A compound of formula (I): wherein R represents a hydroxy substituted C24-C40 straight chain aliphatic group containing at least one double bond in the carbon chain; and at least one carbon in the chain is substituted with a hydroxy group. Such compounds are useful for detecting inflammation, inflammatory disorders and cancer in a subject, and can also be used in therapeutic applications including treatment and/or prevention of these conditions. Pharmaceutical compositions, combinations and supplements, as well as methods of treatment using the described compounds are therefore also described.