A study on Sr/Zn phytate complexes: structural properties and antimicrobial synergistic effects against Streptococcus mutans

Phytic acid (PA) is an abundant natural plant component that exhibits a versatility of applications benefited from its chemical structure, standing out its use as food, packing and dental additive due to its antimicrobial properties. The capacity of PA to chelate ions is also well-established and the formation and thermodynamic properties of different metallic complexes has been described. However, research studies of these compounds in terms of chemistry and biological features are still demanded in order to extend the application scope of PA complexes. The main goal of this paper is to deepen in the knowledge of the bioactive metal complexes chemistry and their bactericide activity, to extend their application in biomaterial science, specifically in oral implantology. Thus, this work presents the synthesis and structural assessment of two metallic phytate complexes bearing the bioactive cations Zn2+ and Sr2+ (ZnPhy and SrPhy respectively), along with studies on the synergic biological properties between PA and cations. Metallic phytates were synthesized in the solid-state by hydrothermal reaction leading to pure solid compounds in high yields. Their molecular formulas were C(6)H(12)0(24)P(6)Sr(4)center dot 5H(2)O and C(6)H(12)0(24)P(6)Zn(6)center dot 6H(2)O, as determined by ICP and HRES-TGA. The metal coordination bond of the solid complexes was further analysed by EDS, Raman, ATR-FTIR and solid C-13 and P-31-NMR spectroscopies. Likewise, we evaluated the in vitro ability of the phytate compounds for inhibiting biofilm production of Streptococcus mutans cultures. Results indicate that all compounds significantly reduced biofilm formation (PA < SrPhy < ZnPhy), and ZnPhy even showed remarkable differences with respect to PA and SrPhy. Analysis of antimicrobial properties shows the first clues of the possible synergic effects created between PA and the corresponding cation in different cell metabolic processes. In overall, findings of this work can contribute to expand the applications of these bioactive metallic complexes in the biotechnological and biomedical fields, and they can be considered for the fabrication of anti-plaque coating systems in the dentistry field.

Automated summary

This paper focuses on the synthesis and structural assessment of two metallic phytate complexes and their synergistic biological properties with phytic acid. The results show that these complexes significantly inhibit biofilm formation of Streptococcus mutans, with zinc phytate demonstrating remarkable differences compared to phytic acid and strontium phytate. These findings contribute to expanding the applications of bioactive metallic complexes in biotechnological and biomedical fields, particularly in dentistry.