FOOD AND FOOD-DERIVED BIOACTIVE COMPOUNDS: RELEVANCE TO HOMEOSTASIS OF THE ANTIOXIDANT, CARDIOVASCULAR, AND IMMUNE SYSTEMS

Abstract

Recent studies support the hypothesis that beyond meeting nutritional needs, diet may modulate various functions in the body, playing detrimental or beneficial roles in some diseases. Concepts in nutrition are expanding from emphasis on preventing adverse nutrient deficiencies to actually increasing survival, to the use of foods to promote a state of well-being and better health by reducing the risk of pathogenic consequences. These concepts are particularly important in light of the increasing cost of health care, the steady increase in life expectancy, and the desire of older people for improved quality of life in their later years. Such changes in emphasis have stimulated and supported research on functional foods to address the physiological effects and health benefits of foods and their bioactive compounds. Among the most promising targets for functional foods’ in vivo modulation are: redox and antioxidant, cardiovascular, and immune systems. In addition, intense research interest has focused on identifying and characterizing biologically active components in foods from both plants and animals that potentially could reduce risks from a variety of chronic diseases or optimize health. Our hypothesis is that dietary consumption of food-derived bioactive compounds (protein-peptides, nutritional supplements, and plant extracts) will have significant in vivo effects on homeostasis within the cardiovascular, immune, and redox-antioxidant systems. To address this hypothesis, the following specific aims are proposed: 1) to determine whether bioactive protein-hydrolysates will lower systolic blood pressure in the spontaneous hypertensive rat (SHR) model; 2) to evaluate the immunomodulatory effect of different doses of six nutritional compounds on an aged murine model with impaired immunological system; and 3) to evaluate the effect of natural antioxidants derived from popular plant extracts (hop and borage) on oxidative stress and tissue α- tocopherol activity. Antioxidant defense system and oxidative status methodology were optimized to facilitate these goals. Also we conducted the validation and start-up of the tail-cuff plethysmography for the hypertension study. We found that all protein-hydrolysates showed a tendency to lower systolic blood pressure over time in the SHR model. However, there was no significant difference between any of the protein hydrolysates tested and the control group. Consumption of the six nutritional compounds tested gave no indication of effectiveness in preventing immune dysfunction caused by aging. On the other hand, the Th1 and Th2 cytokine responses of the aging mice did show a significant difference from that of the young mice, consistent with previous immunological findings. The plant extracts from hop and borage, given as a dietary supplementation neither prevented oxidation nor enhanced the activity of tissue α-tocopherol in a murine retroviral infection model.