Levels of some microelements and essential heavy metals in herbal teas in Serbia

Abstract

Levels of Fe, Mn, Cu, Zn, Mo, Co, Ni, Se, Sn and Al were determined in 14 medicinal plants from Serbia, which are widely used in phytopharmacy as herbal teas. The following plants were investigated: yarrow (Achillea millefolium L.), basil (Ocimum hasilicum L.), St. John's wort (Hypericum perforatum L.), peppermint (Mentha x piperita L.), field horsetail (Equisetum arvense L.), stinging nettle (Urtica dioica L.), thyme (Thymus serpyllum L.), maize silk (Zea mays L. - Maydis stigma), hibiscus (Hibiscus sabdariffa L.), marshmallow (Althaea officinalis L.), chamomile (Matricaria chamomilla L.), rosehip/dog rose (Rosa canina L.), winter savory (Satureja montana L.) and spearmint (Mentha spicata L.). A total of 16 samples of different parts of medicinal plants (root, leaf, flower, herba) were examined, whereby 13 samples were delivered in original package and three samples were loose leaf herbs. Samples were prepared using the microwave digestion technique, and measurements were performed applying the atomic absorption spectrometry and mass spectrometry with inductively coupled plasma. Contents of microelements in the examined samples were in the range: Mn (23.86 - 453.71 mg/kg); Fe (61.87 - 673.0 mg/kg); Cu (6.68 - 24.46 mg/kg); Zn (16.11 - 113.81 mg/kg); Mo (0.576 - 4.265 mg/kg); Co (0.039 - 0.532 mg/kg); Se (0.036 - 0.146 mg/kg); Ni (0.738 - 6.034 mg/kg); Al (154.0 - 3015.0 mg/kg) and Sn (2.68 - 10.22 mg/kg). According to determined amounts of microelements, the investigated samples of herbal teas are considered safe for human consumption.