A compound of formula or a prodrug and/or a pharmaceutically acceptable salt thereof, wherein X is O, N or S; R1 is hydrogen, halo, hydroxy, substituted or unsubstituted alkyl, substituted or unsubstituted hydroxyalkyl, substituted or unsubstituted alkylamine, alkoxy, substituted or unsubstituted aryl or heteroaryl, and substituted or unsubstituted aralkyl or heteroaralkyl; R2 is hydrogen, halo, hydroxy, substituted or unsubstituted alkyl, substituted or unsubstituted hydroxyalkyl substituted or unsubstituted alkylamine, alkoxy, substituted or unsubstituted aryl or heteroaryl, and substituted or unsubstituted aralkyl or heteroalkyl; R3 is hydrogen, halo, hydroxy, substituted or unsubstituted alloy substituted or unsubstituted hydroxyalkyl, substituted or unsubstituted alkylamine alkoxy, substituted or unsubstituted aryl or heteroaryl, and substituted or unsubstituted aralkyl or heteroalkyl; and R4-R7, is used to represent groups R4, R5, R6 and R7 which are H, OH, alkyl, alkoxy, alkylamine, hydroxyalkyl, halo, CF3, NH2, NO2, COOH, C═O.