RESUMEN Los liposomas y los niosomas son actualmente las vesículas lipídicas más estudiadas en el área de la nanomedicina. El sistema formado por bicapas de fosfolipídos en medio acuoso, permite que estas vesículas puedan cargar compuestos tanto hidrofílicos como lipofílicos, proporcionando el aumento de solubilidad de las drogas ya utilizadas en la terapia convencional. El foco del desarrollo de estas vesículas debe estar direccionado para la determinación de una composición ideal, con baja toxicidad, biocompatibilidad y estabilidad por un largo período. Estas características estan relacionadas a los componentes utilizados para la formulación y las substancias que serán encapsuladas. Otro punto importante está relacionado con los métodos utilizados para la formulación, que son importantes en la determinación del tipo de vesícula formada, sea ella grande o pequeña, unilamelar o multilamelar. Teniendo en cuenta los estrictos criterios de acciones aplicadas en el desarrollo de estas vesículas, esta revisión buscó reunir información actualizada sobre los diversos métodos utilizados, incluyendo sus principales componentes, considerando el comportamento de cada uno de ellos, cuando son utilizados en diferentes formulaciones. Además, se incluyeron datos que muestran la importancia de las formulaciones en el área médica, evidenciando estudios realizados con las vesículas liposomas e niosomas como promisorias en esta y en otras áreas. Este abordaje permite una mejor comprensión de la participación de componentes como el colesterol y los surfactantes no-ionicos en las formulaciones y también puede servir de base para la selección de los componentes y métodos ideales para futuras investigaciones en el desarrollo de esas vesículas.

ABSTRACT Liposomes and niosomes are currently the most studied lipid vesicles in the nanomedicine field. The system formed by a phospholipid bilayer in aqueous medium allows these vesicles to carry both hydrophilic and lipophilic compounds, providing an increase in solubility of drugs already used in conventional therapy. The focus on the development of these vesicles should be directed to determining the ideal composition, with low toxicity, biocompatibility and which remains stable for long periods. These characteristics are related to the components used for formulation and the substances that will be encapsulated. Another important point relates to the methods used during formulation, which are important in determining the type of vesicle formed, whether these be large or small, unilamellar or multilamellar. Because of the deliberate actions applied in the development of these vesicles, this review sought to gather updated information regarding the different methods used, including their main components while considering the behavior of each of them when used in different formulations. Also, data showing the importance of formulations in the medical field evidencing studies performed with liposome and niosome vesicles as promising in this area, and others, were included. The approach allows a better understanding of the participation of components in formulations such as cholesterol and non-ionic surfactants, as well as the basis for choosing the ideal components and methods for future research in the development of these vesicles.

Stemodinol, a new natural compound, together with known compounds including jaceidin, stemodin, stemodinoside B, isocrenatoside, verbascoside, crenatoside, and isoverbascoside, were isolated from Stemodia maritima Linn. The antioxidant (DPPH method) and antimicrobial activities of stemodin, stemodinoside B, and crenatoside were investigated. Among the components tested, only crenatoside isolated from the roots showed a high antioxidant power. Stemodin and stemodinoside B exhibited antibacterial activities.

A method for separation and quantification of three flavonoids by reverse-phase high performance liquid chromatography (HPLC) was developed and validated. Flavonoids present in a crude methanolic extract of the inner bark of Dimorphandra gardneriana Tul., Fabaceae, were analyzed. Rutin, isoquercitrin and quercetin were used as calibration standards. The analysis was performed using a Thermo Scientific Hypersil C18 column (250 x 4.0 mm i.d., 5 μm particle size), as stationary phase, with a flow rate of 0.8 mL/min and detection at a wavelength of 356 nm. The proposed method was validated by resolution RE No. 899/2003 of the National Health Surveillance Agency. In this study, an excellent linearity was obtained with r higher than 0.99. Besides, the chromatographic peaks showed good resolution. With other validation data, including precision, specificity, accuracy and robustness, this method demonstrated good reliability and sensitivity, and can be conveniently used for the quantification of rutin, isoquercitrin and quercetin in crude methanolic extract of D. gardneriana pods. Furthermore, there are the advantages of easy sample preparation and short time between each injection.

The chemical investigation of the stems and branches of Macroptilium lathyroides led to the isolation of a mixture of β-sitosterol and stigmasterol. The extracts from the roots allowed the isolation of lasiodiplodin, a mixture of stigmast-4-en-6β-ol-3-one and stigmast-4,22-dien-6β-ol-3-one, de-O-methyllasiodiplodin, genistein and lupinalbin A. The structures of the isolated compounds were assigned on the basis of their NMR data, including comparison of their spectral data with values described in the literature. The antibacterial activity of crude extracts from stems, branches and roots was evaluated. This is the first report involving the chemical investigation of this species.

The chemical composition of the essential oil obtained from the fresh and dried leaves of Lippia gracillis Schauer, Verbenaceae, was analyzed by gas chromatography and gas chromatography/mass spectrometry (GC⁄MS). The yield of essential oil extracted from the dried leaves was significantly higher (p<0.05) when compared to the fresh leaves. Seventeen components were identified. The monoterpenes and sesquiterpene hydrocarbons with 96.26% (w/w) of the total oil obtained of fresh leaves and 86.99% (w/w) of the total oil obtained of dried leaves were the principal compound groups. Thymol was observed dominant (44.42%; 21.3%), followed by carvacrol (22.21%; 21.30%), p-cymene (6.23%; 8.58%), α-pinene (5.65%; 19.42%), β-caryophyllene (5.61%; 3.57%) and other minor constitutes, respectively. Microbiological results obtained by agar diffusion method, micro dilution method and minimum inhibitory concentration (MIC) showed that the essential oil has a relevant antimicrobial activity against E. coli (ATCC 10536), E. coli (Ec 27), Pseudomonas aeruginosa (ATCC 15442), S. aureus (ATCC 12692) and S. aureus (Sa 358), with their inhibition zones ranging from 9 to 13 mm and the MIC ranging from 64 to 512 μg/mL.

Os óleos essenciais de Lantana camara L. e Lantana sp., Verbenaceae, foram obtidos por hidrodestilação e seus componentes analisados por CG/EM. Tal procedimento analítico revelou a predominância dos sesquiterpenos, biciclogermacreno (19,42%), isocariofileno (16,70%), valenceno (12,94%) e germacreno D (12,34%) no óleo de L. camara, enquanto o biciclogermacreno (13,93%), germancreno D (27,54 e β-cariofileno (31,50%), %) destacaram-se como majoritários no óleo de Lantana sp. Os dois óleos foram submetidos a avaliação de atividades antibacteriana e de toxicidade usando as larvas de Artemia salina. Os resultados mostraram considerável atividade antibacteriana do óleo de L. camara, principalmente para Proteus vulgaris (ATCC 13315) e Escherichia coli (ATCC 25922). O óleo de Lantana sp. mostrou-se mais significativo contra Sthaphylococcus aureus (ATCC 10390). As atividades de toxicidade CL50 revelaram resultados inferiores ao limite padrão de 1000 μg/mL.

The essential oils from Lantana camara L. and Lantana sp. Verbenaceae, were obtained by hydrodistillation and analyzed by GC/MS. This GC/MS analysis revealed the sesquiterpenoids bicyclogermacrene (19.42%), isocaryophyllene (16.70%), valencene (12.94%) and germacrene D (12.34%) as majoritaries in the essential oil of L. camara, and bicyclogermacrene (13.93%), germacrene D (27.54 and β-caryophyllene (31.50%) in the essential oil from Lantana sp. The two essential oils were evaluated to antibacterial activity and toxicity using Artemia salina. The results revealed considerable antibacterial activity for essential oil from L. camara, meanly for Proteus vulgaris (ATCC 13315) and Escherichia coli (ATCC 25922). The essential oil of Lantana sp. showed major activity for Sthaphylococcus aureus (ATCC 10390). The evaluation of toxicity CL50 revealed results with minor values to limit pattern of 1000 μg/mL.

Tendo em vista que bactérias resistentes a antimicrobianos representam um desafio no tratamento de infecções, é notória a necessidade de encontrar novas substâncias com propriedades antimicrobianas para serem utilizadas no combate a esses microrganismos. Este trabalho relata a avaliação da atividade antibacteriana, toxicidade e identificação dos componentes químicos do óleo essencial de Croton zehntneri (variedade estragol), planta utilizada na medicina popular como calmante e estimulante do apetite. A atividade antimicrobiana e a concentração inibitória mínima (CIM) foram determinadas pelo método de difusão em discos. A avaliação da toxicidade foi realizada frente à Artemia salina com resultado considerado ativo (CL50 < 100 µg/mL). O óleo essencial das folhas apresentou atividade antibacteriana frente a todas as bactérias testadas exceto contra Salmonella typhimurium, sendo o melhor resultado frente a Shigella flexneri com CIM de 50 µg/mL. A análise da composição química foi obtida por cromatografia gasosa acoplada a espectrometria de massa (CG/EM) e permitiu identificar um total de 97,4% dos componentes, com presença majoritária de estragol (76,8%). A presença de tal constituinte nos impulsiona a realização de estudos com outras bactérias, já que o estragol foi anteriormente relatado como sendo responsável por atividades antibacterianas.

Observing that bacteria resistant to antimicrobials represent a challenge in the treatment of infections, it is notorious the need of finding new substances with antimicrobial features to be used in the fight against these microorganisms. This work relates the evaluation of the antibacterial activity, toxicity and identification of the chemical components of the essential oil of Croton zehntneri (variety estragol), plant used in the popular medicine as tranquilizer and appetite stimulant. The antimicrobial activity and minimum inhibitory concentration (MIC) were determined by the method of diffusion in discs. The evaluation of the toxicity was held through brine shrimp test with results considered active (LC50 < 100 µg/mL). The essential oil of leaves presented antibacterial activity with all the bacteria tested except with Salmonlla typhimurium, being the best result with the Shigella flexneri with MIC of 50 µg/mL. The analysis of the chemical composition was obtained by gas chromatography coupled to mass spectrometry (GC/MS) and permitted to identify a total of 97.4 % of the components, with major presence of estragol (76.8%). The presence of the latter drives us to studies with other bacteria, as the estragol was previously reported as being responsible for antibacterial activities.