Comparison of the effect of three licorice varieties on cognitive improvement via an amelioration of neuroinflammation in lipopolysaccharide-induced mice.
10.4162/nrp.2018.12.3.191
- Author:
Min Ji CHO
1
;
Ji Hyun KIM
;
Chan Hum PARK
;
Ah Young LEE
;
Yu Su SHIN
;
Jeong Hoon LEE
;
Chun Geun PARK
;
Eun Ju CHO
Author Information
1. Department of Food Science and Nutrition, Pusan National University, 2 Busandaehak-ro 63 beon-gil, Geumjeong-gu, Busan 46241, Korea. ejcho@pusan.ac.kr
- Publication Type:Original Article
- Keywords:
BDNF;
cognitive dysfunction;
glycyrrhiza;
Glycyrrhiza uralensis;
inflammation
- MeSH:
Alzheimer Disease;
Animals;
Behavior Rating Scale;
Blotting, Western;
Brain;
Brain-Derived Neurotrophic Factor;
Cognition Disorders;
Cyclooxygenase 2;
Glycyrrhiza uralensis;
Glycyrrhiza*;
Inflammation;
Interleukin-6;
Korea;
Learning;
Memory;
Mice*;
Neurodegenerative Diseases;
Nitric Oxide Synthase Type II;
Toll-Like Receptor 4;
Water
- From:Nutrition Research and Practice
2018;12(3):191-198
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND/OBJECTIVES: Neuroinflammation plays critical role in neurodegenerative disorders, such as Alzheimer's disease (AD). We investigated the effect of three licorice varieties, Glycyrhiza uralensis, G. glabra, and Shinwongam (SW) on a mouse model of inflammation-induced memory and cognitive deficit. MATERIALS/METHODS: C57BL/6 mice were injected with lipopolysaccharide (LPS; 2.5 mg/kg, intraperitoneally) and orally administrated G. uralensis, G. glabra, and SW extract (150 mg/kg/day). SW, a new species of licorice in Korea, was combined with G. uralensis and G. glabra. Behavioral tests, including the T-maze, novel object recognition and Morris water maze, were carried out to assess learning and memory. In addition, the expressions of inflammation-related proteins in brain tissue were measured by western blotting. RESULTS: There was a significant decrease in spatial and objective recognition memory in LPS-induced cognitive impairment group, as measured by the T-maze and novel object recognition test; however, the administration of licorice ameliorated these deficits. In addition, licorice-treated groups exhibited improved learning and memory ability in the Morris water maze. Furthermore, LPS-injected mice had up-regulated pro-inflammatory proteins, such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2, interleukin-6, via activation of toll like receptor 4 (TLR4) and nuclear factor-kappa B (NFκB) pathways in the brain. However, these were attenuated by following administration of the three licorice varieties. Interestingly, the SW-administered group showed greater inhibition of iNOS and TLR4 when compared with the other licorice varieties. Furthermore, there was a significant increase in the expression of brain-derived neurotrophic factor (BDNF) in the brain of LPS-induced cognitively impaired mice that were administered licorice, with the greatest effect following SW treatment. CONCLUSIONS: The three licorice varieties ameliorated the inflammation-induced cognitive dysfunction by down-regulating inflammatory proteins and up-regulating BDNF. These results suggest that licorice, in particular SW, could be potential therapeutic agents against cognitive impairment.
