ISTANBUL JOURNAL OF PHARMACY, vol.44, no.1, pp.11-30, 2014 (ESCI)
Despite the profound therapeutic advantages possessed by herbs, some constituents of herbs have been shown to be potentially toxic. Knowledge on their safety is inadequate although the concerns have been raised over the lack of quality controls. We aimed to determine safety of six herbal mixtures used as tea, included forty plant species, chosen on the basis of their frequency of medicinal use and commercial importance in Turkey. Their cytotoxic activities were evaluated by determining mitochondrial succinate dehydrogenase (XTT) and extracellular lactate dehydrogenase (LDH) activities on human cerviks cell line (HeLa). For their genotoxic activities, two bacterial mutation assays, Ames assay with Salmonella typhimurium TA98 and TA100 strains and umu assay with S. thyphimurium TA1535/pSK1002 strain, were used. The 50% inhibition concentration (IC 50) values of the extracts for LDH and XTT tests were 6.52-63.53 and 18.75-104.67 mg/mL, respectively. In the genotoxicity studies conducted by umu assay, no extracts possessed genotoxic activities at 6.25-25 mg/mL. On the contrary, Ames bacterial mutagenicity assay conducted at the same concentrations revealed that (i) some extracts were shown mutagenic activities with metabolic activation (ii) TA100 strain was more sensitive than TA98 strain to the extracts, (iii) especially, three herbal mixtures may include ingredients shown mutagenic activities both in two strains and with metabolic activation. Our findings showed that herbal teas have some significant toxic effects. Therefore, the researchers and/or national authorities should consider that the use of herbal products may be harmful to human health.