Radish Extract Research Articles

Structure of l-arabino- d-galactan-containing glycoproteins from radish leaves

Two l-arabino- d-galactan-containing glycoproteins having a potent inhibitory activity against eel anti-H agglutinin were isolated from the hot saline extracts of mature radish leaves and characterized to have a similar monosaccharide composition that consists of l-arabinose, d-galactose, l-fucose, 4- O-methyl- d-glucuronic acid, and d-glucuronic acid residues. The chemical structure features of the carbohydrate components were investigated by carboxyl group reduction, methylation, periodate oxidation, partial acid hydrolysis, and digestion with exo- and endo-glycosidases, which indicated a backbone chain of (1→3)-linked β- d-galactosyl residues, to which side chains consisting of α-(1→6)-linked d-galactosyl residues were attached. The α- l-arabinofuranosyl residues were attached as single nonreducing groups and as O-2- or O-3-linked residues to O-3 of the β- d-galactosyl residues of the side chains. Single α- l-fucopyranosyl end groups were linked to O-2 of the l-arabinofuranosyl residues, and the 4- O-methyl-β- d-glucopyranosyluronic acid end groups were linked to d-galactosyl residues. The O-α- l-fucopyranosyl-(1→2)-α- l-arabinofuranosyl end-groups were shown to be responsible for the serological, H-like activity of the l-arabino- d-galactan glycoproteins. Reductive alkaline degradation of the glycoconjugates showed that a large proportion of the polysaccharide chains is conjugated with the polypeptide backbone through a 3- O- d-galactosylserine linkage.

STUDIES ON THE CAPACITY OF pR IN VITRO TO PHOTOCONVERT TO THE LONG‐WVELENGTH Ffr‐FORM. A SURVEY FO TEN PLANT SPECIES*

AbstractStudies on the capacity of Pr in uitro to photoconvert to the long wavelength in uioo‐like Pfr form were performed with extracts from 10 species. Red irradiation, immediately after extraction of crude extracts from 9 species, photoconverted Pr to long‐wavelength Pfr with an absorbance maximum around 735 nm. Red irradiation of soybean extracts, however, photoconverted Pr to short‐wavelength Pfr, with an absorbance maximum at 725 nm. Red irradiation given later than 1.5‐2 h after extraction, to extracts of oats, pea, cucumber, radish, sunflower and soybean, photoconverted Pr to a short‐wavelength Pfr species with an absorbance maximum around 725 nm. In crude extracts of barley, corn, wheat and zucchini, red irradiation, even after a long dark‐incubation period at 4°C of up to 48 h, photoconverted Pr to long‐wavelength Pfr with an absorbance maximum around 735 nm. After incubation at 25°C for 3 h, however, Pr from barley also photoconverted to the short‐wavelength form. It is suggested that in the group exemplified by oats, Pr rapidly undergoes an alteration following extraction, which results in the loss of the capacity of Pr to photoconvert to long‐wavelength Pfr. In contrast, in extracts from the group exemplified by barley, Pr is much more stable and retains the capacity to photoconvert to long‐wavelength Pfr for much longer periods.

The Formation of Phenolic Acids in the Root of Downy Mildew-Infected Japanese Radish

Quinic, prephenic, phenylpyruvic, trans-cinnamic, p-coumaric, and caffeic acids were identified by gas-liquid chromatography in the root extract of Japanese radish infected by Peronospora parasitica. Ferulic and sinapic acids were not detected. These phenolic acids detected did not originate from the infecting hyphae but from the host cells. These phenolic acids were not detected in the healthy root. Since the phenolic acids are considered to be precursors of lignin, the relationship between the phenolic acids detected and lignin formation in the infected plants was discussed.