Abstract:

Background: Vernonia species are widely consumed as vegetables or medicinal herbs for the treatment
of various human diseases in Nigeria. Nevertheless, there exists a growing concern for consumption safety
of those herbal plants, due to increasing environmental pollution. This is because plants can accumulate
some heavy metals that constitute a potential risk to human health. Nonetheless, also essential elements
may be accumulated in plants, which provide nutrients for combating diseases and maintaining human
health. Objectives: The purpose of the study was to analyze some heavy metals and mineral elements on
Vernonia ambigua, V. oocephala and V. pupurea commonly used in Northern Nigerian traditional medicine.
Methods: Atomic absorption spectrometry (AAS) was used to determine the major elements (calcium
and magnesium), trace elements (iron and manganese) and heavy metals (copper, cobalt, chromium,
cadmium, lead and zinc). Results: We found a high Ca and Fe content in V. ambigua, Mg and Co in V.
oocephala, and Cu and Cr in V. pupurea; in contrast, the last specie, showed low accumulation of Pb and
Cd among all studied species. Conclusion: This study revealed that toxic elements concentrations are
lower than the allowed dietary intake (ADI) in all the three Vernonia species. The quantitative estimation of these elements is important to understanding the pharmacological and/or toxicological actions of
medicinal plants for safe use.