Pyridoxine (Vitamin B6) and the Glutathione Peroxidase System; a Link between One-Carbon Metabolism and Antioxidation

Abstract

Vitamin B6 (B6) has a central role in the metabolism of amino acids, which includes important interactions with endogenous redox reactions through its effects on the glutathione peroxidase (GPX) system. In fact, B6-dependent enzymes catalyse most reactions of the transsulfuration pathway, driving homocysteine to cysteine and further into GPX proteins. Considering that mammals metabolize sulfur- and seleno-amino acids similarly, B6 plays an important role in the fate of sulfur-homocysteine and its seleno counterpart between transsulfuration and one-carbon metabolism, especially under oxidative stress conditions. This is particularly important in reproduction because ovarian metabolism may generate an excess of reactive oxygen species (ROS) during the peri-estrus period, which may impair ovulatory functions and early embryo development. Later in gestation, placentation raises embryo oxygen tension and may induce a higher expression of ROS markers and eventually embryo losses. Interestingly, the metabolic accumulation of ROS up-regulates the flow of one-carbon units to transsulfuration and down-regulates remethylation. However, in embryos, the transsulfuration pathway is not functional, making the understanding of the interplay between these two pathways particularly crucial. In this review, the importance of the maternal metabolic status of B6 for the flow of one-carbon units towards both maternal and embryonic GPX systems is discussed. Additionally, B6 effects on GPX activity and gene expression in dams, as well as embryo development, are presented in a pig model under different oxidative stress conditions.

Phytochemical analysis and Evaluation of hepatoprotective effect of Maytenus royleanus leaves extract against anti-tuberculosis drug induced liver injury in mice

“…It results in significant reduction of oxidative stress in liver of mice. The immediate administration of vitamin B6 in mice contributed towards neutrophil reduction in liver and helped in diminishing the oxidative damage to protein and lipids in liver [43]. Vitamin B6 also modulates the kynurenine pathway, sphingosine-1-phosphate, and nuclear factor-kappa B thus lowering inflammation [44].…”

Cerium oxide nanoparticle elicits oxidative stress, endocrine imbalance and lowers sperm characteristics in testes of balb/c mice

“…Furthermore, GPx and GST activities were significantly reduced in the testes of CeO 2 NPs‐treated mice. GPx protects against oxidative damage by reducing hydrogen peroxide to water (Dalto & Matte, ). The combined depletion of GSH, reduction in GPx and GST activities strongly suggest that CeO 2 NPs may adversely affect glutathione metabolic pathway and promote oxidative damage in the testes.…”

Regulation of lipid peroxidation and ferroptosis in diverse species

“…Some oviparous species predispose their young to excretion of metals in both the egg shell and contents (Burger 1994;Skrivan et al 2005). Metal-initiated oxidative stress in the developing animal disrupts long chain PUFA synthesis (Monroig et al 2009), negatively affects mitochondrial genome stability (Guérin et al 2001), and down-regulates transsulfuration and remethylation pathways (Dalto and Matte 2017). Additionally, iron accumulation in avian reproductive organs decreases egg production .…”