Post-column sodiation to enhance the detection of polyacetylene glycosides in LC-DAD-MS analyses: an example from Bidens gardneri (Asteraceae).

The use of liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) in dereplication studies of medicinal plants is a common strategy, but the analyses of polyacetylenes by LC-ESI-MS are little explored and require huge efforts, especially if there are low concentrations in the extracts. A post-column sodiation strategy was successfully applied to enhance the detection of polyacetylene glycosides. Their molecular formulae were proposed by HRESI, whereas the polyacetylene chromophores were determined by UV data. The use of acetic acid in the mobile phase was essential to obtain satisfactory chromatographic resolution, and only the addition of sodium chloride solution allowed good mass spectra, internal calibration and undoubtedly the molar mass determination of polyacetylenes. This new approach has allowed the identification of polyacetylene glycosides from Bidens gardneri extract, guiding the isolation procedures, and two new compounds were obtained. The structures of the isolated polyacetylenes have been confirmed by 1D and 2D NMR, HRMS.

DOSY NMR applied to analysis of flavonoid glycosides from Bidens sulphurea.

2D DOSY 1H NMR has proved to be a useful technique in the identification of the molecular skeleton of the four major compounds of ethyl acetate extract of aerial parts of Bidens sulphurea (Asteraceae). The combination of this technique with HPLC, mass spectrometry and other NMR techniques enabled the identification of four flavonoid glycosides: quercetin-3-O-beta-D-galactopyranoside, quercetin-3-O-beta-D-glycopyranoside, quercetin-3-O-alpha-L-arabinofuranoside and quercetin-3-O-beta-D-rhamnopyranoside.

Chromanones with leishmanicidal activity from Calea uniflora.

The dichloromethane extract of Calea uniflora afforded a mixture of two novel chromanones, uniflorol-A (1) and uniflorol-B (2), and one known chromanone, 2,2-dimethyl-6-(1-hydroxyethyl)-chroman-4-one (3). The structures of these compounds were determined by spectroscopic methods. Biological activity of the compounds against Leishmania major promastigotes was evaluated. Mixture of the novel chromanones 1 and 2 showed significant growth inhibition of the parasite in the micrograms per milliliter range.

Detection of flavonoids in glandular trichomes of Chromolaena species (Eupatorieae, Asteraceae) by reversed-phase high-performance liquid chromatography

In this work, twelve flavonoids were detected in glandular trichomes of two species of Chromolaena through the glandular microsampling technique and HPLC-UV-DAD analysis. This is the first time that the accumulation of flavonoids in glandular trichomes of the genus Chromolaena is reported. Based on the results, we suggest that this technique can be an useful tool in the search of new compounds with medicinal properties as well as in chemotaxonomic studies of Eupatorieae.

Neste trabalho 12 flavonóides foram detectados nos tricomas glandulares de duas espécies de Chromolaena através do emprego da técnica de microamostragem de tricomas glandulares, associada à análise por CLAE. Esta é a primeira vez que se relata o acúmulo de flavonóides em tricomas glandulares no gênero. Com base nos resultados obtidos, podemos sugerir que esta técnica pode ser uma ferramenta útil na busca de substâncias com propriedades medicinais e em estudos quimiotaxonômicos de Eupatorieae.

A new 5-deoxyflavone glycoside from the aerial parts of Calea clausseniana.

A new 5-deoxyflavone glycoside, identified as 7-O-(alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl)-3',4',7-trihydroxyflavone (1), was isolated from the aerial parts of Calea clausseniana. Its structure was determined by spectral analysis.

Enhancing effect of modified beta-cyclodextrins on in vitro skin permeation of estradiol

Estradiol, the most important hormone in females, was complexed with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and randomly methylated beta-cyclodextrin (RM-b-CD). After obtaining the inclusion complexes, they were characterized by DSC, ¹H-NMR and solubility studies. The enhancing effect of CDs on estradiol skin permeation/retention was investigated in vitro using Franz diffusion cells. Both CDs increased estradiol aqueous solubility, but in different proportions. DSC and NMR-H¹ analyses showed that estradiol was complexed with both CDs and RM-beta-CD has stronger interactions with the hormone than HP-beta-CD. Moreover, complexes formation increased estradiol flux through the skin (P<0.01), but the hormone retention in the stratum corneum (SC) only increased after complexation with HP-beta-CD. On the other hand, only RM-b-CD was able to modify estradiol retention in the SC after skin pretreatment with CDs. The results suggest that the enhancing effect of CDs on estradiol flux through the skin may be mainly described as an increase in drug availability on the skin surface due to inclusion complexation. Furthermore, the formation of a significant reservoir of estradiol in the SC due to HP-beta-CD complexation makes it an interesting approach for estradiol transdermal delivery.

Estradiol, o mais importante hormônio feminino, foi complexado com hidroxipropil-beta-ciclodextrina (HP-beta-CD) e metil-beta-ciclodextrina randômica (RM-beta-CD). Após a obtenção dos complexos, os mesmos foram caracterizados por estudos de solubilidade, CDV e RMN-H¹. O efeito das CDs sobre a absorção/retenção do estradiol na pele foi investigado in vitro em células de difusão de Franz. As CDs aumentaram a solubilidade aquosa do estradiol em diferentes proporções. As análises de CVD e RMN-H¹ comprovaram a complexação do estradiol com ambas CDs, sendo que RM-beta-CD apresentou interação mais forte com estradiol do que HP-beta-CD. Mais adiante, a formação de complexos aumentou o fluxo de estradiol através da pele (P<0,01), mas o aumento de fármaco no estrato córneo (EC) foi observado somente após complexação com HP-beta-CD. Por outro lado, somente a RM-beta-CD foi capaz de aumentar a retenção do fármaco no EC após o pré-tratamento da pele com CDs. Os resultados sugerem que o efeito promotor das CDs no fluxo de estradiol pode ser descrito principalmente como aumento da disponibilidade de fármaco na superfície da pele devido à complexação. Além disso, a formação de um significativo reservatório do hormônio no EC torna a complexação com HP-beta-CD uma estratégia interessante para liberação transdérmica do estradiol.

Comparative analysis of triterpenoids from Mikania cordifolia collected from four different locations

The species Mikania cordifolia is distributed across America and widely found throughout Brazilian territory, where is popularly used against snake bites. Methanolic and dichloromethanic extracts prepared from M. cordifolia Robinson collected from four different locations in Brazil were submitted to liquid-liquid extraction and the hexanic phase and residues obtained from this step were analyzed for triterpenoids by gas chromatography. The specimens from Ribeirão Preto-SP and São Carlos-SP showed similar triterpenoid composition: alpha-amyrin, lupeol, lupenone, alpha-amyrin acetate, beta-amyrin acetate, lupeol acetate, taraxasterol acetate, campesterol and beta-sitosterol. Besides these triterpenoids, the specimen from Campos de Jordão-SP presented 11-oxours-12-ene, 11-oxoolean-12-ene and taraxerol acetate, and from Monte Verde, epitaraxerol e taraxerol acetate. The triterpene friedelin could be found in specimens from Ribeirão Preto and São Carlos.

A espécie Mikania cordifolia distribui-se por toda a América e é amplamente encontrada em quase todo o território brasileiro, onde é utilizada popularmente contra mordidas de serpentes. Extratos metanólicos e diclorometânicos preparados a partir e M. cordifolia Robinson coletadas em quatro locais diferentes do Brasil foram submetidos à extração líquido-líquido e os extratos hexânicos e resíduos obtidos nesta etapa foram analisados para a pesquisa de triterpenóides por cromatografia em fase gasosa. Os espécimes coletados em Ribeirão Preto-SP e São Carlos-SP apresentaram os triterpenóides beta-amirina, lupeol, lupenona, acetato de alfa-amirina, acetato de beta-amirina, acetato de lupeol, acetato de taraxasterol, campesterol e beta-sitosterol na suas composições. Além destes trierpenóides, o espécime de Campos de Jordão-SP apresentou 11-oxours-12-eno, 11-oxoolean-12-eno e acetato de taraxerol e, o de Monte verde-MG, epitaraxerol e acetato de taraxerol. A friedelina foi observada apenas nas amostras de Ribeirão Preto-SP e São Carlos-SP.

Estudo fitoquímico de Mikania pseudohoffmanianna G. M. Barroso ex W. C. Holmes / Phytochemical study of Mikania pseudohoffmanianna G. M. Barroso ex W. C. Holmes

This work describes the fractionation of methanol and dichloromethane extracts of aerial parts from the Mikania pseudohoffmanniana G. M. Barroso ex W. C. Holmes. The phytochemical study of extracts led to isolation and the identification of 16 known compounds, including: steroids: campesterol, stigmasterol and 'beta'-sitosterol, diterpenes: ent-15'beta'-E-cinnamoyloxy-kaur-16-en-19-oic acid, ent-15'beta'-Z-cinnamoyloxy-kaur-16-en-19-oic acid and ent-kaur-16-en-19-oic acid, triterpenes: 'alpha'-amyrin, 'beta'-amyrin, 'alpha'-amyrin acetate, 'beta'-amyrin acetate, lupeol, lupeol acetate and friedelin, coumarin: scopoletin, flavonoid: quercetin and caffeoyl quinic acid derivative: 4,5-di-O-[E]-caffeoyl quinic acid

O fracionamento dos extratos diclorometânico e metanólico das partes aéreas de Mikania pseudohoffmanniana G. M. Barroso ex W. C. Holmes resultou na identificação de 16 substâncias: os esteróides: campesterol, estigmasterol e b-sitosterol; os diterpenos: ácido ent-15b-E-cinamoiloxi-caur-16-en-19-óico, ácido ent-15b-Z-cinamoiloxi-caur-16-en-19-óico e ácido ent-caur-16-en-19-óico; os triterpenos: a-amirina, b-amirina, acetato de a-amirina, acetato de b-amirina, lupeol, acetato de lupeol e friedelina; a cumarina: escopoletina; o flavonóide: quercetina e o derivado do ácido cafeoilquínico: 4,5-di-O-[E] -cafeoilquínico

Antimicrobial activity of flavonoids and steroids isolated from two Chromolaena species

The crude extracts (dichloromethanic and ethanolic) and some compounds (8 flavonoids and 5 steroids) isolated from Chromolaena squalida (leaves and stems) and Chromolaena hirsuta (leaves and flowers) have been evaluated against 22 strains of microorganisms including bacteria (Gram-positive and Gram-negative) and yeasts. All crude extracts, flavonoids and steroids evaluated have been shown actives, mainly against Gram-positive bacteria