Yoshihide Hagiwara’s research while affiliated with Kumamoto University and other places

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The degradation of the organophosphorus pesticides malathion, chlorpyrifos, guthion, diazinon, methidathion and parathion in an aqueous extract of young green barley leaves (Hordeum vulgare L) was monitored by gas chromatography. Aqueous solutions of various amounts of freeze-dried young barley leaves containing 5.75 mg l−1 of malathion were incubated at 37 °C and pH 7.4 over prolonged time periods. Over 95% of the malathion degraded in 4 h in a 3% (30 g l−1) solution of young green barley leaves. When the barley solution was autoclaved at 120 °C for 25 min prior to the addition of malathion, no degradation of malathion was observed. When 10 mg l−1 each of the above six pesticides was incubated in a 15% (150 g l−1) solution of young green barley leaves for 3 h at 37 °C and pH 7.4, malathion and chlorpyrifos degraded 100%, whereas parathion (75%), diazinon (54%), guthion (41%) and methidathion (23%) showed lesser degrees of degradation. © 1999 Society of Chemical Industry

Three new saponarin analogs, 6'''-sinapoylsaponarin, 6'''-feruloysaponarin and 4'-glucosyl-6'''-sinapoyl-saponarin were isolated together with four known compounds from young green barley (Hordeum vulgare var. nudum) leaves. Their anti-oxidative effects towards superoxide, photo-oxidation of vitamins and the 1, 1-diphenyl-2-picrylhydrazyl radical were tested. The superoxide-scavenging activity depended on the number of free hydroxy groups. In contrast, the inhibition of vitamin oxidation seemed to be due to the flavone skeleton. In addition, the sinapoyl moiety seemed to be important for radical-scavenging activity.

Beer samples were stored at 50 °C for 90 days, and the amount of acetaldehyde in the samples was measured periodically by gas chromatography. Acetaldehyde in the beer sample was derivatized to 2-methylthiazolidine with cysteamine and quantitatively analyzed with a gas chromatograph equipped with a fused silica capillary column and a nitrogen−phosphorus detector. All beer samples contained acetaldehyde ranging from 30 to 80 μM before storage. The concentration of acetaldehyde in beer samples increased by 873% after 90 days of storage. Significant formation of off-flavor was observed in these samples. When a beer sample was stored at 50 °C for 10 days with 1 1 μg/mL of 2‘‘-O-glycosylisovitexin and butylated hydroxytoluene, the acetaldehyde content was reduced by 60 and 15%, respectively. On the other hand, addition of 1 μg/mL of α-tocopherol increased the acetaldehyde content by 18%. Keywords: Acetaldehyde; antioxidants; beer deterioration; off-flavor

The inhibitory effect of α-tocopherol, β-carotene, 2″-O-glycosyl isovitexin (2″-O-GIV), and butylated hydroxytoluene (BHT) on malonaldehyde (MA) formation from ω3 polyunsaturated fatty acids (PUFA) was determined by gas chromatography. The levels of MA formed from 1 mg each of octadecatetraenoic acid (ODTA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) upon oxidation with Fenton's reagent were 29.8±1.5, 17.2±1.5, and 22.0±0.7 nmol, respectively. BHT was most effective toward protecting all three ω3 PUFA, whereas β-carotene did not exhibit any inhibitory effect. 2″-O-GIV inhibited MA formation from EPA and DHA by 56 and 43%, respectively, showing the second greatest inhibitory activity after BHT. α-Tocopherol inhibited MA formation from ODTA and DHA by 67 and 28%, respectively, but it did not show any activity toward EPA oxidation. The naturally occurring antioxidant, 2″-O-GIV, may be useful to prevent oxidation of ω3 PUFA.

We have previously reported the isolation of a vitamin E analog (α-tocopherol succinate) from a green barley leaf extract, which stimulates the release of prolactin and growth hormone from rat anterior pituitary cells in vitro. In the present study, we tested the commercially available forms of a-tocopherol and also succinic acid. Normal anterior pituitary cells were treated with different commercially available forms of tocopherol (100 μg/ml) and succinic acid (50 to 100 μg/ml). Only α-tocopherol succinate caused a significant increase (P <0.01) in prolactin release. In addition, α-tocopherol, δ-tocopherol, α-tocopherol acetate, α-tocopherol nicotinate, succinic acid disodium salt, and succinic acid butenedoic acid did not affect the prolactin release in vitro. The data demonstrate that of all the biologically active forms of vitamin E, only α-tocopherol succinate possesses the ability to enhance anterior pituitary hormone release in vitro.

Green barley leaf extract, a dried extract of young green barley leaves, is widely used in Japan and other countries as a nutritional supplement. We have recently reported (Badamchian, et.al J. Nutr. Bioc. 5:145-150, 1994), the isolation of a vitamin E analog from green barley leaf extract that stimulates release of prolactin and growth hormone from rat anterior pituitary cells in vitro. This molecule was identified as α-Tocopherol succinate, an analog of α-Tocopherol, or vitamin E. In the present study we tested the commercially available forms of α-Tocopherol and also succinic acid. Treatment of normal anterior pituitary cells with different forms of tocopherol (100μg/ml) and succinic acid (50-100μg/ml) caused significant increase (p<0.01) in prolactin and growth hormone release in only α-Tocopherol succinate-treated cells. α-Tocopherol, δ-Tocopherol, α-Tocopherol acetate, α-Tocopherol nicotinate, succinic acid disodium salt, and succinic acid butenedoic acid did not effect the prolactin and growth hormone release in vitro. Supported by a gift from Hagiwara Institute of Health, Hyogo, Japan.

The inhibitory effect of 2"-O-glycosyl isovitexin (2"-O-GIV), isolated from young barley leaves, on glyoxal formation from the oxidative degradation of three fatty acid ethyl esters was measured. Ethyl linoleate, ethyl linolenate and ethyl arachidonate were oxidized by Fenton's reagent. Glyoxal formed from these fatty acid esters was analysed by gas chromatography after it had been derivatized to quinoxaline with 1,2-phenylenediamine. The comparative study was performed using alpha-tocopherol. Generally, alpha-tocopherol exhibited a greater inhibitory effect at lower levels, whereas 2"-O-GIV showed a greater effect than alpha-tocopherol at higher levels. 2"-O-GIV was more effective than alpha-tocopherol towards fatty acid esters with high numbers of double bonds. 2"-O-GIV exhibited a dose-response effect but alpha-tocopherol did not. Maximum inhibition of 82% was obtained from oxidation of ethyl arachidonate at 8 mumol 2"-O-GIV, whereas maximum inhibition of 77% was observed from oxidation of ethyl arachidonate at 0.25 mumol alpha-tocopherol.

Many aldehydes formed from lipid peroxidation are reportedly implicated in various diseases, including arteriosclerosis. Lecithin, a blood plasma lipid, and cod liver oil (known to have a beneficial effect on coronary artery disease) were oxidized by Fenton's reagent. The oxidation products, malonaldehyde (MA) and glyoxal, were analyzed in the presence of alpha-tocopherol or 2''-O-glycosylisovitexin (2''-O-GIV) by gas chromatography after derivatization to 1-methylpyrazol and quinoxaline, respectively. alpha-Tocopherol inhibited MA and glyoxal formation effectively from 5 mg of lecithin at low doses (1 mu mol), whereas 2''-O-GIV required 6 mu mol to produce the same level of inhibition. However, alpha-tocopherol did not exhibit a satisfactory effect in the case of cod liver oil compared with 2''-O-GIV. Moreover, addition of alpha-tocopherol to cod liver oil increased glyoxal formation slightly. The results of the present study suggested that 2''-O-GIV is an excellent antioxidant for fish oils.