Polyoxovanadate inhibition of: Escherichia coli growth shows a reverse correlation with Ca2+-ATPase inhibition

Abstract

Recently, a global analysis of the structure-activity-relationship of a series of polyoxometalates (POMs) revealed that the most active POMs were ascribed to be polyoxovanadates (POVs), especially decavanadate (V<inf>10</inf>), which was very active against certain bacteria (Bijelic et al., Chem. Commun., 2018). The present study explores this observation and compares the effects of three POVs namely MnV<inf>11</inf>, MnV<inf>13</inf> and V<inf>10</inf> against Escherichia coli growth. It was observed that MnV<inf>11</inf> presents the lowest growth inhibition (GI<inf>50</inf>) value for Escherichia coli followed by the MnV<inf>13</inf> compound, being about 2 times lower than that of V<inf>10</inf>; respectively, the values obtained were 0.21, 0.27 and 0.58 mM. All three compounds were more effective than vanadate alone (GI<inf>50</inf> = 1.1 mM) and also than decaniobate, Nb<inf>10</inf> (GI<inf>50</inf> > 10 mM), an isostructural POM of V<inf>10</inf>. However, the POVs exhibiting the highest antibacterial activity (MnV<inf>11</inf>) were shown to have the lowest Ca2+-ATPase inhibitor capacity (IC<inf>50</inf> = 58 ?M) whereas decavanadate, which was also very active against this membranar ATPase (IC<inf>50</inf> = 15 ?M), was less active against bacterial growth, suggesting that POV inhibition of ion pumps might not be associated with the inhibition of Escherichia coli growth. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.