Lipid-lowering and antioxidative activities of aqueous extracts of Ocimum sanctum L. leaves in rats fed with a high-cholesterol diet

Abstract

The present study was conducted to investigate the lipid-lowering and antioxidative activities of Ocimum sanctum L. (OS) leaf extracts in liver and heart of rats fed with high-cholesterol (HC) diet for seven weeks. The results shows that OS suppressed the high levels of serum lipid profile and hepatic lipid content without significant effects on fecal lipid excretion. Fecal bile acids excretion was increased in HC rats treated with OS. The high serum levels of TBARS as well as AST, ALT, AP, LDH, CK-MB significantly decreased in HC rats treated with OS. OS suppressed the high level of TABARS and raised the low activities of GPx and CAT without any impact on SOD in the liver. As for the cardiac tissues, OS lowered the high level of TABARS, and raised the activities of GPx, CAT, and SOD. Histopathological results show that OS preserved the liver and myocardial tissues. It can be concluded that OS leaf extracts decreased hepatic and serum lipid profile, and provided the liver and cardiac tissues with protection from hypercholesterolemia. The lipid-lowering effect is probably due to the rise of bile acids synthesis using cholesterol as precursor, and antioxidative activity to protect liver from hypercholesterolemia.

Figure 1

Gain of body weight and food consumption in all groups of rats.

Figure 2

Histopathological appearance of liver (H&E×400). Normal hepatocyte had the round nucleus centrally (arrows); the flat endothelial cells (arrow-heads) are around the central vein (CV) (a). Diffuse vacuolar degeneration and necrosis of hepatocytes (arrows) and markedly focal fibrosis (arrow-head) were shown in HC rat (b). Hepatocytes of HC rat treated with aqueous extracts of OS leaves showed less injury of central vein and less fat vacuole (arrows) comparing to HC rat (c).

Figure 3

Histopathological appearance of myocardial cells (H&E×400). Oval-elongate nucleus centrally and homogeneous cytoplasm (arrows) in normal myocardial cell (a). Multi-focal vacuolar degeneration and necrosis of myocardial cells (arrow-heads) in HC rat (b). Apoptosis of myocardiocytes were also observed (arrow in b). Normal myocardial cell morphology with oval-elongate nucleus centrally and homogeneous cytoplasm (arrows) were shown in myocardiocytes of HC rats treated with aqueous extracts of OS leaves (c).

Figure 4

Histopathological appearance of thoracic aorta (H&E×400). Endotherial cells of normal rats were lining on the tunica intima (TI) (arrow-heads) (a). Most of the medial smooth muscle cells (arrows) of the tunica media (TM) oriented horizontal to the aortic canal. Normal amount of collagen fiber and connective tissue were exhibited in the tunica adventitia (TA). Multifocal degeneration, necrosis and disorientation of smooth muscle cells (arrows) in HC rats were shown (b). Multifocal mononuclear cell infiltration in the aortic wall (arrow -heads ) was also shown. No remarkable lesions of aortic tissue was observed in HC rats treated with aqueous extracts of OS leaves (c). Endothelial cells were lining on the tunica intima (arrow-heads). Most of the medial smooth muscle cells (arrows) of the tunica media oriented horizontal to the aortic canal. Normal amount of collagen fiber and connective tissue were exhibited in the tunica adventitia.