulation of GABA-A receptors (possibly at the benzodiazepine or neurosteroid site) and reduction of acoustic startle response (amygdala modulation). Gotu kola inhibits acetylcholinesterase (AChE), mildly increasing synaptic acetylcholine. Anti-inflammatory effects come from NF-kB inhibition (IkB stabilization) and TNF-alpha suppression. Asiatic acid may also activate PPAR-gamma.