The effect of the lipophilic extract of S. willeana and three terpenoids isolated therefrom, camphor, lupeol and oleanolic acid, on oxazolone-induced hypersensitivity was evaluated. The extract reduced the ear edema by 46% at 24 h after challenge. All three terpenoids inhibited the edema and suppressed cytokines release at different rates. Lupeol inhibited the swelling by over 50% and reduced the production of IL-1β by 62%. Camphor caused inhibition of the efferent phase (45% inhibition at 72 h) and the levels of IL-1β, IL-4 and TNF-α (around 80% inhibition). Oleanolic acid diminished moderately the reaction and the levels of IL-4 and TNF-α. We also demonstrated that the three terpenoids inhibited human T-lymphocytes proliferation in a concentration-dependent manner and induced their apoptosis. Thus, these terpenoids could be considered anti-inflammatory constituents of S. willeana
