Cytotoxic activity of lupane-type triterpenes from Glochidion sphaerogynum and Glochidion eriocarpum: two of which induce apoptosis

Six known lupanes lupenone (1), 3-epi-lupeol (2), glochidone (4), glochidonol (5), glochidiol (6) and lup-20(29)-ene-1 beta, 3 beta-diol (7) were isolated from the roots and stem wood of Glochidion eriocarpum and three, 5, 6 and lup-20(29)ene-3 alpha,23-diol (3), were isolated from the roots and stem wood of Glochidion sphaerogynum. Compounds were identified by H-1- and C-13-NMR techniques. Triterpenes 2-7 were tested against the growth of three human tumor cell lines, MCF-7, NCI-H-460 and SF-268. Lupanes 3, 5, and 6 exhibited strong inhibitory effects against all three; thus GI(50) values for 3 were 12.7 +/- 3.7,17.9 +/- 1.1 and 17.9 +/- 0.5, for 59.0 +/- 3.7,4.9 +/- 0.2 and 9.8 +/- 0.5, and for 66.63 +/- 0.7, 7.5 +/- 0.5 and 9.7 +/- 0.3.3. Epilupeol was less active, with GI(50) values of 75.6 +/- 11.7,86.1 +/- 12.4 and 80.9 +/- 2.6 while 7 was moderately active only against MCF-7 (GI(50) = 79.2 +/- 2.4). Additional studies indicated that triterpenes 5 and 6 exerted their anti proliferative activity through the involvement of apoptosis while triterpene 3 did not.