Metabolitos secundarios con efectos tóxicos presentes en la semilla de moringa (moringa oleifera). Revisión

Moringa oleifera is a fast-growing tree used in traditional medicine for its beneficial qualities, among which its antioxidant, antimicrobial, nutritional and therapeutic properties stand out. Its oilseed is used for food, medicine, water treatment and as fertilizers. The seed contains a high percentage of oil (31-42%) and highly digestible proteins (31.4-36%). It also contains secondary metabolites synthesized by the plant, among which are tannins, saponins, phenolic compounds, phytates, flavonoids, terpenoids and lectins. Tannins, saponins and phytates have been reported with toxicological and antinutritional effects, so it is necessary to subject the seed to a treatment before consumption, in order to reduce the content of these secondary metabolites and control the doses of consumption.Moringa oleifera es un árbol de rápido crecimiento utilizado en la medicina tradicional por sus cualidades benéficas entre las que se destaca su capacidad antioxidante, antimicrobiana, sus propiedades nutritivas y terapéuticas. Su semilla oleaginosa, es utilizada en la alimentación, la medicina, el tratamiento de aguas y como fertilizantes. La semilla contiene un alto porcentaje de aceite (31-42%) y de proteínas de alta digestibilidad (31.4-36%). Además contiene metabolitos secundarios sintetizados por la planta, entre los que se destacan taninos, saponinas, compuestos fenólicos, fitatos, flavonoides, terpenoides y lectinas. Los taninos, saponinas y fitatos han sido reportados con efectos toxicológicos y antinutrcionales por lo que es necesario someter la semilla a un tratamiento antes de su consumo, con la finalidad de disminuir el contenido de éstos metabolitos secundarios y controlar las dosis de consumo

Aislamiento y caracterización de bacterias quitinolíticas ruminales

Los principales objetivos del presente estudio fueron aislar y seleccionar bacterias ruminales quitinolíticas con alta capacidad para degradar quitina pura y caparazón de camarón in vitro, e identificar genéticamente a las bacterias seleccionadas usando secuencias de su gen 16S rARN amplificado mediante PCR. El aislamiento de las bacterias ruminales se inicio con un cultivo mixto liofilizado de bacterias quitinolíticas (CMBQ) obtenido de borregos alimentados con una dieta con 25% de caparazón de camarón. Se requirieron tres aislamientos progresivos para obtener dos bacterias ruminales puras. En el primer aislamiento se obtuvieron seis consorcios bacterianos: BQT1, BQT2, BQT3, BQT4, BQT6 y BQT6 , a partir de CMBQ. Por su alta capacidad para degradar quitina pura (62.69 % a las 72 h de incubación) se seleccionó al consorcio BQT1 para el segundo proceso de aislamiento. Se usaron medios de cultivo a base de glucosa, quitina pura o caparazón de camarón y se aislaron 18 colonias (seis de cada uno de los medios de cultivo). De estas colonias se seleccionó el consorcio bacteriano Q6 (aislado del medio de cultivo con quitina pura) ya que causo la mayor degradación (p≤0.01) de quitina (33.31%) y caparazón de camarón (23.10 %) a las 72 h de fermentación. En el tercer aislamiento se obtuvieron dos bacterias, Q6a y Q6b. Estas bacterias no tienen una importante capacidad de degradar caparazón de camarón en cultivos axénicos (17.64 y 12.60% a las 72 h de incubación), pero en cocultivo, su capacidad aumenta ( p≤0.05) a 36.37%. Estos resultados indican una interacción sinérgica en la d egradación del caparazón de camarón entre las dos bacterias aisladas. Para la identificación genética de las dos bacterias aisladas se usaron fragmentos de 796 pb y se encontró que, con un 99% de similitud, Q6a pertenece a la especie Bacillus licheniformis, mientras que Q6b está emparentada al género Enterococcus y sólo falta discernir si pertenece a la especie E. faecium, E. durans o E. lactis._________The main objectives of this study were to isolate and select chitin- degrading rumen bacteria with high capacity to degrade pure chitin and shrimp shell waste in vitro, as well as to identify genetically these bacteria, using their 16S rRNA gene sequences amplified by PCR. The isolation of rumen bacteria was started with a lyophilized chitin -degrading mixed culture (ChDMC), obtained from lambs fed a diet containing 25% shrimp shell waste. Three progressive isolations were required in order to obtain two pure rumen bacteria. In the first isolation six bacteria consortia were obtained: BQT1, BQT2, BQT3, BQT4, BQT5 and BQT6, from the ChDMC. Due to its high capacity to degrade pure chitin (62.69% after 72 h incubation), BQT1 was select ed for the second isolation procedure. Culture media based on glucose, chitin or shrimp shell waste were used, and 18 bacteria colonies were obtained (six from each culture media). The bacteria consortia Q6 (isolated from the culture medium with pure chiti n) was selected from all these colonies, since these bacteria caused the highest (p≤0.01) chitin (33.31%) and shrimp shell waste (23.10%) degradation after 72 h incubation. Two bacteria, Q6a and Q6b, were obtained in the third isolation. Axenic cultures of these bacteria have not an important chitin-degrading capacity (17.64 and 12.60% after 72 h incubation), but in coculture their capacity has a significant (p≤0.05) increase, 36.37%. These results indicate a synergic interaction for chitin degradation between this two isolated bacteria. Fragments of 796 bp were used for the genetic identification of the two isolated bacteria; it was found, with 99% of similitude, that Q6a belongs to the specie Bacillus licheniformis, and Q6b is a family member of the genus Enterococcus, but it is still required to confirm if this bacteria belongs to the specie E. faecium, E. durans or E. lactis.Tesis ( Doctorado en Ciencias, especialidad en Ganadería).- Colegio de Postgraduados, 2008.CONACY

In Vitro Probiotic Potential of Lactic Acid Bacteria Isolated from Aguamiel and Pulque and Antibacterial Activity Against Pathogens

Probiotics can act as a natural barrier against several pathogens, such Helicobacter pylori, a bacterium linked to stomach cancer. The aim of the present study was to isolate and identify lactic acid bacteria (LAB) from pulque and aguamiel, and evaluate their probiotic potential and antimicrobial effect on Escherichia coli, Staphylococcus aureus, and Helicobacter pylori. Ten isolates were selected and evaluated for in vitro resistance to antibiotics and gastrointestinal conditions, and antimicrobial activity against E. coli and S. aureus and the effect on H. pylori strains. 16S rRNA identification was performed. Ten potential probiotic isolates were confirmed as belonging to the genera Lactobacillus and Pediococcus. All the strains were susceptible to clinical antibiotics, except to vancomycin. Sixty percent of the isolates exhibited antimicrobial activity against E. coli and S. aureus. The growth of H. pylori ATCC 43504 was suppressed by all the LAB, and the urease activity from all the H. pylori strains was inhibited, which may decrease its chances for survival in the stomach. The results suggest that LAB isolated from pulque and aguamiel could be an option to establish a harmless relationship between the host and H. pylori, helping in their eradication therapy