Resumen

SALAMANCA CAPUSIRI, Efrain; RUIZ PINELL, Grace; TICONA HUALLPARA, Juan Carlos  y  GIMENEZ TURBA, Alberto. Colorimetric method - XTT: as a tool for high performance evaluation of substances with leishmanicidal activity. BIOFARBO [online]. 2008, vol.16, n.1, pp. 21-27. ISSN 1813-5363.

Leishmaniasis is a group of diseases of great epidemiological impact, considering the fact that  its existing treatments are associated with multiple side effects, and therefore the search for new therapies is important. However, the classical optical screening method for measuring leishmanicidal activity is only qualitative and time consuming, making it difficult to evaluate a large number of substances. Due to these reasons, the XTT method for promastigotes of Leishmania was standarized, based on the mitochondrial enzymatic reduction of the sodium salt of 2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2-H-tetrazolium-5-carboxanilide (XTT) up to formazan crystals, and this reduction is accelerated by the addition of electron couplers such as Fenasin Methosulphate (PMS). During the present work  there was the chance to determine the linear behavior of absorbance at 450nm, the parasite populations (1.5-3x10⁶promastigotes/mL), the time of incubation with the electron couplers (2-4 hours) and correlation (R²) between the count of parasites on a Newbauer chamber and the levels of absorbance detected during the experiment. This colorimetric method with XTT, was validated to determine the leishmanicidal activity of the medicinal plant extracts (Galipea longiflora) and compared with a reference drug (Anfotericine B), having now an easy, reliable, fast and quantitative method to evaluate a large number of possible antiparasitic substances

Palabras llave : XTT; MTT; MTS; PES; PMS; colotimetric method; leishmanicidal activity; IC₅₀; Galipea longiflora; Anfotericina-B.