Nutritional and mineral composition, metal bioaccumulation, and health risk assessment of Diospyros mespiliformis Hochst. Ex A.DC., Ficus thonningii Blume, and Strychnos spinosa Lam : implications for food security and public health.

Abstract

Food insecurity continues to pose a significant challenge in developed and developing nations, prompting the need to identify alternative, nutrient-dense food sources. This study examines the nutritional profile of the fruits of Diospyros mespiliformis Hochst. Ex A.DC., Ficus thonningii Blume, and Strychnos spinosa Lam., emphasising their potential as underutilised yet valuable food resources. In addition, the mineral composition of both leaves and fruits was assessed, alongside bioaccumulation factors (BAFs), to evaluate the extent of mineral uptake from the soil. A health risk assessment was also conducted to determine the safety for human consumption. Nutritional analysis revealed that F. thonningii had the highest moisture (82.07%) and crude fat (3.92%), while S. spinosa seeds were notably rich in crude protein (31.20%). Fibre content was higher in the peels across all species, with S. spinosa peel containing 44.21%. The pulp of D. mespiliformis had the highest carbohydrate content (86.02%) and energy value (391.38 Kcal/100 g). Elemental analysis demonstrated significant levels of essential minerals, including calcium (Ca), iron (Fe), and magnesium (Mg), with S. spinosa leaves particularly high in manganese (Mn) content (1728 mg/Kg). Leaves of D. mespiliformis and F. thonningii showed efficient zinc (Zn) accumulation with BAFs of 1.25 and 1.58, respectively. S. spinosa exhibited a notably high BAF of 25.08 for Mn. The carcinogenic risk factors for arsenic (As), cadmium (Cd), and chromium (Cr) in all the fruit samples exceeded the established safety thresholds. The highest risk was associated with F. thonningii fruit, presenting a carcinogenic risk factor of 0.008 for Cr. While these fruits offer promising nutritional benefits, their potential toxicological risks underscore the need for further safety assessments.