Evaluation of techniques sensibility for the determination of Minthostachys verticillata essential oil toxic capacity

VOGT M.V.; SUTIL S.; TORRES C.; ESCOBAR F.; ZANON S.; SABINI L.

Villa Giardino, Córdoba

Jornada; XV Jornadas de Biología; 2005

Of the numerous techniques used to evalúate the toxic capacity of potential herbal drugs, the cellular analysis of morphological alterations (MA) and physiological are useful. The last ones are detected by colorimetric methods. In this study those techniques were developed to evaluate the cytotoxic capacity of essential oil (EO) obtained from Minthostachys verticillata, whose antimicrobial capacity was verified in vitro (Zanon et al., 1999; Demo et al., 2002; Torres et al., 2004). The oily sample was obtained by hydrodistillation and char¬acterized by gaseous chromatography, verifying the chemotype of the vegetal. The cytotoxic capacity was evaluated on HEp-2 cells monolayers up to 72 h with different concentrations of EO (0.01-1.2 mg/ml). The MA was determinate using an optical microscope. The normal physiology of the cells at 24, 48 and 72 h post treatment (p.t.) was evaluated by the capacity of reduction of MTT by mitochondrial enzymes according to Seth et al., 2004, and the lysosomal incorporation capacity of the vital colorant neutral red (NR) according to Gong et al., 2004. In both cases absorbance was read at 560 nm. The MA was the less sensitive technique of the 3 developed to evaluate the citotoxicity of the EO. The results obtained by MTT and NR at 72 h were similar; nevertheless at 24 and 48 p.t. NR was more sensitive than MTT. The 50% cytotoxic concentration (CC50%) at 72 h, necessary for the determination of the Therapeutic Index of M. verticillata EO in its future application like a pharmacological natural product was of O.60 mg/ml.