Abstract:
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 hs 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 a-glucosidase activity in vitro, which is suggested
to contribute to the improvement of postprandial hyperglycemia.
