Study on selected trace elements and heavy metals in some popular medicinal plants from Sudan

This study reports on the determination of 11 elements in 33 medicinal plants from Sudan and discusses a possible correlation between their curative effects and their trace elements content. Further, a possible accumulation of adverse heavy metals could be excluded. A total of 11 elements (cadmium, lead, mercury, tin, copper, iron, manganese, zinc, chromium, selenium and magnesium) were determined using inductively coupled plasma (ICP)-optical emission spectrometry (ICP-OES), ICP-sector field-mass spectrometry (ICP-sf-MS) and hydride generation (HG)-ICP-OES techniques. The results of the present study showed no heavy metal accumulation in any of the plants. Cd, Pb, Hg and Sn were found only in trace concentrations significantly below the global limits. This indicates the possibility of a safe use of these medicinal plants. Elevated chromium concentrations were found in those phytopharmaca which are employed for the treatment of diabetes mellitus in Sudanese traditional medicine. Cr was detected in the same range as in other plants reported to be applied for diabetes mellitus treatment. Aside from these medicinal plants, some others were identified which could be potential sources for providing reasonable amounts of Cr, Zn, Mn, Se and Mg for the treatment of diabetes mellitus, smooth muscle relaxation and/or against gastro-intestinal cramps.