Estudo fitoquímico dos talos de Croton velutinus baill e análise dos componentes do óleo essencial de Ocimum basilicum var. purpurascens BENTH e de seus derivados por espectroscopia ordenada por difusão (DOSY)

Abstract

Croton velutinus Baill is a plant belonging to the family Euphorbiaceae found in the “cadeia do espinhaço”, that comprises the States of Minas Gerais and Bahia, occurring in rocky fields and sandy soils. Several species of Croton have been studied due to different therapeutics applications. There is no report about the phytochemical study of C. velutinus found in the literature. The hexane and ethanolic extracts of stalks of C. velutinus were subjected to chromatographic procedures, resulting in isolation of two flavonoids, Casticin and 5-hydroxi-3,6,7,4’-tetrametoxyflavone, two sesquiterpenes (6S,7S) 7,11-dihydroxi-bisabol-2-en-4-one and Delobanone and a inedited diterpene clerodane, velutinoic acid. The extracts of Croton velutinus were subjected to assays of larvicidal, antioxidant activities, acetylcholinesterase enzyme inhibition and angiotensin I converting enzyme inhibitors. The second part of this work, consisted in essential oil analysis of Ocimum basilicum var. purpurascens BENTH, plant known like alfavaca roxa by GC-MS and DOSY. The major components in the essential oil were identified as eugenol (65,2%) and β-caryophyllene (23,4%). The resolution of eugenol and β-caryophyllene was performed by Matriz-assisted DOSY (MAD) using the non-ionic surfactant Brij 78 as matrix. Were prepared eugenol derivatives: eugenyl acetate, cis and trans-isoeugenol, for to be analyzed by MAD in binary and ternary mixtures containing vanillin like one of components. The diffusion coeficients of eugenol and β-caryophyllene in the essential oil vary considerably with the change of solvent of CDCl3 to the mixture DMSO-d6:D2O (1:1) with ∆EC 7,27% to ∆EC 89,12% separation, respectively, whereas the binary mixture of this compounds vary of ∆EC 9,39% to 98,33%. The eugenol and vanillin 10 mM mixture showed the variation of ∆EC 35,5% in presence of Brij 78. The larvicidal activity of essential oil, eugenol and their derivatives were obtained from 3rd stage larvae of mosquito Aedes aegypti, and the essential oil showed the most efficient. The structural characterization of the isolated compounds was achieved by spectroscopy methods (MS, IR and NMR 1H e 13C, including one and two dimensional techniques) and by comparison with literature dates.