Antioxidant profile and antimicrobial activity of ascorbic acid: an in vitro study

Abstract

This study evaluated the biological properties of ascorbic acid by assessing its antioxidant capacity using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method and its antimicrobial activity against a panel of bacterial and fungal strains. For the antioxidant assay, DPPH solutions (0.003 mg/mL) were incubated with ascorbic acid at various concentrations (0.0625 – 2 mg/mL). The results revealed excellent dose-dependent radical scavenging activity, with reduction percentages exceeding 94% for concentrations of 0.5 mg/mL and above. The median reduction concentration (RC₅₀) value, determined graphically, was 0.0066 mg/mL, confirming its potent antioxidant power. Microbial susceptibility tests demonstrated that ascorbic acid exerts significant antibacterial activity, with a bactericidal effect observed at a high concentration of 200 mg/mL. In contrast, its activity against yeasts of the genus Candida was weak. This study concludes that ascorbic acid is a highly effective antioxidant at low doses, but its use as an antimicrobial agent requires much higher concentrations for a bactericidal effect, and it exhibits no notable efficacy against fungi. These results highlight a duality of application that is entirely dependent on the concentration used.

https://doi.org/10.70974/mat09225263