Vera Lúcia Garcia

Sesquiterpenes evaluation on Schistosoma mansoni : Survival, excretory system and membrane integrity

The main challenge in schistosomiasis control has been the emergence of drug-resistant parasites. Since the 1970s, praziquantel (PZQ) is the single drug for treatment. This fact highlights the importance to research news chemotherapeutic agents. In the last years, S. mansoni excretory system and tegument have been major targets for drug development. The purpose of this study was to evaluate the effect of sesquiterpenes, alpha-humulene and trans-caryophyllene on S. mansoni survival, excretory system and membrane integrity, after in vitro exposure. The in vitro studies, showed that sesquiterpenes reduced egg production and motor activity of worms at sublethal concentrations, and caused death in a concentration-dependent manner (100 and 200μg/mL). Tegumental analysis by Scanning Electron Microscopy (SEM), showed tegument damage. Additionally, it was possible to observe lesions, evidenced by intense marking trough Hoechst probe, in the tegument and suckers of worms exposed to 200μg/mL. In this study, we also showed that resorufin is only capable of identifying the interaction of sesquiterpenes in males excretory system, Pgp expression and inferring that females are more tolerant to treatments. Thus, the present study results contribute to an understanding of alpha-humulene and trans-caryophyllene effect over these targets, contributing for the development of schistosomicidal drugs.

Leaf and stem anatomy and essential oil composition of four Brazilian Aldama species (Asteraceae) and their taxonomic significance

Aldama La Llave is one of several Asteraceae genera that pose phylogenetic problems. The close similarity between species, as well as the inconsistencies found in the most recent phylogenetic analysis, shows that new data are needed to help delimit group species. Aldama anchusifolia (DC) E.E.Schill. & Panero, Aldama megapotamica (Malme) Magenta & Pirani, Aldama nudibasilaris (S.F.Blake) E.E.Schill. & Panero and Aldama pilosa (Baker) E.E.Schill. & Panero are difficult to identify because they are very closely related. Therefore, the aim of this study was to detect anatomical and phytochemical characteristics to help elucidate phylogenetic issues raised by Aldama. Aerial vegetative organs were prepared using the standard histological techniques. Essential oils were obtained by hydrodistillation, and their components identified using a gas chromatograph coupled to a mass spectrometer and flame ionization detector. Each species presented a set of unique leaf and stem anatomical features. The front view of the epidermal cell walls in the leaves, the presence of secretory ducts in the phloem and medulla sclerification in the stems proved useful in delimiting these species. The essential oils were characterized by the predominance of sesquiterpenes such as t-caryophyllene, germacrene D and bicyclogermacrene. Some unique constituents in each species were also identified as potential chemical markers.

Seasonal variation of the essential oil from two Brazilian native Aldama La Llave (Asteraceae) species

Aldama arenaria and A. robusta are morphologically similar aromatic species that have seasonal development. The yield and chemical composition of essential oils from aerial and underground vegetative organs of these species were compared to verify the production of volatile metabolites in flowering and dormant phases of development and to identify if there are unique compounds for either species. The major compound in the essential oils from A. arenaria leaves was palustrol (16.22%) and for aerial stems was limonene (15.3%), whereas limonene (11.16%) and α-pinene (19.64%) were the major compounds for leaves and aerial stems from A. robusta, respectively. The major compound for the underground organs was α-pinene, in both species and phenological stages. High amounts of diterpenes were found especially for A. arenaria essential oils. Each analyzed species presented unique compounds, which can provide a characteristic chemical profile for both species helping to solve their taxonomic problems. This study characterized for the first time the yield and essential oil composition of A. arenaria and A. robusta, which have medicinal potential, and some of the compounds in their essential oils are unique to each one and may be useful in helping the correct identification of them.

Development of a Gas Chromatography Method for the Analysis of Copaiba Oil

A rapid, simple, precise and economic method for the quantification of main compounds of copaiba resin and essential oils (Copaifera langsdorffii Desf.) by gas chromatography (GC) has been developed and validated. Copaiba essential oil was extracted by hydrodistillation from the copaiba resin. Resin derivatization allowed the identification of diterpenes compounds. A gas chromatography-mass spectroscopy (GC/MS) method was developed to identify compounds composing the copaiba resin and essential oil. Then the GC/MS method was transposed to be used with a flame ionization detector (FID) and validated as a quantitative method. A good correlation between GC/MS and GC/FID was obtained favoring method transposition. The method showed satisfactory sensitivity, specificity, linearity, precision, accuracy, limit of detection and limit of quantitation for β-caryophyllene, α-humulene and caryophyllene oxide analyses in copaiba resin and essential oils. The main compounds identified in copaiba essential oil were β-bisabolene (23.6%), β-caryophyllene (21.7%) and α-bergamotene (20.5%). Copalic acid methyl ester (15.6%), β-bisabolene (12.3%), β-caryophyllene (7.9%), α-bergamotene (7.1%) and labd-8(20)-ene-15,18-dioic acid methyl ester (6.7%) were diterpenes identified from the derivatized copaiba resin. The proposed method is suitable for a reliable separation, identification and quantification of compounds present in copaiba resin and essential oil. It could be proposed as an analytical method for the analysis of copaiba oil fraction in raw and essential oil parent extracts and after they have been incorporate in pharmaceutical formulations.