Celso Vataru Nakamura

Screening of some plants used in the Brazilian folk medicine for the treatment of infectious diseases

Extracts of 13 Brazilian medicinal plants were screened for their antimicrobial activity against bacteria and yeasts. Of these, 10 plant extracts showed varied levels of antibacterial activity. Piper regnellii presented a good activity against Staphylococus aureus and Bacillus subtilis, a moderate activity on Pseudomonas aeruginosa, and a weak activity against Escherichia coli. Punica granatum showed good activity on S. aureus and was inactive against the other standard strains. Eugenia uniflora presented moderate activity on both S. aureus and E. coli. Psidium guajava,Tanacetum vulgare, Arctium lappa, Mikania glomerata, Sambucus canadensis, Plantago major and Erythrina speciosa presented some degree of antibacterial activity. Spilanthes acmella, Lippia alba, and Achillea millefolium were considered inactive. Five of the plant extracts presented compounds with Rf values similar to the antibacterial compounds visible on bioautogram. Of these, three plants belong to the Asteraceae family. This may mean that the same compounds are responsible for the antibacterial activity in these plants. Anticandidal activity was detected in nine plant extracts (P. guajava, E. uniflora, P. granatum, A. lappa, T. vulgare, M. glomerata, L. alba, P. regnellii, and P. major). The results might explain the ethnobotanical use of the studied species for the treatment of various infectious diseases.

Antibacterial activity of Ocimum gratissimum L. essential oil

The essential oil (EO) of Ocimum gratissimum inhibited Staphylococcus aureus at a concentration of 0.75 mg/ml. The minimal inhibitory concentrations (MICs) for Shigella flexineri, Salmonella enteritidis, Escherichia coli, Klebsiella sp., and Proteus mirabilis were at concentrations ranging from 3 to 12 microg/ml. The endpoint was not reached for Pseudomonas aeruginosa (>=24 mg/ml). The MICs of the reference drugs used in this study were similar to those presented in other reports. The minimum bactericidal concentration of EO was within a twofold dilution of the MIC for this organism. The compound that showed antibacterial activity in the EO of O. gratissimum was identified as eugenol and structural findings were further supported by gas chromatography/mass spectra retention time data. The structure was supported by spectroscopic methods.

Recent advances in leishmaniasis treatment

About 1.5 million new cases of cutaneous leishmaniasis and 500,000 new cases of visceral leishmaniasis occur each year around the world. For over half a century, the clinical forms of the disease have been treated almost exclusively with pentavalent antimonial compounds. In this review, we describe the arsenal available for treating Leishmania infections, as well as recent advances from research on plants and synthetic compounds as source drugs for treating the disease. We also review some new drug-delivery systems for the development of novel chemotherapeutics. We observe that the pharmaceutical industry should employ its modern technologies, which could lead to better use of plants and their extracts, as well as to the development of synthetic and semi-synthetic compounds. New studies have highlighted some biopharmaceutical technologies in the design of the delivery strategy, such as nanoparticles, liposomes, cochleates, and non-specific lipid transfer proteins. These observations serve as a basis to indicate novel routes for the development and design of effective anti-Leishmania drugs.

Antileishmanial Activity of Parthenolide, a Sesquiterpene Lactone Isolated from Tanacetum parthenium

ABSTRACT The in vitro activity of parthenolide against Leishmania amazonensis was investigated. Parthenolide is a sesquiterpene lactone purified from the hydroalcoholic extract of aerial parts of Tanacetum parthenium. This isolated compound was identified through spectral analyses by UV, infrared, 1H and 13C nuclear magnetic resonance imaging, DEPT (distortionless enhancement by polarization transfer), COSY (correlated spectroscopy), HMQC (heteronuclear multiple-quantum coherence), and electron spray ionization-mass spectrometry. Parthenolide showed significant activity against the promastigote form of L. amazonensis, with 50% inhibition of cell growth at a concentration of 0.37 μg/ml. For the intracellular amastigote form, parthenolide reduced by 50% the survival index of parasites in macrophages when it was used at 0.81 μg/ml. The purified compound showed no cytotoxic effects against J774G8 macrophages in culture and did not cause lysis in sheep blood when it was used at higher concentrations that inhibited promastigote forms. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis with gelatin as the substrate showed that the enzymatic activity of the enzyme cysteine protease increased following treatment of the promastigotes with the isolated compound. This finding was correlated with marked morphological changes induced by parthenolide, such as the appearance of structures similar to large lysosomes and intense exocytic activity in the region of the flagellar pocket, as seen by electron microscopy. These results provide new perspectives on the development of novel drugs with leishmanicidal activities obtained from natural products.

Antimicrobial activity of Brazilian copaiba oils obtained from different species of the Copaifera genus

The antimicrobial activity of copaiba oils was tested against Gram-positive and Gram-negative bacteria, yeast, and dermatophytes. Oils obtained from Copaifera martii, Copaifera officinalis, and Copaifera reticulata (collected in the state of Acre) were active against Gram-positive species (Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, Bacillus subtilis, and Enterococcus faecalis) with minimum inhibitory concentrations ranging from 31.3-62.5 microg/ml. The oils showed bactericidal activity, decreasing the viability of these Gram-positive bacteria within 3 h. Moderate activity was observed against dermatophyte fungi (Trichophyton rubrum and Microsporum canis). The oils showed no activity against Gram-negative bacteria and yeast. Scannning electron microscopy of S. aureus treated with resin oil from C. martii revealed lysis of the bacteria, causing cellular agglomerates. Transmission electron microscopy revealed disruption and damage to the cell wall, resulting in the release of cytoplasmic compounds, alterations in morphology, and a decrease in cell volume, indicating that copaiba oil may affect the cell wall.

Potent antifungal activity of extracts and pure compound isolated from pomegranate peels and synergism with fluconazole against Candida albicans.

Activity-guided repeated fractionation of crude hydro alcoholic extract prepared from the fruit peel of Punica granatum on a silica-gel column yielded a compound that exhibited strong antifungal activity against Candida spp. Based on spectral analyses, the compound was identified as punicalagin. Punicalagin showed strong activity against Candida albicans and Candida parapsilosis, with MICs of 3.9 and 1.9 microg/ml, respectively. The combination of punicalagin and fluconazole showed a synergistic interaction. MIC for fluconazole decreased twofold when combined with the extract. The FIC index was 0.25. The synergism observed in disk-diffusion and checkerboard assays was confirmed in time-kill curves. The effect of punicalagin on the morphology and ultrastructure in treated yeast cells was examined by scanning and transmission electron microscopy. An irregular budding pattern and pseudohyphae were seen in treated yeasts. By transmission electron microscopy, treated cells showed a thickened cell wall, changes in the space between cell wall and the plasma membrane, vacuoles, and a reduction in cytoplasmic content. Since the punicalagin concentration effective in vitro is achievable in vivo, the combination of this agent with fluconazole represents an attractive prospect for the development of new management strategies for candidiasis, and should be investigated further in in vivo models.

Effect of Brazilian copaiba oils on Leishmania amazonensis.

ETHNOPHARMACOLOGICAL RELEVANCE Copaiba oil has been used in folk medicine since the 19th century. The use of copaiba oils to treat leishmaniasis is cited in several ethnopharmacological studies. Nevertheless, the potential antileishmania of copaiba oils had not been studied. AIM OF THE STUDY Eight different kinds of Brazilian copaiba oils were screened for antileishmanial activity. MATERIALS AND METHODS The antiproliferative effect of copaiba oil on promastigote and amastigote axenic were determined. To determine the survival index peritoneal macrophage were infected with promastigotes of Leishmania amazonensis and treated with copaiba oil. The cytotoxic effect of copaiba oil was assessed on macrophage strain J774G8 by assay of sulforhodamine B. RESULTS Copaiba oils showed variable levels of activity against promastigote forms with IC(50) values in the range between 5 and 22microg/mL. The most active oil was that from Copaifera reticulata (collected in Pará State, Brazil) with IC(50) values of 5, 15, and 20microg/mL for promastigote, axenic amastigote and intracellular amastigote forms, respectively. Amphotericin B showed IC(50) of 0.058 and 0.231microg/mL against promastigote and amastigote forms, respectively. Cytotoxicity assay showed that this copaiba oil obtained from Copaifera reticulata showed low cytotoxicity against J774G8 macrophages. CONCLUSION Copaiba oils showed significant activity against the parasite Leishmania amazonensis.

Antibacterial activity of indole alkaloids from Aspidosperma ramiflorum.

We evaluated the antibacterial activities of the crude methanol extract, fractions (I-V) obtained after acid-base extraction and pure compounds from the stem bark of Aspidosperma ramiflorum. The minimum inhibitory concentration (MIC) was determined by the microdilution technique in Mueller-Hinton broth. Inoculates were prepared in this medium from 24-h broth cultures of bacteria (10(7) CFU/mL). Microtiter plates were incubated at 37 masculineC and the MICs were recorded after 24 h of incubation. Two susceptibility endpoints were recorded for each isolate. The crude methanol extract presented moderate activity against the Gram-positive bacteria B. subtilis (MIC = 250 microg/mL) and S. aureus (MIC = 500 microg/mL), and was inactive against the Gram-negative bacteria E. coli and P. aeruginosa (MIC > 1000 microg/mL). Fractions I and II were inactive against standard strains at concentrations of < or =1000 microg/mL and fraction III displayed moderate antibacterial activity against B. subtilis (MIC = 500 microg/mL) and S. aureus (MIC = 250 microg/mL). Fraction IV showed high activity against B. subtilis and S. aureus (MIC = 15.6 microg/mL) and moderate activity against E. coli and P. aeruginosa (MIC = 250 microg/mL). Fraction V presented high activity against B. subtilis (MIC = 15.6 microg/mL) and S. aureus (MIC = 31.3 microg/mL) and was inactive against Gram-negative bacteria (MIC > 1000 microg/mL). Fractions III, IV and V were then submitted to bioassay-guided fractionation by silica gel column chromatography, yielding individual purified ramiflorines A and B. Both ramiflorines showed significant activity against S. aureus (MIC = 25 microg/mL) and E. faecalis (MIC = 50 microg/mL), with EC50 of 8 and 2.5 microg/mL for ramiflorines A and B, respectively, against S. aureus. These results are promising, showing that these compounds are biologically active against Gram-positive bacteria.

Characteristics of biofilm formation by Candida tropicalis and antifungal resistance.

Candida tropicalis is a common species related to nosocomial candidemia and candiduria. Most Candida spp. infections are associated with biofilm formation on implanted medical devices or on host epithelial cell surfaces. Sessile cells display phenotypic traits dramatically different from those of their free-living, planktonic counterparts, such as increased resistance to antimicrobial agents and to host defenses. The characteristics of C. tropicalis biofilm formation in vitro are described. By an XTT-reduction assay, an increase in metabolic activity was observed up to 24 h of biofilm formation, and this activity showed a linear relationship with sessile cell density. Scanning electron microscopy was used to further characterize C. tropicalis biofilms. The initial adherence of yeast cells was followed by germination, microcolony formation, filamentation and maturation at 24-48 h. Mature biofilms consisted of a dense network of yeast cells and filamentous forms of C. tropicalis. Increased resistance of sessile cells against fluconazole and amphotericin B was also demonstrated. Real-time reverse transcription-PCR quantification showed that sessile cells overexpressed ERG11 (coding for lanosterol 14 alpha-demethylase) and MDR1 (coding for an efflux protein belonging to the major facilitator superfamily). These mechanisms may contribute to the fluconazole resistance of the C. tropicalis biofilm.

Effects of medicinal plant extracts on growth of Leishmania (L.) amazonensis and Trypanosoma cruzi

This study describes the screening of extracts obtained from 19 species of plants used in Brazilian traditional medicine for treatment of a variety of diseases. The extracts were tested against axenic amastigote and promastigote forms of Leishmania (L.) amazonensis, and epimastigote forms of Trypanosoma cruzi in vitro at a concentration of 100 mg/ml. Baccharis trimera, Cymbopogon citratus, Matricaria chamomilla, Mikania glomerata, Ocimum gratissimum, Piper regnellii, Prunus domestica, Psidium guajava, Sambucus canadensis, Stryphnodendron adstringens, Tanacetum parthenium, and Tanacetum vulgare showed significant effects against one or both parasites, with a percentage of growth inhibition between 49.5 and 99%. The extracts showed no cytotoxic effect on sheep erythrocytes. These medicinal plants may be sources of new compounds that are clinically active against L. amazonensis and T. cruzi.