Amyloid beta protein (Abeta)-induced free radical-mediated neurotoxicity is known as a leading hypothesis for a cause of Alzheimer's disease. Abeta increased free radical production and lipid peroxidation in PC12 nerve cells, resulting in apoptosis and cell death. The protective effect of naringenin, a major flavanone constituent isolated from Citrus junos, against Abeta-induced neurotoxicity was investigated using PC12 cells. Pretreatment with isolated naringenin and vitamin C prevented the generation of the Abeta-induced reactive oxygen species. Naringenin resulted in the decrease of Abeta toxicity in a manner of concentration dependence, which was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. However, treatment with these antioxidants inhibited the Abeta-induced neurotoxic effect. The antiamnestic activity of naringenin in vivo was also evaluated using ICR mice with amnesia induced by scopolamine (1 mg/kg body weight). Naringenin, when administered to ICR mice at 4.5 mg/kg body weight, significantly ameliorated scopolamine-induced amnesia as measured in the passive avoidance test. Therefore, these results indicate that micromolecular Abeta-induced in vitro oxidative cell stress is reduced by naringenin and naringenin may be a useful chemopreventive agent against a neurodegenerative disease such as Alzheimer's disease.

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Four sesquiterpene glucosides were isolated from Ixeris sonchifolia Hance. The structure of a new compound (1) was assigned as 9beta-monohydroxy-2,12-dioxo-guaia-3,11(13)-dien-1alpha,5alpha,6beta,7alpha,9beta,10alphaH-12,6-olide-9-O-beta-D- glucopyranoside (ixerinoside). In addition, unambiguous and complete assignments of (1)H NMR chemical shifts for crepidiaside A (2), ixerin Z (3), and 11,13alpha-dihydroixerin Z (4) are presented. The assignments were achieved by two-dimensional NMR (gCOSY, gHSQC, gHMBC, NOESY) and one-dimensional nuclear Overhauser effect (NOE) experiments.

− Extraction process of fucoxanthin from Undaria pinnatifida and stability of fucoxanthin was studied. In this study, to utilized extracted components as a functional food material, ethanol was used as a solvent. The maximum concentration of fucoxanthin was obtained when 80% ethanol solvent was used. The extraction yield of fucoxanthin increased as extraction temperature raised to 50 o C. Water washing of raw material for 5 minutes reduced the salt content about 94%. From the experiment that fucoxanthin content reduced by 30% for 1 day storage at 70 o C, it was demonstrated that fucoxanthin was thermal-unstable above 70 o C. And experimental result of light-stability showed that fucoxanthin was very unstable with light.