Use of 5,6-Dimethylxanthenone-4-Acetic Acid as an Antiviral Agent

A pharmaceutical composition comprising an amount of a compound of formula (I):

• or a pharmaceutically acceptable salt or ester thereof with a pharmaceutically acceptable acid;
• wherein:
• said amount is sufficient to treat a viral infection in a recipient mammal;
• X and Y are O or N, and R1, R2, and R3 are each independently chosen from H, C1-C6 alkyl, halogen, CF3, CN, NO2, NH2, OH, OR, NHCOR, NHSO2R, SR, SO2R, CH2COOH, or NHR, wherein each R is independently C1-C6 alkyl optionally substituted with one or more substituents selected from hydroxy, amino, ethoxy, and methoxy, and each of R1, R2, and R3 may be present at any one of the available carbon positions 1 to 8;
• and
• in each of the carbocyclic aromatic rings in formula (I), up to two of the methine (—CH═) groups may be replaced by an aza (—N═) group;
• and
• any two of R1, R2, and R3 may additionally together represent the group —CH═CH—CH═CH—, such that this group, together with the carbon or nitrogen atoms to which it is attached, forms a fused six membered aromatic ring;
• and one or more pharmaceutically acceptable carriers, diluents or excipients.