Arbutin Content Research Articles

Studies on Resistance of Japanese Pear to Black Spot Disease Fungus (Alternaria kikuchiana TANAKA)

It has been reported that arbutin is one of phenolic compounds in bark, leaf and fruit of Japanese pear, and hydrolyzed into hydroquinone and glucose by β-glucosidase. Six resistant and five susceptible varieties were used to determine the relationship between arbutin content and resistance to black spot disease of Japanese pear. As a result, there was no correlation between amount of arbutin content and resistance to black spot disease.On relationship between leaf age and β-glucosidase activity, its activity was high in young leaf both resistant and susceptible varieties, but not in mature and old leaf in both. β-glucosidase activity was higher in resistant variety than susceptible one. And its activity of resistant variety in very young leaf was 2.3 times more than susceptible one.By injecting with host-specific toxin produced by fungus into very young and young leaves both resistant and susceptible varieties, β-glucosidase activity was inhibited in susceptible variety, but its activity in resistant one was not.It was considered that activity of β-glucosidase in resistant variety is one of the factors of resistance to black spot disease of Japanese pear.

The content of arbutin in some species of the genusSerratula

The content of arbutin in some species of the genusSerratula

Studies on the resistance of Japanese pears to black spot disease fungus (Alternaria kikuchiana TANAKA). VI

Phenoic compounds were separated with chromatographical and chemical techniques from extracts of Japanese pear tissue. And they were identified as arbutin, chlorogenic acid, chlorogenic acid isomers, caffeic acid, quinic acid, catechin and its isomer.The young leaf contained more amount of arbutin, caffeic acid and quinic acid than old one, but did not contain catechins. Much amount of chlorogenic acids were contained in the leaf without any distinction of its age.Infecting with host-specific toxin produce dby the fungus, the young leaf of susceptible variety (Nijusseiki) has been browned at a short time and decreased the content of arbutin and chlorogenic acid. On the other hand, the young leaf of resistant variety (Chojuro) remained green upon the same product treatment and no effect on the content of those phenolic compounds.Reacting the phenolic compounds with polyphenol oxidase extracted from the young leaf of susceptable variety, arbutin and chlorogenic acid were oxidized and browned immediately.So from above results, authors believed that arbutin and chlorogenic acid may have close contact with brown of the leaf infected with that metabolic product.