Elemental measurements and health risk assessment of sub-Saharan African medicinal plants used for cardiovascular diseases’ and related risk factors’ treatment

Background: Dietary factors have been noted to influence the development of cardiovascular diseases (CVDs) which are the number one global cause of death. In this study, the nutritional importance and human health risk of the minerals composition of 20 medicinal plants’ (MPs) parts used for treating CVDs and related risk factors in sub-Saharan Africa (SSA) were assessed. Methods: Inductively coupled plasma technology was used for determining the minerals composition of the MPs while human health risk assessment was based on hazard quotients, hazard indexes and non-carcinogenic risk analysis of the studied heavy metals. Results: The investigation showed varied level of minerals in the studied MPs’ parts with K having the highest concentration in most. Although level of some elements inM. lucida, V. amygdalina leaves, T. cacao seed and Z. officinale rhizome revealed their possibility in preventing the occurrence of atherosclerosis, unsafe levels of some trace elements were recorded in M. lucida and V. amygdalina leaves. V. amygdalina leaves and A. cepa bulb also had their Pb contents higher than the WHO/FAO Codex permitted maximum level for leafy and bulb vegetables, respectively. In spite of the desirable Na/K and Zn/Cu ratios in all the tested MPs with their Cd and Pb levels below the WHO recommended maximum levels for dried medicinal plant materials, health risk assessment showed that habitual use of almost all of the studied MPs would present an unacceptable risk of non-carcinogenic effects on health. With the exception of S. aromaticum flower bud and T. tetraptera fruit, principal component and hierarchical cluster analyses of other plants’ parts (MPs’ parts aside from the leaves) analysed provided a distinction between MPs which have found food applications and those solely used for medicinal purposes. Conclusions: The study revealed that type of MP, plants’ part, maturity stage, agricultural practice, growing environment and conditions, are among the factors determining the safety of plant materials used for CVDs’ and related risk factors’ treatment in SSA. To protect the lives of CVDs patients who rely on traditional medicine for treatment, government of SSA countries and relevant authorities need to set a regulatory limit for maximum acceptable concentration of minerals in MPs used in the region. Assessment of the physicochemical properties and pollution level of soil used for cultivation of these MPs is also encouraged.