o:29672 HPLC, UV-Vis and NMR spectroscopic and DFT characterization of purpurin isolated from Rubia tinctorum L. en Abstract: Purpurin (1,2,4-trihidroxyanthraquinone), a naturally occuring anthraquinone pigment present in the root of Rubia tinctorum (Mull. Arg.) Zahlbr. was isolated from the plant, purified and characterized by HPLC chromatography, UV-vis and NMR spectroscopy. The geometries of the purpurin conformers were optimized using the B3LYP/6-311+G(d,p) level of theory. It was found that all conformations have similar energies and that the corresponding purpurin radicals are planar. In spite of their planarity, there is no significant electron delocalization over the A and C rings. The antioxidant properties of purpurin were investigated using the colorimetric assay as Trolox-equivalent antioxidant capacity, and theoretical BDE (Bond Dissociation Enthalpy). Both methods revealed that purpurin has strong antioxidant capacity. Keywords: Rubia tinctorum; HPLC-UV; antioxidant activity; anthraquinone; DFT study 1552099 10.2298/HEMIND120419058M 1552101 0367-598X 2023-05-20T07:16:26.410Z 44 no 46 Zoran Marković Državni univerzitet u Novom Pazaru 0000-0001-5964-049X Nedeljko Manojlović person Svetlana Jeremić Državni univerziet u Novom Pazaru person 0000-0001-5571-6880 Miroslav Živić person application/pdf 532154 https://phaidrabg.bg.ac.rs/o:29672 no yes 1 70 92000001 20A01 Hemijska industrija 67 1 77 88 2018