Se presenta el estudio de la actividad antibacteriana de la especie vegetal Diplostephium tolimense Cuatrec. (Asteraceae), colectada en el páramo del nevado del Tolima, la cual cuenta con pocos estudios químicos y farmacológicos, al igual que muchas otras especies de este ecosistema. A partir de un extracto etanólico crudo y mediante partición biodirigida se obtiene la fracción más simple de mayor actividad frente a Staphylococcus aureus (ATCC 25923). Paralelamente se realizan análisis fitoquímicos a las porciones de mayor bioactividad obtenidas durante todo el proceso. Se observa que la acción antibacteriana se incrementa al aumentar la simplicidad química del extracto y que terpenos y flavonoides parecen estar relacionados con la acción revelada. Se trata del primer reporte, hasta la fecha conocido, de actividad antibacteriana in vitro para D. tolimense.

A study of antibacterial activity of the Diplostephium tolimense Cuatrec (Asteraceae) vegetal species, which was collected in the paramo of Tolima, is presented. This species, as many others of this ecosystem, has had few chemical and pharmacological studies. The simplest fraction with the largest activity against Staphylococcus aureus (ATCC 25923), is obtained starting from a raw ethanol extract and by means of bioassay guided partition. Parallelly, phytochemical analyses to the portions of greater bioactivity, obtained during the whole process, are carried out. It is observed that antibacterial action increases as the chemical simplicity increases and that the presence of terpenes and flavonoids seems to be related with this action. This is the first report, so far well-known, of in vitro antibacterial activity for D. tolimense.

Asteraceae weed species associated with rice (Oryza sativa L.) in the state of Tolima-Colombia were gathered, identified and morphologic, pharmacognostic and bromatologically characterized. Allelopathic activity for those organic fractions of weed with high content of sesquiterpene lactone was evaluated on the germination and radicle length of O. sativa seeds in filter paper. Both crude extract and chromatographic fractions were incubated for 120 hours at concentrations of 200, 400 and 600 ppm. Cultivation of the grainswas associated to 12 weed species which presented great variability in its morphologic characteristics and farmacognostic index. Chloroformic fractions gave significant differences with the ethanolic extract due to the effect on the cellular division and the radicle elongation of the O. sativa seeds, activity that seems to be associated to the content of sesquiterpene lactone.

Se recolectaron e identificaron especies de arvense de la familia Asteraceae asociadas al cultivo de arroz (Oryza sativa L.) en el Tolima-Colombia, y se caracterizaron morfológica, bromatológica y farmacognósticamente. Las fracciones orgánicas de la arvense con mayor contenido de sesquiterpenlactonas se evaluó por su actividad alelopática sobre la germinación y elongación de la radícula de semillas de O. sativa, colocadas en papel filtro a concentraciones de 200, 400 y 600 ppm e incubadas durante 120 horas. El cultivo de la gramínea se encontró asociado a 12 especies invasoras que presentaron gran variabilidad en sus características morfológicas y en los índices farmacognósticos. Las fracciones clorofórmicas mostraron diferencias significativas con el extracto etanólico crudo por el efecto sobre la división celular y el crecimiento radicular de semillas de O. sativa, actividad que parece estar asociada al contenido de sesquiterpenlactonas.

Foi analizada a composição do óleo esencial das partes aéreas de doze variedades de alfavaca (Ocimum spp). A análise foi feita por cromatografía gasosa-espectrometria de massas (CG-EM) e encontrou-se que dez das amostras foram caracterizadas pela presença de uma alta porcentagem de cinamato de metila (35-80%), o qual define o químiotipo destas variedades. Somente uma das variedades apresentou o químiotipo cariofileno e mais uma o químiotipo linalol. As variedades "crespa morada", "virgen pequeña", e "virgen morada" apresentam o subtipo cinamato > linalol. A "blanca compacta" e a "crespa blanca" têm o subtipo cinamato de metila > linalol > 1,8-cineol. A "castilla morada" têm o subtipo cinamato de metila > metil eugenol. O subtipo linalol > cinamato de metila foi apresentado pela "verde de folhas grandes". Cariofileno > metil eugenol foi o subtipo da alfavaca "clavo". Cinamato de metila (constituindo mais do 62% do total do óleo esencial) foi o químiotipo para as outras variedades: "canela", "querendona morada", "dulce de castilla" e "zancona morada".

Essential oil compositions of aerial parts from twelve basil cultivars (Ocimum spp) were analysed by gas chromatography-mass spectrometry (GC-MS). Ten of them were characterized by the presence of a high percentage of methyl cinnamate (35-80%), which defined the chemotype for these varieties. Only one presented the caryophyllene chemotype and another, the linalool chemotype. Three of the basils, "purple ruffles", "little virgin" and "purple virgin" exhibited the methyl cinnamate > linalool subtype. "White compact" and "white ruffles" showed the methyl cinnamate > linalool > 1,8-cineole subtype. Methyl cinnamate > methyl eugenol was the subtype for "purple castle". The variety "large green leaves" exhibited the linalool > methyl cinnamate subtype. Caryophyllene > methyl eugenol subtype was determined for "clove basil". The rest of the basils "cinnamon", "purple lovingly", "sweet castle" and "purple long-legged", belonged to the methyl cinnamate chemotype in which methyl cinnamate constituted more than 62% of the total essential oil content.