RESUMEN
Jotropha gossypifolio L. (Etphorbiaceae) and Cleome viscosa, L. (Capparidacae), Thai-plant species, have phytocidal chemical components and responsible for controlling and repelling insects from the host plants. To avoid potential toxic pollutant contaminating aquatic ecosystems, this present study was investigated for acute toxicity. Guppy fish (Poecilia reticulata) were selected for the bioassay experiments. The experiments were repeated 5 times and the 24-h LC50 was determined for the guppies. The acute toxicity experiments were carried out by static method and behavioral changes in guppies were determined for each Jatropha gossypifolia L. and Cleome viscosa, L. concentration extract which extracted by Soxhlet extraction method with ethanol as solvent. Water temperature was regulated at 20 +/- 1 degrees C. Data obtained from the acute toxicity tests were evaluated using the probit analysis statistical method. The 24-h LC50 value for guppy was estimated as ca. 3100 ppm (r2=0.95) and 5300 ppm ((r2=0.96) for Jatropha gossypifolia L. and Cleome viscosa, L. extract, respectively. However, in this concentration, no mortality was observed at higher concentration for 30 second.