Effect of seasonality on chemical profile and antifungal activity of essential oil isolated from leaves Psidium salutare (Kunth) O. Berg.

Medicinal plants play a crucial role in the search for components that are capable of neutralizing the multiple mechanisms of fungal resistance. Psidium salutare (Kunth) O. Berg is a plant native to Brazil used as both food and traditional medicine to treat diseases and symptoms such as stomach ache and diarrhea, whose symptoms could be related to fungal infections from the genus Candida. The objective of this study was to investigate the influence of seasonal variability on the chemical composition of the Psidium salutare essential oil, its antifungal potential and its effect on the Candida albicans morphogenesis. The essential oils were collected in three different seasonal collection periods and isolated by the hydrodistillation process in a modified Clevenger apparatus with identification of the chemical composition determined by gas chromatography coupled to mass spectrometry (GC/MS). The antifungal assays were performed against Candida strains through the broth microdilution method to determine the minimum fungicidal concentration (MFC). Fungal growth was assessed by optical density reading and the Candida albicans dimorphic effect was evaluated by optical microscopy in microculture chambers. The chemical profile of the essential oils identified 40 substances in the different collection periods with γ-terpinene being the predominant constituent. The antifungal activity revealed an action against the C. albicans, C. krusei and C. tropicalis strains with an IC50 ranging from 345.5 to 2,754.2 µg/mL and a MFC higher than 1,024 µg/mL. When combined with essential oils at sub-inhibitory concentrations (MIC/16), fluconazole had its potentiated effect, i.e. a synergistic effect was observed in the combination of fluconazole with P.salutare oil against all Candida strains; however, for C. albicans, its effect was reinforced by the natural product in all the collection periods. The results show that the Psidium salutare oil affected the dimorphic transition capacity, significantly reducing the formation of hyphae and pseudohyphae in increasing concentrations. The results show that P. salutare oil exhibits a significant antifungal activity against three Candida species and that it can act in synergy with fluconazole. These results support the notion that this plant may have a potential use in pharmaceutical and preservative products.

Ethnobotany of the genus Taraxacum-Phytochemicals and antimicrobial activity.

Plants belonging to the genus Taraxacum have been used in traditional healthcare to treat infectious diseases including food-borne infections. This review aims to summarize the available information on Taraxacum spp., focusing on plant cultivation, ethnomedicinal uses, bioactive phytochemicals, and antimicrobial properties. Phytochemicals present in Taraxacum spp. include sesquiterpene lactones, such as taraxacin, mongolicumin B, and taraxinic acid derivatives; triterpenoids, such as taraxasterol, taraxerol, and officinatrione; and phenolic derivatives, such as hydroxycinnamic acids (chlorogenic, chicoric, and caffeoyltartaric acids), coumarins (aesculin and cichoriin), lignans (mongolicumin A), and taraxacosides. Aqueous and organic extracts of different plant parts exhibit promising in vitro antimicrobial activity relevant for controlling fungi and Gram-positive and Gram-negative bacteria. Therefore, this genus represents a potential source of bioactive phytochemicals with broad-spectrum antimicrobial activity. However, so far, preclinical evidence for these activities has not been fully substantiated by clinical studies. Indeed, clinical evidence for the activity of Taraxacum bioactive compounds is still scant, at least for infectious diseases, and there is limited information on oral bioavailability, pharmacological activities, and safety of Taraxacum products in humans, though their traditional uses would suggest that these plants are safe.

Cholecalciferol, Ergosterol, and Cholesterol Enhance the Antibiotic Activity of Drugs.

Background: This is the first report demonstrating the antibiotic-modifying activity of cholecalciferol. AIM: In this study, cholecalciferol was evaluated against multiresistant strains of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. METHODS: The antibacterial and modulatory effects of cholecalciferol, ergosterol, and cholesterol (8-512 µg/mL) were evaluated by microdilution assay against multiresistant bacterial strains. RESULTS: Cholecalciferol, when combined with aminoglycosides, was more effective against P. aeruginosa, reducing the concentration of amikacin and gentamicin necessary to inhibit bacterial growth from 156.25 to 39.06 µg/mL and from 39.06 to 9.76 µg/mL, respectively. It is possible that cholecalciferol, due to its lipid-soluble nature, had a lipophilic interaction with the cell membrane, enhancing antibiotic uptake. Cholesterol and ergosterol were used to see if the mechanism of action of cholecalciferol was similar to that of these lipid compounds. Ergosterol and cholesterol increased aminoglycoside activity, where the effect was greater with higher subinhibitory concentration of sterol. CONCLUSIONS: There is no reported study on the use of cholesterol and ergosterol as modulators of antibiotics or any other drug, making this the first study in this area highlighting the interaction between cholesterol, ergosterol, and cholecalciferol with regard to modifying aminoglycoside activity.

Inhibition of the TetK efflux-pump by the essential oil of Chenopodium ambrosioides L. and α-terpinene against Staphylococcus aureus IS-58.

The use of natural products is crucial to suppress the development of these micro-organisms and to reduce the concentration necessary to inhibit these microrganisms, reducing the toxicity risks also. In this study, the essential oil from Chenopodium ambrosioides Leaves and its main constituent α-Terpinene were used in the antibacterial and potentiating activity of antibiotics and ethidium bromide assays, against the bacterial strains Staphylococcus aureus IS-58, carriers of efflux pumps. The Minimum Inhibitory Concentration (MIC) was determined using a microdilution method. The capacity of the aforementioned was also tested in combination with tetracycline and ethidium bromide, with the aim of improving the activity of the antibacterials. The MIC of the C. ambrosioides L. essential oil and of α-Terpinene were above 1024 µg/mL, comprising a clinically irrelevant value. However, when associated with the antibiotics, the C. ambrosioides L. essential oil, significantly decreased the MIC of tetracycline and ethidium bromide. The efflux pump is the only mechanism the bacteria possesses to reduce the toxicity of ethidium bromide, and thus this reduction in the MIC demonstrates that the C. ambrosioides L. essential oil is an effective option in the inhibition of the efflux pump present in these micro-organisms.

Menadione (vitamin K) enhances the antibiotic activity of drugs by cell membrane permeabilization mechanism.

Menadione, vitamin K3, belongs to the class of lipid-soluble vitamins and lipophilic substances as menadione cause disturbances in the bacterial membrane, resulting in damage to the fundamental elements for the integrity of the membrane, thus allowing increased permeability. Accordingly, the aim of this study was to evaluate in vitro the antibiotic-modifying activity of menadione in multiresistant strains of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, with a gradual increase in its subinhibitory concentration. In addition, menadione was compared with cholesterol and ergosterol for similarity in mechanism of drug modulatory action. Antibiotic-modifying activity and antibacterial effect were determined by the broth microdilution assay. Menadione, cholesterol and ergosterol showed modulatory activity at clinically relevant concentrations, characterizing them as modifiers of bacterial drug resistance, since they lowered the MIC of the antibiotics tested. This is the first report of the antibacterial activity of menadione and its potentiation of aminoglycosides against multiresistant bacteria.

Phytochemicals from fern species: potential for medicine applications.

Ferns are an important phytogenetic bridge between lower and higher plants. Historically they have been used in many ways by humans, including as ornamental plants, domestic utensils, foods, and in handicrafts. In addition, they have found uses as medicinal herbs. Ferns produce a wide array of secondary metabolites endowed with different bioactivities that could potentially be useful in the treatment of many diseases. However, there is currently relatively little information in the literature on the phytochemicals present in ferns and their pharmacological applications, and the most recent review of the literature on the occurrence, chemotaxonomy and physiological activity of fern secondary metabolites was published over 20 years ago, by Soeder (Bot Rev 51:442-536, 1985). Here, we provide an updated review of this field, covering recent findings concerning the bioactive phytochemicals and pharmacology of fern species.

Psidium guajava L., from ethnobiology to scientific evaluation: Elucidating bioactivity against pathogenic microorganisms.

ETHNOPHARMACOLOGICAL RELEVANCE: The use of popular plants has guided pharmaceutical research aimed at combating pathogenic microorganisms. Psidium guajava L. is a plant of great versatility and it has been used both as food and as a therapeutic agent. Root, bark, leaves, fruits, flowers and seeds are used for medicinal purposes, especially in infusions and decoctions for oral and topical use. P. guajava is utilized in symptomatology treatment related to organ malfunction and of diseases caused by the action of pathogenic and/or opportunistic microorganisms. Many pharmacological studies have been conducted to scientifically assess its therapeutic potential. AIMS OF STUDY: The aim of the current study is to relate the popular use of this plant and its bioscientific assessment as a therapeutic agent in the treatment of diseases and symptoms caused by the action of protozoa, fungi, bacteria and viruses, and also evaluate the safety for the usage and the interaction with drugs. MATERIALS AND METHODS: A bibliographic database the ethnobiology of Psidium guajava (2005-2015) and the pharmacological infections and parasitic diseases (2010-2015). Searches were done in scientific disclosure databases such as PubMed, Web of Science, and Scopus. RESULTS: P. guajava leaf extracts were scientifically investigated for the treatment of diseases caused by protozoa (leishmaniasis, malaria, giardiasis, amoebiasis and trichomoniasis), fungi (dermatosis, systemic and mucocutaneous diseases), bacteria (respiratory, mucocutaneous and gastrointestinal infections, cholera, gastritis and stomach ulcers, oral and periodontal infections, venereal diseases and urinary infections) and viruses (herpes, influenza, rotavirus disease and AIDS). The toxicity assays indicates the safet for usage. CONCLUSIONS: Highlight and elucidate the therapeutic potential and versatility of P. guajava. They also justify using ethnobiology efficiency to guide pharmacological studies. Some limitations can be observed in this kind of study, as the lack for ethnobiological informations and the absence of some controls in the assays.

Cytoprotective Effect of Lygodium venustum Sw. (Lygodiaceae) against Mercurium Chloride Toxicity.

Mercury is a very dangerous metal when humans come into contact with it, whether through the air or skin or by ingestion. The aim of this work was to investigate the possible effects of the ethanol extract and fractions of Lygodium venustum Sw. against mercurium chloride toxicity towards Escherichia coli strain ATCC25922. The polyphenols and flavonoids present in the extract and fractions were quantified in mg equivalent of gallic acid/g sample and mg equivalent of quercetin/g sample, respectively. The in vitro FRAP method demonstrated the antioxidant activity of the samples. The antibacterial activity of the natural products was evaluated by microdilution method and by assays to elucidate the possible cytoprotective action when combining the natural products samples and mercurium chloride, utilizing the extract and fractions at a subinhibitory concentration. The results obtained in this work indicate that the ethanol extract and fractions of L. venustum are an alternative source of natural products with cytoprotective action, where this protection is correlated with antioxidant and chelating activity, due to the presence of total phenols and flavonoids.

Psidium guajava L. and Psidium brownianum Mart ex DC.: Chemical composition and anti - Candida effect in association with fluconazole.

The therapeutic combinations have been increasingly used against fungal resistance. Natural products have been evaluated in combination with pharmaceutical drugs in the search for new components able to work together in order to neutralize the multiple resistance mechanisms found in yeasts from the genus Candida. The aqueous and hydroethanolic extracts from Psidium brownianum Mart ex DC. and Psidium guajava L. species were evaluated for their potential to change the effect of commercial pharmaceutical drugs against Candida albicans and Candida tropicalis strains. The tests were performed according to the broth microdilution method. Plate readings were carried out by spectrophotometry, and the data generated the cell viability curve and IC50 of the extracts against the yeasts. A chemical analysis of all the extracts was performed for detection and characterization of the secondary metabolites. The total phenols were quantified in gallic acid eq/g of extract (GAE/g) and the phenolic composition of the extracts was determined by HPLC. Fluconazole and all extracts presented high Minimum Inhibitories Concentrations (MICs). However, when associated with the extracts at sub-inhibitory concentrations (MIC/16), fluconazole had its effect potentiated. A synergistic effect was observed in the combination of fluconazole with Psidium brownianum extracts against all Candida strains. However, for Psidium guajava extracts the synergistic effect was produced mainly against the Candida albicans LM77 and Candida tropicalis INCQS 400042 strains. The IC50 values of fluconazole ranged from 19.22 to 68.1 µg/mL when it was used alone, but from 2.2 to 45.4 µg/mL in the presence of the extracts. The qualitative chemical characterization demonstrated the presence of phenols, flavonoids and tannins among the secondary metabolites. The concentration of total phenols ranged from 49.25 to 80.77 GAE/g in the P. brownianum extracts and from 68.06 to 82.18 GAE/g in the P. guajava extracts. Our results indicated that both P. brownianum and P. guajava extracts are effective on potentiating the effect of fluconazole, and therefore, these plants have the potential for development of new effective drugs for treating fungal infections.

Phytochemical analysis and modulation of antibiotic activity by Luehea paniculata Mart. & Zucc. (Malvaceae) in multiresistant clinical isolates of Candida spp.

The high incidence of fungal infections has led to the continuous search for new drugs. Extracts of Luehea paniculata, a tree of multiple medicinal uses, were evaluated for anti-Candida activity, as well as its modulator potential of the Fluconazole antibiotic. Chemical prospecting of ethanol extracts of leaf and bark was carried out, the quantification of total phenols and flavonoids, characterized by the HPLC-DAD technique. The rosmarinic acid and the vitexin flavonoid were observed as major constituents in ELELP and ESWELP, respectively. Antioxidant activity was also evaluated by the method of scavenging the free radical DPPH, and quercetin was used as standard, obtaining IC50 values: 0.341 (mg/mL) for ELELP and 0.235 (mg/mL) for ESWELP. The microdilution assay was performed for antifungal activity against strains of Candida albicans, C. krusei, and C. tropicalis and showed minimum inhibitory concentrations values ≥1024 µg/mL. In the modulator action of extracts on Fluconazole against multiresistant clinical isolates of Candida (subinhibitory concentration minimum of 128 µg/mL), a significant synergism was observed, indicating that the extracts potentiated the antifungal effect against C. tropicalis, where antioxidant flavonoids could be responsible. This is the first report about modifying activity of the antibiotic action of a species of the genus Luehea.

Enhancement of the antibiotic activity of aminoglycosides by alpha-tocopherol and other cholesterol derivates.

Alpha-tocopherol, one of the most abundant isoforms of vitamin E, is a biologically active liposoluble vitamin and potent antioxidant. It occurs naturally in foods of plant and animal origin. Because of its lipophilic character, it can cause perturbations in the bacterial cell membrane, resulting in damage to components essential for the integrity of the membrane, thereby allowing an increase in permeability. This is the first report of the modulatory effect of alpha-tocopherol in multiresistant bacteria. We evaluated alpha-tocopherol against multiresistant strains of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, and determined if there was any similarity with the mechanism of modulatory action of cholesterol and ergosterol. When combined with aminoglycosides in a microdilution broth assay, alpha-tocopherol possibly acted through a lipophilic action on the cell envelope, modulating more effectively P. aeruginosa and E. coli, when compared with S. aureus.

Citotocixidade e atividade antiparasitária de Lygodium venustum SW / Cytotoxic and antiparasitic activity of Lygodium venustum SW

. Doenças parasitárias infecciosas como leishmaniose e doença de Chagas tem se difundido nas últimas décadas a locais onde antes não se observava sua ocorrência. São consideradas negligenciadas por assolarem países pobres e serem marginalizadas farmacologicamente. O tratamento não apresenta muitas opções de fármacos e estes demonstram relevante toxicidade contribuindo para o aparecimento de diversos efeitos colaterais. A pesquisa com produtos naturais tem se mostrado uma interessante alternativa para a procura por novos fármacos. Lygodium venustum é uma samambaia cosmopolita de hábito lianescente encontrada na encosta na Chapada do Araripe, considerada por algumas populações americanas como planta medicinal para o tratamento de dermatoses, infecções, micoses e tricomoníases. Neste estudo foi avaliada sua atividade anti-parasitária contra Leishmania brasiliensis e Trypanosoma cruzi, bem como sua citotoxicidade através de ensaios n vitro. Foram testadas a fração hexânica e o extrato etanólico obtido das folhas de Lygodium venustum em diferentes concentrações. Para os testes in vitro de T. cruzi, foi utilizado o clone CL-B5 e para Leishmania brasiliensis foram utilizadas formas promastigotas. O ensaio de citotoxicidade foi realizado com linhagens de fbroblastos. L. venustum não apresentou atividade antiparasitária clinicamente relevante na forma de extrato etanólico bruto nem como fração hexânica contra Leishmania. A fração hexânica apresentou uma atividade intermediária contra T. cruzi, porém a concentração de efeito moderado possui citotoxicidade máxima tornando-se inviável para aplicação clínica. Entretanto, a citoxicicidade apresentada poderá ser útil em pesquisas sobre atividade antineoplásica em células tumorais.

Infectious and parasitic diseases like leishmaniasis and Chagas disease have spreading recent decades to places not observed before. They are considered neglected by desolating poor countries and marginalized pharmacologically. There are not many options for the treatment and these drugs have shown signifcant toxicity contributing to the appearance of several side effects. Research on natural products has been shown to be an interesting alternative to the search for new drugs. Lygodium venustum is a cosmopolitan fern with latescence habit found on the Chapada do Araripe, considered by some American popula-tions as a medicinal plant for the treatment of skin diseases, infections, fungal infections and trichomoniasis. This study evaluated its antiparasitic activity against Trypanosoma cruzi and Leishmania brasiliensis, as well as its cytotoxicity through trials in vitro. We tested the ethanolic extract and hexane fraction obtained from the leaves of L. venustum at different concentrations. For in vitro tests of T. cruzi, we used the clone CL-B5 and for L. brasiliensis we used promastigotes. The cytotoxicity assay was performed with strains of fbroblasts. L.venustum showed no antiparasitic activity clinically relevant in the form of crude ethanolic extractor as the hexane fraction against Leishmania. The hexane fraction showed an intermediate activity against T.cruzi, but the concentration of moderate effect has maximum cytotoxicity becoming unfeasible for clinical application. However, the cytotoxicity presented may be useful in research on antineoplastic activity in tumor cells.

Citotocixidade e atividade antiparasitária de Lygodium venustum SW / Cytotoxic and antiparasitic activity of Lygodium venustum SW

. Doenþas parasitárias infecciosas como leishmaniose e doenþa de Chagas tem se difundido nas últimas décadas a locais onde antes nÒo se observava sua ocorrÛncia. SÒo consideradas negligenciadas por assolarem países pobres e serem marginalizadas farmacologicamente. O tratamento nÒo apresenta muitas opþ§es de fármacos e estes demonstram relevante toxicidade contribuindo para o aparecimento de diversos efeitos colaterais. A pesquisa com produtos naturais tem se mostrado uma interessante alternativa para a procura por novos fármacos. Lygodium venustum é uma samambaia cosmopolita de hábito lianescente encontrada na encosta na Chapada do Araripe, considerada por algumas populaþ§es americanas como planta medicinal para o tratamento de dermatoses, infecþ§es, micoses e tricomoníases. Neste estudo foi avaliada sua atividade anti-parasitária contra Leishmania brasiliensis e Trypanosoma cruzi, bem como sua citotoxicidade através de ensaios n vitro. Foram testadas a fraþÒo hexÔnica e o extrato etanólico obtido das folhas de Lygodium venustum em diferentes concentraþ§es. Para os testes in vitro de T. cruzi, foi utilizado o clone CL-B5 e para Leishmania brasiliensis foram utilizadas formas promastigotas. O ensaio de citotoxicidade foi realizado com linhagens de fbroblastos. L. venustum nÒo apresentou atividade antiparasitária clinicamente relevante na forma de extrato etanólico bruto nem como fraþÒo hexÔnica contra Leishmania. A fraþÒo hexÔnica apresentou uma atividade intermediária contra T. cruzi, porém a concentraþÒo de efeito moderado possui citotoxicidade máxima tornando-se inviável para aplicaþÒo clínica. Entretanto, a citoxicicidade apresentada poderá ser útil em pesquisas sobre atividade antineoplásica em células tumorais.(AU)

Infectious and parasitic diseases like leishmaniasis and Chagas disease have spreading recent decades to places not observed before. They are considered neglected by desolating poor countries and marginalized pharmacologically. There are not many options for the treatment and these drugs have shown signifcant toxicity contributing to the appearance of several side effects. Research on natural products has been shown to be an interesting alternative to the search for new drugs. Lygodium venustum is a cosmopolitan fern with latescence habit found on the Chapada do Araripe, considered by some American popula-tions as a medicinal plant for the treatment of skin diseases, infections, fungal infections and trichomoniasis. This study evaluated its antiparasitic activity against Trypanosoma cruzi and Leishmania brasiliensis, as well as its cytotoxicity through trials in vitro. We tested the ethanolic extract and hexane fraction obtained from the leaves of L. venustum at different concentrations. For in vitro tests of T. cruzi, we used the clone CL-B5 and for L. brasiliensis we used promastigotes. The cytotoxicity assay was performed with strains of fbroblasts. L.venustum showed no antiparasitic activity clinically relevant in the form of crude ethanolic extractor as the hexane fraction against Leishmania. The hexane fraction showed an intermediate activity against T.cruzi, but the concentration of moderate effect has maximum cytotoxicity becoming unfeasible for clinical application. However, the cytotoxicity presented may be useful in research on antineoplastic activity in tumor cells.(AU)

Atividade antibacteriana, antifúngica e moduladora da atividade antimicrobiana de frações obtidas de Lygodium venustum SW / Antibacterial, antifungal and antimicrobial modulatory activities of fractions from Lygodium venustum SW

The traditional use of plants in popular medicine has also indicated the way in the search for pharmacological agents. The need for new drugs is evidenced by the strong resistance of microorganisms. The fern Lygodium venustum had its antimicrobial potential measured, in this work, by the broth microdilution method. Its ability to modulate the action of antibiotics was also tested. Its hexane, dichloromethane and methanol fractions obtained from the ethanolic extract of fresh leaves were assayed. The Minimum Inhibitory Concentration was evaluated from the standard strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Candida albicans, Candida tropicalis and Candida krusei. To check the modulating activity of antibiotics were used multi-resistant strains of P. aeruginosa, E. coli and S. aureus and the same yeast strains used in CIM. The drugs used in modulating were antifungal and aminoglycosides. All results showed MIC >1024ug/mL activity. The fractions neither enhanced the action of antifungal agents against strains of Candida, nor the aminoglycosides against P. aeruginosa. However, interesting results potentiating the action of these were obtained against the E. coli and S. aureus. Such results suggest that secondary metabolites which are in this plant may be used to create new drugs in combination with aminoglycosides. This was the first report of activity-modifying action of antibiotics for fractions obtained from a fern family Lygodiaceae.

O tradicional uso das plantas na medicina popular vem indicando um caminho na busca de agentes farmacológicos. A necessidade de novos fármacos é evidenciada pela acentuada resistência dos microorganismos. A samambaia Lygodium venustum teve neste trabalho seu potencial antimicrobiano avaliado através do método de microdiluição em caldo. Também foi testada a sua capacidade de modular a ação de antibióticos. Foram ensaiadas suas frações hexânica, diclorometano e metanólica obtidas a partir do extrato etanólico das folhas frescas. A Concentração Inibitória Mínima foi avaliada frente às linhagens padrões de Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Candida albicans, Candida krusei e Candida tropicalis. Na verificação da atividade moduladora de antibióticos foram utilizadas linhagens multirresistentes de P. aeruginosa, E. coli e S. aureus e as mesmas linhagens fúngicas utilizadas na CIM. As drogas usadas na modulação foram antifúngicos e aminoglicosídeos. Todos os resultados da CIM demonstraram atividade > 1024ug/mL. As frações não potencializaram a ação dos antifúngicos contra as linhagens de Candida, nem dos aminoglicosídeos frente à P. aeruginosa. Porém, interessantes resultados potencializando a ação destes foram obtidos frente à E. coli e S. aureus. Tais resultados sugerem que metabólitos secundários existentes no vegetal poderão ser utilizados para constituição de novas drogas em associação com aminoglicosídeos. Este foi o primeiro relato de atividade modificadora da ação de antibióticos por frações obtidas de uma pteridófita da família Lygodiaceae.

Evaluation of the anti-Leishmania activity of ethanol extract and fractions of the leaves from Pityrogramma calomelanos (L.) link.

Leishmaniasis is caused by parasites of the genus Leishmania. Recent reports about leishmaniasis show a few number of drugs available, indicating the necessity of new drugs. In this study, the ethanol extract and fractions of Pityrogramma calomelanos (L.) link. (Pteridaceae) were assayed to verify the cytotoxicity and in vitro leishmanicidal activity against promastigote forms of Leishmania brasiliensis. The cytotoxic assay was performed using fibroblasts NCTC929. The studies indicated a leishmanicidal effect of the ethanol extract and the ethyl-acetate fraction. However, a high cytotoxic effect was observed. The hexane and methanol fractions did not show leishmanicidal activity, nor cytotoxic effect. The phytochemical screening detected the presence of alkaloids, a class of secondary metabolites with a known leishmanicidal activity. This is the first study reporting an anti-Leishmania and cytotoxic effect of P. calomelanos, being an interesting approach in the search for drugs against this disease.

Modulation of the norfloxacin resistance in Staphylococcus aureus by Croton campestris A. and Ocimum gratissimum L.

INTRODUCTION: Some species of Staphylococcus are often recognized as etiological agents of many animal and human opportunistic infections. This study is the first test of change in resistance of antibiotic activity by Croton campestris A. and Ocimum gratissimum L. against multiresistant strains of Staphylococcus aureus. OBJECTIVE: In this study, the hexane and methanol extract of Croton campestris A. and Ocimum gratissimum L. was tested for antibacterial activity alone and in combination with norfloxacin against the strain SA1199B. MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) and the modulatory effect of extracts was assayed using microtitre assay. RESULTS: By the fact of the MIC observed was not clinically relevant (MIC= 512 to ≥1.024 µg/ml), the antibiotic activity of norfloxacin was enhanced when this antibiotic was combined with sub-inhibitory concentrations of extracts, mainly the hexane extracts. CONCLUSIONS: These results indicate that the assayed extracts present compounds that can be used as a putative efflux pump inhibitor, indicating that Croton campestris A. and Ocimum gratissimum L. can be a source of plant derived products with antibiotic modifier activity.