Withanolide A

terpenoid · nervous · endocrine · Oral

Withanolide A, a terpenoid. Steroidal withanolide; the primary neurotrophic / anxiolytic bioactive of Withania somnifera root. Promotes neurite… Oral half-life 3 h.

Steroidal withanolide; the primary neurotrophic / anxiolytic bioactive of Withania somnifera root. Promotes neurite outgrowth + synaptic reconstruction in preclinical models (BDNF/CREB axis); modulates GABA-A receptors. Lower cytotoxicity than withaferin A — the "therapeutic" withanolide in CNS contexts. Higher in root than leaf — KSM-66 (root-only) is enriched in withanolide-A relative to withaferin-A. Isomer of withaferin-A, same MW (470.60).

Root-dominant withanolide; the neurotrophic + anxiolytic component most associated with ashwagandha clinical adaptogen effects. Isomer of withaferin-A (same C28H38O6 formula, different stereochemistry).

Pharmacokinetics

• Oral — t½ 3 h · F 5% · ka 1.596 h⁻¹ · Vd 6000 L

Sources: PMID:39963957, PMID:35268576