In vivo antioxidant potential and cardioprotective activities of baccaurea angulata fruit in relation to suppressed inflammatory response

Abstract

Cardiovascular diseases remain the single leading cause of deaths globally. Diet rich in fruits and vegetables is highly important in the maintenance of best possible cardiovascular health. Malaysia has a variety and large quantity of underutilized fruits which are rich in phenolic compounds. In the present study, cardiovascular protective effects of an underutilized Baccaurea angulata fruit were studied using a cholesterol-fed rabbit model. The study was divided into 5 parts. The objective of part one was to identify and quantify some phenolic compounds in the methanolic extracts of B. angulata whole fruit (WF), skin (SK) and pulp (PL). By using the ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC/MS-MS) based approach, a total of 17 compounds were detected and characterized on the basis of their chromatographic retention time, UV-vis spectra and mass spectra in the negative-ion mode and data from the literature. Part two was aimed at evaluating the effects of WF, SK and PL juices of B. angulata administered at a nutritional dose of 1 ml/kg/day on malondialdehyde (MDA) levels and antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) as well as on total antioxidant capacity (TAC) in rabbits fed with high-cholesterol diet for 12 weeks. The results showed that B. angulata fruit had modulating effects on lipid peroxidation and antioxidant enzyme activities in rabbits fed with high-cholesterol diet. It significantly (p<0.05) lowered the concentrations of plasma MDA. SOD, GPX, CAT and TAC decreased with cholesterol feeding and recovered with B. angulata juice administrations. The purpose of part three was to evaluate and compare the effects of three different B. angulata WF juice doses administered at nutritional doses of 0.5 ml/kg/day, 1 ml/kg/day and 1.5 ml/kg/day on serum, aorta & liver MDA levels, antioxidant enzymes (SOD, GPx and CAT) as well as on total antioxidant capacity in rabbits fed with cholesterol diet for 12 weeks. The results showed that higher doses (1 ml/kg/day and 1.5 ml/kg/day) of B. angulata WF juice exerted better antioxidant activity. Part four of the study was aimed at evaluating and comparing the effects of three different B. angulata WF juice concentrations administered at nutritional doses of 0.5 ml/kg/day, 1 ml/kg/day and 1.5 ml/kg/day on 12 serum, aorta & liver inflammatory biomarkers of atherosclerosis such as vascular cell adhesion molecule 1 (VCAM-1), intercellular cell adhesion molecule 1 (ICAM-1), P-selectin, C-reactive protein (CRP), IL-1, IL-2, IL-6, IL-7, IL-8, IL-10, IL-18, and tumor necrosis factor α (TNF- α) in rabbits fed with cholesterol diet for 12 weeks. The results showed that B. angulata inhibited inflammatory biomarkers of atherosclerosis. Lastly, the aim of part five was to investigate the plaque-reducing activities of B. angulata fruit as a new anti-atherogenic plant in high-cholesterol fed rabbits for 12 weeks. Rabbits fed with cholesterol diet only successfully developed severe, extensive and more densely distributed human-like atherosclerotic lesions. However, supplementation of B. angulata fruit juice to rabbits fed with cholesterol diet significantly (p<0.001) reduced atherosclerotic lesions. In conclusion, B. angulata fruit was shown to enhance plasma antioxidant enzyme activities, inhibit inflammatory biomarkers and reduce progression of atherosclerotic plaque in cholesterol-fed rabbits. Thus, B. angulata fruit plays a favorable role on several mechanisms involved in combating atherosclerosis.