Fernanda R. Garcez

Bioactive pentacyclic triterpenes from the stems of Combretum laxum.

Two new triterpene glucosides, β-d-glucopyranosyl 2α,3β,24-trihydroxyolean-12-en-28-oate and β-d-glucopyranosyl 2α,3β,23,24-tetrahydroxyurs-12-en-28-oate, in addition to nine known compounds belonging to three different triterpene classes (oleanane-, ursane- and lupane-type) have been isolated from the stems of a specimen of Combretum laxum growing in the “Pantanal” of the central-western region of Brazil. Among the known triterpenes, β-d-glucopyranosyl 2α,3β,6β-trihydroxyolean-12-en-28-oate is reported for the first time in the Combretaceae, while bellericoside and asiatic acid are described for the first time in the genus Combretum. The structures of the isolated compounds have been established on the basis of spectral techniques (1D-, 2D-NMR and MS). Their in vitro antifungal activities against standard strains of Candida albicans, C. krusei and Cryptococcus neoformans were also evaluated in this work.

Larvicidal activity against Aedes aegypti of some plants native to the West-Central region of Brazil.

A total of 42 ethanolic extracts from 30 different plant species, native to the Pantanal and Cerrado of the West-Central region of Brazil, have been evaluated for their larvicidal activity against Aedes aegypti larvae, the vector of dengue and dengue hemorrhagic fevers. Among the extracts tested, that obtained from the trunk bark of Ocotea velloziana was the most active. Using a bioassay-directed fractionation of this extract, the active constituent was isolated and characterized as the aporphine alkaloid (+)-dicentrine. Its structure was established on the basis of (1)H and (13)C NMR spectra, optical rotation and by comparison with an authentic sample. This is the first report on the larvicidal activity against A. aegypti of this alkaloid. Our results suggest that (+)-dicentrine may be considered as a promising natural mosquito larvicidal agent.

Limonoids from Trichilia elegans ssp. elegans

Abstract From the seeds of Trichilia elegans ssp. elegans , six new limonoids, four of which possess the uncommon seco -A, B and D carbocyclic rings, have been isolated, together with two known limonoids-kihadanin A and B and 3-O-β- d -glucopyranosyl-sitosterol . The structures of these compounds have been established on the basis of 1D and 2D NMR spectroscopic techniques.

Phenylpropanoids and other bioactive constituents from Nectandra megapotamica.

From the trunk bark of Nectandra megapotamica (Lauraceae) four phenylpropanoids, elemicin, isoelemicin, (±)-erythro-1-(3,4,5-trimethoxyphenyl)-1,2-propanediol and (±)-threo-1-(3,4,5-trimetoxyphenyl)-1,2-propanediol have been isolated, in addition to 3,4,5-trimethoxybenzoic acid, (-)-epicatechin and trans-1(10)-epoxy-4(15)-caryophyllene. The diastereoisomeric erythro- and threo- phenylpropanoids are being reported for the first time in a plant taxon as well as the occurrence of the other compounds in Nectandra. The structures of the isolated compounds have been established on the basis of 1D and 2D NMR spectroscopic techniques. Their in vitro antifungal activities against standard strains of Candida albicans, C. krusei, C. tropicalis and Cryptococcus neoformans and antioxidant properties were also evaluated in this work.

Antimicrobial activity of some medicinal plants from the cerrado of the central-western region of Brazil

Ethanol extracts from six selected species from the Cerrado of the Central-Western region of Brazil, which are used in traditional medicine for the treatment of infectious diseases and other medical conditions, namely Erythroxylum suberosum St. Hil. (Erythroxylaceae), Hyptis crenata Pohl. ex Benth. (Lamiaceae), Roupala brasiliensis Klotz. (Proteaceae), Simarouba versicolor St. Hil. (Simaroubaceae), Guazuma ulmifolia Lam. (Sterculiaceae) and Protium heptaphyllum (Aubl.) March. (Burseraceae), as well as fractions resulting from partition of these crude extracts, were screened in vitro for their antifungal and antibacterial properties. The antimicrobial activities were assessed by the broth microdilution assay against six control fungal strains, Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans, and five control Gram-positive and negative bacterial strains, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Toxicity of the extracts and fractions against Artemia salina was also evaluated in this work. All plants investigated showed antimicrobial properties against at least one microorganism and two species were also significantly toxic to brine shrimp larvae. The results tend to support the traditional use of these plants for the treatment of respiratory and gastrointestinal disorders and/or skin diseases, opening the possibility of finding new antimicrobial agents from these natural sources. Among the species investigated, Hyptis crenata, Erythroxylum suberosum and Roupala brasiliensis were considered the most promising candidates for developing of future bioactivity-guided phytochemical investigations.

Chemical constituents from Terminalia glabrescens

A new oleanane-type triterpene (3b,6b,23,28-tetrahydroxyolean-12-ene) was isolated from the leaves of Terminalia glabrescens, together with ursolic, 2a-hydroxyursolic, oleanolic, maslinic, arjunolic, sumaresinolic and asiatic acids, squalene, phytol, sitosterol-3-O-b-D-glucopyranoside and n-alkanes. Friedelin, taraxerol, lupeol, lupenone, betulin, betulone, betulinic acid, arjunglucoside I, stigmastane-3b,6a-diol, b-sitosterol, (-) catechin,b-D-pyranotagatose, b-D-furanofructose and a-D-furanofructose were obtained from the trunk bark.

Cytotoxic Aporphine Alkaloids from Ocotea acutifolia

Two new aporphinoid alkaloids, (+)-6 S-ocoteine N-oxide and (+)-norocoxylonine, were isolated from the leaves and trunk bark of OCOTEA ACUTIFOLIA (Lauraceae) along with thirteen aporphine analogues, one morphinan alkaloid, and one flavonoid. The aporphine alkaloids (+)-thalicsimidine and (+)-neolitsine are reported for the first time for the genus OCOTEA. The structures of all compounds were established on the basis of 1D- and 2D-NMR spectroscopic techniques, optical rotation and/or mass spectrometry data. The cytotoxic potential of eight of the aporphine alkaloids against four human cancer cell lines (Hep-2, MCF-7, B16-F10 and 786-0) was also evaluated.

Seco-protolimonoids from Trichilia elegans ssp. elegans

Abstract Three novel seco -A ring protolimonoids have been isolated from the seeds and bark of Trichilia elegans ssp. elegans . Their structures have been established on the basis of 1D and 2D NMR spectroscopic techniques.

A nitropropanoyl-glucopyranoside from Indigofera suffruticosa

Abstract An investigation of root and stem of Indigofera suffruticosa has led to the isolation of a new nitropropanoyl- glucopyranoside [2,3,4,6-tetra(3-nitropropanoyl) α- d -glucopyranose]. Its structure was determined by spectroscopic methods as well as GC analysis of the corresponding alditol acetate.

Eudesmane and rearranged eudesmane sesquiterpenes from Nectandra cissiflora

Four eudesmane-type sesquiterpenes, costic acid (1), 12-carboxyeudesman-3,11(13)-diene (2), viscic acid (3), 3-oxo-γ-costic acid (4) and two rearranged eudesmane derivatives, 3α-hydroxyisoiphion-11(13)-en-12-oic acid (5) and 5β-hydroxy-4-oxo-11(13)-dehydroiphionan-12-oic acid (6), in addition to (-)-epicatechin, have been isolated from the trunk bark of Nectandra cissiflora. This is the first reported occurrence in the Lauraceae of 3-6. The structures of the isolated compounds have been established on the basis of 1D and 2D NMR spectroscopic techniques. The 13C NMR assignments of 3, 5 and 6 are given here for the first time, as well as some corrections to the previously reported chemical shift assignments of 4.