Antibacterial Activity of Polyoxometalates Against Moraxella catarrhalis

Abstract

The antibacterial activity of 29 different polyoxometalates (POMs) against Moraxella catarrhalis was investigated by determination of the minimum inhibitory concentration (MIC). The Preyssler type polyoxotungstate (POT) [NaP5W30O110]14− demonstrates the highest activity against M. catarrhalis (MIC = 1 μg/ml) among all tested POMs. Moreover, we show that the Dawson type based anions, [P2W18O62]6−, [(P2O7)Mo18O54]4−, [As2Mo18O62]6−, [H3P2W15V3O62]6−, and [AsW18O60]7− are selective on M. catarrhalis (MIC range of 2-8 μg/ml). Among the six tested Keggin type based POTs ([PW12O40]3−, [H2PCoW11O40]5−, [H2CoTiW11O40]6−, [SiW10O36]8−, [SbW9O33]9−, [AsW9O33]9−), only the mono-substituted [H2CoTiW11O40]6− showed MIC value comparable to those of the Dawson type group. Polyoxovanadates (POVs) and Anderson type POMs were inactive against M. catarrhalis within the tested concentration range (1-256 μg/ml). Four Dawson type POMs [P2W18O62]6−, [(P2O7)Mo18O54]4−, [As2Mo18O62]6−, [H3P2W15V3O62]6− and the Preyssler POT [NaP5W30O110]14− showed promising antibacterial activity against M. catarrhalis (MICs < 8 μg/ml) and were therefore tested against three additional bacteria, namely S. aureus, E. faecalis, and E. coli. The most potent antibacterial agent was [NaP5W30O110]14−, exhibiting the lowest MIC values of 16 μg/ml against S. aureus and 8 μg/ml against E. faecalis. The three most active compounds ([NaP5W30O110]14−, [P2W18O62]6−, and [H3P2W15V3O62]6−) show bacteriostatic effects in killing kinetics study against M. catarrhalis. We demonstrate, that POM activity is mainly depending on composition, shape, and size, but in the case of medium-size POTs (charge is more than −12 and number of addenda atoms is not being higher than 22) its activity correlates with the total net charge.

One-pot synthesis of a new generation of hybrid bisphosphonate polyoxometalate gold nanoparticles as antibiofilm agents

“…In contrast, it has been evidenced that gold nanoparticles (AuNPs) are non-toxic, [7][8][9] and in the last decade conjugates of AuNPs with antibiotics [10][11][12][13][14] or other antibacterial agents [15][16][17][18][19] have been shown to improve antibacterial activity against biolms. Besides, several polyoxometalates (POMs), which can be seen as negatively charged molecular oxides incorporating metals (mainly tungsten, molybdenum and vanadium) in high oxidation states, 20 have shown important antibacterial activity, [21][22][23][24][25][26] and notably two examples of anti-biolm POM composites have been reported in the literature. 27,28 In this context, the use of POMs as active antibacterial agents supported by AuNPs represents a promising alternative.…”

In vivo toxicity evaluation of two polyoxotungstates with potential antidiabetic activity using Wistar rats as a model system

“…W 6+ , V 5+ ). Earlier studies showed that these inorganic drug candidates possess potential anti-viral, [10][11][12] -bacterial, 13,14 -protozoal, 15 -tumor, 16,17 -Alzheimer 18 and -diabetic activities. 8,9 However, their molecular modes of action are poorly understood.…”

Minerals in biology and medicine

“…90 POM activity depends on composition, shape, and size, but in the case of medium-size polyoxotungstates (POTs, charge > À12 and number of addenda atoms #22) the activity correlates with the total net charge. 91 POMs exhibiting the highest activity towards Helicobacter pylori are mostly Keggin-type POTs, polyoxovanadotungstates and large highly negatively-charged POMs, whereas in the case of Streptococcus pneumoniae, the most active POMs were ascribed to be polyoxovanadates, especially decavanadate, which was also very active against other bacteria.…”