Sesquiterpene lactones Tricyclic for use in the treatment of obesity and related diseases and conditions treatable nontherapeutic

A compound of formula (I), for use in treating or preventing obesity in a warm-blooded animal. ** (See formula) ** wherein, A1, A2 and A3 independently of one another represent CH2 diradicals **, ** CH-O-R1 or C **> = O, and B1, B2 and B3 independently of one another represent diradicals ** C> = CH2, ** CH-CH2-R1, or ** C (OH) -CH2-O-R1; in which R1 is hydrogen, a straight chain or branched chain having 1 to 12 carbon atoms, or a -C (O) - n-CRa> (CH2) = CRaRb (where n is zero or an integer from 1 to 12 and Ra and Rb independently are selected from a group Z, consisting of hydrogen and an alkyl group straight chain or branched chain alkyl having 1 to 6 carbon atoms which is unsubstituted or it is substituted by hydroxyl) and R1 * is R1 as defined above or an alkoxy group of straight chain or branched chain alkyl having 1 to 12 carbon atoms, wherein the compound of formula (I) may be in the free form in the form of a pharmaceutical salt and / or nutraceutically acceptable as tautomers and / or as solvates.