Masao Hasegawa

The latency of spinach chloroplast phenolase

Abstract The latent phenolase in spinach chloroplast membranes could be activated by treatment with various detergents. Examination by thin-layer gel filtration showed the presence of two active proteins (one with lower MW called protein A and the other, protein B). The protein B was converted to A by dilution or on standing, and the latter conversely to the former by concentration. On freezing, an extract of the acetone powder of the chloroplasts, phenolase activity was strikingly reduced, and this is ascribed to an association of the protein A and a low MW (diffusible) substance giving rise to an inactive enzyme-inhibitor complex. The activity declined from autumn to winter, and it appears that the second type of latency due to the formation of the above complex is also involved.

The formation of polyphenols in trees I. Administration of c glucose and subsequent distribution of radioactivity

Abstract After administration of uniformly labelled 14 C-glucose to a kino vein in Eucalyptus sieberiana , labelled polyphenols were found in the kino. The distribution of radioactivity and the presence of labelled sugars and polyphenols in the sapwood, indicated in situ formation of polyphenols from sugars.

BIOSYNTHESIS OF DIHYDROXYCOUMARINS IN DAPHNE ODORA AND CICHORIUM INTYBUS

Abstract The biosynthesis of daphnin and daphnetin-8-glucoside in Daphne odora and of cichoriin in Cichorium intybus was studied using labelled cinnamic acids as precursors, and it is suggested that these compounds are produced mainly via p-coumaric acid, but not via caffeic acid.

A transglucosylase in Daphne odora converting daphnin to daphnetin 8-glucoside

Abstract The hydrolysis of daphnin (daphnetin 7-glucoside) and the transglucosylation from this glucoside to daphnetin forming daphnetin 8-glucoside have been studied using an enzyme preparation from the flowers of Daphne odora . Both the reactions seem to be controlled by the same enzyme having a high substrate specificity. Some other properties of this enzyme are described.

New indanone compounds from Onychium japonicum

A new indanone glucoside pteroside M has been isolated from fronds of Onychium japonicum Pteridaceae. The structure of its aglycone pterosin M has been established by 13C NMR, PMR spectra and degradation with nitric acid.

Conversion of daphnin to daphnetin-8-glucoside in Daphne odora

Abstract Daphnetin-8-glucoside is found in Daphne odora and an enzyme preparation from the plant was found to be capable of converting daphnin (daphnetin-7-glucoside) to the 8-glucoside.

Flavonoid glycosides from fiveCyathea species

The leaves of 5 fern species of the genusCyathea, i.e.C. fauriei, C. mertensiana, C. leichhardtiana, C. podophylla andC. hancockii, have been chemically analysed.The former 3 species have kaempferol 3-sophoroside (sophoraflavonoloside) and kaempferol 7-rhamnoglucoside as glycosidic components, and the latter 2 species contain kaempferol 3-galactoside (trifolin) and kaempferol 3-rhamnoglucoside (nicotiflorin). In addition, vitexin, orientin, kaempferol 3-glucoside (astragalin), kaempferol 3-rhamnoside (afzelin) and kaempferol 7-arabinoside are detected as common constituents in all the 5 species analysed.

Transglucosylases in Cichorium intybus converting cichoriin to esculin

Abstract The heads of Cichorium intybus contain two enzymes concerned in the formation of esculin (esculetin 6-glucoside) from cichoriin (esculetin 7-glucoside). Both enzymes can catalyse two reactions, i.e. hydrolysis (HD) of cichoriin to give esculetin, and transglucosylation (TG) from this glucoside to the liberated aglucone forming esculin. One of them, designated enzyme A, is a high molecular weight protein with predominantly TG activity, and dissociates during isolation into the other enzyme having higher HD activity. Enzyme A shows high substrate specificity and different pH optima in HD and TG reactions, as in the case with the transglucosylase from Daphne odora.

Distribution of stizolamine in some leguminous plants

Abstract The seeds of 38 species of 29 genera in 21 tribes of the Leguminosae were screened for stizolamine. It was detected in 19 species of the subfamily Lotoideae. Its occurrence in Lotoideae was wide (82% in tribes, 56% both in genera and species) but sporadic. The content was fairly varied (0·249–9540 nmol/g of seeds), the largest amount occurring in Stizolobium hassjoo.

Microbial Degradation of Bergenia, a Phenolic C-Glucoside

A strain of soil bacteria was isolated by elective culture with bergenia, a C-glucoside having dihydroisocoumarin structure, as a sole carbon source, and was identified as Erwinia herbicola. In growth or replacement medium, the bacterium degraded bergenin to yield at least two major degradation products, one of them being identified as 4-O-methylgallic acid (compound I), an aglycone of bergenin. The bacterium seemed to utilize the sugar moiety of bergenin preferentially as carbon and energy sources, since the rate of further transformation of compound I by the bacterium was slow. In replacement culture with compound I, gallic acid was detected as one of the metabolites. A possible pathway for microbial degradation of bergenin is proposed.