Two new dammarane triterpenes isolated from Cleome khorassanica Bunge & Bien with cytotoxicity against DU-145 and LNCaP prostate cancer cell lines

From the aerial parts of Cleome khorassanica Bunge & Bien, a new 3-oxo-4-oxa-A-homo-25,26,27-trinordammarano-24,20-lactone triterpene (1), a new natural product 20,25-dihydroxy-3-oxodammarane triterpene (2), together with known 5-hydroxy-3,6,7,8,3′,4′,5′-heptamethoxyflavone (3), have been isolated and characterized. The chemical structure of the new compounds was determined by 1D and 2D NMR and HR tandem MS measurements. All three compounds were subjected to biological tests for evaluation of their cytotoxicity against prostate (DU-145 and LNCaP) cancer cells. Compounds 1, 2, and 3 showed cell growth inhibition in a dose dependent manner against DU-145 and LNCaP cells.