Comparison of the effect of three licorice varieties on cognitive improvement via an amelioration of neuroinflammation in lipopolysaccharide-induced mice

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.

Antitumor Effects of Genipin: New and Emerging Insights from Recent Studies

Genipin, an aglycone derived from geniposide found in Gardenia jasminoides, is known to be an excellent natural cross-linker, strong apoptosis inducer, and antiviral agent. Although evidence suggests antiviral activity of genipin in several in vitro viral infection systems, there have been few literatures which review antitumor effects of genipin in a variety of in vitro/in vivo models of cancers yet. In this review, we present some of the latest findings in the studies of genipin focusing on antitumor effects and its mechanisms. In brief, genipin inhibits mitochondrial uncoupling protein 2 to increase accumulation of reactive oxygen species, leading to ROS/c-Jun N-terminal kinase-dependent apoptosis of cancer cells. Genipin also increase tissue inhibitors of metalloproteases (MMP), resulting to decrease activities of MMP-2 which plays a key role in metastasis of cancers. Genipin has shown a biphasic effects on cell death and survival in cancer cells as many other plant-derived phytochemicals do. Finally we discuss the potential of genipin as a promosing novel antitumor agent which could be applicable to chemotherapy and/or chemoprevention for cancers.

Current Trends in Studies of Epstein-Barr Virus (EBV) Associated Gastric Carcinoma

EBV infection has been causally associated with incidence of many carcinomas. EBV-associated gastric carcinoma (EBVaGC) has been classified as a unique gastric carcinoma subset, suggesting EBV infection is related to the development of gastric cancer. In this study, general trends of EBVaGC studies for last half-decades were reviewed in several perspectives of clinical significance, virological importance and etiological interests. Throughout this comprehensive reviewing, new study trends of EBV and EBVaGC for next half-decades were suggested.