The goals of the study were to determine: the antimicrobial and antioxidant activities of essential oil and plant extracts aqueous and ethanolic of Psidium cattleianum Sabine; the chemical composition of the essential oil of P. cattleianum; and the phytochemical screening of aqueous and ethanolic extracts of the same plant. Regarding the antimicrobial activity, the ethanolic extract exhibited moderate antimicrobial activity with respect to bacteria K. pneumoniae and S. epidermidis, whereas, regarding other microorganisms, it showed activity considered weak. The aqueous extract and the essential oil showed activity considered weak, although they inhibited the growth of microorganisms. About the antioxidant potential, the ethanolic and aqueous extracts exhibited a scavenging index exceeding 90%, while the essential oil didn´t show significant antioxidant activity. Regarding the phytochemical composition, the largest class of volatile compounds identified in the essential oil of P. cattleianum included the following terpenic hydrocarbons: α-copaene (22%); eucalyptol (15%), δ-cadinene (9.63%) and α-selinene (6.5%). The phytochemical screening of extracts showed the presence of tannins, flavonoids, and triterpenoids for aqueous and ethanolic extracts. The extracts and essential oils inhibit the growth of microrganisms and plant extracts showed significant antioxidant activity. Also, the phytochemical characterization of the essential oil showed the presence of compounds interest commercial, as well as extracts showed the presence of important classes and compounds with biological activities.Keywords: Psidium cattleianum, antimicrobial action, microdilution, GC-MS, antioxidant activity. Atividade antimicrobiana e antioxidante do óleo essencial e diferentes extratos vegetais de Psidium cattleianum Sabine ResumoOs objetivos do trabalho foram determinar: as atividades antimicrobiana e antioxidante do óleo essencial e dos extratos vegetais aquoso e etanólico de Psidium cattleianum Sabine; a composição química do óleo essencial P. cattleianum e a triagem fitoquímica dos extratos vegetais aquoso e etanólico da mesma planta. Quanto à atividade antimicrobiana, o extrato etanólico apresentou atividade antimicrobiana moderada frente as bactérias K. pneumonieae e S. epidermidis, enquanto frente aos demais micro-organismos apresentou atividade considerada fraca. O extrato aquoso e o óleo essencial apresentaram atividade considerada fraca, embora tenham inibido o crescimento dos micro-organismos. Em relação ao potencial antioxidante, os extratos etanólico e aquoso apresentaram índice de sequestro superior a 90%, enquanto o óleo essencial não apresentou atividade antioxidante significativa. Para a composição fitoquímica, a maior classe de compostos voláteis identificados no óleo essencial de P. cattleianum foram os hidrocarbonetos terpênicos, sendo eles: α-copaeno (22%), eucaliptol (15%), δ-cadineno (9,63%) e α-selineno (6,5%). Na triagem fitoquímica dos extratos verificou-se a presença de taninos, flavonóides e triterpenói...

In this study focused on research on plants as a source of alternative and natural antimicrobial substances, the chemical composition of the essential oil from Prunus myrtifolia (L.) Urb. was assessed through gas chromatography coupled to mass spectrometry (GC/MS) and phytochemical screening of different extracts (aqueous, ethanolic, ethyl acetate, and hexanic) from the same plant, as well as the antimicrobial effect against the following microorganisms: Pseudomonas aeruginosa, Salmonella Typhimurium, Proteus mirabilis, Klebsiella pneumoni, Escherichia coli, Enterococcus faecalis, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis and Candida albicans, through determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values, using the micro-dilution broth method. Finally, the goal was to assess the antioxidant activity of essential oil and plant extracts using the DPPH free radical method (2.2-diphenyl-1-picrylhydrazyl). The largest class of volatile compounds identified in P. myrtifolia oil belongs to aldehydes represented by benzaldehyde compounds. With respect to antimicrobial activity, all extracts and essential oil showed activity against the microorganisms assessed, with exception of hexanic extract. Among the extracts assessed, aqueous and ethanolic extracts were the most effective. Antioxidant activity of aqueous, ethanolic and ethyl acetate extracts was confirmed; however, antioxidant activity of essential oil and hexanic extract was not observed.

Aim The homogenisation of historically isolated gene pools has been recognised as one of the most serious conservation problems in the Antarctic. Lichens are the dominant components of terrestrial biotas in the Antarctic and in high mountain ranges of southern South America. We study the effects of dispersal strategy and migration history on their genetic structure to better understand the importance of these processes and their interplay in shaping population structure as well as their relevance for conservation. Location Maritime Antarctic and southern South America. Methods Populations of three fruticose lichen species, Usnea aurantiacoatra, U. antarctica and Cetraria aculeata, were collected in different localities in the Maritime Antarctic and southern South America. Usnea aurantiacoatra reproduces sexually by ascospores, whereas the other two species mostly disperse asexually by symbiotic diaspores. Samples were genotyped at 8–22 microsatellite loci. Different diversity and variance metrics, Bayesian cluster analyses and Discriminant Analysis of Principal Components (DAPC) were used to study population genetic structure. Historical migration patterns between southern South America and the Antarctic were investigated for U. aurantiacoatra and C. aculeata by approximate Bayesian computation (ABC). Results The two vegetative species display lower levels of genetic diversity than U. aurantiacoatra. Antarctic populations of C. aculeata and South American populations of U. aurantiacoatra display much stronger genetic differentiation than their respective counterparts on the opposite side of the Drake Passage. Usnea antarctica was not found in South America but shows comparably low levels of genetic differentiation in Antarctica as those revealed for U. aurantiacoatra. Phylogeographic histories of lichens in the region differ strongly with recent colonisation in some instances and potential in situ persistence during Last Glacial Maximum (LGM) in others. Patterns of genetic diversity indicate the presence of glacial refugia near Navarino Island (South America) and in the South Shetland Islands. ABC analyses suggest that C. aculeata colonised the Antarctic from Patagonia after the LGM. Results for U. aurantiacoatra are ambiguous, indicating a more complex population history than expressed in the simplified scenarios. Main Conclusions Mode of propagation affects levels of genetic diversity, but the location of glacial refugia and postglacial colonisation better explains the diversity patterns displayed by each species. We found evidence for glacial in situ survival of U. aurantiacoatra on both sides of the Drake Passage and postglacial colonisation of Antarctica from South America by C. aculeata. Maintaining the strong genetic differentiation of Antarctic populations of C. aculeata requires strict conservation measures, whereas populations of U. aurantiacoatra are exposed to a much lower risk due to their higher diversity and connectivity.

The goal of this study was to assess the antimicrobial activity of the essential oil and aqueous, alcoholic, and ethyl acetate extracts of Guarea kunthiana A. Juss against ten Salmonella serotypes from poultry origin (Enteritidis, Infantis, Typhimurium, Heidelberg, Mbandaka, Give, Saintpaul, Ohio, Gallinarum, and Agona); the insecticidal potential of the oil and extracts against larvae and adults of Alphitobius diaperinus (Coleoptera: Tenebrionidae) (Panzer, 1797); and also to determine the antioxidant activity of these compounds using the capture method of radical 2.2-diphenyl-2-picrylhydrazyl (DPPH). With respect to the antimicrobial activity of the essential oil of G. kunthiana, the most sensitive serotypes were Infantis, Typhimurium, and Give, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 54.6 µg/ml. Regarding the other serotypes tested, the action of the oil was classified as moderate, weak, or inactive. With respect to the extracts, the greatest microbial susceptibility was observed in the activity of the alcoholic extract, with MIC and MBC values of 0.39 mg/ml for the serotype Infantis, and MIC and MBC values of 0.78 mg/ml for the serotype Gallinarum. The results of the insecticidal activity of the essential oil and the extracts were found to be low, with 28% mortality of larvae and 12% of adults, at a concentration of 200 mg/ml. Regarding the extracts, the best results were observed using the alcoholic extract at concentrations of 10%, with 34 and 44% mortality of larvae and adults, respectively. The values of antioxidant activity showed that there were no significant differences between the synthetic antioxidant butylhydroxytoluene (BHT), the essential oil, and the alcoholic extract, revealing that both the essential oil and the alcoholic extract of G. kunthiana exhibited high antioxidant capacity.

The essential oils are extracted from plant compounds and can present activities antimicrobial and antioxidant properties. The goals of the present study were: (a) to determine the chemical composition of the essential oil of Guarea kunthiana A. Juss using the method of gas chromatography coupled to mass spectrometry (GC-MS); (b) to evaluate the antimicrobial potential of this oil using the broth microdilution method against different microorganisms: five Gram-negative bacteria, four Gram-positive bacteria and a yeast and (c) to determine the antioxidant activity of the oil using the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical assay. The GC-MS analyses allowed identifying 13 constituents, representing 96.52% of the essencial oil composition. The main compounds identified were α-zingiberene (34.48%), β-sesquiphellandrene (22.90%), and α-curcumene (16.17%). With respect to the antimicrobial activity, the essential oil was effective against all the microorganisms tested, except for the bacteria E. coli and K. pneumoniae, which were resistant to the action of the oil. From a general point of view, Gram-positive bacteria were more susceptible to the action of the essential oil than Gram-negative bacteria. The essential oil exhibited antioxidant potential.Keywords: Guarea kunthiana, essential oil, chemical composition, antimicrobial activity, antioxidant. Composição química, potencial antimicrobiano e antioxidante do óleo essencial de Guarea kunthiana A. Juss ResumoOs óleos essenciais são compostos extraídos de plantas e podem apresentar propriedades antimicrobianas e antioxidantes. O objetivo deste trabalho foi (a) determinar a composição química do óleo essencial de Guarea kunthiana A. Juss pelo método de cromatografia gasosa acoplada à espectrometria de massas (CG-EM); (b) avaliar o potencial antimicrobiano deste óleo pelo método de microdiluição em caldo frente a diferentes micro-organismos, sendo cinco bactérias Gram-negativas, quatro Gram-positivas uma levedura e (c) por fim, determinar a atividade antioxidante do óleo pelo método de captura do radical livre 2,2-difenil-1-picril hidrazil (DPPH). As análises de CG-EM resultaram na identificação de 13 constituintes, representando 96,52% da composição do óleo essencial. Os principais compostos identificados foram α-Zingibereno (34,48%), β-Sesquifelandreno (22,90%) e α-Curcumeno (16,17%). Em relação à atividade antimicrobiana, o óleo essencial foi efetivo frente a todos os micro-organismos testados exceto para as bactérias E. coli e K. pneumoniae, as quais se apresentaram resistentes à ação do óleo. Em geral, as bactérias Gram-positivas foram mais suscetíveis à ação do óleo essencial em relação às Gram-negativas. O óleo essencial apresentou potencial.Palavras-chave: Guarea kunthiana, óleo essencial, composição química, atividade antimicrobiana, antioxidante.