Formulation-Dependent Cardiomodulatory Effects of Combined Aqueous Extracts of Beta vulgaris and Hibiscus sabdariffa in Male Wistar Rats

Abstract

Background: Plant-derived phytochemicals have attracted considerable attention for their potential to preserve cardiac integrity and modulate cardiovascular health. Aim: This study investigated the formulation-dependent cardiomodulatory effects of combined aqueous extracts of Beta vulgaris (beetroot) and Hibiscus sabdariffa (roselle) in male Wistar rats by evaluating cardiac biomarkers, relative heart weight, and myocardial histopathology.  Methods: Twenty-five adult male Wistar rats were randomly allocated to five groups (n = 5): control, 1:1 beetroot-roselle combination (400 and 800 mg/kg), and 1:3 beetroot-roselle combination (400 and 800 mg/kg). Three rats from each group were euthanised for analysis (n = 3 biological replicates). Extracts were administered orally for 28 consecutive days. Cardiovascular function was evaluated using relative heart weight, serum creatine kinase-myocardial band (CK-MB), cardiac troponin-T (cTnT), myoglobin, and histopathological examination of myocardial tissues. Data were analysed using one-way ANOVA followed by Tukey's post hoc test, with significance set at p < 0.05.  Results: Administration of the combined extracts significantly reduced relative heart weight compared with the control, with greater reductions observed in the 1:3 formulation. The 1:1 formulation produced modest, non-significant decreases (p > 0.05) in CK-MB, cTnT, and myoglobin concentrations, whereas the 1:3 formulation significantly lowered all three cardiac biomarkers (p < 0.05), indicating improved preservation of myocardial integrity. Histopathological evaluation revealed normal myocardial architecture in the control group and all treatment groups except the 1:3 formulation at 800 mg/kg, which exhibited mild sarcoplasmic vacuolation and focal myocardial degeneration. Conclusion: Combined aqueous extracts of Beta vulgaris and Hibiscus sabdariffa exert formulation-dependent cardiomodulatory effects in male Wistar rats. The 1:3 formulation demonstrated superior modulation of cardiac injury biomarkers; however, mild myocardial alterations at the highest dose suggest that effects are dose-dependent and require careful optimisation. These findings should be interpreted cautiously and confirmed in appropriate cardiovascular injury models before therapeutic application.