Methylene Chloride Fraction of Salicornia herbacea L. Suppresses Glutamate‐induced Neuronal Cytotoxicity and Improves Galactose‐induced Learning and Memory Impairment

Abstract

Salicornia herbacea L., also called as glasswort, is a halophyte growing in salt marshes and has been used as a seasoned vegetable and a traditional medicine for various disorders. It is a nutrient‐rich herb containing plenty of bioactive compounds such as selenium, flavonoids. In this study, we in vitro examined if ethanol extract from glasswort is neuroprotective under oxidative stress‐induced environment. Hippocampal HT22 cells were treated with 5 mM glutamate in the presence of ethanol extract from glasswort or its subfractions in five different solvents (hexane, methylene chloride, ethyl acetate, butanol, and water). Ethanol (EtOH) extract and methylene chloride‐soluble subfraction (MC fraction) of the herb were effective in protecting HT22 cells from glutamate‐induced toxicity. In addition, EtOH extract and MC fraction induced intracellular antioxidant enzyme NQO1's activity and inhibited ROS production. The levels of Nrf2 and its downstream antioxidant enzymes were significantly elevated by both EtOH extract and MC fraction. We further investigated whether MC fraction is protective against galactose‐induced cognitive decline in animal model. C57BL/6J mice were fed MC fraction, and intraperitoneally injected with D‐galactose on a daily‐basis to generate oxidative stress and cause learning and memory impairments. After 6 weeks, behavioral and biochemical tests were conducted. The group fed MC fraction decreased escape latency time, reduced DNA damage and lipid peroxidation, and enhanced NQO1 enzyme activity in tissues, compared to D‐galactose‐treated control group. Overall, these findings suggest that MC fraction of glasswort extract could be a promising agent for AD prevention.Support or Funding InformationThis work was supported by the Food Functionality Evaluation program funded by the Ministry of Agriculture, Food and Rural Affairs through Korea Food Research Institute, and by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Project No. 2013R1A1A2013362).