A new enzyme assay method for screening a-glucosidase inhibitors with rapidity and simplicity was developed. The enzyme-substituted a-glucosidases for this assay was glucoamylase. Samples were spotted or developed on the silica gel plate. The agar solution containing substrate was poured on the plate, and paper impregnated with enzyme was layered on the agar. After incubation, an inhibitory circle would appear around the inhibitor. By using this method, more than 200 strains of marine microorganisms were screened. Among them, three active strains were found to secrete inhibitors in the culture medium.

ng seven tumor cell lines. Selective inhibition of K562 and HT-29 cells was observed from a methanolic extract in the range of 16-125 μg/mL. Radicalscavenging activity was greatest in an extract composed primarily of flavonol glycosides. Seven flavonol glycosides were isolated and purified from whole fruit for further evaluation; the anthocyanin cyanidin 3-galactoside was also purified for comparison with the flavonoids. Three flavonol monoglycosides were newly identified by 13C NMR as myricetin 3-α-arabinofuranoside, quercetin 3-xyloside, and 3-methoxyquercetin 3-β-galactoside (isorhamnetin); the other four isolated were the previously identified myricetin 3-β-galactoside, quercetin 3-β-galactoside, quercetin 3-α-arabinofuranoside, and quercetin 3-α-rhamnopyranoside. These compounds were evaluated for 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity and ability to inhibit low-density lipoprotein oxidation in vitro. Most of the flavonol glycosides showed antioxidant activity comparable or superior to that of vitamin E; cyanidin 3-galactoside showed activity superior to that of the flavonoids as well as vitamin E or Trolox in both antioxidant assays.

Five caffeic acid derivatives were found in the roots of yacon, Smallanthus sonchifolius (Poepp. And Endl.) H. Robinson, Asteraceae, as the major water-soluble phenolic compounds. The structures of these compounds were determined by analysis of spectroscopic data. Two of these were chlorogenic acid (3-caffeoylquinic acid) and 3,5-dicaffeoylquinic acid, common phenolic compounds in plants of the family Asteraceae. Three were esters of caffeic acid with the hydroxy groups of aldaric acid, derived from hexose. The structure of the aldaric moiety was determined by hydrolysis and comparison of NMR spectra with those of standard aldaric acids. The compounds were novel caffeic acid esters of altraric acid: 2,4-or 3,5-dicaffeoylaltraric acid, 2,5-dicaffeoylaltraric acid, and 2,3,5-or 2,4,5- tricaffeoylaltraric acid.

The chemical species of iodine in seven marine algae Codium fragile, Ulva pertusa, Monostroma nitidum, Gracilaria confervoides, Sargassum Kjellmanianum, Dictyopteris divaricata and Laminaria japonica were studied using neutron activation analysis combined with chemical separation. The contents of total iodine, water-soluble iodine, soluble organic iodine, I- and 103 were determined. The results indicate that the chemical species and contents of iodine in various algae are remarkably different. The highest iodine content of 734 mg/kg (wet basis) was found in Laminaria japonica, with 99.2% of the total iodine being water soluble. The iodine contents of the other six algae are. lower and soluble iodine makes up 16-41% of the total. In the aqueous leachate, iodine is mainly I-, which amounts to 61-93% of total water-soluble iodine; the percentages of organic iodine making up 5.5-37.4%, while the contents of IO3- are the lowest, 1.4-4.5%. This result suggests that the mechanism of iodine enrichment is different for various algae and that its bioavailability varies as well.

2-(3,4-Dihydroxyphenyl)ethanol (DPE), the major phenolic compound in olive oil, may contribute the antioxidative activities and other beneficial effects to olive oil. However, the lack of commercial available DPE and procedures sensitive enough to quantitatively determine DPE in body fluids have limited the bioavailability and metabolism studies on this phenolic compound. In the present study, DPE was synthesized with high yield and high purity and administered orally to rats. DPE concentration in rat plasma, after absorption, was measured using a sensitive GC-MS-SIM method. The results indicated that the highest level of DPE in plasma was detected at 5-10 min after administration. During this period, the concentration of DPE fluctuated widely with the individual.