Browsing by Autor "Billmary Z. Contreras Moreno"

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Composición Química y Evaluación de la Actividad Antimicrobiana del Aceite Esencial de Espeletia Schultzii Wedd (Asteraceae) Recolectada en el Estado Trujillo – Venezuela
(2016) Libia del Valle Alarcón Pineda; Alexis Peña; Judith Velasco; Alfredo Usubillaga; Billmary Z. Contreras Moreno; Luís B. Rojas; Deisy Ramírez; Rosa Aparicio
The essential oil of fresh leaves Espeletia schultzii Wedd (Asteraceae) obtained by hydrodistillation was rich in hydrocarbon monoterpenes. The analysis of its volatile components by chromatography gas-mass spectrometry (GC-MS) allowed the identification of 13 components, which constituted 100% of essential oil of which the majority were α-pinene (50.11%), β-pinene (16.28%) and β-myrcene (14.71%). The antibacterial activity of the essential oil was assessed using methods agar diffusion and broth microdilution discs against Staphylococcus aureus (ATCC 25923) Enterococcus faecalis (ATCC 29212), Salmonella typhi (CDC57), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 23357) and Pseudomonas aeruginosa (ATCC 27853) and antifungal activity against Candida albicans (CDC-B385) and Candida krusei (ATCC 6258). This oil showed only activity antibacterial, with variation in the results according to the method used by the diffusion method agar disk inhibited by Gram positive bacteria (S. aureus and E. faecalis) with inhibition halos of 7 to 9 mm in diameter and minimum inhibitory concentration values (MIC) ranging between 280 and 580 mg / mL, using the broth microdilution method, inhibited the development of all microorganisms tested at concentrations of 10 to 100 ug / mL. These results revealed that the sensitivity of the method plays an important role in the evaluation of this oil as an antibacterial, It is more sensitive the broth microdilution method. This is the first report of the activity antibacterial essential oil obtained from the leaves of this species.
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.