Protective role of Spondias mombin leaf and Cola acuminata seed extracts against scopolamineinduced cognitive dysfunction
The leaves of Spondias mombin L. (Anacardiaceae) when chewed with Cola acuminata (P. Beauv.) Schott & Endl. (Sterculiaceae) seeds have memory enhancing and anti-ageing properties. This study sought to investigate the protective effect of hydroethanolic leaf extract of Spondias mombin (SM) and Cola acuminata seed extract (CA) against scopolamine-induced cognitive dysfunction. SM or CA (50, 100 or 200 mg/kg, p.o.) or SM +CA (50 mg/kg, p.o.) was administered to rats for 3 consecutive days. One hour post-treatment on day 3, scopolamine (3 mg/kg i.p) was administered and 5 min later, the Y-maze test or Morris water maze test (MWM; days 3–7) was conducted. The rat’s brains were isolated for the estimation of oxidative-nitritive stress status following the MWM task. The antioxidant capacity of SM and CA was also evaluated in vitro using the 1,1- diphenyl-2-picrylhydrazyl (DPPH), nitric oxide (NO) and ferric ion reducing power (FRAP) assays. Pretreatment of rats with SM, CA or SM + CA significantly ameliorated the learning and memory impairment induced with scopolamine as evidenced in Y-maze and MWM paradigms. Moreover, SM, CA or SM + CA significantly attenuated the oxidative-nitritive stress induced by scopolamine, evidenced in the decrease in malondialdehyde and nitrite levels and restoration of glutathione, catalase and superoxide dismutase levels. Furthermore, SM and CA showed promising free radical scavenging effect against DPPH and moderate antioxidant activity in NO and FRAP tests. This study showed that Spondias mombin and Cola acuminata have significant protective effect against scopolamine-induced memory deficit that could be attributed to their antioxidant properties.
Keywords: Dementia; Lipid peroxidation; Nitrite; Morris water maze; Y-maze