In vitro antimicrobial activity of essential oils from Heterothalamus Less. (Asteraceae) against clinically relevant bacterial and fungal species

Essential oils are natural, complex, and volatile compounds produced by the secondary metabolism of plants, which often serve as a protection against fungal or bacterial attack. Two species of the Asteraceae family, Heterothalamus alienus (Spreng.) O. Kuntze and Heterothalamus psiadioides Less., are used in folk medicine and recognised for their production of bioactive substances. However, little evidence of their antimicrobial properties currently exists. The aim of this study was to examine the in vitro antimicrobial activity of essential oils from H. alienus and H. psiadioides against clinically relevant bacterial and fungal species. The major chemical components of the essential oils used are terpene substances, of which β-pinene is the major component. Analysis of antibacterial activity was conducted using the disc diffusion method against 22 bacteria (18 gram-positive strains, including 13 enterococci strains resistant or multiresistant to antibiotics, and 4 Gram-negative strains) and 9 fungi (6 yeasts and 3 filamentous fungi). The results indicated that essential oils from Heterothalamus species have a strong antimicrobial effect against gram-positive bacteria and yeasts, variable activity against filamentous fungi, and no activity against gram-negative bacteria. The most prominent results were observed in the sensitivity of Enterococcus faecalis (antibiotic- and multidrug-resistant strains) to the essential oils. In conclusion, this study demonstrates the potential for essential oils from Heterothalamus species for use as both an antiseptic and disinfectant in future approaches to control of clinically relevant gram-positive bacteria and fungi.(Atividade antimicrobiana in vitro de óleos essenciais de Heterothalamus Less. (Asteraceae) contra espécies bacterianas e fúngicas clinicamente relevantes). Óleos essenciais são compostos naturais, complexos e voláteis produzidos no metabolismo secundário de plantas, os quais muitas vezes servem como proteção contra o ataque de fungos ou bactérias. Duas espécies da família Asteraceae, Heterothalamus alienus (Spreng.) O. Kuntze e Heterothalamus psiadioides Less., são utilizadas na medicina popular e reconhecidas por suas substâncias bioativas. Entretanto, existem poucas evidências sobre suas proprieda-des antimicrobianas. O objetivo deste estudo foi avaliar a atividade antimicrobiana in vitro dos óleos essenciais de H. alienus e H. psiadioides contra cepas clinicamente relevantes de bactérias e fungos. Os principais componentes químicos dos óleos essenciais utilizados são as substâncias terpênicas, da qual o β-pineno é o componente majoritário. A análise da atividade antimicrobiana foi conduzida usando a técnica de difusão em disco contra 22 bactérias (18 gram-positivas, incluindo 13 enterococos resistentes ou multirresistentes a antibióticos, e 4 gram-negativas) e 9 fungos (6 leveduras e 3 fungos filamentosos). Nossos resultados indicaram que os óleos essenciais das espécies de Heterothalamus possuem forte atividade antimicrobiana contra bactérias gram-positivas e leveduras, atividade variável contra fungos filamentosos e nenhuma atividade contra bactérias gram-negativas. O resultado mais proeminentes observado foi a sensibilidade de Enterococcus faecalis resistentes e multirresistentes aos óleos essenciais. Em conclusão, este estudo demonstra o potencial dos óleos essenciais das espécies Heterothalamus para serem usados como antissépticos e desinfetantes, abordando o controle de bactérias gram-positivas e fungos de importância clínica

Atividade antimicrobiana in vitro de óleos essenciais de Heterothalamus Less. (Asteraceae) contra espécies bacterianas e fúngicas clinicamente relevantes

Essential oils are natural, complex, and volatile compounds produced by the secondary metabolism of plants, which often serve as a protection against fungal or bacterial attack. Two species of the Asteraceae family, Heterothalamus alienus (Spreng.) O. Kuntze and Heterothalamus psiadioides Less., are used in folk medicine and recognised for their production of bioactive substances. However, little evidence of their antimicrobial properties currently exists. The aim of this study was to examine the in vitro antimicrobial activity of essential oils from H. alienus and H. psiadioides against clinically relevant bacterial and fungal species. The major chemical components of the essential oils used are terpene substances, of which β-pinene is the major component. Analysis of antibacterial activity was conducted using the disc diffusion method against 22 bacteria (18 gram-positive strains, including 13 enterococci strains resistant or multiresistant to antibiotics, and 4 Gram- -negative strains) and 9 fungi (6 yeasts and 3 filamentous fungi). The results indicated that essential oils from Heterothalamus species have a strong antimicrobial effect against gram-positive bacteria and yeasts, variable activity against filamentous fungi, and no activity against gram-negative bacteria. The most prominent results were observed in the sensitivity of Enterococcus faecalis (antibiotic- and multidrug-resistant strains) to the essential oils. In conclusion, this study demonstrates the potential for essential oils from Heterothalamus species for use as both an antiseptic and disinfectant in future approaches to control of clinically relevant gram-positive bacteria and fungi.Óleos essenciais são compostos naturais, complexos e voláteis produzidos no metabolismo secundário de plantas, os quais muitas vezes servem como proteção contra o ataque de fungos ou bactérias. Duas espécies da família Asteraceae, Heterothalamus alienus (Spreng.) O. Kuntze e Heterothalamus psiadioides Less., são utilizadas na medicina popular e reconhecidas por suas substâncias bioativas. Entretanto, existem poucas evidências sobre suas proprieda- -des antimicrobianas. O objetivo deste estudo foi avaliar a atividade antimicrobiana in vitro dos óleos essenciais de H. alienus e H. psiadioides contra cepas clinicamente relevantes de bactérias e fungos. Os principais componentes químicos dos óleos essenciais utilizados são as substâncias terpênicas, da qual o β-pineno é o componente majoritário. A análise da atividade antimicrobiana foi conduzida usando a técnica de difusão em disco contra 22 bactérias (18 gram-positivas, incluindo 13 enterococos resistentes ou multirresistentes a antibióticos, e 4 gram-negativas) e 9 fungos (6 leveduras e 3 fungos filamentosos). Nossos resultados indicaram que os óleos essenciais das espécies de Heterothalamus possuem forte atividade antimicrobiana contra bactérias gram-positivas e leveduras, atividade variável contra fungos filamentosos e nenhuma atividade contra bactérias gram-negativas. O resultado mais proeminentes observado foi a sensibilidade de Enterococcus faecalis resistentes e multirresistentes aos óleos essenciais. Em conclusão, este estudo demonstra o potencial dos óleos essenciais das espécies Heterothalamus para serem usados como antissépticos e desinfetantes, abordando o controle de bactérias gram-positivas e fungos de importância clínica

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Evaluation of antimicrobial and antibiofilm activity of Heterothalamus sp. essential oils against Enterococus faecalis

Óleos essenciais são produtos naturais produzidos no metabolismo secundário de certos vegetais, com propriedades, entre outras, de defesa contra agentes nocivos. No sul do Brasil, destacam-se duas espécies da família Asteraceae, Heterothalamus alienus e Heterothalamus psiadioides, cujas substâncias bioativas ainda são pouco estudadas quanto as suas propriedades. O objetivo do estudo foi avaliar a ação antimicrobiana desses óleos essenciais e a atividade antibiofilme do óleo essencial de H. psiadioides. Os óleos foram obtidos a partir da hidrodestilação das folhas e caracterizados por cromatografia em fase gasosa acoplada a espectrometria de massas. O espectro de ação foi avaliado contra bactérias e fungos. A concentração inibitória mínima (CIM) foi determinada para cocos Gram-positivos resistentes a agentes antimicrobianos, como Enterococcus faecalis resistente a vancomicina (ERV), e a ação antibiofilme foi avaliada tanto pela interferência dos componentes dos óleos sobre a aderência microbiana quanto por sua ação sobre biofilme estabelecido. Os óleos essenciais de Heterothalamus sp. são constituídos por compostos terpênicos, sendo o β-pineno o componente majoritário. Ambos foram eficazes contra as bactérias Gram-positivas e fungos avaliados, porém não inibiram as bactérias Gram-negativas. A CIM variou entre 4 – 16%, sendo que isolados ERV foram também inibidos. A ação do óleo essencial de H. psiadioides diminuiu a aderência microbiana e, em menor escala, causou disrupção do biofilme pré-formado; no entanto, não foi verificada completa inibição do biofilme. Os resultados fornecem informações importantes sobre de ação antimicrobiana desses óleos essenciais e indicam o uso potencial dessas espécies como medicinais.Essential oils are natural substances produced on secondary metabolism of some plants, with properties, among others, of defense against harmful agents. In southern Brazil, Heterothalamus alienus and Heterothalamus psiadioides (Asteraceae) are recognized by bioactive substances that are still little studied by their properties. The aim of this study was to evaluate the antimicrobial activity of essential oils from Heterothalamus sp. and the antibiofilm action of H. psiadioides essential oils. The oils were obtained from the hydrodistillation of the leaves and characterized by gas chromatography coupled mass spectrometry. The spectrum of action was determinate against bacteria and fungi. The minimal inhibitory concentration (MIC) was evaluated for Gram-positive cocci with antimicrobial resistance, as vancomycin-resistent Enterococcus faecalis (VRE) and the antibiofim action was assessed both by interference of the components of the oils on microbial adherence and by its action on established biofilm. The essential oils consist in terpene compounds, and the β-pinene was the major component. The essential oils were effective against Gram-positive bacteria and fungi, but did not inhibit Gram-negative bacteria. The MIC range 4 to 16% and the VRE isolates were also inhibit. The action of essential oils reduced microbial adherence and disrupted de pre-formed biofilm. However, the biofilm was not completely inhibited. These findings provide important information about the antimicrobial activity of these essential oils and indicated the potential use of this species as medicinal

In vitro study of different concentrations of sodium hypochlorite in Enterococcus faecalis

Enterococos são cocos Gram-positivos, membros da microbiota humana e animal, sendo também encontrados em alimentos, solo e água. A resistência de enterococos a antibióticos têm sido muito estudada em amostras alimentares, ambientais e clínicas, porém poucos relatos avaliam a ação de biocidas sobre esses microrganismos. O hipoclorito de sódio (NaOCl) é um desinfetante muito utilizado na indústria de alimentos para destruir microrganismos existentes em superfícies do processo de fabricação. O objetivo do presente estudo foi investigar o efeito de duas concentrações de NaOCl (2,5% e 8,5%) sobre vinte e dois Enterococcus faecalis isolados de carne de frango e correlacionar com o perfil de resistência antimicrobiana dos isolados. A sensibilidade das amostras de enterococos frente às diferentes concentrações de NaOCl (exposição de 10 minutos a temperatura ambiente) foi realizada através da técnica dos cilindros carreadores de aço inox tipo 304. Dois isolados (9,09%) apresentaram crescimento após a exposição à concentração 8,5% de NaOCl e cinco (23%) na concentração de 2,5%. Não foi encontrada relação entre tolerância ao biocida e o perfil resistência. É importante salientar que alguns mecanismos de tolerância aos biocidas podem ser transferíveis para outras células bacterianas e se tornar um grande problema de saúde pública.Enterococci are Gram-positive cocci, members of the microbiota and feed, also found in food, soil and water. The resistance of enterococci to antibiotics has been widely studied in food samples, environmental and clinical, however, few reports have evaluated the action of these biocides on this microorganisms. Sodium hypochlorite (NaOCl) is a disinfectant widely used in the food industry to eliminate bacterial on surfaces of the manufacturing process. The aim of this study was to investigate the effect of two concentrations of NaOCl (2.5% and 8.5%) over twenty-two Enterococcus faecalis isolates from chicken meat poultry and correlate with the antimicrobial resistance profile of isolates strains. The sensitivity of the samples enterococos against the different concentrations of NaOCl (exposure of 10 minutes at room temperature) was performed through the cylinder carriers of type 304 stainless steel. Two isolates (9.09%) showed grow before exposure to a concentration of 8.5% NaOCl and five (23%) at a concentration of 2.5%.No relationshipwasfound between biocide tolerance and resistance profile. It is noteworthy that some mechanisms of tolerance to biocides may be transferable to other bacterial cells and become a major public health problem in the future

Evaluation of antimicrobial and antibiofilm activity of Heterothalamus sp. essential oils against Enterococus faecalis

Óleos essenciais são produtos naturais produzidos no metabolismo secundário de certos vegetais, com propriedades, entre outras, de defesa contra agentes nocivos. No sul do Brasil, destacam-se duas espécies da família Asteraceae, Heterothalamus alienus e Heterothalamus psiadioides, cujas substâncias bioativas ainda são pouco estudadas quanto as suas propriedades. O objetivo do estudo foi avaliar a ação antimicrobiana desses óleos essenciais e a atividade antibiofilme do óleo essencial de H. psiadioides. Os óleos foram obtidos a partir da hidrodestilação das folhas e caracterizados por cromatografia em fase gasosa acoplada a espectrometria de massas. O espectro de ação foi avaliado contra bactérias e fungos. A concentração inibitória mínima (CIM) foi determinada para cocos Gram-positivos resistentes a agentes antimicrobianos, como Enterococcus faecalis resistente a vancomicina (ERV), e a ação antibiofilme foi avaliada tanto pela interferência dos componentes dos óleos sobre a aderência microbiana quanto por sua ação sobre biofilme estabelecido. Os óleos essenciais de Heterothalamus sp. são constituídos por compostos terpênicos, sendo o β-pineno o componente majoritário. Ambos foram eficazes contra as bactérias Gram-positivas e fungos avaliados, porém não inibiram as bactérias Gram-negativas. A CIM variou entre 4 – 16%, sendo que isolados ERV foram também inibidos. A ação do óleo essencial de H. psiadioides diminuiu a aderência microbiana e, em menor escala, causou disrupção do biofilme pré-formado; no entanto, não foi verificada completa inibição do biofilme. Os resultados fornecem informações importantes sobre de ação antimicrobiana desses óleos essenciais e indicam o uso potencial dessas espécies como medicinais.Essential oils are natural substances produced on secondary metabolism of some plants, with properties, among others, of defense against harmful agents. In southern Brazil, Heterothalamus alienus and Heterothalamus psiadioides (Asteraceae) are recognized by bioactive substances that are still little studied by their properties. The aim of this study was to evaluate the antimicrobial activity of essential oils from Heterothalamus sp. and the antibiofilm action of H. psiadioides essential oils. The oils were obtained from the hydrodistillation of the leaves and characterized by gas chromatography coupled mass spectrometry. The spectrum of action was determinate against bacteria and fungi. The minimal inhibitory concentration (MIC) was evaluated for Gram-positive cocci with antimicrobial resistance, as vancomycin-resistent Enterococcus faecalis (VRE) and the antibiofim action was assessed both by interference of the components of the oils on microbial adherence and by its action on established biofilm. The essential oils consist in terpene compounds, and the β-pinene was the major component. The essential oils were effective against Gram-positive bacteria and fungi, but did not inhibit Gram-negative bacteria. The MIC range 4 to 16% and the VRE isolates were also inhibit. The action of essential oils reduced microbial adherence and disrupted de pre-formed biofilm. However, the biofilm was not completely inhibited. These findings provide important information about the antimicrobial activity of these essential oils and indicated the potential use of this species as medicinal