A técnica de cromatografia líquida acoplada a um espectrômetro de massas com ionização "electrospray" (LC-ESI-MS/MS) foi usada para a determinação simultânea de resíduos de dez sulfonamidas (SAs: sulfacetamida, sulfatiazol, sulfamerazina, sulfametazina, sulfametoxipiridazina, sulfametazol, sulfacloropiridazina, sulfametoxazol, sulfadimetoxina e sulfaquinoxalina) em ovos. As amostras foram preparadas por precipitação das proteínas com acetonitrila seguida por extração em fase sólida. Após remoção do solvente e reconstituição, os extratos finais foram injetados no LC-ESI-MS/MS no modo positivo para todas as sulfonamidas. O método validado resultou em recuperação entre 87 e 116% com desvios padrão relativo entre 8,5 e 27,2%, CCa entre 101,0 e 122,1 ng g -1 e CCb entre 114,5 e 138,8 ng g -1 . O método analítico, no qual foram utilizadas amostras fortificadas, foi validado baseado na Decisão da Comissão 2002/657/CE.Liquid chromatography-electrospray ionization -tandem mass spectrometry (LC-ESI-MS/MS) was used to simultaneous determination of ten sulfonamide (SAs) residues (sulfacetamide, sulfathiazole, sulfamerazine, sulfamethazine, sulfamethoxypyridazine, sulfamethizole, sulfachloropyridazine, sulfamethoxazole, sulfadimethoxine and sulfaquinoxaline) in eggs. Samples were extracted with acetonitrile and the supernatants were cleaned up by solid phase extraction. After solvent evaporation and reconstitution, aliquots of the final extracts were injected into a LC-ESI-MS/MS in positive mode for all sulfonamides. The validated method resulted in recoveries ranging between 87 and 116% with relative standard deviations between 8.5 and 27.2%, CCa between 101.0 and 122.1 ng g -1 , and CCb between 114.5 and 138.8 ng g -1 . The analytical method, using fortified samples, was validated based on the Commission Decision 2002/657/EC.
publicado na web em 04/09/2013 TERPENES FROM Nasutitermes genus TERMITES (Isoptera, Termitidae, Nasutitermitinae). The chemical composition of the front gland of termites has been studied for over 40 years. The genus Nasutitermes, considered the most evolved of the Termitidae family, has a peculiarity that sets it apart from the others: a caste of soldiers that carry a terpenic mixture used in defense. This secretion is formed by mono, sesqui and diterpenes from trinervitane, kempane and rippertane skeletons, only found in termites. This article sought to review the scientific literature and contribute to the knowledge on the chemical composition of the secretion of the Nasutitermes soldiers from the interesting aspects of its behavior.Keywords: Nasutitermes; terpenes; chemical defense. INTRODUÇÃOTérmitas, usualmente conhecidos por cupins, estão entre as espé-cies de insetos mais abundantes nas regiões tropicais e subtropicais do planeta. Esses insetos são conhecidos pelos prejuízos econômicos que causam em áreas urbanas, devido ao ataque às construções e madeiras em geral. Algumas espécies são também consideradas pragas agrícolas e florestais. Mas, do ponto de vista ecológico, são muito benéficos para a natureza: apresentam papel fundamental na constituição química e física do solo; atuam na reciclagem de materiais a base de celulose; e suas construções, túneis e caminhos dentro do solo e de seus ninhos podem servir de abrigo para outros animais. Existem mais de 2900 espécies de cupins. 1Os térmitas são eusociais com alto nível de organização social, formada por castas, a saber, dos reprodutores (de forma simplificada, são os alados que se transformam em reis e rainhas), operários e soldados, que exercem papéis específicos na colônia (Figura 1). As castas apresentam diferenças morfológicas, fisiológicas de desenvolvimento e funcionais, sendo que na maioria das espécies os soldados e operários são estéreis.O rei e a rainha são responsáveis pela reprodução. Como todos os insetos hemimetábolos, dos ovos eclodem ninfas que, no caso dos cupins, podem se transformar em operários, soldados ou alados, os futuros reprodutores. Há uma nomenclatura diferente para algumas fases, assim, ninfas muito jovens podem ser chamadas de "larvas". Os alados saem voando das colônias originais, tanto de ninhos epígeos (sobre o solo), arborícolas (em árvores), como de aberturas no solo, no caso de cupins subterrâneos, e vão perder as asas, formar novos casais, fundando novas colônias. Os operários são os responsáveis por praticamente todas as tarefas da colônia como, por exemplo, cuidado à prole, alimentação das outras castas, construção e/ou reparação do cupinzeiro, enquanto os soldados são responsáveis pela defesa da colônia. A defesa pode ser física, química ou uma combinação de ambas. Algumas espécies possuem mandíbulas bem desenvolvidas, usadas no ataque direto aos invasores. Outras espécies utilizam tanto o método físico quanto o químico já que possuem, além das mandíbulas, substâncias químicas que são ejetadas sobre o inimigo. Há...
The defensive secretion of the frontal gland from termite soldiers is a mixture of monoterpenes, sesquiterpenes and diterpenes, the latter being the most representative. Analyses of the dichloromethane extract from soldiers of the Brazilian termite, Nasutitermes macrocephalus (Silvestri, 1903) (Isoptera, Nasutitermitinae), described for the first time, allowed to identify the presence of two monoterpenes (-pinene and limonene) and two sesquiterpenes (-transcaryophyllene and -selinene) by GC-EIMS, and the isolation of one rippertane and six trinervitane diterpenes by RP-HPLC. The chemical structures of the purified compounds were elucidated by interpretation of their spectroscopic data (1D and 2D NMR, EIMS, HRESIMS, and specific optical rotation) and the complete unequivocal assignment of the 3α-hydroxy-trinervita-1(15),8(19)-dien-2-one (6) was included in this paper, to complement the lack of information in the literature. Antibacterial, antifungal and cytotoxicity against cancer cell lines activities were evaluated. In particular, the compounds 2,3-dihydroxytrinervita-1(15),8(19)-diene (2) and 3-hydroxy-15-rippertene (7) exhibited the better activities against the clinically isolated Gram-positive bacterium methicillin-resistant Staphylococcus aureus BMB 9393, both with a MIC value of 31.2 g mL-1. This is the first description of a rippertane diterpene (7) as an antibacterial agent.
Termites are insects with a complex social organization on castes among which soldiers are the only responsible for the colony defense. The soldiers of the Nasutitermes genus use chemical defense, which comprises a mixture of mono, sesqui and mainly diterpenes. The new diterpene 2b,3a-dihydroxy-trinervita-1(15),11-diene, found in Nasutitermes macrocephalus, was isolated using preparative high performance liquid chromatography (HPLC) and identified by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) techniques. The absolute stereochemistry determined was supported by ab initio calculations and by comparison of the experimental circular dichroism data with the theoretical results. The isolated diterpene was evaluated against the bacteria Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative), and the fungi Candida albicans and Aspergillus brasiliensis. The isolated diterpene presented minimal inhibitory concentrations of 62.5 and 62.5 µg mL -1 against S. aureus and C. albicans, respectively. Keywords: Nasutitermes macrocephalus, biological activities, HPLC IntroductionTermites are insects present all over the world, with about 2750 species living in tropical and subtropical regions.1 They are social insects with castes responsible for distinct functions: workers are tasked to build the mound and to feed the others castes; king and queen respond for reproduction, resulting in eggs that become larvae that may become workers, soldiers or winged (secondary breeding).2,3 Soldiers are responsible for the defense of the mound and, depending on the species they will present mechanical and/or chemical defense.1,2,4,5 The Nasutitermes genus (Isoptera: Termitidae: Nasutitermitinae) is the most evolved among the termites since their soldiers use only chemical defense, avoiding contact with the enemies. 5They produce and storage a mixture of mono, sesqui and diterpenes in the frontal gland, resulting in a sticky secretion that is ejected against the enemies.6-10 The great success of the Nasutitermes evolution has been attributed to this defense method.2 The monoterpenes are the same compounds found in plants, like a-pinene, b-pinene, limonene and terpinolene, and they are associated with the protection of the colony from fungal infections. 11Sesquiterpenes are in minor quantity, as found in N. gracilirostris, N. torresi, N. triodiae, N. octopilis and N. macrocephalus. 9,12,13 The skeletons of the diterpenes found in termites (trinervitanes, kempanes and rippertanes) are broadly described in all species, 14 and are related to both species communication, as they are blind, and to defense. 15 Although there are several studies on the identification of these diterpenes, just a few of them focused on the biological activities of those substances. For example, one study presented five compounds with antibacterial activity against Bacillus subtilis and Escherichia coli.16 Therefore, several molecules with interesting biological activities produced by species in the Nasutitermes ...
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