Abstract
Effects of purpurogallin (PPG), an antioxidant on high cholesterol diet-induced atherosclerosis,
and changes in blood lipid profile and lipid peroxidation product malondialdehyde
(MDA), aortic tissue MDA, chemiluminescence (M-CL), a marker for antioxidant reserve
and antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), and glutathione
peroxidase (GSH-Px )] were investigated in rabbits. The rabbits were divided into three groups: Group
I, regular rabbit chow; Group II, same as Group I+cholesterol (1%); and Group III,
same as Group II+PPG (14 mg/kg, orally, daily). Serum concentrations of triglycerides
(TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density
lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C),
and blood MDA were measured before and after 4 and 10 weeks on the respective diets.
The aorta was removed at the end of 10 weeks for assessment of atherosclerotic changes,
MDA concentration, M-CL, and antioxidant enzymes. Coronary arteries were also examined
for atherosclerotic changes. Serum TC, LDL-C, and LDL-C/HDL-C ratio increased whereas
HDL-C decreased in Group II and their values were similar in Groups II and III. Aortic
tissue MDA, M-CL, CAT, and GSH-Px activity increased in Group II but these values in Group III were lower than in Group
II except for MDA which was greater in Group III than in Group II. Atherosclerotic
changes were greater in Group II than in Group III. Histological changes were similar
in Groups II and III. Atherosclerotic changes were also observed in the coronary arteries
of Groups II and III, however, they were less in Group III than in Group II. Increased
levels of aortic MDA and decreased levels of antioxidant reserve, which were associated
with the development of atherosclerosis, suggest a role for oxygen radicals in the
pathogenesis of hypercholesterolemic atherosclerosis. The protection afforded by PPG,
which was associated with reversal of the antioxidant reserve to control level, in
spite of hypercholesterolemia, supports the hypothesis that oxygen radicals are involved
in the development of hypercholesterolemic atherosclerosis. These results suggest
that PPG retard the development of hypercholesterolemic atherosclerosis because of
its antioxidant activity without lowering blood cholesterol level.
