Flavonoid-rich fractions of C. volubile and V. amygdalina alleviates arsenic-induced neurotoxicity by improving neurosignaling and antioxidant capacity in rats' brain

Abstract

Purpose: This study evaluated the effects of flavonoid-rich extracts from Clerodendrum volubile and Vernonia amygdalina (FCV and FVA., respectively) on arsenic-induced neuropathy. Methods: Thirty male Wistar rats were divided into six groups (n = 5); control, arsenic (40 ppm NaAsO2), arsenic + FCV (100 mg/kg), arsenic + FVA (100 mg/kg), arsenic + FCV + FVA (50 mg/kg each), and arsenic + vitamin C (100 mg/kg). Brain tissues were processed for biochemical assays, and the levels of metal ions (arsenic, calcium, zinc, copper, iron, potassium, sodium, manganese, and magnesium) were determined. Results: Phytochemical analysis confirmed the presence of flavonoids in FCV and FVA Arsenic levels were markedly elevated (24-folds). At the same time, all other metal ions were significantly (p < 0.05) reduced in the brain of arsenic-intoxicated rats. Neurotoxicity was characterised by inhibited acetylcholinesterase and upregulated adenosine deaminase and monoamine oxidase-A activities. Compared to the control, arsenic-exposed rats had significantly (p < 0.05) reduced total thiol levels, catalase, and glutathione peroxidase activities, while malondialdehyde and nitric oxide levels were increased. However, treatment with FCV and FVA significantly (p < 0.05) reduced arsenic accumulation, increased the levels of other metal ions, improved neurosignalling enzymes, and augmented the antioxidant capacity in the exposed rats' brains. These effects were comparable to those elicited by vitamin C treatment. Conclusion: These findings highlight the neuroprotective properties of FCV and FVA against arsenic-induced neuropathy mediated via improved neurosignalling and augmentation of cellular antioxidant capacity.

Keywords

• Arsenic
• Neuropathy
• Phytotherapy
• Antioxidant
• Oxidative stress