ABSTRACT
Os ácidos triterpênicos são metabólitos comuns na família Myrtaceae, especialmente no gênero Eugenia. O ácido ursólico foi descrito como um dos principais constituintes, nas folhas de Eugenia brasiliensis, coletada no Sudoeste do Brasil. Uma partição prévia, por solventes, do extrato etanólico ou do extrato clorofórmico de E. brasiliensis, seguida por uma purificação por cromatografia de contra-corrente de alta velocidade (CCCAV), conduziu ao isolamento do ácido ursólico com alto grau de pureza (> 97 por cento). Esta substância, também foi isolada por cromatografia convencional de coluna aberta (rendimento de 0.22 por cento a partir do extrato etanólico), e caracterizada por 13C-RMN, GC-EM e co-injeção com padrão comercial em CG-DIC, na forma do éster metílico. A técnica de CCCAV, usualmente usada para triterpenos glicosilados, foi aqui aplicada para a aglicona. As fases móvel e estacionária, no experimento de CCCAV, foram geradas pela mistura de n-hexano : acetato de etila : metanol : água, na proporção 10:5:2,5:1. A seleção do sistema de solventes (fases estacionária e móvel) foi determinada pela máxima distribuição eqüitativa do ácido ursólico em ambas as fases, medida por densitometria e monitorada por cromatografia em camada delgada, CCD, usando-se ácido ursólico comercial como referência.
Triterpene acids are common metabolites in the Myrtaceae family, especially in the genus Eugenia. Ursolic acid was found in Eugenia brasiliensis collected in Southeastern Brazil. A previous solvent partition of the ethanol or chloroform extracts of the leavesof E. brasiliensis, followed by rapid high-speed counter-current chromatography (HSCCC) afforded ursolic acid in high purity (> 97 percent). This compound was also purified apart by conventional column chromatography (yield of 0.22 percent from the ethanolic extract) and characterized by 13C-NMR, GC-MS and co-injection of its methyl ester with standards in GC-FID. The HSCCC technique, usually applied to triterpene glycosides, was here applied successfully to an aglycone, to which examples are rarely described. The mobile and stationary phase for the HSCCC experiment were derived from the two-phase solvent system composed by n-hexane : ethyl acetate : methanol : water in the proportion of 10:5:2.5:1. The choice of the developing solvent system for optimum HSCCC separation was determined by TLC coupled to densitometric measurements of ursolic acid in both stationary and mobile phase, generated by the upper and lower layer of the system above. Commercial ursolic acid was used as standard.
ABSTRACT
Cholecystokinin (CCK-8) coexists with dopamine in some neurons and modulates dopaminergic neurotransmission. In the present study we determined the effect of CCK-8 on stereotyped behavior in supersensitive dopaminergic system. Adult male Wistar rats, weighing 200-250 g, were used. Dopaminergic supersensitivity was induced by long-term haloperidol (HAL) treatment (30 days: 1.0 mg/kg twice a day). Seventy-two hours after HAL withdrawal animals received CCK-8 (14.5 nmol/5 µl) or saline intracerebroventricularly (icv) before being tested for apomorphine (APO, 0.6 mg/kg, sc)-induced stereotyped behavior. experimental groups were: long-term HAL-treated rats that received saline (HSAL, N = 9) or CCK-8 (HCCK, N = 11) icvand long-term saline-treated rats that received CCK-8(SCCK,N = 9) or saline (SSAL, N = 8) icv. As expected, HSAL rats showed statistically significant higher stereotypy scores than SSAL rats (42 + or - 1.7 vs 31 + or - 1.6; P<0.05) and CCK-8 icv reduces stereotypy in dopaminergic-supersensitive rats, and suggest that the dopamine supersensitivity phenomenon can be modulated by CCK-8