A substituted hydroquinone of formula: wherein: R a, R b = H, C 1-4 acyl, arylC 1-4 alkyl, C 6 -C 10 arylCO, HOOC(CH 2) n CO, C 1 -C 7 alkylNHCO, phosphono, phosphonooxymethyl, C 1 -C 6 acyloxymethyl, C 1 -C 6 acyloxy-1-ethyl, C 1 -C 6 alkoxycarbonyloxymethyl, or C 1 -C 6 alkoxycarbonyloxy-1-ethyl; R 1 = COOR 4, (CH 2) n COOR 4, SO 3 H, (CH 2) n SO 3 H, or CONH-R 10; one of R2 or R3 is H and the other is R5; R 4 = H, C 1-4 alkyl, arylC 1-4 alkyl, morpholino-C 1 -C 6 alkyl, pyrrolidino-C 1 -C 6 alkyl, N-methylpiperazino-C 1 -C 6 alkyl, C 1 -C 6 acyloxymethyl, C 1 -C 6 acyloxy-1-ethyl, C 1 -C 6 alkoxycarbonyloxymethyl, C 1 -Cealkoxycarbonyloxy-1-ethyl, or (oxodioxolyl)methyl; o-methoxyphenyl (guaiacol ester); R 5 = R 6, R 7, or R 8 R 6 = CONH-R 9, CONHCOR 9, CONH(CH 2) n -R 9, CONHCH(COOR 4)(CH 2) k R 9,; wherein k = 0-4; R 7 = benzoheteroaryl substituted with at least one or more groups selected from: COOR 4, (CH 2) n COOR 4, SO 3 H, (CH 2) n SO 3 H, OR 4, 5-membered N-containing heterocycles, or fluorine; R 8 = (CH 2) m X(CH 2) p R 9; X = O, S, SO 2, NH, NAc, or N(CH 2) q R 9; R 9 = aryl, heteroaryl, substituted with at least one or more groups selected from COOR 4, (CH 2) n COOR 4, (CH 2) n SO 3 H, OR 4, SO 3 H, 5-membered N-containing heterocycles, fluorine, C=O, orNHCO-R 10; R 10 = aryl, heteroaryl, substituted with at least one or more groups selected from COOR 4, (CH 2) n COOR 4, (CH 2) n SO 3 H, OR 4, SO 3 H, 5-membered N-containing heterocycles, or fluorine; wherein the aryl of R 9 and R 10 is an aromatic group containing from 6 to 14 carbon atoms, selected among phenyl, naphthyl, biphenyl group; and the heteroaryl of R 9 and R 10 is an aromatic group containing 1 to 14 carbon atoms and one or more nitrogen; and n, m, p and q are independently 1-4. R a, R b = H, C 1-4 acyl, arylC 1-4 alkyl, C 6 -C 10 arylCO, HOOC(CH 2) n CO, C 1 -C 7 alkylNHCO, phosphono, phosphonooxymethyl, C 1 -C 6 acyloxymethyl, C 1 -C 6 acyloxy-1-ethyl, C 1 -C 6 alkoxycarbonyloxymethyl, or C 1 -C 6 alkoxycarbonyloxy-1-ethyl; R 1 = COOR 4, (CH 2) n COOR 4, SO 3 H, (CH 2) n SO 3 H, or CONH-R 10; one of R2 or R3 is H and the other is R5; R 4 = H, C 1-4 alkyl, arylC 1-4 alkyl, morpholino-C 1 -C 6 alkyl, pyrrolidino-C 1 -C 6 alkyl, N-methylpiperazino-C 1 -C 6 alkyl, C 1 -C 6 acyloxymethyl, C 1 -C 6 acyloxy-1-ethyl, C 1 -C 6 alkoxycarbonyloxymethyl, C 1 -Cealkoxycarbonyloxy-1-ethyl, or (oxodioxolyl)methyl; o-methoxyphenyl (guaiacol ester); R 5 = R 6, R 7, or R 8 R 6 = CONH-R 9, CONHCOR 9, CONH(CH 2) n -R 9, CONHCH(COOR 4)(CH 2) k R 9,; wherein k = 0-4; R 7 = benzoheteroaryl substituted with at least one or more groups selected from: COOR 4, (CH 2) n COOR 4, SO 3 H, (CH 2) n SO 3 H, OR 4, 5-membered N-containing heterocycles, or fluorine; R 8 = (CH 2) m X(CH 2) p R 9; X = O, S, SO 2, NH, NAc, or N(CH 2) q R 9; R 9 = aryl, heteroaryl, substituted with at least one or more groups selected from COOR 4, (CH 2) n COOR 4, (CH 2) n SO 3 H, OR 4, SO 3 H, 5-membered N-containing heterocycles, fluorine, C=O, orNHCO-R 10; R 10 = aryl, heteroaryl, substituted with at least one or more groups selected from COOR 4, (CH 2) n COOR 4, (CH 2) n SO 3 H, OR 4, SO 3 H, 5-membered N-containing heterocycles, or fluorine; wherein the aryl of R 9 and R 10 is an aromatic group containing from 6 to 14 carbon atoms, selected among phenyl, naphthyl, biphenyl group; and the heteroaryl of R 9 and R 10 is an aromatic group containing 1 to 14 carbon atoms and one or more nitrogen; and n, m, p and q are independently 1-4.