In this article, the reactivity of the anthraquinone molecule, the electron density distribution in the molecule, the distance between the bonds, and the physicochemical parameters extracted from the root extract of the plant "Rubia tinctorum L" are studied using quantum chemical methods (DFT, PM3, , TS-DFT was performed in Gaussian 09 using the 6-31G basis set. The reactivity, bond energies, electron density distribution of the molecule were calculated, the structure was analyzed by IR spectroscopy and compared with the spectra obtained from the "Spectral Database for Organic Compounds SDBS" database. The degree of agreement between the quantum chemical calculations and the spectra obtained from the basis set was evaluated by finding the correlation coefficient by the method of least squares.