Phytochemical composition and antioxidant properties of baccaurea angulata fruit juice and its effects on cardiovascular disease biomarkers in diet-induced atherosclerotic rabbits

Abstract

Atherosclerosis is the underlying disease process in the blood vessels that usually results in coronary heart disease (CHD) and cerebrovascular disease, which are the most common forms of cardiovascular disease (CVD). A high level of serum cholesterol is mainly identified as an important risk factor in the development and progression of premature atherosclerosis. Previous studies on Baccaurea angulata (BA), a Malaysian underutilized fruit, showed that it is very rich in fiber and antioxidants. The present study was thus undertaken to evaluate the potential health benefits of BA fruit juice on cardiovascular disease biomarkers in diet-induced atherosclerotic rabbits. The studies were carried out in three distinct phases. In phase one, the effect of solvents [methanol and phosphate buffered saline (PBS)] using cold extraction was examined on the total phenolic content (TPC), total flavonoid content (TFC), and total carotene content (TCC), free radical scavenging activities and lipid peroxidation inhibition activities of the various fruit parts (skin, pulp and whole fruit) using spectrophotometer. The results indicated that the methanol crude extracts significantly (p<0.01) contained higher TPC, TFC and TCC than PBS extracts in all the fruits parts. The edible portion had the highest and most significant (p<0.01) TPC (15357.77±150.72 µg gallic acid equivalence (GAE)/g), TFC (37.32±0.55 mg quercetin equivalence (QE)/g), and TCC (6571.43±185.86 µg ?-carotene equivalence (BC)/100 g) [dry weight sample] among the methanol crude extracts. In phase two, thirty-five healthy male adult rabbits (Oryctolagus cuniculus; New Zealand White strain) with a body weight of 2300–2800 g were used. The rabbits were randomly assigned to one of the seven rabbit groups. Four groups were fed cholesterol diet (1% cholesterol) and 0, 0.5, 1.0, and 1.5 mL of juice per kg of rabbit daily (hypercholesterolemic groups), while the other three groups were fed commercial rabbit pellet and 0, 0.5, and 1.0 mL of juice per kg of rabbit per day (normocholesterolemic groups) for 90 days. Blood samples were taken before and after the experimental period. The serum, aorta and liver homogenates were also analyzed for biochemical biomarkers. The results showed that the physiological dysfunctions of the hemopoietic system, caused by the high-cholesterol diet, were significantly (p<0.01) normalized by the administration of BA whole fruit juice, especially at the highest dose (1.5 mL/kg/day). In phase three, histopathological studies were carried out to evaluate the percentage of atherosclerotic lesion accrued using different staining techniques (Hematoxylin & eosin, van Gieson and Sudan IV). The result showed that the supplementation of high-cholesterol diet of the hypercholesterolemic rabbits with only 0.5 mL BA per kg rabbit per day significantly (p<0.001) attenuated aortic fatty streak development. Higher BA fruit juice doses used (1.0 and 1.5 mL per kg rabbit per day) also significantly decreased further the development of aortic fatty streaks. Therefore, the phytochemical composition and antioxidant properties of BA whole fruit juice have substantially proved its potential health benefits as an effective hypocholesterolemic, anti-inflammatory and anti-atherosclerotic agent for the management of CVD biomarkers. Further studies may be needed to corroborate these facts.