## 1 Introduction  
Over the last five hundred years, with increased contact between dissimilar populations and the development of a global trading system, the use of plants for food has concentrated on about 30 crop species out of an estimated 30,000 edible species, which are now the basis of a considerable amount of the world's agriculture [1]. This has resulted in the underutilization of many plant species. Legumes are essential food crops that provide high-quality protein and micronutrients that may promote health and livelihoods, particularly in underdeveloped nations [2]. With close to 765 genera and over 19,500 species, the Leguminoseae is the third-largest plant family and second in economic importance only to Poaceae [3, 4]. Drought, severe heat, salt, and heavy metal stress, among other abiotic factors, have reduced the legume yield by around 50% globally. Underutilized legumes are often better able to tolerate extreme and unfavourable environmental conditions, such as drought, high salinity, and low soil fertility, compared to other commonly grown crops. This is due to the unique adaptations and traits these legumes have evolved to survive in areas with limited resources. Underutilized legumes are a common crop in developing nations, but their economic impact on international markets is modest. Despite their superior dietary potentials, they are commonly used as animal feed and for other agricultural purposes by resource-constrained farmers. By utilizing these underutilized legumes in agriculture, farmers can increase their crop yields and reduce their dependence on chemical inputs, while also contributing to the preservation of crop diversity and food security. Numerous underutilized legumes have a lot of untapped potential in terms of their nutritive qualities due to their remarkably high protein content. In addition to their nutritional benefits, legumes produce secondary metabolites, some of which are toxic or poisonous, that act as deterrents to predators [5]. Several of these secondary metabolites are being investigated for their potential as pharmacological agents [6]. The metabolites that have been found in the leaves and fruiting parts include flavonoids, alkaloids, terpenoids, nonprotein amino acids, and others. Underutilized legumes belong to the family Leguminosae (Fabaceae) [7], and the Leguminosae family was traditionally divided into three well-known, long-recognized and widely accepted subfamilies, Caesalpinioideae DC., Mimosoideae DC., and Papilinoideae DC, each of which has in the past been considered a separate plant family [7,8]. However, because Mimosoideae and Papilinoideae are nested inside a paraphyletic Caesalpinioideae [9], this categorization does not effectively describe evolutionary relationships within the family [10]. Thus, the new Leguminosae classification, based on the evolutionary structure and representing a consensus opinion of the international legume systematics community, recognises six subfamilies, namely Papilionidaee DC., Caesalpinioideae DC., Detarioideae Burmeist., Dialioideae LPWG, Cercidoideae LPWG. and Duparquetioideae LPWG. [2]. The traditionally recognised subfamily Mimosoideae is recognized as a distinct clade nested within the recircumscribed Caesalpinioideae [11]. A diagram of the phylogenic classification of the Leguminosae family and the genera of interest is shown in Figure 1.  
The new subfamily Caesalpinioideae, which includes the mimosoid clade, with over 4600 species in 152 genera comprised of trees, shrubs, and lianas, is the second-largest legume subfamily [12]. The subfamily is widespread across the tropical dry, savanna, and wet lowland tropical rainforests. The subfamily Caesalpinioideae is best known for its shade and ornamental species, such as _Acacia farnesiana_ (sweet acacia), _Baudini barlettiii_ (orchid tree), and _Cercis siliquastrum_ (the Judas tree, or redbud), as well as some of the world's fastest-propagating problematic invasive weeds, such as _Leucaena leuccephala_ (white popinac).