Effects of ethanolic and aqueous extracts of Hibiscus acetosella on 2,4-Dinitrophenylhydrazineinduced oxidative stress in Wistar rats

Oxidative stress is associated with ageing and the development of chronic diseases. Reactive oxygen species (ROS), when produced in excess, lead to protein structural modifications in cells and alterations of their functions. Moreover, oxidative stress stimulates red blood cell loss in several systemic conditions, and it is a root contributor to anaemia in these systemic conditions. This study evaluates the antioxidant activities of ethanolic and aqueous leaf extracts of Hibiscus acetosella in 2,4-dinitrophenylhydrazine (2,4-DNPH)-induced oxidative stress in Wistar rats. The phytochemical constituents were analysed using gas chromatography-mass spectrometry (GCMS). The in vitro antioxidant activities were assessed through 2,2-diphenyl-1-picrylhydrazyl (DPPH), phosphomolybdenum and ferric chloride assays. For the in vivo antioxidant study, Wistar rats were divided into 9 groups. Oxidative stress was induced through the oral administration of 2,4-DNPH (40 mg/Kg b.w.) for 7 days. Hibiscus acetosella leaf extracts were administered orally (100, 200, 400 mg/Kg b.w.) for 28 days following the induction of oxidative stress. Oxidative stress biomarkers catalase (CAT), glutathione (GSH) and malondialdehyde (MDA) were analysed using rat blood serum. The GC-MS identified several compounds, such as squalene and neophytadiene, that have been shown to have antioxidant activities; these compounds may have contributed to the antioxidant activities observed in the in vivo studies. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay revealed ethanolic extracts of H. acetosella to have significantly higher percentage inhibition (p < 0.001) compared to the aqueous extracts of H. acetosella. Phosphomolybdenum assay revealed ethanolic extracts to have significantly greater antioxidant capacity (p = 0.001) compared to aqueous extracts of H. acetosella. The FeCl3 reducing assay revealed ethanolic extracts of H. acetosella to have significantly higher antioxidant activity (p = 0.002) compared to aqueous extracts of H. acetosella. The MDA levels were significantly different between the treatment groups (p = 0.045). The negative control group had significantly higher MDA concentrations when compared to the normal control group (p = 0.023). The GSH concentrations differed significantly among the treatment groups (p = 0.002). The ethanolic (400 mg/Kg b.w.) group had significantly higher GSH levels when compared to the negative control group (p = 0.011) and the normal control group (p = 0.021). The CAT levels in rats differed significantly among the treatment groups (p = 0.002). The ethanolic (400 mg/Kg b.w.) group had significantly the highest CAT activity when compared to the negative control group (p = 0.008) and positive control group (p = 0.032). From the results, H. acetosella has shown the potential for remedial interventions in oxidative stressrelated conditions.