Salacia oblonga improves cardiac fibrosis and inhibits postprandial hyperglycemia in obese Zucker rats.
Diabetes has a markedly greater incidence of cardiovascular disease than the non-diabetic population. The heart shows a slowly developing increase in fibrosis in diabetes. Extended cardiac fibrosis results in increased myocardial stiffness, causing ventricular dysfunction and, ultimately, heart failure. Reversal of fibrosis may improve organ function survival. Postprandial hyperglycemia plays an important role in the development of type 2 diabetes and cardiovascular complications, and has been proposed as an independent risk factor for cardiovascular diseases. Salacia oblonga (S.O.) is traditionally used in the prevention and treatment of diabetes. We investigated the effects of its water extract on cardiac fibrosis and hyperglycemia in a genetic model of type 2 diabetes, the obese Zucker rat (OZR). Chronic administration of the extract markedly improved interstitial and perivascular fibrosis in the hearts of the OZR. It also reduced plasma glucose levels in non-fasted OZR, whereas it had little effect in the fasted animals, suggesting inhibition of postprandial hyperglycemia in type 2 diabetic animals, which might play a role in improvement of the cardiac complications of OZR. Furthermore, S.O. markedly suppressed the overexpression of mRNAs encoding transforming growth factor betas 1 and 3 in the OZR heart, which may be an important part of the overall molecular mechanisms. S.O. dose-dependently inhibited the increase of plasma glucose in sucrose-, but not in glucose-loaded mice. S.O. demonstrated a strong inhibition of alpha-glucosidase activity in vitro, which is suggested to contribute to the improvement of postprandial hyperglycemia.
Herbal Medicines Research and Education Center, Faculty of Pharmacy A15, The University of Sydney, NSW 2006, Australia. yuhao@pharm.usyd.edu.au
Yuhao
Y
Li
Gang
G
Peng
Qian
Q
Li
Suping
S
Wen
Tom Hsun-Wei
TH
Huang
Basil D
BD
Roufogalis
Johji
J
Yamahara
D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D029753:Celastraceae / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D017931:DNA Primers; D004195:Disease Models, Animal; D004719:Endomyocardial Fibrosis / Q000188:drug therapy*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006352:Heart Ventricles / Q000473:pathology; D006652:Histological Techniques; D007003:Hypoglycemia / Q000188:drug therapy*; D008297:Male; D010936:Plant Extracts / Q000627:therapeutic use*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011924:Rats, Zucker; D016212:Transforming Growth Factor beta / Q000378:metabolism; D044004:Xanthones / Q000627:therapeutic use; D000520:alpha-Glucosidases / Q000378:metabolism
D001786:Blood Glucose; D017931:DNA Primers; D010936:Plant Extracts; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D044004:Xanthones; C013592:mangiferin; D000520:alpha-Glucosidases