Withaferin A is a bioactive steroidal lactone (withanolide) primarily isolated from the roots and leaves of Withania somnifera (Ashwagandha). It exhibits anti-inflammatory, anti-tumor, anti-angiogenic, and neuroprotective properties through mechanisms including NF-κB inhibition, Hsp90 modulation, and induction of apoptosis. The compound features an ergostane skeleton with a characteristic α,β-unsaturated ketone in ring A and a δ-lactone side chain. It is studied for potential therapeutic applications in cancer, neurodegenerative diseases, and metabolic disorders. Chemically stable under standard conditions but sensitive to strong bases and prolonged light exposure.