Equol Effectively Inhibits Toxic Activity of Human Neutrophils without Influencing Their Viability

Abstract

Equol (7,4′-dihydroxy-isoflavan, or 4′,7-isoflavandiol) is a chroman derivative produced by intestinal bacteria in response to soy isoflavone intake in some, but not in all, humans. Equol shows strong anti-oxidant, anti-estrogenic, anti-cancerous and anti-inflammatory properties. The antioxidative capacity of equol has recently received considerable attention, and it has been used for preventing and treating several diseases. We investigated the effect of equol on human neutrophils, extra- and intracellular formation of oxidants, the phosphorylation of protein regulating NADPH oxidase and its effect on apoptosis. Neutrophils, isolated from blood from healthy subjects, were tested upon activation with various stimulants, proper for reactive oxygen species (ROS) production and treated by equol. Equol has the ability to reduce the toxic action of neutrophils. With increasing concentrations, equol decreased the amount of oxidants produced by neutrophils both extra- and intracellularly. The phosphorylation of p40^phox (a component of NADPH oxidase, responsible for the assembly of functional oxidase in intracellular membranes) was reduced in the presence of equol. The experiments showed that equol did not change the number of viable, apoptotic or dead neutrophils significantly in all concentrations used. These results indicate the promising effect of equol in the operation of ROS in different mechanisms in the model of inflammation.

Equol, a soybean metabolite with estrogen-like functions, decreases lipopolysaccharide-induced human neutrophil extracellular traps in vitro

“…However, we think that the high concentration of equol may potentially inhibit NET formation. Pažoureková et al (31) reported that a high concentration of equol suppressed ROS production in neutrophils. The inhibition of ROS production leads to PAD4 nuclear transfer inhibition, which may decrease NET formation.…”

Gut microbiome modulation during treatment of mucositis with the dairy bacterium Lactococcus lactis and recombinant strain secreting human antimicrobial PAP

“…Interestingly, this genus is currently formed by one species, A . equolifaciens , which produces an isoflavone metabolite, named equol, with anti-cancerous and anti-inflammatory properties 37 , 38 . Moreover, studies reveal that equol is exclusively produced by the intestinal microbiota 39 .…”

Potential Protective Effects of Equol (Soy Isoflavone Metabolite) on Coronary Heart Diseases—From Molecular Mechanisms to Studies in Humans

“…The equol protected macrophages from oxidative stress induced by L-lactate dehydrogenase or oxLDL by reducing the lipid peroxidation product malondialdehyde (MDA), enhancing the antioxidant glutathione, or increasing the activities of the antioxidant enzyme superoxide dismutase (SOD) [89,90]. Equol treatment on neutrophils that were activated with various stimulants to produce ROS caused reduced toxic action of the ROS; for example, equol decreased the phosphorylation of the proteins regulating NADPH oxidase [91]. Phagocytic cells, after being incubated with equol for 1 h, showed a significant reduction in the intracellular production of superoxide anion and hydrogen peroxide [92].…”