Toxicity of Glandularia selloi (Spreng.) Tronc. leave extract by MTT and neutral red assays: influence of the test medium procedure

Cytotoxicity assays using cell cultures may be an alternative to assess biological toxicity of plant extracts with potential phytotherapeutic properties. This study compared three methods to prepare culture media for the exposure of Vero cells to plant extracts. Leaves of Glandularia selloi (Spreng.) Tronc. were used to prepare culture medium with aqueous extract, extract in culture medium and methanol extract. Toxicity was assessed using the MTT and neutral red (NR) assays. In general, alterations in the cellular functions were found in all extracts and assays. Cytotoxic effect occurred at lower doses in aqueous extract and the range of effect of the methanol extract was small. The procedure of preparing the test medium has an effect on the outcome of the assay. Cytotoxicity of plant extract can be assessed by MTT and NR assays. Aqueous extract added to the culture medium presented the best profile to assess cytotoxicity.