Abstract: The present invention relates to a method of treatment and/or prophylaxis of a microbial infection, comprising the step of administering an effective amount of a compound of formula (I), in which X and Y are either the same or different and selected from a heteroatom; is a double or single bond depending on the heteroatoms X and Y; R1 to R5 are either the same or different and selected from hydrogen or a non-deleterious substituent; and R6 and R7 are either the same or different and selected from hydrogen and a non-deleterious substituent or one of R6 and R7 are absent when there is a double bond present, pharmaceutically acceptable salts or derivatives, pro-drugs, tautomers and/or isomers thereof. The present invention also relates to a method for protecting a subject from radiation damage, a method of cancer radiotherapy and use as an antimicrobial or radioprotective agent of the compound of formula (I) defined above.