Han Suk Young

Antimutagenic effect of plant flavonoids in theSalmonella assay system

The antimutagenic effects of 27 kinds of plant flavonoids on the mutagenicity of aflatoxin B1(AFB1) and N-methyl-N′-nitro-N-nitrosoguanidine(MNNG) inSalmonella typhimurium TA100 were investigated. In the mixed applications of AFB1 (1 μg/plate) with the flavonoids (300 μg/plate) in the presence of a mammalian metabolic activation system (S9 mix), chrysin, apigenin, luteolin and its glucoside, kaempferol, fisetin, morin, naringenin, hesperetin, persicogenin, (+)-catechin and (−)-epicatechin showed the antimutagenic effect against AFB1 with more than 70% inhibition rate. A little or no antimutagenicities except flavone against MNNG (0.5 μg/plate) were observed. For the antimutagenicity of the flavonoids on AFB1, the flavonoid structure that contains the free 5-, 7-hydroxyl group seemed to be essential. However, saturation of the 2,3-double bond or elimination of the 4-keto group did not affect the activity.

Flavonoids from the whole plants ofOrostachys japonicus

From the whole plants ofOrostachys japonicus, kaempferol, quercetin, astragalin, quercitrin, isoquercitrin, cynaroside, afzelin, 3-O-α-L-rhamnosyl-7-O-β-D-glucosyl kaempferol, and 3,7-di-O-β-D-glucosyl kaempferol were isolated and characterized by spectral data.

Flavonoids from the leaves ofRhododendron brachycarpum

The flavonoids isolated from the leaves ofRhododendron brachycarpum, were identified as quercetin, avicularin, quercitrin and hyperin.

Hypoglycemic and hypolipemic effects ofIxeris dentata in diabetic rats

Blood glucose and total lipid levels in rats with streptozotocin-induced diabetes were determined after intraperitoneal administration of methanolic extract ofIxeris dentata whole plants and its main component, cynaroside (=luteolin 7-O-β-D-glucoside). From the data obtained, it was concluded that intraperitoneal administration of the methanolic extract produced a significant hypoglycemic effect. Total blood lipids were also decreased. Cynaroside in the streptozotocin-diabetic rats failed to exhibit hypoglycemic effect but a significant hypolipemic activity was observed. Thus, it is suggested that this methanolic extract may contain one or more hypoglycemic and hypolipemic principles including the main flavone glucoside, cynaroside, which can significantly reduce the levels of triglyceride and total cholesterol in streptozotocin-diabetic rats.

Triterpenoid glycosides fromRosa rugosa

From the underground parts ofRosa rugosa(Rosaceae), 28-O-glucosides of euscaphic acid, tormentic acid and arjunic acid were isolated and characterized by spectral data.

Phytochemical study onPrunus davidiana

From the stem ofPrunus davidiana, naringenin and its glucoside, kaempferol and its glucoside, dihydrokaempferol, kaempferide glucoside, hesperetin glucoside, quercetin glucoside, d-catechin and β-sitosterol glucoside were isolated.

Chemical study on the stem ofCudrania tricuspidata

From the stem ofCudrania tricuspidata, β-sitosterol, β-sitosterol glucoside, arthocarpesin, norarthocarpetin, and 5-O-methyl genistein were isolated and characterized by spectral data.

Phenolic compounds of the leaves ofEucommia ulmoides

From the leaves ofEucommia ulmoides, quercetin, astragalin, isoquercitrin, quercetin 3-O-β-D-sambubioside and chlorogenic acid were isolated and characterized by spectral data.

Further study on the constituents ofRhododendron brachycarpum

From the leaves ofRhododendron brachycarpum, rhododendrin, grayanotoxin I and guaijaverin were isolated and characterized by spectral data.

Phytochemical study onCatalpa ovata

From the stem bark ofCatalpa ovata, lupeol, 2(4-hydroxyphenyl)ethyl triacotanoate, a mixture of 9-hydroxy α-lapachone and α-lapachone, 9-methoxy α-lapachone, ferulic acid, 6-feruloyl catalpol, catalposide and 6′-feruloyl sucrose were isolated and identified.