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

Abstract

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 C6H12024P6Sr4·5H2O and C6H12024P6Zn6·6H2O, 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 13C and 31P-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.

New Insights into the In Vitro Antioxidant Routes and Osteogenic Properties of Sr/Zn Phytate Compounds

“…In fact, strontium ranelate was administered to treat osteoporotic diseases; however, its negative side effects, such as those related to a significant increase in non-fatal heart attacks and blood clotting [ 46 , 47 ], have drastically restricted its use and have motivated the search for new organic carriers of bioactive cations. In this sense, our group developed metallic complexes with organic moieties, such as phytic acid, that can increase their osteogenic effects [ 39 , 43 ]. Herein, the goal of the present study was to analyze the role of these phytate compounds regarding their antioxidant and osteogenic properties for their potential use in bone tissue engineering applications, especially when the regeneration of tissues is associated with oxidative stress conditions.…”

“…The Sr 4 C 6 H 12 O 24 P 6 ·5H 2 O and Zn 6 C 6 H 12 O 24 P 6 ·4H 2 O derivatives (named SrPhy and ZnPhy, respectively) were synthesized via a hydrothermal reaction of PA with the corresponding metal chloride salt and characterized following the same methodology described in a previous study [ 43 ]. Both complexes were obtained in high yields (>90%) and free of chloride impurities.…”

“…In this sense, we recently developed two metallic phytate derivatives bearing Sr 2+ or Zn 2+ (named as SrPhy and ZnPhy) and studied their structural characteristics and antimicrobial activity, finding a synergistic effect of the cations with PA in the reduction of bacterial biofilm of Streptococcus mutans [ 43 ]. Here, we report the biological properties of the two metallic phytates that were found while exploring the complementary dual action of the cations and phytate rings on the PA properties.…”

One Scaffold, Two Conformations: The Ring-Flip of the Messenger InsP8 Occurs under Cytosolic Conditions

“…Frost et al reported as early as 1979 that alkali cations stabilize the axial conformation of InsP 6 [ 43 ]. There have since been multiple studies showing that complexation of various metals promotes the transition to axial InsP 6 [ 47 , 50 , 51 , 52 ]. Hager et al could subsequently show that Mg 2+ ions help to stabilize 5PCP-InsP 5 in an axial conformation [ 28 , 43 ].…”

One Scaffold, Two Conformations: The Ring-Flip of the Messenger InsP₈ Occurs under Cytosolic Conditions

“…Frost et al reported as early as 1979, that alkali cations stabilize the axial conformation of InsP6 [38]. There have since been multiple studies showing that complexation of various metals facilitates the transition to axial InsP6 [42,[45][46][47]. Hager et al could subsequently show that Mg 2+ ions help to stabilize 5PCP-InsP5 in an axial conformation [23,38].…”