Gilda Guimarães Leitão

Screening of Central and South American plant extracts for antimycobacterial activity by the Alamar Blue test

Forty eight ethanolic crude extracts and fractions (hexane, dichloromethane, ethyl acetate and n-butanol) from ten Brazilian plants (Leguminosae, Monimiaceae and Verbenaceae), 1 from Costa Rica (Verbenaceae) and 1 from Argentina (Verbenaceae) were screened for anti-mycobacterium activity against Mycobacterium tuberculosis (ATCC-27294H37Rv), by the Alamar Blue test, at a fixed concentration of 100 µg/mL. Out of the forty eight, seven were active at this concentration, corresponding to Lantana trifolia (hexane and dichloromethane extracts from leaves), Vitex cooperi (methanol:water, 1:1 extract from barks), Lippia lacunosa (hexane and dichloromethane extracts from leaves) and Lippia rotundifolia (hexane and dichloromethane extracts from leaves), all from the Verbenaceae family.

Chemistry and pharmacology of monimiaceae: a special focus on Siparuna and Mollinedia

The chemistry and pharmacology of species of the family Monimiaceae are reviewed, with special attention given to the genera Mollinedia and Siparuna, the two most important and representative in Brazil. The isolation of benzylisoquinoline alkaloids and kaempferol derivatives from Siparuna apiosyce is reported, as well as the isolation of aporphines from the fruits of Siparuna arianeae. Cinnamic acid derivatives and a gamma-lactone were isolated from Mollinedia gilgiana and Mollinedia marliae.

Isolation of chavibetol from essential oil of Pimenta pseudocaryophyllus leaf by high-speed counter-current chromatography

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).

Ethnopharmacological versus random plant selection methods for the evaluation of the antimycobacterial activity

The municipality of Oriximina, Brazil, has 33 quilombola communities in remote areas, endowed with wide experience in the use of medicinal plants. An ethnobotanical survey was carried out in five of these communities. A free-listing method directed for the survey of species locally indicated against Tuberculosis and lung problems was also applied. Data were analyzed by quantitative techniques: saliency index and major use agreement. Thirty four informants related 254 ethnospecies. Among these, 43 were surveyed for possible antimycobacterial activity. As a result of those informations, ten species obtained from the ethnodirected approach (ETHNO) and eighteen species obtained from the random approach (RANDOM) were assayed against Mycobacterium tuberculosis by the microdilution method, using resazurin as an indicator of cell viability. The best results for antimycobacterial activity were obtained of some plants selected by the ethnopharmacological approach (50% ETHNO x 16,7% RANDOM). These results can be even more significant if we consider that the therapeutic success obtained among the quilombola practice is complex, being the use of some plants acting as fortifying agents, depurative, vomitory, purgative and bitter remedy, especially to infectious diseases, of great importance to the communities in the curing or recovering of health as a whole.

Investigation of the antimycobacterial activity of 36 plant extracts from the brazilian Atlantic Forest

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 activity against M. kansasii. Cytotoxicity test with VERO cells was performed with the five extracts active against M. tuberculosis. Only the extract of Peschiera affinis was identified as non-toxic in the concentration of 100µg/mL.

Step‐Gradient CCC Separation of Phenylpropanoid and Iridoid Glycosides from Roots of Stachytarpheta cayennensis (Rich.) Vahl

Abstract Glycosylated phenylpropanoids and iridoids were isolated from the ethyl acetate extract from the roots of Stachytarpheta cayennensis by step gradient countercurrent chromatography (CCC). The chosen gradient utilized a stepwise increase of the butanol ratio in a normal phase separation, utilizing a biphasic EtOAc:BuOH:H2O solvent system, 1:X:1 v/v/v, in four steps: A−X=0.05, B−X=0.2, C−X=0.5 and D−X=1.0. The sequential increase of BuOH in the organic phase of the CCC solvent system, and wash‐off of stationary phase allowed the isolation of 4 compounds identified as martinoside, isoverbascoside, verbascoside, ipolamiide, and two more iridoid glycosides. These compounds covered a wide span of polarities.

Gradient Elution for Triterpene Separation from Cecropia lyratiloba Miquel by HSCCC

Abstract The triterpenoid pool from the dichloromethane fraction obtained from the methanolic extract of roots of Cecropia lyratiloba Miquel was submitted to CCC using a gradient elution consisting of Hex/EtOAc/MeOH/H2O—1/2/X/1 (X=0.5 (A); 0.75 (B); 1.0 (C); 1.5 (D); 2.0 (E)) in five steps. The lower aqueous phase was used as mobile phase, 2 mL/min at 850 rpm. This procedure led to the isolation of tormentic acid and a mixture of tormentic and euscaphic acids. In order to improve the triterpene separation the fractions Fr 31–49 were submitted to a new CCC run using a fine adjustment of the methanol concentration in the gradient elution system. This separation procedure led to the isolation of euscaphic acid, 3‐acetyl tormentic acid and a mixture of tormentic and isoarjunolic acids.

Separation of Free and Glycosylated Flavonoids from Siparuna guianensis by Gradient and Isocratic CCC

Abstract The separation of free and glycosylated flavonoids from the ethyl acetate extract of the leaves of Siparuna guianensis by step‐gradient and isocratic mode HSCCC is described. The initial fractionation of the extract by a two‐step gradient composed of Hexane∶EtOAc∶MeOH∶H2O 0.6∶4.0∶0.05∶1.0 v/v/v/v (A) and 0.6∶4.0∶0.7∶1.0 (B), reverse phase HSCCC, yielded a sequence of a mixture of diglycosyl flavonoids, followed by a mono‐glycosyl flavonoid and by quercetin, a free flavonoid. The final separation of the more polar and very closely related (structurally and chemically) glycosylated flavonoids, not easily separable by HPLC, was achieved by isocratic normal phase elution, with the solvent system Hexane∶EtOAc∶BuOH∶MeOH∶H2O, 0.6∶4.0∶1.0∶0.05∶1.0. The optimization of the solvent ratios for the gradient and for the isocratic elution is discussed.

Anatomical and chemical analyses of leaf secretory cavities of Rustia formosa (Rubiaceae).

Foliar secretory cavities, commonly called leaf pellucid glands, have been reported in many families of vascular plants. In the Rubiaceae, these structures have only been found in the sister genera Rustia and Tresanthera, which are also anomalous within the family because they have poricidal anthers, and in the distantly related Heterophyllaea. General leaf anatomy, with particular attention to secretory cavities, as well as the chemical analysis of the secreted substances of Rustia formosa, is presented here for the first time. The secretory structures have been found in the lamina between the palisade and spongy parenchymas and in the cortical region of the petiole. The chemical analysis showed that the essential oil secreted is a complex mixture of at least 75 components, mostly of sesquiterpenoid composition. Illustrations of the leaf anatomy, details of the secretory structures of Rustia formosa, a gas chromatogram, and a table of the principal components of the leaf essential oil are included.

Isolation of two bioactive diterpenic acids from Copaifera glycycarpa oleoresin by high-speed counter-current chromatography

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 high-speed countercurrent chromatography (HSCCC) and (iii) to determine the rhodamine 6G Pdr5p activity of these acids. METHODOLOGY HSCCC was used for the preparative separation of the diterpenes. Spectroscopic methods were used to establish their identity. RESULTS The gas chromatogram of the oleoresin showed approximately 30 compounds. The two major ones, kaur-16-en-18-oic and polyalthic acids, were isolated in high purity. Kaur-16-en-18-oic acid exhibited the highest rodomine 6G Pdr5p activity among the tested compounds. CONCLUSION HSCCC was shown to be a quick and effective tool in the isolation and purification of diterpenes from Copaifera oleoresin. This is the first report on the use of HSCCC for the fractionation of an oleoresin from Copaifera and the isolation of diterpenes therein.