NEW COMPOUNDS WITH DNA STRAND-SCISSION ACTIVITY FROM THE COMBINED LEAF AND STEM OF UVARIA-HAMILTONII

Two flavanones, hamiltones A (1) and B (2), an aurone, hamiltrone (3), a chalcone, hamilcone (4), and a tetrahydroxanthene, hamilxanthene (5 ), were isolated from Uvaria hamiltonii extracts guided initially by f ractionation based on DNA strand-scission and/or 9KB cytotoxicity assa ys. Compounds 2-5 have not been reported previously, while 1 is new as a natural product. Structural assignments were made based on extensiv e spectroscopic measurements. Compounds 1-3 were inactive in the 9KB c ytotoxicity assay, with compounds 4 and 5 having weak activity. In the DNA strand-scission assay, 3 was the most active compound found in th e DNA strand-scission assay, being 10 times more potent than 1 or 2. C ompound 4 was only weakly active, and 5 was inactive.