Bioactive proteins from edible plants of Solanum genus.

Abstract

Bioactive proteins have been detected in manydifferent food sources. Beyond their nutritionalvalue many of them exhibit functional effects bothon the producing and on the consuming organisms.In recent years it has been recognized that proteinsprovide a rich source of biologically activepeptides. The genus Solanum has a great varietyof edible species that are an important source ofprotein. In this sense, some proteins might beinvolved in the response to wounding in plantdefense mechanisms like patatine and solamarineand snakin 1 and 2 isolated from S. tuberosumtubers and cyphomine isolated from S. betaceumfruits. They have shown in vitro inhibitory actionon hydrolases released by microorganisms involvedin cell wall degradation during the invasion process.They also have in vitro inhibitory effect onphytopathogenic microorganism growth for bothbacteria and fungi. It is thought that these proteinscould be part of the so-called pathogenesis-relatedproteins. As they are also present in edible tissue,these proteins have been studied from a functionalpoint of view. The purified proteins showedantioxidant or antiradical activities by a series ofin vitro tests, including DPPH, ABTS, hydroxyland superoxide radicals scavenging activityassays, anti-human low-density lipoproteinperoxidation tests, protections against hydroxylradical-mediated DNA damages, peroxynitritemediateddihydrorhodamine 123 oxidations andâ-carotene bleaching assay. A non mutagenic effectBioactive proteins from edible plants of Solanum genuswas observed in solamarine and cyphomine;solamarine also showed an antimutagenic effectagainst a direct mutagen. At present, an enzymatichydrolysis process on proteins is being carried outin order to obtain smaller molecules (peptides andfree amino acids) with improved nutritional qualityand safety. Three bioactive peptides (5A, 5C and6C) from potato protein hydrolysate fractions haverecently been isolated and showed antioxidantactivity. Hence, it would be possible to generatenew products and carry out alternative applicationsfor several agricultural and nutritional products.