The functional food market is capturing considerable attention worldwide. Functional foods are defined as "food products that provide specific health benefits beyond the traditional nutrients they contain" or "food containing significant levels of biologically active components giving health benefits beyond basic nutrition". They are made from natural ingredients and are consumed as part of the normal diet. There are many examples of biologically active food proteins possessing physiological significance beyond the pure nutritional requirements relating to available nitrogen for normal growth and maintenance. As the impact of functional foods on human health has grown over the past decade, so has the volume of knowledge detailing the beneficial roles of naturally occurring and food derived bioactive peptides. Most often hidden or inactive in the sequence of proteins, the bioactive peptides are released and activated during gastro-intestinal proteolysis by digestive enzymes, controlled in vitro proteolysis, food processing or fermentation. Bioactive peptides from both plant and animal proteins have been discovered. This varied role of bioactivity in a plethora of physiological processes introduces a completely new dimension to be considered while enumerating and describing dietary protein quality.
Hypertension, often called the "silent killer", is a major public health problem worldwide and a major independent risk factor for heart failure, stroke, coronary heart diseases and myocardial infarction. The renin angiotensin system (RAS) plays an important role in the regulation of blood pressure. The angiotensin converting enzyme is the key enzyme that functions in the RAS to regulate blood pressure. It converts the angiotensin I to a powerful vasoconstrictor and also degrades bradykinin, a vasodilator to inactive fragments. Therefore current attention focuses on the mechanism of controlling blood pressure through the inhibition of angiotensin I-converting enzyme (ACE). Since the original discovery of ACE inhibitors in snake venom, pharmacological ACE inhibitors captopril, enalapril, lisinopril and ramipril have been developed and are currently in use. These inhibitors are modified short peptides that bind tightly to the active site of ACE competing with Angiotensin I for occupancy. Bioactive peptides are increasingly gaining importance as alternates in hypertension therapy since the synthetic inhibitors are associated with adverse side effects. Dietary antihypertensive peptides are short amino acid chains produced by digestion or processing of proteins. Latent or inactive in the parent protein, when hydrolysed at the strategic zone releases peptides that exert ACE inhibitory activity in a number of ways.
The food sources available and the antihypertensive peptide sequences tailored from them by a number of ways, characterized by different methods and ACE inhibition quantitated by various assays are increasing day by day in volume and details. This database aims to provide comprehensive information on these various aspects of food derived antihypertensive peptides that are available in literature.
Twenty most common amino acids are represented by their standard single letter codes. Atypical amino acids viz hydroxyproline and pyroglutamic acid are represented as Hyp and Glp respectively. The sources viz insect protein, hemoglobin, macroglobulin, murine casein, fig latex etc from which ACE inhibitors are derived in several cases, which are not considered as food sources per se are not accommodated in the database.