Synthesis of some symmetrical curcumin derivatives and their anti-inflammatory activity.

Curcumin is not only a frequently used food additive, but it is also a well-known constituent of Indonesian traditional medicines. Several beneficial effects are ascribed to curcumin, eg, its antiinflammatory properties. In order to study the antiinffammatory activity, a series of curcumin derivatives were prepared and the inhibition of the carrageenin-induced oedema by these compounds was established. It appeared that the para hydroxy groups in curcumin are important for antiinflammatory activity. This activity is enhanced when, in combination with the para hydroxy groups, the meta positions are occupied with alkyl groups. Since the methyl derivatives are more active than the corresponding ethyl and tert-butyl derivatives, it is suggested that sterical hindrance is involved.