Synergism of crude extracts and essential oils from medicinal plants with antimicrobial drugs

The emergence of resistant strains to conventional antimicrobial drugs has been constant as well as research aimed new alternatives of antibacterial agents. Therefore, considering that natural products have been an important potential source of new antimicrobial drugs, aim to verify the synergism by disk and time kill curve method between antimicrobials (extracts-Ext. and essential oils-EO) from four plant and eight antimicrobial drugs against Staphylococcus aureus and Escherichia coli strains from human specimens. The S. aures strains were highly susceptible with all plant antimicrobials (eg., 1.24 mg/ml with Vernonia polyanthes Ext. and 2.21 mg/ml with Eugenia uniflora EO for the Minimal Inhibitory Concentration-MIC). According disk method, the Bacharis dracunculifolia and V. polyanthes EO had synergism with all eight tested drugs while only Matricaria chamomilla Ext. showed synergism against S. aureus. The synergism was found with V. polyanthes and E. uniflora Ext. while M. chamomilla Ext. had antagonism against E. coli strains. By time kill curve, the bacterial growth inhibition was superior when drugs were tested alone and the synergism effect also was verified. The antagonism effect was detected only for E. coli strains and only with Ext. Results indicated the potential use of these products as coadjutants during treatment of infectious diseases.

Effects of mineral stress on the vegetative development of greenhouse-grown bell pepper plants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Biochemical changes during the induction of mineral stress in plants of bell pepper cultivated in fertigation system

The greenhouse production associated with the fertigation management, have established in Brazil as economical alternative for several horticultural species. With this strategy this study had as aim to evaluate possible impacts in the metabolism of plants of bell pepper (Capsicum annuum L.; cv Elisa) in response to the increase of mineral concentration in the soil. During the experiments, the some nutrient concentrations were altered, to obtain high values of electric conductivity (EC) in the soil solution. The EC values commonly observed in the traditional fertigation system were adopted, as control. It was also verified the possibility of reduction of the mineral stress impact by the application of organic matter in the soil. Parameters of the antioxidative response system, as the superoxide dismutase (SOD) and catalase enzyme activities besides the proline content were evaluated to measure the extension of the saline stress and their effects on the plants. The increase of EC of the soil induced to the increase of the proline concentration and the SOD activity. Unexpectedly, it was verified that the saline stress inhibited the activity of the enzyme catalase. It was also concluded that the monitoring of EC of the soil is an indispensable tool to reach success in the fertigation system and that the study of the activity of the enzymes of the antioxidative response system, and the proline contents can be assumed as indicators in of the levels of stress in bell pepper plants (Capsicum annuum L.; cv Elisa).

Chemistry and pharmacology of some plants mentioned in the letter of Pero Vaz de Caminha

Brazil has a long tradition in the study of medicinal plants. When the Portuguese arrived to the new colony, Pero Vaz de Caminha, the scriber of the fleet, left the first impressions of the local and the inhabitants. He clearly mentions how the Indians use natural dye as tincture to paint their bodies. This article reviews the phytochemical and pharmacological characteristics of these colorants and other medicinal plants recently identified mentioned in this letter.