Silent metabolism and not-so-silent biological activity: possible molecular mechanisms of stress response in edible desert legumes

Abstract

In the arid/semi-arid regions of India, there are many legumes often growing in the wild like Prosopis cineraria, Cyamopsis tetragonoloba and Acacia senegal. These legumes accumulate useful metabolites, often as glycosides, such as flavonoids and isoflavonoids under conditions of stress like heat and low rainfall. When required, some of these metabolites are produced by the activity of glycoside hydrolase enzymes like β-glucosidase rather than de novo biosynthesis. Local human populations have been consuming food prepared from the edible portions of these plants since ancient tradition. However, studies on phytochemical-cum-metabolic aspects are surprisingly limited in these plants—these being important parameters for developing them into scientifically-validated holistic health foods. It is important that this task is carried out for indigenous plants with useful antioxidant-guided medicinal properties rather than always depending upon expensive and imported exotic foods. The current article highlights research insights and perspectives from our work on edible desert legumes as well as those of other international research groups active in this area, particularly pertaining to flavonoids and their metabolism in planta. A few possible research goals for legume plant scientists are also suggested.