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

Abstract

Six known lupanes lupenone (1), 3-epi-lupeol (2), glochidone (4), glochidonol (5), glochidiol (6) and lup-20(29)-ene-1β,3β-diol (7) were isolated from the roots and stem wood of Glochidion eriocarpum and three, 5, 6 and lup-20(29)ene-3α,23-diol (3), were isolated from the roots and stem wood of Glochidion sphaerogynum. Compounds were identified by 1H- and 13C-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 GI50 values for 3 were 12.7 ± 3.7, 17.9 ± 1.1 and 17.9 ± 0.5, for 5 9.0 ± 3.7, 4.9 ± 0.2 and 9.8 ± 0.5, and for 6 6.63 ± 0.7, 7.5 ± 0.5 and 9.7 ± 0.3.3. Epilupeol was less active, with GI50 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 antiproliferative activity through the involvement of apoptosis while triterpene 3 did not.