Cycloartane Triterpenoids from <i>Kleinhovia hospita</i>

Four new cycloartane triterpenoids, together with the known gardenolic acid B, were isolated from <i>Kleinhovia hospita</i>. The triterpenoids (<b>1</b>−<b>3</b>) contain a unique 21,23-diacetal side-chain, while compound <b>4</b> contains two α,β-unsaturated ketone moieties. Their structures and relative configurations were determined by spectroscopic methods, including 2D NMR and IR. These compounds showed promising hepatoprotective effects on nitrofurantoin-induced cytotoxicity in human liver-derived Hep G2 cells.