New antitumor sesquiterpenoids from Santalum album of Indian origin

Three new campherenane-type (1, 4, 7) and three new santalane-type (9, 11, 12) sesquiterpenoids, and two aromatic glycosides (21, 22) together with 12 known metabolites including alpha,beta-santalols (14, 18), (E)-alpha,beta-santalals (15, 19), alpha,beta-santaldiols (16, 20), alpha-santalenoic acid (17), and vanillic acid 4-O-neohesperidoside were isolated from Santalum album chips of Indian origin. The structures of the new compounds, including absolute configurations, were elucidated by 1D- and 2D-NMR spectroscopic and chemical methods. The antitumor promoting activity of these isolates along with several neolignans previously isolated from the same source was evaluated for both in vitro Epstein-Barr virus early antigen (EBV-EA) activation and in vivo two-stage carcinogenesis assays. Among them, compound 1 exhibited a potent inhibitory effect on EBV-EA activation, and also strongly suppressed two-stage carcinogenesis on mouse skin. (c) 2006 Elsevier Ltd. All fights reserved.