Enhancement of Extract Yield, Antioxidant, and Anti-Inflammatory Properties of Mentha pulegium L., through Fermentation with Geotrichum candidum G110 via Polyphenol Deglycosylation, without Genotoxic Effects

Abstract

This study investigated the potential of solid-state fermentation using the fungus Geotrichum candidum G110 as a biological approach to modulate the functional properties of Mentha pulegium extracts, in comparison with conventional maceration. As a proof-of-concept study, the effects of fermentation on extraction yield, phytochemical composition, and biological activities were systematically evaluated to establish the feasibility of this biotransformation approach. HPLC-DAD analysis revealed chromatographic changes consistent with the deglycosylation of polyphenolic compounds, suggesting a conversion of glycosylated phenolics into their corresponding aglycone forms and the appearance of newly detected metabolites. While total polyphenol and flavonoid contents were found to decrease upon fermentation, the fermented extract (E+G) exhibited comparatively higher antioxidant and anti-inflammatory activities relative to the unfermented extract (E–G). The extraction yield increased by 45.4% (from 14.33 ± 0.57% to 20.83 ± 1.25%), the DPPH IC₅₀ value decreased from 0.17 ± 0.02 to 0.09 ± 0.00 mg/mL, and the anti-inflammatory IC₅₀ decreased from 0.392 ± 0.02 to 0.233 ± 0.04 mg/mL. These observations may be associated with the enhanced bioavailability of aglycone forms potentially generated through fermentation-driven deglycosylation, among other possible biotransformation mechanisms. Genotoxicity assays indicated no detectable genotoxic effects associated with the fermented extract, suggesting an acceptable safety profile for further investigation. These results demonstrate the potential of Geotrichum candidum G110 fermentation as a promising biotechnological approach to enhance the functional properties of Mentha pulegium extracts. However, further mechanistic and in vivo studies are required to confirm these preliminary findings and support potential applications in the pharmaceutical, cosmetic, and nutraceutical sectors.