Isorhamnetin health benefit and published trials

Quercetin and isorhamnetin are common constituents of some herb extracts, such as extracts of gingko leaves and total flavones of Hippophae rhamnoides L.

Isorhamnetin and adipose tissue
Isorhamnetin Represses Adipogenesis in 3T3-L1 Cells.
Obesity (Silver Spring). 2009 Feb; Biospectrum Life Science Institute, Gunpo City, Gyunggi Do, Republic of Korea, Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul, Republic of Korea.
Adipocyte dysfunction is strongly associated with the development of obesity, which is a major risk factor for many disorders including diabetes, hypertension, and heart disease. It is generally accepted that the regulation of adipogenesis or adipokines expression prevents obesity. In this study, we show that isorhamnetin inhibits adipocyte differentiation, as evidenced by reduced triglyceride accumulation and glycerol-3-phosphate dehydrogenase activity. Our results indicate that isorhamnetin inhibits adipogenesis through downregulation of PPAR-gamma and C/EBP-alpha.

Isorhamnetin antioxidant studies
Comparison of the preventive activity of isorhamnetin glycosides from atsumi-kabu (red turnip, Brassica, campestris L.) leaves on carbon tetrachloride-induced liver injury in mice.
Biosci Biotechnol Biochem. 2008 March. Igarashi K, Mikami T, Takahashi Y, Sato H. Department of Bioresource Engineering, Faculty of Agriculture, Yamagata University, 1-23 Wakaba-machi, Tsuruoka-shi, Yamagata 997-8555, Japan.
Isorhamnetin 3-O-glucoside, which is contained together with isorhamnetin 3,7-di-O-glucoside in atsumi-kabu leaves, suppressed increases in the plasma ALT and AST activities of mice with liver injury induced by the injection of carbon tetrachloride, but no suppression by isorhamnetin 3,7-di-O-glucoside was apparent. This result indicates that the release of glucose at the 7-position in isorhamnetin 3,7-di-O-glucoside was very important to mitigating liver injury.

Isorhamnetin is a good antioxidant
Inhibitory effect of isorhamnetin and hesperidin on the oxidation of high-density lipoproteins (HDL) induced by Copper.
Sichuan Da Xue Xue Bao Yi Xue Ban. 2007 Nov. Division of Peptides Related with Human Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China.
To test the inhibitory effect of isorhamnetin and hesperidin on the HDL oxidation induced by Cu2+. The serum HDL was isolated by the one step density gradient ultracentrifugation. The HDL oxidation was induced by Cu2+ in vitro for different length of periods. Isorhamnetin and hesperidin at 5 micromol/L, respectively, were added 3 h before the copper oxidation. Both isorhamnetin and hesperidin inhibit the oxidation of HDL, but isorhamnetin was stronger.

Effect of storage and processing
Quercetin and isorhamnetin in sweet and red cultivars of onion (Allium cepa L.) at harvest, after field curing, heat treatment, and storage.
J Agric Food Chem. 2010 Feb 24; Olsson ME, Gustavsson KE, Vågen IM.Department of Horticulture, Swedish University of Agricultural Sciences, PO Box 103, SE-230 53 Alnarp, Sweden.
Effects of heat treatment and storage on quercetin and isorhamnetin content, major and minor components of isorhamnetin, and quercetin glucosides and aglycone, were investigated in onion (Allium cepa L.). The sweet onion 'Recorra' and red onions 'Hyred' and 'Red Baron' were cultivated in the south part of Norway and thereafter stored for eight months. The onions were either not field dried, but stored directly, or field dried and then stored, or field dried and then heat treated before storage. Neither storage nor heat treatment caused any major differences in total flavonol content in the investigated sweet onion as well as in the red onion cultivars. The two major quercetin glucosides differed in their changes in content during storage; quercetin-4'-glucoside did not show any consistent changes during storage in the two red cultivars, independent of treatment, whereas quercetin-3,4'-diglucoside increased significantly by 30 or 51%, respectively, during storage in 'Hyred' and 'Red Baron' in the 24 h heat treated onions. Isorhamnetin-4'-glucoside, which might possibly be of special interest from a human health point of view, was present at 2-3 times higher amount in the sweet onion cultivar than in the two red cultivars. Some of the quercetin glucosides present at lower concentrations, isorhamnetin-3,4'-diglucoside, quercetin-3,7,4'-triglucoside, and quercetin-7,4'-diglucoside, increased during storage in all treatments in both 'Hyred' and 'Red Baron', though sometimes a decrease was found at the end of storage.

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