Antiobesity and antihyperglycemic effects of ginsenoside Rb1 in rats.
OBJECTIVE
Obesity and type 2 diabetes are national and worldwide epidemics. Because currently available antiobesity and antidiabetic drugs have limited efficacy and/or safety concerns, identifying new medicinal agents, such as ginsenoside Rb1 (Rb1) as reported here, offers exciting possibilities for future development of successful antiobesity and antidiabetic therapies.


METHODS
Changes in feeding behavior after acute intraperitoneal administration of Rb1 and the effects of intraperitoneal Rb1 for 4 weeks on body weight, energy expenditure, and glucose tolerance in high-fat diet (HFD)-induced obese rats were assessed. We also examined the effects of Rb1 on signaling pathways and neuropeptides in the hypothalamus.


RESULTS
Acute intraperitoneal Rb1 dose-dependently suppressed food intake without eliciting signs of toxicity. This inhibitory effect on feeding may be mediated by central mechanisms because Rb1 stimulated c-Fos expression in brain areas involved in energy homeostasis. Consistent with this, Rb1 activated the phosphatidylinositol 3-kinase/Akt signaling pathway and inhibited NPY gene expression in the hypothalamus. Four-week administration of Rb1 significantly reduced food intake, body weight gain, and body fat content and increased energy expenditure in HFD-induced obese rats. Rb1 also significantly decreased fasting blood glucose and improved glucose tolerance, and these effects were greater than those observed in pair-fed rats, suggesting that although Rb1's antihyperglycemic effect is partially attributable to reduced food intake and body weight; there may be additional effects of Rb1 on glucose homeostasis.


CONCLUSIONS
These results identify Rb1 as an antiobesity and antihyperglycemic agent.
Xiong
Ye
Y
Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
Shen
Ling
L
Liu
Kristina J
KJ
Tso
Patrick
P
Xiong
Yuqing
Y
Wang
Guangji
G
Woods
Stephen C
SC
Liu
Min
M
D000818:Animals; D019440:Anti-Obesity Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004041:Dietary Fats; D002149:Energy Intake; D005215:Fasting / Q000502:physiology; D005247:Feeding Behavior / Q000187:drug effects; D036145:Ginsenosides / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D005951:Glucose Tolerance Test; D006943:Hyperglycemia / Q000517:prevention & control*; D007274:Injections, Intraperitoneal; D007408:Intestinal Absorption / Q000502:physiology; D020738:Leptin / Q000097:blood; D008297:Male; D009765:Obesity / Q000139:chemically induced / Q000188:drug therapy; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D013649:Taste / Q000187:drug effects / Q000502:physiology
D019440:Anti-Obesity Agents; D001786:Blood Glucose; D004041:Dietary Fats; D036145:Ginsenosides; D020738:Leptin; C442759:ginsenoside Rb1; D019869:Phosphatidylinositol 3-Kinases