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Antioxidative activity of pea bean (Phaseolus vulgaris L.) extract was evaluated by using a linoleic acid system, and the methanol extract exhibited strong antioxidative activity as measured by the thiocyanate method. The crude methanol extract was partitioned between the n-butanol phase (BP) and the water phase (WP). Then, the antioxidative activity of the BP and the WP was determined by using a linoleic acid system. The WP showed strong antioxidative activity, while BP showed only weak activity as measured by the thiocyanate method. Next, the synergistic antioxidative action of WP with a-tocopherol was examined by using linoleic acid and iiposome systems. The WP had a synergistic effect with a-tocopherol in both the food model and liposome systems. For purification and isolation of the antioxidative substances of the pea bean, preparative high-performance liquid chromatography was carried out with an octadecylsilyl column. Five fractions were collected, and antioxidative activity was determined in a linoleic acid system. Although fraction 1 had strong activity by the thiocyanate method, the purification of this active fraction was difficult; therefore, the partly characte~ ized active fraction was investigated. The contents of total phenolics and sugars were 0.31 _+ 0.01 mg/g of fraction 1 and 406.1 +_ 0.1 rag/g, respectively. The ninhydrin chromogenic reaction was positive, and the ultraviolet absorption spectral ~ max value in distilled water was 264.0 nm, indicating that the water-soluble antioxidative components from pea bean may be a new type of antioxidant. Isolation and identification are currently being investigated.KEY WORDS: Antioxidant, Phaseolus vulgaris L., synergistic effect.Lipid peroxidation is known as one of the major factors in the deten'oration of foods dttH_ng storage and processing. In addition, it is thought to induce physiological obstruction causing cell aging or carcinogenesis (1). The addition of antioxidants has become popular as a means of increasing the shelf life of food products and improving the stability of lipids and lipid-containing foods by preventing loss of sensory and nutritional quality.Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) have been used widely in foods but are suspected to be carcinogenic (2,3). Tocopherols and ascorbic acid are now widely used as safe natural antioxidants. However, the antioxidant activities of tocopherols and ascozbic acid are lower than those of synthetic antioxidants. Hence much research has been conducted to find safe antioxidants with high antioxidative activity from natural sources (4-9).Pea bean (Phaseotus vulgaris L.) is cultivated throughout the world for its pods and seeds and consumed in various dishes. However, there are few reports about the antioxidative activity of pea bean extract. The effects of navy bean (P. vulgaris L.) hull extract on the oxidative stability of edible oil were reported by Onyeneho and Hettiarachchy (10), but this report did not include chemical studies of the bean antioxidants.In this pa...

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SummaryLipid peroxidation of liposome made of egg lecithin was induced by glucosone (D-arabino-hexos-2-ulose), a secondary product of Maillard reaction or glycation of protein. Lipid peroxidation was assessed with measurement of TBARS (thiobarbituric acid reacting substances), POV (peroxide value), and HPLC measurement of MDA (malondialde hyde).EDTA and DTPA (diethylenetriamine-pentaacetic acid) in hibited the lipid peroxidation assessed by each method described above, indicating involvement of metal ions. The observed reduction of Fe3+ to Fe2+ by glucosone might be a critical step of the lipid peroxidation. Our findings suggest a possible role of lipid peroxidation of low-density lipo proteins (LDL) induced by glucosone in atherosis caused by diabetes mellitus.

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We compared the cytotoxicity of hydrogen peroxide (H2O2), tertiary butyl hydroperoxide (t-BHP) and methyl linoleate hydroperoxide (MLHP) to V79 cells, using a colony formation assay. In all cases L-buthionine-(S,R)-sulphoximine enhanced the cytotoxicity, and Quin 2 inhibited it. Nordihydroguaiaretic acid (NDGA) and o-phenanthroline suppressed the cytotoxicity of H2O2 and t-BHP, but they had no effect on the cytotoxicity of MLHP. These results suggest that the biological effects of t-BHP are similar to those of H2O2 and not to those of lipid hydroperoxides. In the course of the experiments, we found that NDGA, an antioxidant and food additive, was a potent inhibitor of cytotoxicity of H2O2.

SummaryGlucosone (D-arabino-hexos-2-ulose), a typical enediol prod uct formed both in the Maillard reaction and Tradiolysis of sugars, decreased survival of Chinese hamster lung V79 cells, which were in cubated under MEM for 4h. Inhibition of the decrease in cell servival by catalase and SOD suggests the role of active oxygen species, namely H2O2 and O2-, in the biological effects of glucosone. H2O2 was formed in the medium during oxidative degradation of glucosone. Inhibition of the formation of H2O2 by SOD indicates that the formation of H2O2 and the consequent decrease of the cell survival was enhanced by O2-. These results suggest that the mechanisms of the effects of glucosone on the mammalian cells in the absence of Cu2+ are different from those in the presence of Cu2+.

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