Five new phorbol esters with cytotoxic and selective anti-inflammatory activities from Croton tiglium.

Five new phorbol esters, (four phorbol diesters, 1 – 4 , and one 4-deoxy-4α-phorbol diester, 5 ), as well as four known phorbol esters analogues ( 6 – 9 ) were isolated and identified from the branches and leaves of Croton tiglium . Their structures were elucidated mainly by extensive NMR spectroscopic, and mass spectrometric analysis. Among them, compound ( 1 ) was the first example of a naturally occurring phorbol ester with the 20-aldehyde group. Compounds 2 – 5 , and 7 – 9 showed potent cytotoxicity against the K562, A549, DU145, H1975, MCF-7, U937, SGC-7901, HL60, Hela, and MOLT-4 cell lines, with IC 50 values ranging from 1.0 to 43 μM, while none of the compounds exhibited cytotoxic effects on normal human cell lines 293T and LX-2, respectively. In addition, compound 3 exhibited moderate COX-1 and COX-2 inhibition, with IC 50 values of 0.14 and 8.5 μM, respectively. [ABSTRACT FROM AUTHOR]