A high yield of betulinic acid (up to 17% from the ethanolic extract) was found in the leaves of Eugenia florida collected in south-eastern Brazil, making this species a potential commercial source of the title compound. Extracts of E. florida were subjected to solvent partition, and rapid high-speed counter-current chromatography (HSCCC) was applied to the semi-crude extracts to afford betulinic acid in high purity. The mobile and stationary phases were derived from the two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (10:5:2.5:1). The developing solvent system (stationary and mobile phases) for optimum HSCCC separation was chosen by dissolving the fraction to be chromatographed in the proposed solvent mixture and determining the amount of betulinic acid in each phase by densitometric TLC. Purified betulinic acid was characterized by 13C-NMR, GC-MS and co-injection of its methyl ester with standards in GC-FID. The HSCCC technique is commonly employed to isolate triterpene glycosides, but is applied in this study to an aglycone.
Naftoquinonas são metabólitos secundários produzidos por algas, fungos, plantas e animais, caracterizadas por apresentarem múltiplas atividades biológicas. Em Angiospermae as naftoquinonas são encontradas em diversas famílias com destaque para Bignoniaceae, Ebenaceae, Plumbaginaceae, Verbenaceae, dentre outras. O perfil químico da família Bignoniaceae distingue-se pela ocorrência predominante de terpenóides e quinonas, além de alcalóides, flavonóides e derivados não nitrogenados de cadeia longa, entre outros. Esse trabalho visa apresentar as atividades biológicas descritas na literatura para as naftoquinonas isoladas de espécies da família Bignoniaceae, em particular dos gêneros Handroanthus, Paratecoma, Tabebuia e Tecoma.
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