RESUMO
The leaves of Cyclocarya paliurus with sweet taste are often used as herbal tea in People's Republic of China. In this study eight previously undescribed seco-dammarane type triterpenoids, cyclocariols A-H along with seven known compounds were isolated and characterized from its leaves. A possible biogenetic pathway for seco-dammarane type triterpenoids formation has been discussed. Cyclocariols A-H were evaluated for their cytotoxicities against human liver (SMMC-7721) and breast cancer (BT-549) cell lines. Cyclocariols A, B, E, and H were also tested against human colon tumor (HCT-116) cell lines, where all four exhibited good activities with IC50 values of 6.53, 4.94, 8.24, and 6.48 µM, respectively.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Juglandaceae/química , Folhas de Planta/química , Triterpenos/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Triterpenos/química , Triterpenos/isolamento & purificação , DamaranosRESUMO
In the field of nuclear medicine, nuclear security and astrophysics, Compton imaging is a promising technique for gamma-ray source imaging. We are developing a Compton imager using two layers of CdZnTe pixel array detectors. In this paper, the backward-scattering effect within such imagers is numerically studied using Geant4 Monte Carlo Package. From images reconstructed based on forward-scattering and backward-scattering imaging events, the imaging precision was investigated in a comparative analysis, in regard to energy resolution and position resolution. Furthermore, to establish a method to use backward-scattering imaging events properly so that the imaging efficiency can be significantly improved, the difference between reconstruction from forward-scattering and backward-scattering imaging events was analyzed to uncover a causal mechanism.