Ketoglutaric acid treatment enhances the antioxidant status of broccoli sprouts

Abstract

Background: Ketoglutaric acid (α-KGA) is a dicarboxylic ketoacid with strong biological activity, whose main role in eukaryotic organisms is to participate in the Krebs cycle. In the present study, we tested whether the application of α-KGA to edible sprout culture would increase the content of low-molecular-weight antioxidants by improving their mitochondrial activity. For this purpose, broccoli sprouts were treated at the beginning of germination with an aqueous solution of α-KGA, at various concentrations (0, 0.1, 1, and 10 mmol L^-1), which after 5 days of germination were analyzed for markers of antioxidant status, oxidative stress, and energy metabolism.

Results: We showed that α-KGA promotes the production of antioxidants, which was manifested by increased content of ascorbic acid, glutathione, and polyphenols, as well as higher expression of the relevant enzymes for the biosynthesis of these substances (galactono-1,4-lactone dehydrogenase, glutathione synthase, phenylalanine ammonia-lyase). Induction of antioxidant biosynthesis was associated with an increase in mitochondrial activity, as we observed both an increase in the expression of respiratory proteins (aconitase 1, H⁺-ATPase) as well as an increase in ATP levels, oxidation of NADH, and an accumulation of reactive oxygen species and a consequent increase in the expression of antioxidant enzymes (manganese superoxide dismutase, catalase).

Conclusion: The above results showed that the application of α-KGA to the culture medium can improve the antioxidant status of edible sprouts. However, the effect obtained largely depends on the concentration of α-KGA in the medium, which shows that the mechanism of α-KGA effect on sprouts is based on the phenomenon of hormesis. © 2025 Society of Chemical Industry.

Keywords: antioxidants; broccoli sprouts; functional food; immunoblotting; oxidative stress; volatile compounds.