There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Spectroscopy is the study of matter interacting with electromagnetic radiation (e.g., light). The electromagnetic spectrum in Figure 1 illustrates the many different types of electromagnetic radiation, including gamma rays (γ-rays), X-rays, ultraviolet (UV) radiation, visible light, infrared (IR) radiation, microwaves, and radio waves. The frequency (ν) and wavelength (λ) ranges associated with each form of radiant energy are also indicated in Figure 1.

Introduction to Spectroscopy

Differently substituted flavanones were isolated from Leguminosae and their antibacterial activity was comparatively studied against methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MICs) of phytochemical flavanones to clinical isolates of MRSA were determined by a serial agar dilution method. The structure-activity relationship has indicated that 2',4'- or 2',6'-dihydroxylation of the B ring and 5,7-dihydroxylation of the A ring in the flavanone structure are important for significant anti-MRSA activity and that substitution with a certain aliphatic group at the 6- or 8-position also enhances the activity. Among the thirteen flavanones tested, tetrahydroxyflavanones with these structural characteristics isolated from Sophora exigua and Echinosophora koreensis showed intensive activity to inhibit the growth of all MRSA strains at 3.13-6.25 micrograms/ml. The present hydroxyflavanones would be useful in the phytotherapeutic strategy against MRSA infections.

Comparative Study on the Antibacterial Activity of Phytochemical Flavanones against Methicillin-resistant Staphylococcus aureus.

The increasing incidence of drug-resistant pathogens has drawn the attention of the pharmaceutical and scientific communities towards studies on the potential antimicrobial activity of plant-derived substances, an untapped source of antimicrobial chemotypes, which are used in traditional medicine in different countries. The aim of this review is to provide recent insights regarding the possibilities of the most important natural antimicrobial compounds derived from plant sources containing a wide variety of secondary metabolites, which are useful as alternative strategies to control infectious diseases. This review will focus on natural plant products as a useful source of antimicrobial molecules, active in particular, on bacteria and fungi. When considering that many of these compounds, which have been used for centuries, are a source of new drugs and that there are ever-increasing technical breakthroughs, it can be envisaged that in the next years some different molecules discovered by ingenious screeni...

Plant-derived antimicrobial compounds: alternatives to antibiotics.

Seaweed produces metabolites aiding in the protection against different environmental stresses. These compounds show antiviral, antiprotozoal, antifungal, and antibacterial properties. Macroalgae can be cultured in high volumes and would represent an attractive source of potential compounds useful for unconventional drugs able to control new diseases or multiresistant strains of pathogenic microorganisms. The substances isolated from green, brown and red algae showing potent antimicrobial activity belong to polysaccharides, fatty acids, phlorotannins, pigments, lectins, alkaloids, terpenoids and halogenated compounds. This review presents the major compounds found in macroalga showing antimicrobial activities and their most promising applications.

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Antimicrobial Action of Compounds from Marine Seaweed

Avaliação In vitro da atividade antimicrobiana e moduladora dos extratos etanólico e hexânico de bulbo de Costus arabicus

Actividad antimicrobiana y efecto combinado sobre medicamentos antifúngicos y antibacterianos del fruto de Morinda citrifolia L.

Simple Summary The chemical characterization showed a composition of fatty acids that are normally found in other fixed oils that stand out for presenting relevant antibacterial activities alone and/or in association with antibiotics of various classes, such as β-lactams, aminoglycosides, and fluoroquinolones, with lauric acid, myristic acid, oleic acid, and palmitic acid being the main acids in the oil. In this way, further investigations are important to verify if the main compounds present in the oil, in isolation, have antibacterial potential and the modulation capacity verified in the tests carried out with the fixed oil. Abstract Artocarpus heterophyllus (jackfruit) is an evergreen tree distributed in tropical regions and is among the most studied species of the genus Artocarpus. The jackfruit almond has been highlighted in relation to phytochemical studies, biological properties, and application in the development of food products. This study aimed to analyze jackfruit fixed oil regarding chemical components, antibacterial property alone, and in association with antibiotics against standard and MDR bacteria strains. In the analysis of the oil by gas chromatography coupled to a flame ionization detector (GC-FID), a high content of saturated fatty acids (78.51%) was identified in relation to unsaturated fatty acids (17.07%). The main fatty acids identified were lauric acid (43.01%), myristic acid (11.10%), palmitic acid (6.95%), and oleic acid (15.32%). In the antibacterial analysis, broth microdilution assays were used. The oil presented minimum inhibitory concentration (MIC) ≥ 1024 μg/mL in antibacterial analysis for standard and MDR bacterial strains. The oil showed synergistic effects in the association with gentamicin, ofloxacin, and penicillin against MDR strains, with significant reductions in the MIC of antibiotics. The results suggest that the fixed oil of A. heterophyllus has fatty acids with the potential to synergistically modify antibiotic activity.

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Modification of Antibiotic Activity by Fixed Oil of the Artocarpus heterophyllus Almond against Standard and Multidrug-Resistant Bacteria Strains

Hoy en dia, es ampliamente conocido que las cepas patogenas resistentes a antibioticos se estan convirtiendo en uno de los mayores problemas de salud en el campo de la ciencias de la salud. Tambien se sabe que los acidos grasos pueden presentar actividad antimicrobiana. Los aceites de maiz y de soja son ricos en acidos grasos. En este sentido, esta investigacion dirigida para evaluar la actividad antibacteriana y modulador de estos dos aceites fijos usados industrialmente. Ambas pruebas se realizaron utilizando el metodo de microdilucion de concentracion inhibitoria minima en 1,024 mg/ml. La actividad de los aminoglucosidos se mejoro mediante la combinacion de aceite de maiz usando E. coli 27. Uno de los mecanismos que podrian explicar la sinergia hacia el aceite de maiz, en parte, podria ser debido a la naturaleza hidrofobica de los lipidos saturados e insaturados presentes en la muestra. Los resultados indican que los aceites fijos podrian desempenar un papel como una forma alternativa para potenciar de los farmacos antimicrobianos.

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In vitro evaluation of the antibacterial and modulatory activities of corn and soy fixed oils

O estresse oxidativo esta envolvido na patofisiologia de diversas doencas cronicas e degenerativas. Deste modo, a busca por compostos com potencial antioxidante torna-se necessario. Compostos de origem vegetal tem atraido a atencao de pesquisadores devido a sua facil obtencao, baixa toxicidade em mamiferos e pelo grande numero de especies vegetais ainda nao estudas. Deste modo, o objetivo do presente estudo foi avaliar o potencial antioxidante in vitro de sete extratos de especies de plantas nativas do Brasil em modelo de inducao de peroxidacao lipidica em preparacao de cerebro bovino pelo metodo de formacao de substâncias reativas ao acido tiobarbiturico (TBARS). Os extratos hidroalcoolicos de Psidium sobraleanum, Psidium eugeniaefolia, Ocimum basilicum, Lipia sidoides, Licania tomentosa, Melissa officinalis e Mauricia flexuosa foram incubados em tres concentracoes diferentes (3μg/ml, 30μg/ml e 300μg/ml) junto com indutor de peroxidacao lipidica, terc-butilhidroperoxido (t-BOOH) [1mM], utilizando homogenato de cortex de cerebro bovino. Os extratos de Psidium sobraleanum (Araca-de-viado), Psidium eugeniaefolia (Araca Preto) e Lipia sidoides (Alecrim Pimenta) na concentracao de 300μg/ml bloquearam significativamente cerca de 50% (p<0,05) a peroxidacao lipidica induzida por t-BOOH em homogenato de cerebro bovino, demonstrando um potencial antioxidante in vitro. Em estudos similares relacionam o efeito protetor de extratos vegetais a acao de especies reativas de oxigenio (ERO) a presenca de compostos antioxidantes em grande quantidade, os quais neutralizam as ERO impedindo sua reacao com os lipideos presentes na membrana celular evitando o processo de peroxidacao lipidica. Os presentes resultados demonstram potencial antioxidante de tres de sete extratos avaliados in vitro, o que pode demonstrar a presenca de compostos antioxidantes em concentracoes significativas nestes extratos vegetais. Estas especies vegetais ainda sao pouco estudadas e estudos adicionais estao sendo realizados com o objetivo de identificar os mecanismos de acao bem como o potencial de protecao dos extratos em modelos in vivo.
Agradecimento: PBDA  Unipampa; INCT-APA (Instituto Nacional de Ciencia e Tecnologia Antartico de Pesquisas Ambientais), CNPq, FAPERJ, FAPERGS.

Saulo R. Tintino

Papers

Avaliação In vitro da atividade antimicrobiana e moduladora dos extratos etanólico e hexânico de bulbo de Costus arabicus

Actividad antimicrobiana y efecto combinado sobre medicamentos antifúngicos y antibacterianos del fruto de Morinda citrifolia L.

Modification of Antibiotic Activity by Fixed Oil of the Artocarpus heterophyllus Almond against Standard and Multidrug-Resistant Bacteria Strains

In vitro evaluation of the antibacterial and modulatory activities of corn and soy fixed oils

Atividade Antioxidante de Plantas Brasileiras em Modelo de Estresse Oxidativo in vitro