This study aimed to chemically characterize commercial Essentials oils and determine their thermal properties and their antimicrobial and antioxidant activities. Essential oils extracted from leaves of Rosemary, lemongrass, cloves, orange, Tahiti lemon and thyme were studied, with chemical characterization by gas chromatography/mass spectrometry, thermoanalytical characterization and antimicrobial (microdilution) and antioxidant (ferric reduction activities power - FRAP). The chemistry of the essential oils composition was consistent with literature data and justified their thermal behavior. Comparing the thermal stability between the studied essential oils results revealed the optimization of the da Tonset = 106.6to clove`s essential oils. The results of differentiated antimicrobial and antioxidant activity justified by factors that influence the biological functions of Essentials oils, such as the origin of the plant (climate conditions), forms of cultivation and harvesting of the raw material, parameters and extraction method. Thus, it emphasizes the importance of a Brazilian production of essentials to take advantage of the technological and analytical capacity of national research centers, to provide the market with traceable products with certified identity.

The use of new natural antimicrobials has gained attention from the pharmaceutical and food industry, in addition to end consumers, as additive options to conventional antibiotics for resistant microorganisms and also as natural preservatives. Essential oils are secondary plant metabolites that protect plants against predators and pathogens. The aim of this study was to evaluate thermal properties of cinnamon essential oil (EO) and its antibacterial activity. Ten components were identified, with (E) - cinnamic acid (67.70%) being the major component. Cinnamon EO was thermally stable up to 106.6ºC (Tonset) and Tdec occurred at 178.5 °C and Toffset up to 216.0 °C. There was endothermic transition; enthalpy variation (∆H) and activation energy (Ea) was -531.6 KJ Kg-1 and -1.26 ± 0.03 J mol-1, respectively. Bacterial strains showed distinct resistance to tested antibiotics and variation in Minimum Inhibitory Concentration values ranging from 0.8 to 1.6 mg mL-1. Cinnamon EO initiated bactericidal effect against all bacteria tested after four hours of contact and Minimum Bactericide Concentration was 0.4 mg mL-1, exception for Bacillus cereus (0.8 mg mL-1). Analysis of cinnamon thermal properties EO showed its stable thermal performance up to 106.6 °C and broad spectrum, that may be an antimicrobial proposal.

How to citeComplete issue More information about this article Journal's homepage in redalyc.org Scientific Information System Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Non-profit academic project, developed under the open access initiative

No abstract

O presente trabalho teve como objetivo analisar a estabilidade térmica de um óleo essencial comercial de tomilho, submetido a cinco temperaturas diferentes de tratamentos térmicos e dois estados de armazenamento. Utilizou-se as técnicas de Análise Termogravimétrica e Calorimetria Exploratória Diferencial e a estabilidade termoquímica do óleo essencial foi caracterizada por meio de Cromatografia Gasosa e Espectroscopia no Infravermelho por Transformada de Fourier. Houve estabilidade e sem perda de massa do óleo essencial de tomilho até aproximadamente 75 °C. Resultados indicaram que não ocorreu flutuação do comportamento térmico nas amostras estocadas hermeticamente durante os tratamentos térmicos, enquanto que nas amostras acondicionadas em estado aberto, o comportamento térmico foi otimizado até o tratamento a 60 °C. As alterações da composição química e dos grupo funcionais do óleo essencial sob aquecimento e condição de acondicionamento também foram avaliadas.