A licorice ethanolic extract with peroxisome proliferator-activated receptor-gamma ligand-binding activity affects diabetes in KK-Ay mice, abdominal obesity in diet-induced obese C57BL mice and hypertension in spontaneously hypertensive rats.
The metabolic syndrome, including type 2 diabetes, insulin resistance, obesity/abdominal obesity, hypertension and dyslipidemia, is a major public health problem. Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligands such as thiazolidinediones are effective against this syndrome. In this study, we showed that nonaqueous fractions of licorice (Glycyrrhiza uralensis Fisher) extracted with ethanol, ethyl acetate and acetone, but not an aqueous extract, had PPAR-gamma ligand-binding activity with a GAL4-PPAR-gamma chimera assay. Some prenylflavonoids including glycycoumarin, glycyrin, dehydroglyasperin C and dehydroglyasperin D, a newly found compound, were identified as active compounds with PPAR-gamma ligand-binding activity in the nonaqueous fraction of licorice. A licorice ethanolic extract contained these four active compounds at a total concentration of 16.7 g/100 g extract. Feeding the licorice ethanolic extract at 0.1-0.3 g/100 g diet [approximately 100 to 300 mg/(kg body x d)] for 4 wk decreased (P < 0.05) blood glucose level in younger (6 wk old) and older (13 wk old) diabetic KK-Ay mice and reduced (P < 0.05) weights of intra-abdominal adipose tissues in high fat diet-induced obese C57BL mice. An increase in blood pressure in spontaneously hypertensive rats was suppressed (P < 0.01) by 3 wk of oral administration of the licorice ethanolic extract at 300 mg/(kg body x d). These findings indicate that licorice ethanolic extract is effective in preventing and ameliorating diabetes, ameliorating abdominal obesity and preventing hypertension, and suggest that licorice ethanolic extract would be effective in preventing and/or ameliorating the metabolic syndrome.
Mae
Tatsumasa
T
Functional Foods Development Division, Life Science RD Center, Kaneka Corporation, Takasago, Hyogo 676-8688, Japan. Tatsumasa.Mae@kn.kaneka.co.jp
Kishida
Hideyuki
H
Nishiyama
Tozo
T
Tsukagawa
Misuzu
M
Konishi
Eisaku
E
Kuroda
Minpei
M
Mimaki
Yoshihiro
Y
Sashida
Yutaka
Y
Takahashi
Kazuma
K
Kawada
Teruo
T
Nakagawa
Kaku
K
Kitahara
Mikio
M
D000085:Acetates; D000096:Acetone; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002460:Cell Line; D002522:Chlorocebus aethiops; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000235:genetics / Q000517:prevention & control; D004041:Dietary Fats; D000431:Ethanol; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D006035:Glycyrrhiza; D008024:Ligands; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D009765:Obesity / Q000517:prevention & control; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots; D010957:Plasmids; D051381:Rats; D011918:Rats, Inbred SHR; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000187:drug effects; D045162:Thiazolidinediones / Q000494:pharmacology*; D014157:Transcription Factors / Q000187:drug effects / Q000502:physiology*; D014162:Transfection
D000085:Acetates; D001786:Blood Glucose; D004041:Dietary Fats; D005419:Flavonoids; D008024:Ligands; D010936:Plant Extracts; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; D045162:Thiazolidinediones; D014157:Transcription Factors; D000096:Acetone; D000431:Ethanol; C007650:ethyl acetate