Tabernaemontana stapfiana Britten (Apocynaceae) Stem Bark Prevents Alcl3-Induced Cognitive Disability: Antioxidant and Anti-Inflammatory Activities in Wistar Rats

Abstract

The present study aimed to evaluate the protective effects of aqueous and ethanol extracts of Tabernaemontana stapfiana (T. stapfiana) on cognitive disability induced by aluminum chloride (AlCl₃) in Wistar rats. Forty-five Wistar rats were distributed in different groups of five animals each. Test groups were daily given AlCl₃ (100 mg/kg) following by the doses of the extracts for 21 days. At the end of treatment period, rats were sacrificed and the brain homogenate and serum were prepared and used to evaluate oxidative stress in brain and serum cytokines using colorimetric tests and ELISA, respectively. The findings of this study showed that reduced brain, body weight, and antioxidant enzymes (reduced glutathione [GSH], catalase [CAT], and superoxide dismutase [SOD]), while it increases oxidant biomarkers (malondiadehyde (MDA), nitric oxide (NO) and inflammatory cytokines (IL-10, TNF-α, IL-1β, and IL-6). Therefore, the administration of aqueous or ethanol extracts of T. stapfiana stem bark significantly (p < 0.001) reduced the IL-10, TNF-α, IL-1β, and IL-6 levels in AlCl₃-treated rats compared to non treated rats. Moreover, the extracts significantly (p < 0.001) changed the oxidant-antioxidant balance by reducing the MDA and NO levels, while increasing SOD and GSH concentrations caused and NO in AlCl₃-treated rats as compared to nontreated rats. Conclusively, aqueous or ethanol extracts of T. stapfiana stem bark prevented the oxidative stress and inflammation in brain, which made the brain to be not change after administration of the causative agent of cognitive impairment (CI), AlCl₃.

Keywords: Tabernaemontana stapfiana; cognitive impairment; inflammation; oxidative stress.

Figure 1

Body and brain weights post a cotreatment with ACl₃ and the aqueous and ethanol extracts of T. stapfiana stem bark in rats. Barchart represent means ± standard error of means (SEM), n = 5 rats per group. Asterisks indicate the groups treated with extracts vs. negative control. α and β indicate negative control vs. positive control difference. ns: indicate not significant at p  > 0.05. NC = normal control, NEGC = negative control, PC = positive control.