IWABUCHI Setuko Tohoku University, Faculty of Agriculture, 農学部, 助手 (50089794)
OKUBO Kazuyoshi Tohoku University, Faculty of Agriculture, Professor, 農学部, 教授 (00005612)
須山 享三 東北大学, 農学部, 助教授 (70005635)
|Budget Amount *help
¥16,800,000 (Direct Cost : ¥16,800,000)
Fiscal Year 1995 : ¥6,900,000 (Direct Cost : ¥6,900,000)
Fiscal Year 1994 : ¥9,900,000 (Direct Cost : ¥9,900,000)
There are many reports on the enzymatic defense of plant kingdom against active oxygen radicals such as SOD (super oxide dismutase), but no report on the non enzymatic mechanism. Also, measurement of active oxygen radicals have been done by electron spin resonance (ESR) and enzymatic methods, but recently we have found photon emission in the presence of hydroperoxide and acetaldehyde.
Oxygen-radical-scavenging characteristics of DDMP (2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one) conjugated saponins in legumenous plants will be the focus of this research. We have isolated genuine saponins, soyasaponins alphag, betag, betaa, gammag and gammaa from soybean, and soyasaponin alphaa from scarlet runner bean. Also soyasaponin betag was isolated from rootstock of the American groundnut. The structure was identified by ^1H-NMR and ^<13>C-NMR and by chemical techniques. A high concentration of DDMP saponin was observed around the cell in fibrovascular bundles connecting the stem to the plumule.
The chemiluminescence (CL) of catechins were measured in the presence of active oxygen species and acetaldehyde (MeCHO). (-) -Epigallocatechin (EGC) exhibited the strongest CL among flavonoids, anthocyanins and catechins. The CL intensity, P,was dependent on the concentrations of active oxygen species, X,such as H_2O_2, catalytic species, Y,such as EGC and receptive species, Z,such as MeCHO as follows ; p=k[X] [Y] [Z] (k ; photon constant). DDMP saponins showed oxygen-radical-scavenging activity assayd by using the xanthin oxidase-NH2OH methods, ESR and chemiluminescence. One milligram of DDMP saponin/mg exhibited superoxide-scavenging activity of a degree equvalent to 17.1 units of superoxide dismutase/ml measured by the ESR spin trappin method. We have found that group A and DDMP saponins are Y equivalent to EGC and Z equivalent to MeCHO,respectively.