Study on the Interaction of 4'-Hydroxychalcones and their Mannich Derivatives with Calf Thymus DNA by TLC and Spectroscopic Methods, a DNA Cleavage Study

Table 1: UV-Vis absorption maxima of chalcone derivatives 1A, 1B and 2A, 2B (20 μM) without and in the presence of ctDNA (50 μM). UV-Vis absorption maxima(λ_max) of the free ctDNA is 258 nm. ctDNA binding constants (K) of chalcone analogs (1A-B), determined by spectrophotometric titration.

Compound	λ_max free^a (nm)	λ_max bound^a (nm)	Δλ (nm)	Binding constant (M^-1)
1A	352	352 251	0 7^b	6.1 x 10⁴
2A	327	327 258	0 0	-
1B	373	370 252	3 6^b	3.9 x 10⁴
2B	376 310	376 310 258	0 0 0	-

^a Data are expressed as a result of three independent measurements.
^bDifference of wavelength from the UV-Vis absorption maxima of the free ctDNA (λ_max = 258 nm).