RESUMO
Premyrsinane-type diterpenoids have been considered to originate from the cyclization of a suitable 5,6- or 6,17-epoxylathyrane precursor. Their biological activities have not been sufficiently explored to date, so the development of synthetic or microbial approaches for the preparation of new derivatives would be desirable. Epoxyboetirane A (4) is an 6,17-epoxylathyrane isolated from Euphorbia boetica in a large enough amount to be used in semi-synthesis. Transannular cyclization of 4 mediated by Cp2TiIIICl afforded premyrsinane 5 in good yield as an only diasteroisomer. To enhance the structural diversity of premyrsinanes so their potential use in neurodegenerative disorders could be explored, compound 5 was biotransformed by Mucor circinelloides NRRL3631 to give rise to hydroxylated derivatives at non-activated carbons (6-7), all of which were reported here for the first time. The structures and absolute configurations of all compounds were determined through extensive NMR and HRESIMS spectroscopic studies.
RESUMO
Resumo Este estudo buscou caracterizar perfil e operacionalização de Comitês de Ética em Pesquisa. Foi enviado questionário eletrônico aos 645 comitês existentes à época e respondido por 129 coordenadores. As respostas foram categorizadas por frequência e média e passaram por teste estatístico. Os resultados obtidos indicaram que a maioria dos coordenadores concluíra mestrado ou doutorado em Ciências Biológicas e da Saúde. Os comitês funcionavam há mais de nove anos em instituições de ensino superior com apoio institucional insuficiente. Os membros eram capacitados por meio da leitura das regulamentações e orientações do Comitê. A distribuição de protocolos era feita por afinidade temática, e a decisão grupal se dava por consenso ou votação. Conclui-se que os comitês estão consolidados e cumprem a regulamentação ética, mas necessitam dialogar mais com pesquisadores e a Comissão Nacional de Ética em Pesquisa.
Abstract This study aimed to characterize the Research Ethics Committees in their profile and operationalization. An electronic questionnaire was sent to the 645 existing committees at the time and answered by 129 coordinators. The answers were categorized by frequency and mean of the answers and passed by a statistical test. The results indicated that most of the coordinators had a degree in Biological and Health Sciences, at Masters and PhD levels. The committees had been operating for more than nine years in higher education institutions, with insufficient institutional support. Members were empowered by readings of the Committee';s regulations and guidelines. The distribution of protocols was done by subject affinity and the group decision was given by consensus or vote. It is concluded that the committees are consolidated, comply with ethical regulations, but they need to dialogue more with researchers and with the National Commission of Ethics in Research.
Resumen Este estudio tuvo como objetivo caracterizar el perfil y la operatividad de los Comités de Ética de la Investigación. Se les envió un cuestionario electrónico a los 645 comités existentes a la fecha y fue respondido por 129 coordinadores. Las respuestas se clasificaron por la frecuencia y el promedio y se sometieron a una prueba estadística. Los resultados obtenidos indicaron que la mayoría de los coordinadores finalizaron su magíster o doctorado en Ciencias Biológicas y de la Salud. Los comités funcionaban hace más de nueve años en instituciones de educación superior, con apoyo institucional insuficiente. Se capacitaba a los miembros por medio de la lectura de las normas y directrices del Comité. La distribución de los protocolos se realizó por afinidad temática y la decisión grupal se estableció por consenso o por votación. Se concluyó que los comités están consolidados y cumplen con las normas éticas, pero necesitan dialogar más con los investigadores y con la Comisión Nacional de Ética de la Investigación.
Assuntos
Humanos , Masculino , Feminino , Bioética , Revisão Ética , Comitês de Ética em Pesquisa , Ética em Pesquisa , Pesquisa/normas , Experimentação Humana , Ciências HumanasRESUMO
Aiming to optimize macrocyclic lathyrane-type diterpenes as effective Pgp modulators, the phytochemical study of the methanolic extract of Euphorbia boetica aerial parts was carried out. Two new macrocyclic 6,17-epoxylathyrane-type diterpenes, named epoxyboetiranes A (1) and B (2), along with three known analogues (3-5) were isolated. Epoxyboetirane A (1), a triacetate isolated in large amounts, was hydrolyzed to give epoxylathyrol (6). In order to study the effect of the substitution pattern of the macrocyclic scaffold on MDR reversal, 6 was acylated with aroyl, phenylacetyl, cinnamoyl and alkanoyl chlorides/anhydrides, yielding eight new esters, epoxyboetiranes C-J (7-14). The ability of compounds 1-14 as P-glycoprotein (Pgp, ABCB1) modulators was evaluated through combination of transport and chemosensitivity assays, using L5178Y mouse T lymphoma cell line transfected with the human MDR1 gene. In the transport assay, excepting 1, 3 and 6, the compounds, at non-cytotoxic concentrations, displayed strong MDR reversing activity in a dose-dependent mode, exhibiting all the new acyl derivatives (7-14) a many fold increase in the activity when compared with 1. Apart from 11 and 12, all compounds exhibited remarkable synergistic effects in combination with doxorubicin. An ATPase assay, using membrane vesicles from mammalian cells overexpressing Pgp, was also performed with two representatives of the modulators (4 and 5). The results suggest that both compounds compete with substrates for the Pgp drug-binding sites.
