The Effect of a Herbal Product Containing Vernonia Amygdalina L. (Asteraceae) and Hibiscus Sabdariffa L. (Malvaceae) on Glycemic Index in Sub-Acute Dexamethasone Treated Mice

This study focused on evaluating the potentials of two variants of water soluble polyherbal nutraceutical products containing Vernonia amygdalina (Bitter leaf) and Hibiscus sabdariffa (Zobo calyces) in mitigating the toxicity due to dexamethasone a widely used synthetic corticosteroid associated with adverse effects, including hyperglycemia, and oxidative stress among others. The two polyherbal products variants: POWSG-D-(10% w/w bitter leaf decoction and 10% w/w Zobo decoction extract), and POWSG-C-10% w/w bitter leaf cold maceration extract and 10% w/w Zobo decoction extract) were used in this study. Phytochemical analysis and physico-chemical parameters (residue on drying, total ash and loss on drying) were done following standard methods as recommended by the World Health Organization (WHO) for herbal product. In vitro antioxidant assay was done using the DPPH (2,2-diphenyl-1-picrylhydrazyl) spectrophotometric method. Effect on glycemic index (fasting blood sugar) was done in vivo in sub-acute dexamethasone treated mice. phytochemical analyses confirmed the presence of phenolics with the UV-Visible spectra showing corroborating characteristic absorption peaks at 198-202 nm and 273–275 nm, evidence for phenolics. Quality assessments demonstrated good granule flow properties, with cold maceration granules exhibiting superior compressibility. Antioxidant activity was moderate, with IC50 values of 500 µg/mL and 800 µg/mL for POWSG-C and POWSG-D respectively, compared to Vitamin C (IC50: 9 µg/mL). From the result of the bioassay, the high dose (800 mg/kg body weight) decoction successfully mitigated hyperglycemia on the sub-acute dexamethasone induced mice with 1.75mMol/L and 1.80mMol/L on day 18 and 25 respectively compared to the other group of animals. These findings highlight the potential of this polyherbal formulation as a cost-effective, accessible nutraceutical for the treatment of hyperglycemia especially for immuno-compromised subjects undergoing corticosteroid regimen, and for general health and wellbeing with further optimization recommended to enhance efficacy and antioxidant activity.