Boscia foetida Schinz is an indigenous plant with reported medicinal and nutritional importance in the local communities. Likewise, Ximenia americana L. is also an indigenous wild plant widely used across Southern African countries with reported phytochemical,nutritional, and bioactivity data. This study was designed to evaluate the preliminary qualitative screening of the roots and leaves of B. foetida, phytochemical profile and mineral content of B.foetida roots extract, and the effect of long-term frozen storage on the nutritional composition and phytochemical profiles of the wild plum (Ximenia americana) fruit parts.Both B. foetida n-hexane root extract and wild plum (X. americana) n-hexane fruit parts extracts were subjected to GC-MS analysis. The root extract revealed the presence of various bioactive compounds such as lupenone, γ-sitosterol, 9-octadecenoic acid (Z)-, methyl ester,and 9-octadecenamide (Z). The preliminary qualitative screening of the roots and leaves showed the presence of phenols, alkaloids, saponins, terpenoids, triterpenoids, coumarins,proteins, reducing sugars, sterols, flavonoids, tannins, glycosides and saponins highlighting the potential of B. foetida as a medicinal plant. The roots contained significant amounts of K, Ca,Na and Mg. The following elements were at permissible values: Mn, Cr, Fe, Cu, K, Ca, Mg,and Na, while Pb, Co, Ni, and Zn were found at higher amounts exceeding the permissible values. The preliminary data obtained shows that B. foetida roots are a potential source of minerals and phytochemicals that can be useful in herbal products preparations.Wild fruits play a crucial role in the well-being of people, wild plum (X. americana) being one of such fruits. However, one of the main variables influencing the nutritional value of fruits is postharvest treatment, hence it is crucial to protect these nutrients through adequate processing and storage. The effect of long-term storage on the nutrient contents of the wild plum fruit parts at -4°C after 3 and 6 months was investigated. The results showed that mineral elements such as Mg, K, Ca, Cu, Mn, Ni, and Fe were well preserved during the entire frozen storage period with K and Ca being the most retained across the fruit parts. Proximates and antinutrients were also preserved. Although the antinutrients showed a certain degree of retention, their recorded values in the kernels of the wild plum are below the permissible toxic levels, except tannins in the pulp after harvest (post-harvest) relative to the previous limit by FAO/WHO. The phytochemicals showed a significant variation except alkane hydrocarbons. Losses of nutritional qualities mostly occurred in the first month of freezing. Taking into consideration xv some essential nutrients losses, to effectively contribute to the nutritional needs and food security, it would be necessary to preserve the wild plum fruits by frozen storage within a period not exceeding 6 months. Non-carcinogenic and carcinogenic health risk assessments were conducted for the heavy metals detected. The carcinogenic health risk analysis revealed that lead and nickel values in the roots (B. foetida) and pulp and kernels of the wild plum (X. americana) were above the specified limits set by the United States Environmental Protection Agency (USEPA). Furthermore, there were no non-carcinogenic health risks associated with the studied heavy metals, except lead in the pulp, which showed values of hazard quotient (HQ) and hazard index (HI) above 1. In view of the study result, continuous regulatory control is suggested to ensure the safety of the marketed plant products made from the two plants collected from the study area. The current study result will also contribute to the body of literature on the safety of edible indigenous fruits and plant parts in Botswana.

Thesis (MSc of Chemical and Forensic sciences)---Botswana International University of Science and Technology, 2024