Background and objective: Cadmium (Cd) is a toxic
heavy metal which causes oxidative damage to various
tissues and associated with hypertension. Antioxidants
have been used to protect against Cd intoxication.
Asiatic acid (AA) is a pentacyclic triterpenoid extracted
from Bua-Bok (Centella asiatica) and possesses
strong antioxidant activities. This study aimed to investigate
whether AA could attenuate hypertension
and oxidative stress in rats chronically exposed to Cd.
Methods: Male Sprague-Dawley rats were exposed
to Cd daily via consumption of water containing 10
ppm cadmium chloride for 16 weeks. Rats in the
control groups received deionized water as drinking
water. AA (15 or 30 mg/kg b.w.) was orally administered
once daily for the last 4 weeks of the experiment.
Results: Cd induced hypertension in rats by increasing
arterial blood pressure and peripheral vascular resistance.
Cd significantly attenuated the vasodilating
responses to acetylcholine (p < 0.05) while the vasodilating
responses to sodium nitroprusside were unchanged.
AA in a dose-dependent manner significantly
improved hemodynamics and increased
endothelial-dependent responses (p < 0.05). AA alleviated
oxidative stress, enhanced blood glutathione
and increased plasma nitrate/nitrite level. Moreover,
AA also reduced the accumulation of Cd in blood and
vascular tissues.Conclusions: These results suggest that AA is a pro tective antioxidant against Cd-induced hypertension,
endothelial dysfunction and oxidative stress