3H-spiro 1-benzofuran-2,1′-cyclohexane derivatives of Heliotropium filifolium were studied.
The structurally related terpenoid derivatives differentially induced trout cytokines.
Activity is related to substitutions in cyclohexane C-7′ and benzene C-7 positions.
Filifolinone is the most active immunostimulatory compound identified.
Terpenoid derivatives can be used as immunostimulants or vaccine adjuvants.