Investigation of the cytocidal potential of Rhinella jimi skin methanol extracts.

CONTEXT: Amphibian skins have wide variety of biologically active compounds associated with the natural defenses of these animals. OBJECTIVES: To study the in vitro anticancer activity of methanol extracts of the skin of Rhinella jimi Stevaux (Anura: Bufonidae). MATERIAL AND METHODS: The extract was obtained by cold methanol extraction for 96 h using dried skins (295 mg). The methanol skin extract was dried under reduced pressure, giving a 5.5% yield. In order to test for growth-inhibitory activity, in vitro tests were performed with the following cancer cell lines using concentrations ranging between 0.25-250 µg/mL of the extract by 48 h: K562 (leukemia), MCF-7 (breast), NCI-ADR (breast with MDR phenotype), UACC-62 (melanoma), NCI460 (lung), PCO3 (prostate), HT-29 (colon), OVCAR (ovary), and 786-0 (kidney). RESULTS: The methanol extract of R. jimi produced a growth inhibition in a dose-dependent manner against the most of the assayed cell lines. In addition to the growth inhibition, the extract induced the cell death in the ovary and colon lines (EC50 0.125 and 0.2 µg/mL, respectively), demonstrating 100% of inhibition with 2.5 µg/mL. However, prostate and leukemia cell lines demonstrated less sensitivity, with EC50 of 24 and 235 µg/mL, respectively. This is the first report about the anticancer activity by natural products from the skin of R. jimi. CONCLUSIONS: The methanol extracts of R. jimi significantly affected the growth of several cell lines, demonstrating that these compounds are a potential source of substances that could be utilized in cancer treatments.

Estudo químico-biológico dos óleos essenciais de Hyptis martiusii, Lippia sidoides e Syzigium aromaticum frente às larvas do Aedes aegypti / Chemical-biological study of the essential oils of Hyptis martiusii, Lippia sidóides and Syzigium aromaticum against larvae of Aedes aegypti and Culex quinquefasciatus

O interesse pelos bioensaios frente à larvas de Aedes aegypti e Culex quinquefasciatus deve-se ao fato de que estas espécies estão distribuídas por todo o território nacional, sendo portanto uma atividade realizada por inúmeros pesquisadores do Brasil. Os óleos essenciais de Syzigium aromaticum (L.) Merr. & Perry, Lippia sidoides Cham.,e Hyptis martiusii Benth.,foram testados no combate ao transmissor da dengue e da filariose. As larvas de terceiro estádio foram expostas em triplicatas a diferentes concentrações (1000, 500, 250, 100, 50, 25 e 10 ppm). As análises foram observadas após dez minutos do início do tratamento, e mostraram resultados bastante significativos, com potencialidade de mortalidade de até 100 por cento das larvas testadas, indicando acentuados efeitos tóxicos de alguns constituintes voláteis presentes nos óleos. Para os óleos de S. aromaticum, L. sidoides e H. martiusii foram constatadas, frente à Aedes aegypti, valores respectivos de CL50 de 21,4; 19,5 e 18,5 ppm e frente ao Culex quinquefasciatus, 14,5; 16,6 e 27,5 ppm, respectivamente.

The interest for a biological assay against larvae of Aedes aegypti and Culex quinquefasciatus is due to the fact that these species are distributed by the whole national territory, being therefore an activity carried out by countless researchers of Brazil. The essential oils of Syzigium aromaticum, Hyptis martiusii and Lippia sidoides were tested in the combat of the transmitter of the dengue and of the filariosis, using larvae of third stadium were exposed in triplicate to different concentrations (1000, 500, 250, 100, 50, 25 and 10 ppm). The larvicidal activity was observed after ten minutes of the beginning of the treatment, in the end showed very significant results, with mortality potentials of up to 100 percent of the tested larvae, indicating accentuated toxical effects in some representatives of the volatile compounds present in the oils. For the oils of S. aromaticum, L. sidoides and H. martiusii DL50 of 1,0; 1,0 and 8,0 ppm, respectively, were observed.