| Abstract: | Hypercholesterolemia, low HDL-C and oxygen radicals have been implicated in the
development of atherosclerosis. Lignan complex isolated from flaxseed (Linum usitatissimum Linn., Linseed, Hindi —
Alsi) contains
secoisolariciresinol diglucoside (SDG), 3-hydroxy-3methylglutaric acid (HMGA)
and cinnamic acids. SDG and cinnamic acids are antioxidants and HMGA is a
hypocholesterolemic agent. Antioxidants are known to reduce hypercholesterolemic
atherosclerosis. Researchers at Department of Physiology, College of Medicine,
University of Saskatchewan, Saskatoon, Sask., Canada carried out studies to
determine if lignan complex reduces (i) serum cholesterol, (ii) oxidative stress
and (iii) atherosclerosis in hypercholesterolemic rabbits. Rabbits were assigned
to four groups: Group I, control; Group II, lignan complex control (lignan
complex, 40mg/kg body wt daily orally); Group III, 0.5% cholesterol; Group IV,
0.5% cholesterol diet+lignan complex, (40mg/kg body wt daily orally). Blood
samples were collected before (time 0) and after 1 and 2 months of experimental
diets for measurement of serum triglycerides (TG), total cholesterol (TC),
LDL-C, HDL-C and serum malondialdehyde (MDA), a lipid peroxidation product. At
the end of the protocol, the aorta was removed for measurement of
atherosclerotic plaques, MDA and aortic tissue chemiluminescence (Aortic CL), a
marker of antioxidant reserve. Rabbits in Group III developed atherosclerosis
(50.84±6.23% of the intimal surface of the aorta was covered with
atherosclerotic changes) which was associated with an increase in the serum TG,
TC, LDL-C, HDL-C, MDA and aortic MDA and antioxidant reserve. Lignan complex
reduced the development of atherosclerosis by 34.37% and this was associated
with a decrease in serum TC by 20%, LDL-C by 14%, TC/HDL-C by 34%, serum MDA by
35% and aortic MDA by 58%. Serum HDL-C was elevated by 30% in
hypercholesterolemic rabbits and by 25% in normocholesterolemic rabbits with
lignan complex. Lignan complex did not affect the TC and LDL-C and serum MDA in
the normocholesterolemic rabbits. However, it increased the aortic MDA in the
normocholesterolemic rabbits. |
