Browsing by Autor "Bernardo Chataing"

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Activity of acnistins against Leishmania mexicana, Trypanosoma cruzi and Plasmodium falciparum
(2009) Bernardo Chataing; Antoine Hocquette; S.B. Díaz; Alexis Valentin; Alfredo Usubillaga
Acnistin A and E, two withanolides with a bicyclic side-chain at C-17, isolated from the leaves of Acnitus arborescens (L) Schlecht that grows in the Venezuelan Andes inhibited the growth of Leishmania mexicana and Trypanosoma cruzi in cultured medium. On the other hand acnistins A, E, and L, also inhibited the growth of a chloroquine-resistant strain and a chloroquine-sensitive strain of Plasmodium falciparum in cultured medium. Data indicated that acnistins exerted a higher inhibitory activity upon these parasites that ketoconazole, mevastatin and lapachol in the same conditions of assay.
Cytotoxic activity of acnistins upon human cancer cells
(2009) Bernardo Chataing; Alfredo Usubillaga; M César Pérez; Ramón Méndez
The cytotoxic activity against human A375 melanoma, MCF7 breast cancer and K652 leukemia cells of acnistins A, E and L, isolated from the leaves of Acnistus arborescens (L) Schletcht (Solanaceae) and the derivatives, 2,3-5,6-diepoxi-acnistin A and acnistin F, obtained in the laboratory by hemisynthesis, were examined using a microculture tetrazolium (MTT) assay. The objectives were to determine if these compounds have cytotoxic activity against cancer cells; to determine the type of interaction between acnistin A with ketoconazole and a-solamargine as well as the type of interaction between acnistin E with a-solamargine and a-chaconine, two compounds which interfere with neutral lipid metabolism. On the other hand this study was addressed to obtain evidence about acnistin moieties that are important for activity. Results indicated that acnistins A, E and L were cytotoxic to human A375 melanoma cells with IC50 values ranging between 0.19 to 80.5 µM, depending on the time of exposition to the steroidal lactone. Also, acnistins A and E were cytotoxic toward MCF7 breast cancer and K652 leukemia cells, with IC50 values ranging from 10.2 to 134.4 µM. The effectiveness of acnistins A and E against the human A375 melanoma cells was greater than against the other cell lines. The results suggested that presence of an a,b-unsaturated ketone, an epoxy moiety between C-5 and C-6, and an hydroxyl group at C-17 are required for activity.
Potencial parasiticida de Pimenta racemosa (Myrtales: Myrtaceae)
(Universidad Internacional de La Rioja, 2017) Elsa Nieves; Leidy Stefany Calles; Maritza Rondón; Billmary Z. Contreras Moreno; Bernardo Chataing
American trypanosomiasis, leishmaniasis and schistosomiasis are parasitic diseases that affect millions of people in the world and are a serious public health problem, mainly in Latin American. Current treatments are not satisfactory, hence the need for new compounds. The objective of this work was to determine the bioactive potential of the plant Pimenta racemosa (Myrtales: Myrtaceae) against parasites. Different bioassays were carried out with different parts of the Pimenta racemosa plant to determine the toxic activity on Artemia salina, on human erythrocytes and its parasiticidal effect against Leishmania amazonenesis, Trypanosoma cruzi and Schistosoma mansoni. Lethal concentrations were calculated and PERMANOVA analyzes were performed. The results showed that P. racemosa does not produce a toxic or cytotoxic effect. It also showed no effect against L. amazonensis promastigotes or against T. cruzi epimastigotes, presented high lethal concentrations being determined that are not within the range to be considered bioactive. While P. racemosa showed parasiticidal activity against the immature forms of S. mansoni, causing greater mortality and morphological alterations in the miracidia than in the cercariae and an attenuation effect on S. mansoni cercariae was evidenced. The parts of P. racemosa fine branches presented the lowest LC50 of 0.10 mg/ml (0.08-0.14 mg/ml). Data are provided on the bioactivity of P. racemosa, no biological activity was evidenced against L. amazonensis and T. cruzi. However, P. racemosa presented a low cytotoxicity, with no toxic effect and biocidal activity against the immature forms of S. mansoni. Therefore, it is suggested to deepen the studies to potentiate its antiparasitic secondary metabolites against S. mansoni.
Tratamiento topico del herpes simplex, el herpes zoster y el herpes genital con una mezcla de alcaloides de solanaceas
(1998) Bernardo Chataing; Nersa Buitriago de Cristancho; Alfredo Usubillaga
Editorial. El síndrome TMT y el síndrome TMA. Síntomas, Efectos, Epidemiología, Etiología, Terapia y Contraindicaciones