Syntheses and structure-activity relationship study of santamarine, douglanine, dihydrosantamarine and four series of 1-/3-oxygenated eudesman-12,6α-olides

Abstract

Herein, we report the syntheses and structure-activity relationships of Santamarine, Douglanine, dihydrosantamarine, 1-oxygenated and 3-oxygenated eudesman-12,6α-lactones. The anti-inflammatory and anti-cancer activities were measured by the inhibition on induction of intercellular adhesion molecule (ICAM-1), killing function of cytotoxic T lymphocytes (CTLs), and cytotoxic activities to cell lines (VA-13, HepG-2, and WI-38), respectively. α-Methylene-γ-lactones 13 with a 1-oxo-2-en moiety showed significant inhibition toward ICAM-1(IC50 12.8 μM), the killing function of CTLs (IC50 11.0 μM) and the VA-13 cell line (IC50 2.84 μM), 21 with α-bromo-ketone moiety showed significant inhibition to VA-13(IC50 1.85 μM). Both 13 ((cell viability)/(inhibitory activity of ICAM-1) = 6.0-fold, WI-38/VA-13 = 1.28-fold) and 21 (WI-38/VA-13 = 1.28-fold) were within safety satisfaction. To conclude, the α,β-unsaturated-ketone and α-bromo-ketone moieties were essential for α-methylene-eudesman-12,6α-olides' anti-inflammatory and anti-cancer activities.