Maria Auxiliadora Coelho Kaplan

Antimicrobial activity in vitro of plumbagin isolated from Plumbago species

Plumbagin is a naturally occurring naphthoquinone isolated from roots of Plumbago scandens. The plant was collected at the Campus of Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. P. scandens is used as a traditional medicine for the treatment of several diseases. The antimicrobial activity of plumbagin was evaluated using the macrodilution method. The compound exhibited relatively specific activity against bacteria and yeast. The minimum inhibitory concentration test showed the growth inhibiton of Staphylococcus aureus at a concentration of 1.56 g/ml and of Candida albicans at a concentration of 0.78 g/ml. These results suggest the naphthoquinone plumbagin as a promising antimicrobial agent.

Pentacyclic triterpenes from Chrysobalanaceae species: cytotoxicity on multidrug resistant and sensitive leukemia cell lines.

Plants are known as important source in the search for new anti-cancer agents. Cytotoxicity-guided fractionation of leaves and fruits from Licania tomentosa Bench and leaves from Chrysobalanus icaco L. resulted in the isolation of betulinic, oleanolic and pomolic acids. These triterpenoids inhibited the growth and induced apoptosis of K562, an erythroleukemia cell line. Most importantly, they also inhibited the proliferation of Lucena 1, a vincristine-resistant derivative of K562 that displays several multidrug resistance (MDR) characteristics. Taken together, our findings emphasize the anti-tumor activity of these triterpenes on leukemia cell lines and call attention to their potential as anti MDR agents.

Essential oil analysis of 10 Piperaceae species from the Brazilian Atlantic forest

The volatile composition of ten Piperaceae species, comprising three genera (Ottonia, Piper and Peperomia) has been studied. The species were collected in a typical fragment of the Brazilian Atlantic forest, constantly being damaged by human action. The essential oils were obtained by hydrodistillation in a modified Clevenger-type apparatus and their analyses were performed by GC and GC/MS. Identification of the substances was made by comparison of mass spectra and retention indices with literature records. A great number of non-oxygenated monoterpenes and sesquiterpenes were identified. Most of these sesquiterpenes are derived from E,E-farnesyl-PP, suggesting a preference of these species to synthesize metabolites from this pathway. Arylpropanoids, although being common compounds produced by Piperaceae species, were not found in these oils.

Antileishmanial activity of isolated triterpenoids from Pourouma guianensis

The inhibiting activity of triterpenoids isolated from the methanolic extract of Pourouma guianensis (Moraceae) leaves is described for promastigotes and intracellular amastigotes of Leishmania amazonensis. Whereas the fractions containing apigenin, friedelin, epi-friedelinol, arjunolic acid, hyptatic acid B, stigmasterol and sitosterol were of no or relatively low inhibitory activity, fractions containing tormentic acid, 2alpha,3beta-dihydroxyursan-12-en-28-oic acid, 2alpha,3beta-dihydroxyolean-12-en-28-oic acid, oleanolic acid and ursolic acid were very potent in inhibiting promastigote growth at 100 microg/ml. Of the eleven isolated compounds, however, only ursolic acid and oleanolic acid showed high activity against intracellular amastigotes (IC50 value = 27 microg/ml and 11 microg/ml, respectively), which was superior to the control drug Glucantime (IC50 value = 83 microg/ml). The antileishmanial activity of oleanolic acid was directed against the parasite and not due to activation of nitric oxide intermediates by macrophages, but this triterpenoid also significantly inhibited the phagocytic capacity of those cells at concentrations above 40 microg/ml, indicating a cytotoxic effect. These results indicate that Pourouma guianensis contains many triterpenoids and some, such as ursolic and oleanolic acids, may serve as lead compounds for new antileishmanial drugs, but chemical modifications may be necessary to avoid unselective cytotoxicity.

Anthelmintic activity of the latex of Ficus species

The latex of some species of Ficus (Moraceae) has been traditionally used as vermifuge in Central and South America. It has been accepted that anthelmintic activity is due to a proteolytic fraction called ficin. In the present study, the anthelmintic activity of the latex of Ficus insipida Willd. and Ficus carica L. has been investigated in NIH mice naturally infected with Syphacia obvelata, Aspiculuris tetraptera and Vampirolepis nana. The latex of F. insipida, administered by intragastric route in doses of 4 ml/kg/day during three consecutive days, were effective in the removal of 38.6% of the total number of S. obvelata, being inexpressive in the removal of A. tetraptera (8.4%) and segments of V. nana (6.3%). The latex of F. carica, administered in doses of 3 ml/kg/day, during three consecutive days, was effective in the removal of S. obvelata (41.7%) and it did not produce significant elimination of A. tetraptera (2.6%) and V. nana (8.3%). The observed high acute toxicity with hemorrhagic enteritis, in addition to a weak anthelmintic efficacy, do not recommend the use of these lattices in traditional medicine.

More phloroglucinols from Hypericum brasiliense

Three new phloroglucinols (hyperbrasilols B and C, and isohyperbrasilol B) have been isolated from a petrol extract of the leaves and flowers of Hypericum brasiliense. Their structures were established by spectroscopic methods including two-dimensional-NMR heteronuclear correlations. EI and D/Cl-mass spectral, NMR, IR and UV data are reported. All three phloroglucinols were antibacterial against Bacillus subtilis in a TLC bioautographic assay.

The anti-allergic activity of the acetate fraction of Schinus terebinthifolius leaves in IgE induced mice paw edema and pleurisy

Schinus is a genus of the Anacardiaceae family and contains Schinus terebinthifolius, the Brazilian pepper tree that is widely used in folk medicine. We investigate the anti-allergic activity of the ethyl acetate fraction of S. terebinthifolius Raddi (ST fraction). HPLC analysis reveled that gallic acid, methyl gallate and 1,2,3,4,6-pentagalloylglucose are the major aromatic components of the fraction. Oral pre-treatment with the ST fraction (100 mg/kg) significantly inhibited paw edema induced by compound 48/80 (100 ng/paw) and to a lesser extent, the allergic paw edema (OVA, 3 microg/paw). The ST fraction (100 and 200 mg/kg) also inhibited the edema induced by histamine (100 microg/paw), preventing mast cell degranulation and, consequently, histamine release in Wistar rat peritoneal mast cells induced by C 48/80 (5 microg/mL). This histamine inhibition was also observed after mast cell pre-treatment with both methyl gallate and 1,2,3,4,6-pentagalloylglucose (100 microg/mL), the isolated compounds from the ethyl acetate fraction. Pre-treatment with the ST fraction (100 mg/kg) significantly inhibited total leukocyte and eosinophil accumulation in pleural cavities 24 h after the intrathoracic injection of OVA (12.5 microg/cavity). This effect was related to the inhibition of CCL11/eotaxin and CCL5/RANTES in pleural lavage fluid. Pre-treatment with this fraction (100 mg/kg) failed to reduce the cell influx that was observed after LPS-injection into pleural cavity (250 ng/cavity). These findings demonstrate the anti-allergic effect of the ST fraction, which includes the inhibition of edema formation and histamine release caused by mast cell degranulation and eosinophil influx into the pleural cavity probably reflected by the decreased levels of chemokines in recovered pleural lavage fluid.

Flavonoids as chemotaxonomic markers for Asteraceae.

Flavonoids have been shown to be good taxonomic markers for Asteraceae. More than 800 compounds comprising 4700 flavonoid occurrences were included in a computational system specially made for chemotaxonomic purposes. Some implications of flavonols, flavones and other types as well as structural features of them are discussed for tribes and subtribes of Asteraceae.

Antimicrobial activity of benzylisoquinoline alkaloids from Annona salzmanii D.C.

Bark of Annona salzmanii D.C. (Annonaceae), used in Brazilian folk medicine, was found to contain four benzylisoquinoline alkaloids, namely reticuline, anonaine, laurelliptine and isoboldine. Only anonaine possesses some antibacterial property while all four alkaloids show some antifungal activity.

Iridoids as systematic markers in dicotyledon

Abstract Iridoid evolution is postulated to involve a gradual increase in the state of oxidation. From this, it appears that the iridoid-containing dicotyledons bifurcated at a primitive stage near the Ericales into the Cornales, with an extension to a Dipsacales branch and a Gentianiflorae branch, and into the Lamiiflorae.