Jk Bastos

In vitro antileishmanial, antiplasmodial and cytotoxic activities of phenolics and triterpenoids from Baccharis dracunculifolia D. C. (Asteraceae)

Baccharis dracunculifolia (Asteraceae), the most important plant source of the Brazilian green propolis (GPE), displayed in vitro activity against Leishmania donovani, with an IC(50) value of 45 microg/mL, while GPE presented an IC(50) value of 49 microg/mL. Among the isolated compounds of B. dracunculifolia, ursolic acid, and hautriwaic acid lactone showed IC(50) values of 3.7 microg/mL and 7.0 microg/mL, respectively. Uvaol, acacetin, and ermanin displayed moderate antileishmanial activity. Regarding the antiplasmodial assay against Plasmodium falciparum, BdE and GPE gave similar IC(50) values (about 20 microg/mL), while Hautriwaic acid lactone led to an IC(50) value of 0.8 microg/mL (D6 clone).

Brazilian Propolis: Seasonal Variation of the Prenylated p-Coumaric Acids and Antimicrobial Activity

Brazilian green propolis, which is used in food and beverages to improve health and to prevent diseases, demostrates antioxidant, antimutagenic, and antimicrobial activities. Most biological activities are thought to be related to the high levels of drupanin, artepillin C, and baccharin, which are compounds also present in Baccharis dracunculifolia D.C. (Asteraceae). Since propolis chemical composition depends on the region and the period of collection, as well as its plant origin, the effect of seasonal variation on the both content of prenylated p-coumaric acids and in vitro antimicrobial activity of Brazilian propolis from four different sites, was performed. The results showed that MIC values ranged from 100 to 300 μg/mL against both Staphylococcus aureus and Kocuria rhizophila, while none of the propolis samples was active against Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. HPLC analysis showed that the content of drupanin, artepillin C, and baccharin varied throughout the year, as well as among the different study sites. Also, it is suggested that Baccharis dracunculifolia is the main botanical source of Brazilian propolis in sites 1 and 2, while in sites 3 and 4, other plant species are also used by bees to produce propolis. All the evaluated propolis samples exhibited similar antibacterial activity, but different contents of prenylated p-coumaric acids throughout the year.

Schistosomicidal and trypanocidal structure-activity relationships for (+/-)-licarin A and its (-)- and (+)-enantiomers

(±)-Licarin A (1) was obtained by oxidative coupling, and its enantiomers, (-)-licarin A (2) and (+)-licarin A (3), were resolved by chiral HPLC. Schistosomicidal and trypanocidal activities of these compounds were evaluated in vitro against Schistosoma mansoni adult worms and trypomastigote forms of Trypanosoma cruzi. The racemic mixture (1) displayed significant schistosomicidal activity with an LC₅₀ value of 53.57 μM and moderate trypanocidal activity with an IC₅₀ value of 127.17 μM. On the other hand, the (-)-enantiomer (2), displaying a LC₅₀ value of 91.71 μM, was more active against S. mansoni than the (+)-enantiomer (3), which did not show activity. For the trypanocidal assay, enantiomer 2 showed more significant activity (IC₅₀ of 23.46 μM) than enantiomer 3, which showed an IC₅₀ value of 87.73 μM. Therefore, these results suggest that (±)-licarin A (1) and (-)-licarin A (2) are promising compounds that could be used for the development of schistosomicidal and trypanocidal agents.

The effect of the dibenzylbutyrolactolic lignan (−)-cubebin on doxorubicin mutagenicity and recombinogenicity in wing somatic cells of Drosophila melanogaster

The dibenzylbutyrolactolic lignan (-)-cubebin was isolated from dry seeds of Piper cubeba L. (Piperaceae). (-)-Cubebin possesses anti-inflammatory, analgesic and antimicrobial activities. Doxorubicin (DXR) is a topoisomerase-interactive agent that may induce single- and double-strand breaks, intercalate into the DNA and generate oxygen free radicals. Here, we examine the mutagenicity and recombinogenicity of different concentrations of (-)-cubebin alone or in combination with DXR using standard (ST) and high bioactivation (HB) crosses of the wing Somatic Mutation And Recombination Test in Drosophila melanogaster. The results from both crosses were rather similar. (-)-Cubebin alone did not induce mutation or recombination. At lower concentrations, (-)-cubebin statistically reduced the frequencies of DXR-induced mutant spots. At higher concentrations, however, (-)-cubebin was found to potentiate the effects of DXR, leading to either an increase in the production of mutant spots or a reduction, due to toxicity. These results suggest that depending on the concentration, (-)-cubebin may interact with the enzymatic system that catalyzes the metabolic detoxification of DXR, inhibiting the activity of mitochondrial complex I and thereby scavenging free radicals. Recombination was found to be the major effect of the treatments with DXR alone. The combined treatments reduced DXR mutagenicity but did not affect DXR recombinogenicity.

Trypanocidal structure–activity relationship for cis- and trans-methylpluviatolide

The trypanocidal activity of racemic mixtures of cis- and trans-methylpluviatolides was evaluated in vitro against trypomastigote forms of two strains of Trypanosoma cruzi, and in the enzymatic assay of T. cruzi gGAPDH. The cytotoxicity of the compounds was assessed by the MTT method using LLC-MK2 cells. The effect of the compounds on peroxide and NO production were also investigated. The mixture of the trans stereoisomers displayed trypanocidal activity (IC50 approximately 89.3 microM). Therefore, it was separated by chiral HPLC, furnishing the (+) and (-)-enantiomers. Only the (-)-enantiomer was active against the parasite (IC50 approximately 18.7 microM). Despite being inactive, the (+)-enantiomer acted as an antagonistic competitor. Trans-methylpluviatolide displayed low toxicity for LLC-MK2 cells, with an IC50 of 6.53 mM. Furthermore, methylpluviatolide neither inhibited gGAPDH activity nor hindered peroxide and NO production at the evaluated concentrations.

Immunomodulatory/anti-inflammatory effects of Baccharis dracunculifolia leaves

A possible immunomodulatory/anti-inflammatory effect of Baccharis dracunculifolia (Bd) and its major compound – caffeic acid (Ca) – on cytokines production (IL-1β, IL-6 and IL-10) by murine macrophages was investigated. Cells were incubated with Bd and Ca, and the inhibitory concentrations were tested before or after macrophages challenge with LPS. Bd and Ca stimulated IL-1β and inhibited IL-6 and IL-10 production. In LPS-challenge protocols, Bd prevented LPS action either before or after LPS challenge, whereas Ca prevented LPS effects only after LPS addition. Bd modulatory action on cytokines production may be at least in part mediated by Ca, since it has been shown to inhibit the transcription factor NF-κB. Further studies are still needed to evaluate Bd efficacy in inflammatory diseases, in order to explore its antiinflammatory activity in vivo.

Constituents of Baccharis dracunculifolia DC (Asteraceae) with in vitro antileishmanial, antiplasmodial and cytotoxic activities

Baccharis dracunculifolia D.C. (Asteraceae) is the most important plant source of the Brazilian green propolis. The aim of this work was to evaluate the antileishmanial and antiplasmodial activities of B. dracunculifolia and its isolated compounds. The leave rinse extract of B. dracunculifolia (BdE) showed in vitro antileishmanial activity against Leishmania donovani, displaying an IC50 value of 45µg/mL, while green propolis hydroalcoholic extract (GPE) showed an IC50 value of 49µg/mL. Among the isolated compounds, ursolic acid and hautriwaic acid lactone, showed the highest antileishmanial activities, displaying IC50 values of 3.7µg/mL and 7.0µg/mL, respectively. The pentacyclic triterpene Uvaol, as well as the flavonoids acacetin and ermanin showed IC50 values of 15.0µg/mL, 18.0µg/mL and 40.0µg/mL, respectively. Regarding the antiplasmodial assay against Plasmodium falciparum, BdE and GPE showed similar IC50 values (about 20µg/mL). Hautriwaic acid lactone displayed moderate antiplasmodial activity, with IC50 values of 0.8µg/mL (D6 clone) and 2.2µg/mL (W2 clone). In order to compare the effect on the parasites with toxicity with mammalian cells, the cytotoxic activity of the samples were evaluated against the Vero cells, showing that all evaluated compounds exhibited no cytotoxicity in the maximum dose tested. Acknowledgements: To FAPESP for financial support (2006/60142–4) and FAPESP (2007/04175–9, CAPES (PDEE/BEX 0387/04–5) and CNPq (119831/2007–4) for fellowships.

EFEITO ANTICARIOGÊNICO DO ÓLEO-RESINA DE COPAIFERA PAUPERA

A carie dentaria e uma patologia bucal muito comum causada por bacterias cariogenicas formadoras de biofilme sobre a superficie do dente, neste sentido a busca por novas alternativas terapeuticas para o controle da carie dental deve ser investigado. O oleo-resina extraido da arvore de copaiba tem sido empregado na profilaxia e tratamento de diversas patologias. Assim, este trabalho teve por objetivo avaliar a atividade antibacteriana do oleo-resina de Copaifera paupera (ORCP) e o efeito sinergico associado a clorexidina frente as bacterias representativas da carie dental. As bacterias avaliadas foram Streptococcus mutans (ATCC 25175), Enterococcus faecalis (ATCC 4082 e isolado clinico) Streptococcus salivarius (ATCC 25975 e isolado clinico), Streptococcus sanguinis (ATCC 10556 e isolado clinico), Lactobacillus casei (ATCC 11578 e isolado clinico), Streptococcus mitis (ATCC 49456) e Streptococcus sobrinus (ATCC 33478). Foi realizado a determinacao da Concentracao Inibitoria Minima (CIM), determinacao da Concentracao Bactericida Minima (CBM) e avaliacao do efeito sinergistico do ORCP e clorexidina utilizando o Indice de Concentracao Inibitoria Fracionada (ICIF). Os resultados da CIM/CBM exibiram valores promissores para o ORCP que variaram entre 12,5 e 100 µg/mL, sendo considerada uma potente atividade antibacteriana. Quanto a ICIF o efeito antagonico foi observado para todas as bacterias avaliadas. Assim, com base neste estudo in vitro o oleo-resina de C. paupera demonstrou ser um promissor agente antibacteriano frente as bacterias cariogenicas, mas sem demonstrar efeito sinergistico em associacao com a clorexidina.