Produtos naturais: atividades antibacteriana e imunomoduladora in vitro e perfil bioquímico in vivo

Natural products such as essential oils have diverse biological properties and are important sources for research. In addition, the essential oils are present in our daily lives, both in products like shampoos, soaps and foods, as well as alternative therapies such as aromatherapy. We aimed to investigate the biological activities of natural products, the results are presented in the form of three manuscripts. We investigated the antibacterial action of essential oils of tea tree (Melaleuca alternifolia), geranium (Perlagonium graveolens), palmarosa (Cymbopogon martinii) and their major compounds respective 1-terpinen-4-ol, citronellol and geraniol in liquid and vapor phase (Chapter I). The effectiveness of essential oils and their main components such as antimicrobial agents, was demonstrated by direct contact and vapor form using three different methodologies and the information of the damage caused by these vapors using transmission electron microscopy. In another part of the study, we aimed to assess serum biochemical parameters and oxidative stress in rats subjected to inhalation of palmarosa essential oil and geraniol during thirty days (Chapter II). Mices treated with natural products had total cholesterol levels decreased and it was found beneficial effects of the essential oil on oxidative stress. Concluding the study, we evaluated the immunomodulatory action of C. martinii essential oil and geraniol as the production of proand anti-inflammatory by human monocytes (Chapter III). Different concentrations tested showed no cytotoxic effects on monocytes. The production of tumor necrosis factor (TNF)-α was not affected by C. martinii and geraniol, and only the concentration of 5 mg/mL of C. martinii, there was a stimulus for their production. Furthermore, at all concentrations of geraniol and C. martinii increased by interleukin (IL) -10 by human monocytes. The results showed that the noncytotoxic concentrations of oil and geraniol ...Produtos naturais, como os óleos essenciais, possuem diversas propriedades biológicas bem como são importantes fontes para a pesquisa. Além disto, os óleos essenciais estão presentes em nossa rotina, tanto em produtos como xampus, sabonetes e alimentos, assim como em alternativas terapêuticas como a aromaterapia. Objetivamos investigar atividades biológicas de produtos naturais, sendo os resultados apresentados na forma de três manuscritos. Investigamos a ação antibacteriana dos óleos essenciais de tea tree (Melaleuca alternifolia), gerânio (Perlagonium graveolens), palmarosa (Cymbopogon martinii) e seus respectivos compostos majoritários 1-terpinen-4-ol, citronelol e geraniol em sua fase líquida e gasosa (Capítulo I). Foi demonstrada a eficácia dos óleos essenciais e seus principais componentes como agentes antimicrobianos por contato direto e na forma de vapor utilizando três diferentes metodologias e foram destacados os danos causados por esses vapores utilizando informações de microscopia eletrônica de transmissão. Em outra parte do estudo, objetivamos analisar parâmetros bioquímicos séricos e o estresse oxidativo de ratos submetidos à inalação do óleo essencial de palmarosa e geraniol durante 30 dias (Capítulo II). Ratos tratados com os produtos naturais apresentaram níveis de colesterol total diminuídos bem como foi verificado efeitos benéficos do óleo essencial sobre o estresse oxidativo. Finalizando o estudo, avaliamos a ação imunomoduladora do óleo essencial de C. martinii e geraniol quanto à produção de citocinas pró- e anti-inflamatórias por monócitos humanos (Capítulo III). As diferentes concentrações testadas não mostraram efeitos citotóxicos em monócitos. A produção do fator de necrose tumoral (TNF)-α não foi afetada por C. martinii e geraniol, sendo que somente na concentração de 5 μg/mL de C. martinii, houve estímulo para a sua produção. Por outro lado, em todas as..

Antimicrobial activity of essential oils

Natural products have been studied aiming to understand their biological properties. Thus, this study aimed to investigate the antimicrobial activity of twenty-seven essential oils (EOs) used in aromatherapy procedures, a natural therapy with great emphasis currently used against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa strains. The agar dilution method was carried out and minimal inhibitory concentration against 50% and 90% of strains (MIC50% and MIC90% values) were reported. The S.aureus strains were highly susceptible with MIC90% from 0.21mg/mL to black pepper (Piper nigrum) and tea tree (Melaleuca alternifolia) to 26.52mg/mL with copaiba (Copaifera officinalis) EO. Cinnamon (Cinnamomum cassia) and clove (Syzygium aromaticum) EOs were effective against E.coli (2.0mg/mL) while the S.aromaticum EO was against P.aeruginosa (8.29mg/mL). Thus, the higher susceptibility of Gram-positive bacteria when compared with Gram-negative strains was found, and a large variability in the potential antibacterial has also been observed

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

Essential oils from herbs against foodborne pathogens in chicken sausage

Consumption of chicken meat and its products, especially sausage, have increased in recent years. However, this product is susceptible to microbial contamination during manufacturing, which compromises its shelf life. The flavoring and preservative activities of essential oils (EO) have been recognized and the application of these antimicrobial agents as natural active compounds in food preservation has shown promise. The aim of this study was to evaluate the effect of Ocimum basilicum and Origanum vulgare EO on Listeria monocytogenes and Salmonella Enteritidis strains in artificially inoculated samples of fresh chicken sausage. First, the minimal inhibitory concentration (MIC) of EO in vitro was determined. The sausage was prepared and kept at +/- 4 degrees C; then, the inoculation of individual bacteria was carried out. EO were added at 0.3%, 1.0% and 1.5%v/w. After 0, 5, and 24 hours, the most probable number method (MPN) was performed. Transmission electron microscopy (TEM) was used to view the damage caused by these EO on bacterial morphology and/or structure. Only the 1.5% concentration was effective in reducing L. monocytogenes. 0.3% of O. vulgare EO was able to reduce the MPN/g of Salmonella Enteritidis (2 log) after 5 hours trials. O. basilicum EO showed no effect on Salmonella after 5 hours, but decreased by 2 log after 24 hours. O. vulgare EO at 1% gave a greater reduction of S. Enteritidis at 5 hours, increasing or maintaining this effect after 24 hours. The results confirmed the potential benefits of use EO in control of foodborne pathogens.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Effect of inhaling cymbopogon martinii essential oil and geraniol on serum biochemistry parameters and oxidative stress in rats

The effects of the inhalation of Cymbopogon martinii essential oil (EO) and geraniol on Wistar rats were evaluated for biochemical parameters and hepatic oxidative stress. Wistar rats were divided into three groups (n = 8): G1 was control group, treated with saline solution; G2 received geraniol; and G3 received C. martinii EO by inhalation during 30 days. No significant differences were observed in glycemia and triacylglycerol levels; G2 and G3 decreased (P < 0.05) total cholesterol level. There were no differences in serum protein, urea, aspartate aminotransferase activity, and total hepatic protein. Creatinine levels increased in G2 but decreased in G3. Alanine aminotransferase activity and lipid hydroperoxide were higher in G2 than in G3. Catalase and superoxide dismutase activities were higher in G3. C. martinii EO and geraniol increased glutathione peroxidase. Oxidative stress caused by geraniol may have triggered some degree of hepatic toxicity, as verified by the increase in serum creatinine and alanine aminotransferase. Therefore, the beneficial effects of EO on oxidative stress can prevent the toxicity in the liver. This proves possible interactions between geraniol and numerous chemical compounds present in C. martinii EO

Effects of Ocimum basilicum Linn Essential Oil and Sodium Hexametaphosphate on the Shelf Life of Fresh Chicken Sausage

Although consumers and the food industry have an interest in reducing the use of synthetic additives, the consumption of processed meat in Brazil has been increasing because of the easy preparation and low cost. Owing to the antimicrobial and antioxidative properties of Ocimum basilicum essential oil (EO), it has potential applications in food products. Polyphosphates are already used in meat processing with the goal of improving the quality of the products. The aim of this work was to assess the effects of sodium hexametaphosphate (SHMP) and O. basilicum EO, when added separately or together, on physical, chemical, and microbiological parameters during the shelf life of chicken sausage. We also performed sensory analysis of the product prepared in this manner. Six different treatments were produced in which the substances were tested together or separately, and the content of EO was 0.3 or 0.03%. The samples were analyzed after 1, 7, and 15 days of storage at 4 degrees C. An increase in pH on days 7 and 15 in samples that contained SHMP was observed. In the samples that contained either 0.3 or 0.03% EO, coliforms were inhibited throughout the study period (P < 0.05), which was not observed in samples with EO plus SHMP, thus demonstrating that the stabilizer blocked the antibacterial action of EO. There was a reduction in the cook loss and increased compressive force in the samples with 0.5% SHMP, contributing to greater juiciness of the product. The EO had substantial impact on acceptability of samples, but it did not influence the activities already described of polyphosphate.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

In vitro antibacterial and chemical properties of essential oils including native plants from Brazil against pathogenic and resistant bacteria

The antimicrobials products from plants have increased in importance due to the therapeutic potential in the treatment of infectious diseases. Therefore, we aimed to examine the chemical characterisation (GC-MS) of essential oils (EO) from seven plants and measure antibacterial activities against bacterial strains isolated from clinical human specimens (methicillin-resistant Staphylococcus aureus (MRSA) and sensitive (MSSA), Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium) and foods (Salmonella Enteritidis). Assays were performed using the minimal inhibitory concentration (MIC and MIC90%) (mg/mL) by agar dilution and time kill curve methods (log CFU/mL) to aiming synergism between EO. EO chemical analysis showed a predominance of terpenes and its derivatives. The highest antibacterial activities were with Cinnamomun zeylanicum (0.25 mg/mL on almost bacteria tested) and Caryophyllus aronzaticus EO (2.40 mg/mL on Salmonella Enteritidis), and the lowest activity was with Eugenia uniflora (from 50.80 mg/mL against MSSA to 92.40 mg/mL against both Salmonella sources and P aeruginosa) EO. The time kill curve assays revealed the occurrence of bactericide synergism in combinations of C. aromaticus and C. zeylanicum with Rosmarinus. officinalis. Thus, the antibacterial activities of the EO were large and this can also be explained by complex chemical composition of the oils tested in this study and the synergistic effect of these EO, yet requires further investigation because these interactions between the various chemical compounds can increase or reduce (antagonism effect) the inhibitory effect of essential oils against bacterial strains