Withangulatin A, a New Withanolide from Physalis angulata

Abstract
A new withanolide as a topoisomerase II inhibitor, withangulatin A was isolated from the whole herb of Physalis angulata L. (Solanaceae). The structure of withangulatin A was established as (20S,22R)-15.alpha.-acetoxy-5.beta.,6.beta.-epoxy-4.beta.,14.alpha.-dihydroxy-1-oxowitha-2,16,24-trienolide (I) on the basis of spectroscopic and chemical evidence.
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