Effect of tiger nuts (Cyperus esculentus) on antioxidant capacity and culture-based gut microbial changes in high-fat diet-fed rats

Aim: Diet-induced oxidative stress and alterations in the intestinal microbial environment are central contributors to obesity-associated metabolic disorders. Functional foods rich in bioactive compounds have emerged as promising dietary interventions to mitigate these disturbances. Cyperus esculentus L. [tiger nut (TN)] is a nutrient-dense tuber rich in dietary fiber, oleic acid, tocopherols, flavonoids, phenolic acids, and phytosterols, which may exert antioxidant, hypolipidemic, and potential prebiotic effects. This study aims to investigate the dose-dependent effects of TN supplementation on oxidative stress, inflammatory status, lipid metabolism, liver histopathology, and selected culture-based gut bacterial indicators in a high-fat diet (HFD)-induced rat model. Methods: Twenty-five male rats were allocated into five groups: a normal control group, an HFD control group, and three HFD groups supplemented with TN powder at 10%, 20%, or 30% (w/w). Biochemical markers of oxidative stress, lipid profile, and inflammation were evaluated, and liver histopathology was examined. Gut bacterial assessment was performed using culture-based isolation and phenotypic identification of selected bacterial groups. Results: TN supplementation significantly increased anti-oxidant enzymes, reduced lipid peroxidation, improved serum lipid profile, and decreased inflammatory markers compared with the control group, with the greatest improvements observed in the 20% TN group. Histopathological examination demonstrated marked attenuation of HFD-induced hepatic injury, with the 20% TN group exhibiting near-normal hepatic architecture. Culture-based microbial assessment suggested that TN supplementation may favorably influence selected intestinal bacterial indicators. Conclusions: TN supplementation, particularly at the 20% inclusion level, effectively ameliorated HFD-induced oxidative stress, dyslipidemia, inflammation, and hepatic injury. Culture-based findings suggest that TN supplementation may favorably influence selected intestinal bacterial indicators. However, confirmation using sequencing-based microbiome approaches is required before definitive conclusions regarding prebiotic effects or gut microbiota modulation can be drawn.