We report the synthesis and characterization of three new complexes of the natural flavonoid 5-hydroxyflavone (primuletin) and Al (III), Ga (III), In (III), respectively. The physico-chemical properties and structural features of these three novel compounds have been investigated by elemental and thermogravimetric analysis, molar conductance and several spectroscopic techniques, including FT-IR, UV-Vis and mass spectra. Based on the experimental data, the general chemical formula of the complexes iswhere M is the cation and n = 2 for Al (III), n = 0 for Ga (III), n = 1, for In (III); each one of the three 5-hydoxyflavone molecules acts as a monoanionic bidentate chelate ligand in the complexes. DFT calculations further sustain the proposed structures of the complexes. Cytotoxicity was studied using MTS assay on cervical, breast, colon and ovary adenocarcinoma cell lines.The central metal ions exert cytotoxic effects in a disparate manner: Al (III) enhances, while Ga (III) and In (III) decrease the cytotoxicity of the ligand.As a means to investigate the mechanism underlying the cytotoxic effects of the complexes, interactions with calf thymus DNA, human serum albumin and transferrin were also carried out.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

The deleterious effects of ionizing radiation are a major concern of the modern world. In the last decades, outstanding interest has been given to developing new therapeutic tools designed for protection against the toxic effects of ionizing radiation. Deinococcus spp. are among the most radioresistant organisms on Earth, being able to survive extreme doses of radiation, 1000-fold higher than most vertebrates. The molecular mechanisms underlying DNA repair and biomolecular protection, which are responsible for the remarkable radioresistance of Deinococcus bacteria, have been a debatable subject for the last 60 years. This paper is focused on the most recent findings regarding the molecular background of radioresistance and on Deinococcus bacteria response to oxidative stress. Novel proteins and genes involved in the highly regulated DNA repair processes, and enzymatic and non- enzymatic antioxidant systems are presented. In addition, a recently proposed mechanism that may contribute to oxidative damage protection in Deinococcus bacteria is discussed. A better understanding of these molecular mechanisms may draw future perspectives for counteracting radiation-related toxicity.