Fig 1.
Structure, numbering and acid-base equilibrium of studied QBAs.
Table 1.
Spectroscopic properties of alkanolamine (QOH) and iminium (Q+) forms of QBAs.
Fig 2.
Acid-base properties of 3 μM macarpine.
Dependence of absorbance at 495 nm (black) and fluorescence at 450 nm (red) on pH, n = 3. Mean values ± SD and fits to Eq (4) are shown. Inset: Absorption (black) and emission (red) spectra of iminium (—) and alkanolamine (…) form. Ordinates are the same as for bigger figure.
Fig 3.
Black–macarpine, red–sanguilutine, blue–chelirubine, green–sanguinarine, gold–sanguirubine, violet–chelerythrine; 1 –benzene, 2 –diethyl ether, 3 –octanol, 4 –ethanol, 5 –methanol, 6–0.01M borate buffer, pH 9.45. Samples in borate buffer (dashed box) excluded from fitting.
Fig 4.
Absorbance and fluorescence spectra of QBAs in absence and presence of ctDNA.
QBAs (3 μM in 20mM acetate buffer, 200 mM NaCl, 2mM EDTA, pH 5) in absence (—) and presence (…) of ctDNA (DNA base pair-to-drug ratio 15.9:1). a-f–absorption spectra, g-l–emission spectra; a, g–sanguinarine, b, h–chelerythrine, c, i–chelirubine, d, j–sanguilutine, e, k–sanguirubine, f, l–macarpine. Note that intensities are in arbitrary units due to conversion to wavenumber scale using Eq (1).
Fig 5.
Representative fit of macarpine-DNA interaction.
Macarpine (10 μM) binding to salmon testes DNA (0–116 μM bp) in 0.05 M citrate buffer, pH 6.15, [Na+] = 0.122 M was measured as a fluorescence change at 625 nm. Data were fitted to 1:1 binding model using DynaFit software.