Ethanolic Extract of Opuntia ficus-indica var. saboten Ameliorates Cognitive Dysfunction Induced by Cholinergic Blockade in Mice

Abstract

The stem of Opuntia ficus-indica var. saboten is edible and has been used as a medicinal herb on Jeju Island in Korea. We previously reported that the butanolic extract of O. ficus-indica var. saboten exerts the enhancement of long-term memory in mice. However, the antiamnesic effects of O. ficus-indica var. saboten and its mode of action has not been clearly elucidated. In the present study, we explored the effects of the ethanolic extract of stems of O. ficus-indica var. saboten (EOFS) on cognitive performance in mouse and attempted to delineate its mechanism of action. We used the passive avoidance, Y-maze, and novel object recognition tests to assess its effects on cognitive functions in scopolamine-induced memory-impaired mice. We observed that EOFS (100, 200, and 400 mg/kg) ameliorated scopolamine-induced cognitive dysfunction. We also explored its mechanism of action by conducting an acetylcholinesterase (AChE) activity assay using the mouse whole brain and Western blot using the mouse hippocampal tissue. Western blot analysis and the ex vivo study revealed that EOFS increased the levels of phosphorylated extracellular signal-regulated kinase and cAMP response element-binding protein (CREB) and the levels of brain-derived neurotrophic factor (BDNF) expression in the hippocampus. It also inhibited AChE activity in the brain. Our findings suggest that EOFS would be useful for the treatment of cholinergic blockade-induced cognitive dysfunction.

Keywords: MAP kinase; Opuntia ficus-indica var. saboten; acetylcholinesterase; brain-derived neurotrophic factor; learning and memory.