Fifteen triterpene acids, viz., seven of the β-boswellic acids (ursane-type) (1—7), two of the α-boswellic acids (oleanane-type) (8, 9), two of the lupeolic acids (lupane-type) (10, 11), and four of the tirucallane-type (12—14, 16), and two cembrane-type diterpenes (17, 18), isolated from the MeOH extract of the resin of Boswellia carteri (Burseraceae), together with a triterpene acid 15 (the acetyl derivative of 14), were examined for their inhibitory effects on the induction of Epstein–Barr virus early antigen (EBV-EA) by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells and on activation of (±)-(E)-methyl-2[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexemide (NOR 1), a nitrogen oxide (NO) donor, and cytotoxic activities against three human neuroblastoma cell lines, IMR-32, NB-39, and SK-N-SH in vitro. On evaluation against the EBV-EA activation induced by TPA, seven compounds, 2, 10, 11, and 13—16, showed potent inhibitory effects on EBV-EA induction. Upon evaluation against activation of NOR 1, five compounds, 7, 13, and 14—16, showed potent inhibitory effects. Further, fifteen compounds, 1—7, 9—11, 13—15, 17, and 18, exhibited potent cytotoxic activities with IC50 values of 4.1—82.4 μM against all of the three human neuroblastoma cells tested.
2006 The Pharmaceutical Society of Japan