Marama bean [Tylosema esculentum (Burch.) A. Schreib.]: an indigenous plant with potential for food, nutrition, and economic sustainability

Developing countries need to explore undervalued indigenous plants to fully enhance their food and nutrition security, health, and economic viability. This review explores the nutritional, phytochemical, and economic potential of marama bean (Tylosema esculentum, Fabaceae), a non-nodulating indigenous legume that can be cultivated in and is well-adapted to dry or low moisture conditions. Marama bean is popularly referred to as 'green gold' due to the considerable value derived from its above ground and underground organs. The seeds have nutritional value comparable to legumes such as groundnut and soybean. In addition, the seeds are a rich source of phytochemicals such as phenolic acids, phytosterols, flavonoids, behenic acid and griffonilide while carbohydrates are abundant in the tubers. Based on the existing literature, marama bean remains poorly explored, mainly anecdotal with limited scientific evidence available to support its nutritional and medicinal uses as well as economic benefits. This has been ascribed to a shortage of clear research goals and limited resources specifically directed to this underutilized indigenous plant. From an economic and commercial perspective, the high phytochemical content suggests the possibility of developing a functional health drink and associated value-added products. However, efficient cultivation protocols for marama bean, especially to ensure the sustainable supply of the plant material, remain crucial. Furthermore, novel approaches, especially the use of molecular techniques that can facilitate rapid selection of desired traits in marama, are recommended. These anticipated improved agronomical traits will enhance the commercial and economical potential of marama and also contribute to rural-urban food-nutrition sustainability globally.