Composition and evaluation of the antimicrobial activity of the essential oil of Senecio selloi Spreng DC / Composição e avaliação da atividade antimicrobiana do óleo essencial de Senecio selloi Spreng DC

The essential oil of the aerial parts of Senecio selloi Spreng. DC. was extracted by hydrodistillation and analyzed by GC/MS. Nineteen compounds were identified, representing 99.9% of the total. The main compounds were found to be sesquiterpene hydrocarbons (71.3%), most of them with a bisabolane skeleton (59.4%). The major constituent was α-zingiberene (54%), followed by monoterpene α-isolimonene (16%). The essential oil was also tested against two Gram-positive and two Gram-negative bacterial species, three yeasts, and an algae. From the strains assayed, only Bacillus subtilis ATCC 6633 showed susceptibility (MIC and MBC = 4400 µg/mL) to the essential oil.

O óleo essencial das partes aéreas de Senecio selloi Spreng DC. foi extraído por hidrodestilação e analisado por CG/EM. Dezenove constituintes foram identificados, representando 99,9% do total. Os principais compostos fornecidos foram sesquiterpenos hidrocarbonetos (71,3%), a maioria destes com esqueleto bisabolano (59,4%). O constituinte majoritário foi a-zingibereno (54%), seguido do monoterpeno a-isolimoneno (16%). O óleo essencial foi testado contra duas cepas Gram-positivas e duas Gram-negativas, três fungos e uma alga. De todas as linhagens testadas somente Bacillus subtilis ATCC 6633 mostrou suscetibilidade (CIM e CBM = 4400 µg/mL) para o óleo essencial.

Protein electrophoretic patterns and antifreezing activity in the leaf apoplast in the tropical andean species Senecio niveoaureus

Tropical high mountain plants have different adaptations to survive extreme daily temperature fluctuations and specially freezing night conditions. In winter plant species, survival to low temperatures is related to the ability of the cell to produce specific low molecular weight proteins (antifreezing proteins) and to export them to the apoplast. In order to see if high mountain tropical plants survive to low temperatures through the same mechanism we collected, during a 24 hourperiod, leaves from Senecio niveoaureus growing at 3,300 and 3,600 m.o.s.l, in the Páramo de Palacio, Chingaza, Colombia. Leaf apoplast proteins had MW between 3512 kDa. Electrophoretic patterns were different depending on the altitude and the time of sampling. However the observed variations could not be linked to changes in temperature or to the altitudinal gradient. Antifreeze activity was detected in leaf apoplast of plants at different altitudes. This is the first report of antifreeze activity in a high mountain tropical species.