Helquat derivatives of general formula I, in which substituents R1 and R2 are independently selected from a group comprising H and C1 to C4 alkyl, up to three of S1,2, S1′,2′, S3,4 and S3′,4′ are present, each of S1,2, S1′,2′, S3,4 and S3′,4′ independently represents a linker consisting of a bivalent hydrocarbon chain having 3-6 carbon atoms, preferably hydrocarbon chain having 4 carbon atoms, and one to four atoms selected from the carbon atoms with the descriptor 2, 4, 2′, and 4′ are substituted with a substituent R3 of general formula II, wherein R4 is substituted or unsubstituted heteroaryl, T1 and T2 are independent linkers that bridge atoms N5 with C8 and N5′ with C8′, wherein T1 and T2 independently represent a bivalent hydrocarbon chain having 2-5 carbon atoms, preferably 2 or 3 carbon atoms; and anions (X1)− and (X2)− independently represent anions of pharmaceutically acceptable salts.