The indane diastereoisomers, PH 2 and PH 5: divergence between their effects in delayed‐type hypersensitivity models and a model of colitis

Objectives Compounds PH 2 and PH 5 are distereoisomers of novel indane compounds, synthesised as analogues of secondary metabolites of the fern, Onychium . In this study, we compare their effects on a variety of inflammatory models. Methods In an effort to extend our knowledge of their anti‐inflammatory profile, we have investigated their activity in two models of delayed‐type hypersensitivity ( DTH ); the methylated bovine serum albumin model ( mBSA ) and the oxazolone contact hypersensitivity ( CHS ) model, on IL 2 release from Jurkat cells and in the dextran sulphate sodium ( DSS ) murine model of inflammatory bowel disease. Key findings Both diastereoisomers are equipotent in reducing paw swelling in the mBSA model and in inhibiting interleukin ( IL ) 2 release from Jurkat cells. They are equally ineffective in the oxazolone contact hypersensitivity model ( CHS ). Only the diastereoisomer, PH 5, protects against DSS ‐induced colitis and of its two enantiomers, only the S,S‐enantiomer, PH 22, possesses this activity. PH 2 is ineffective in the DSS model. Conclusions The results suggest that the beneficial effect of PH 5, and its enantiomer PH 22, in the DSS model is a consequence of an action on a target specific to the colitis model. The implications of such data suggest an unknown target in this disease model that may be exploited to therapeutic advantage.