Quercetin and gossypin inhibit the Plasma Membrane Ca2+-ATPase by different mechanisms?.

ONTIVEROS, M; GENTILE,L.; RINALDI, D.E; MANGIALAVORI, I. .; MARDER, M; ROSSI, J.P.; FERREIRA GOMES, M

Tucuman

Congreso; . III Latin American Federation of Biophysical Societies (LAFeBS). IX IberoAmerican Congress of Biophysics. XLV Reunion Annual SAB 2016.; 2016

LAFeBS- SAB

Flavonoids are commonly found in fruit and vegetables and some have been reported to reach micromolar concentration in human blood plasma. These compounds are related to health benefits, including antioxidant capacity and cancer chemoprotective properties. One mechanism proposed for the protective effects, is that these flavonoids trigger the apoptosis of malignant cells through the Ca2+?dependent mitochondrial pathway, which can be activated through the elevation of cytosolic calcium. Some flavonoids, like quercetin and gossypin inhibit Ca2+ transport systems, as the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) and the plasma membrane Ca2+-ATPase (PMCA). These compounds inhibit SERCA, however, the effect of flavonoids on PMCA is not yet well-defined. PMCA is a calmodulin regulated P-type ATPase responsible for the preservation of low intracellular Ca2+ concentration in all the eukaryotic cells. We have evaluated the effect of different types of flavonoids on calcium pump activity. We studied in detail those that inhibited PMCA with high affinity. Among the compounds studied, quercetin, a flavonol aglycone , and gossypin, a flavonol glycoside, inhibited PMCA with a K0.5 of 0.34 ± 0.01 and 10.1 ± 0.5 μM, respectively. In this work we study the mechanism of inhibition of PMCA by these flavonoids.