Systematic Review of the Agro-Ecological, Nutritional, and Medicinal Properties of the Neglected and Underutilized Plant Species Tylosema fassoglense

Neglected and Under-utilized plant Species (NUS) can contribute to food system transformation in Sub-Saharan Africa, but many are understudied. Here, we conducted a systematic review of 37 empirical studies to synthesize the evidence from Sub-Saharan Africa about the agro-ecological characteristics, nutritional properties, and medicinal properties of the NUS Tylosema fassoglense. Overall, the evidence is highly fragmented and lacks a comprehensive description of the species characteristics, properties, and benefits. Most reviewed studies focus on the eastern part of Africa and a few on the southern part, suggesting its limited geographic distribution. Studies on agro-ecological properties, and especially on morphological characteristics, indicate that the species' long tuberous roots and large vegetative systems help it adapt to harsh climatic conditions. The species is also utilized for medicinal and nutrition purposes by different communities across its range due to its phytochemical, macro-, and micronutrient content, along with its favorable physico-chemical properties. In particular, the seeds contain many different amino acids, while their calcium, magnesium, phosphorus, zinc, and carbohydrate content is comparable to Tylosema esculuntum, the better studied species in the Tylosema genus. These demonstrate the species' potential to contribute to nutrition and food security. Furthermore, parts of the plant contain many phytochemicals, such as phenolics, alkaloids, flavonoid, terpenoids, and tannins (mainly in the roots), and for this reason local communities use it to treat various conditions. Overall, our systematic review suggests that although Tylosema fassoglense has some potential to contribute towards food security, nutrition, health, and livelihoods, there are many remaining knowledge gaps that constrain its effective integration into agricultural production systems and possible contribution to food system transformation in the region.