Gilda Guimarães Leitão

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Brazilian plant extracts belonging to 16 species of 5 different families (71 extracts) were tested against the stable DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free-radical. The ability to scavenge DPPH radical was measured in these experiments by the discoloration of the solution. Ginkgo biloba and rutin, commonly used as antioxidants for medical(More)
Lippia alba (Miller) N.E. Brown is an aromatic herb that occurs in practically all regions of Brazil and has a large importance in Brazilian folk medicine. This species is characterized by a variability in morphology and in the chemical composition of the essential oil. The present work focused on the ethnopharmacological investigation of Lippia alba,(More)
Counter-current chromatography (CCC) was used to isolate chavibetol from the essential oil of leaves of Pimenta pseudocaryophyllus (Gomes) Landrum. Chavibetol was obtained in high purity (98%) and mass recovery (94.4%). Methyleugenol was also isolated. The CCC biphasic solvent system used was composed of hexane:n-butanol:methanol:water (12:4:4:3, v/v/v/v).
The natural naphthopyranones paepalantine [structure: see text], paepalantine-9-O-beta-D-glucopyranoside [structure: see text] and paepalantine-9-O-beta-D-allopyranosyl-(1-->6)-O-beta-D-glucopyranoside [structure: see text] were separated in a preparative scale from the ethanolic extract of the capitula of Paepalanthus bromelioides by high-speed(More)
Thirty-six plant extracts from the brazilian Atlantic Forest were tested for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv and M. kansasii, using the method REMA in seriate concentrations of 100 to 0.20 μg/mL. Among the thirty six extracts tested, five were active against M. tuberculosis, and three of these extracts also showed(More)
INTRODUCTION Phytochemical and biological studies carried out on Copaifera species showed that their oleoresins and isolated compounds have various biological activities. OBJECTIVE The aims of this work were (i) to analyse the Copaifera oleoresin by gas chromatography-mass spectrometry, (ii) to isolate the diterpenic acids from this oleoresin by(More)
The flavone glycosides, named scutellarein-7-O-beta-D-apiofuranoside and apigenin-7-O-beta-D-apiofuranosyl-(1-->2)-beta-D-apiofuranoside, and the flavone celtidifoline (5,6,4',5'-tetrahydroxy-7,3'-dimethoxyflavone), along with other 11 known compounds, were isolated from leaves of the ethyl acetate extract of Lantana trifolia L. using step gradient High(More)
The buffy-headed marmoset (Callithrix flaviceps) is apparently the only predispersal herbivore of the seeds of Siparuna guianensis at the Caratinga Biological Station in southeastern Brazil. Both the fruit receptacles and the frutioles (seeds) of S. guianensis are relatively rich in nutrients such as carbohydrates, proteins, and lipids, but the receptacles(More)
'Countercurrent chromatography' (CCC) is an ideal technique for the recovery, purification and isolation of bioactive natural products, due to the liquid nature of the stationary phase, process predictability and the possibility of scale-up from analytical to preparative scale. In this work, a method developed for the fractionation of Schinus(More)