Neuroprotective effect of Ginkgo biloba and L-Ascorbic Acid on Mercury Chloride (HgCl2)-Induced Oxidative stress and Neuroinflammation in Adult Male Wistar Rats.
Authors: Auza Moses Ibrahim , Abraham Sunday Musa , B. Oladele Sunday , M. Bauchi Zainab , M. Danborno Angela 
Published: September 2024

Mercury chloride HgCl2, known scientifically as mercuric chloride, is a potent compound with a long history of use in various fields. It has been used in antiseptics and disinfectants, and even in the production of batteries and electroplating. Despite its utility, HgCl2 is highly toxic, posing significant health risks upon exposure. Chronic exposure can lead to severe neurological damages. Ginkgo biloba extract (EGB 761) is widely used for its neuroprotective properties, which include enhancing cognitive function and memory, particularly in age-related conditions like Alzheimer's disease. Ascorbic acid is vital for the synthesis of collagen, the repair of tissues, and the enzymatic production of certain neurotransmitters. As a powerful antioxidant, ascorbic acid helps protect cells from damage by free radicals. The present study was to evaluate the effects of Ginkgo biloba and L-Ascorbic Acid on Mercury Chloride (HgCl2)-Induced Oxidative stress and Neuroinflammation in Adult Male Wistar Rats for the period of 21 days. A total of 48 adult male Wistar rats were randomly divided into 6 groups of 8 rats each. The control group received distilled water only all through the period of the experiment serving as the positive control. HgCl2 Only Group received (5 mg/kg HgCl2 Only), Group HgCl2 + A. A (LD) received (5 mg/kg HgCl2 + 100 mg/kg A. A (LD), Group HgCl2 + A. A (HD) received (5 mg/kg HgCl2 + 500 mg/kg A. A (HD), Group HgCl2 + EGB 761 (LD) received (5 mg/kg HgCl2 + 100 mg/kg EGB 761 (HD) and Group HgCl2+ EGB 761 (HD) received (5 mg/kg HgCl2 + 500 mg/kg EGB 761 (HD). At the end of the administration, the animals were then subjected to Y maze test and were humanely sacrificed on day 22 of the experiment and brain were excised. 1 g of tissues immediately homogenized, the homogenates were centrifuged and the supernatant was utilized to assay for antioxidants enzymes (MDA, SOD, CAT and GSH) using spectrophotometric and some inflammatory cytokines (TNF- α and IL-6) activity in brain tissue. The result showed significant (P<0.05) impairment in spatial learning in HgCl2 Only Group, Ascorbic acid (500 mg) treated animals showed significant (p < 0.05) improvement in the spatial learning deficits and the Ginkgo biloba (100 mg and 500 mg) treated group of animals showed more alternations. The result also showed a significant (p < 0.05) decrease of superoxide dismutase (SOD) in HgCl2 group when compared to controls. Tissue catalase (CAT) and GSH activity decreased significantly (P < 0.05) in HgCl2 group when compared with control rats. Malondialdehyde concentrations increased significantly (P < 0.05) in HgCl2 treated group when compared to controls. Ascorbic acid (500 mg/kg), being a potent antioxidant caused significant (P < 0.05) decrease in MDA level, significant (P < 0.05) increase in CAT, SOD level thereby mitigating mercury-induced oxidative stress. The administration of Ginkgo Biloba Extract markedly ameliorated the toxic effects of HgCl2 on the previous parameters indicating also that Ascorbic acid and Ginkgo Biloba Extract has neuro protective property.