Withaferin A
Withaferin A, a terpenoid. Steroidal lactone (withanolide) and the dominant cytotoxic / anti-inflammatory constituent of Withania somnifera leaf.… Oral half-life 4 h.
Steroidal lactone (withanolide) and the dominant cytotoxic / anti-inflammatory constituent of Withania somnifera leaf. Mechanisms: covalent binding to vimentin (intermediate filament disruption — anti-metastatic), NF-κB pathway inhibition (anti-inflammatory), proteasome modulation, heat-shock response. Most-studied bioactive of ashwagandha in cancer + inflammation models. Higher concentrations in leaf extracts (Sensoril, ~3% by weight of leaf-extract product) than root-only (KSM-66, <0.05% of root extract). MW 470.60.
Withanolide steroidal lactone; the most-studied ashwagandha bioactive in cancer + anti-inflammatory contexts. Reactive Michael acceptor — covalent inhibitor of vimentin + several proteasome subunits. Higher in leaf extracts than root.
Pharmacokinetics
- Oral — t½ 4 h · F 5% · ka 1.843 h⁻¹ · Vd 8500 L
Sources: PMID:39963957, PMID:35268576