Polycyclic Aromatic Hydrocarbons in Commercial Herbal Teas

The presence of polycyclic aromatic hydrocarbons (PAHs) in medicinal plants may result in health risk to consumers, which are generally hoping that a natural remedy may be helpful in the healing process. Contamination of herbal teas with PAHs can occur as a result of environmental pollution as well as during processing (in some drying or preservation stages that allow combustion products to come into contact with medicinal plants). This research fits into current concerns directed towards establishing the PAHs’ contamination level of plant resources, the focus being on the priority PAHs as established by the US Environmental Protection Agency’s and by the European Union. In this study, the PAHs’ content of several commercial herbal teas brands (basil, chamomile, mulberry, plantain, dandelion, mint, St. John's wort, black locust, common elder, lime, marigold and fennel) was assessed by reversed-phase high performance liquid chromatography (HPLC) using an Agilent 1100 system with fluorescence and photodiode array detectors. The obtained data revealed that: 1) the maximum overall PAH’s contamination in the studied herbal teas was recorded for dandelion (131.15 mg/ kg), mulberry (27.78 mg/ kg) and St.John’s wort (18.28 mg/ kg), all of these exposing high surface area of leaves; 2)from the 15 tracked PAHs, only three were present in all samples (acenaphthene, fluorene and benzo(b)fluoranthene), while anthracene and benzo(g,h,i)perylene were quantified in only two samples; 3) the maximum levels of individual PAHs were recorded in dandelion: 30.79 ppb naphthalene, 28.91 mg/ kg pyrene, 23.79 mg/ kg phenanthrene and 10.28 mg/ kg benzo(b)fluoranthene. 4) the lowest PAHs concentrations were recorded in basil and fennel (1,96 and 2.20 mg/ kg), these being the least contaminated also in terms of PAH’s range (only 7 from the 15 studied PAHs).