[Show abstract][Hide abstract] ABSTRACT: Phialophora verrucosa is one of the etiologic agents of chromoblastomycosis, a fungal infection that affects cutaneous and subcutaneous tissues. This disease is chronic, recurrent and difficult to treat. Several studies have shown that secreted peptidases by fungi are associated with important pathophysiological processes. Herein, we have identified and partially characterized the peptidase activity secreted by P. verrucosa conidial cells. Using human serum albumin as substrate, the best hydrolysis profile was detected at extreme acidic pH (3.0) and at 37 �C. The enzymatic activity was completely blocked by classical metallopeptidase inhibitors/chelating agents as 1,10-phenanthroline and EGTA. Zinc ions stimulated the metallo-type peptidase activity in a dose dependent manner. Several proteinaceous substrates were cleaved, in different extension, by the P. verrucosa metallopeptidase activity, including immunoglobulin G, fibrinogen, collagen types I and IV, fibronectin, laminin and keratin; however, mucin and hemoglobin were not susceptible to proteolysis. As metallopeptidases participate in different cellular metabolic pathways in fungal cells, we also tested the influence of 1,10-phenanthroline and EGTA on P. verrucosa development. Contrarily to EGTA, 1,10-phenanthroline inhibited the fungal viability (MIC 0.8 lg/ml), showing fungistatic effect, and induced profound morphological alterations as visualized by transmission electron microscopy. In addition, 1,10-phenanthroline arrested the filamentation process in P. verrucosa. Our results corroborate the supposition that metallopeptidase inhibitors/chelating agents have potential to control crucial biological events in fungal agents of chromoblastomycosis.
[Show abstract][Hide abstract] ABSTRACT: The leaves and bark of Croton cajucara, a shrub from the Amazon region, have been used in folk medicine to treat diabetes, malaria, and gastrointestinal and liver disorders. The essential oil from the leaves, rich in linalool, presented antileishmanial and antimicrobial activities. A chemotype of this species was found with an essential oil rich in 7-hydroxycalamenene. During our studies of the C. cajucara essential oil, we isolated 7-hydroxycalamenene at > 98 % purity. The minimum inhibitory concentration of 7-hydroxycalamenene against Absidia cylindrospora, Cunninghamella elegans, Mucor circinelloides, Mucor circinelloides f. circinelloides, Mucor mucedo, Mucor plumbeus, Mucor ramosissimus, Rhizopus microsporus, Rhizopus oryzae, and Syncephalastrum racemosum ranged from 19.53 to 2500 µg/mL. The reference drug used, amphotericin B, presented a minimum inhibitory concentration ranging from 0.085 µg/mL to 43.87 µg/mL. 7-Hydroxycalamenene also altered spore differentiation and total lipid content. Ultrastructural analysis by transmission electron microscopy showed significant alterations in the cellular structure of R. oryzae.
[Show abstract][Hide abstract] ABSTRACT: Current therapies for glioblastoma multiforme (GBM) are not effective. This study investigated the activity of the M. officinalis essential oil (EO) and its major component (citral) in GBM cell lines. Both EO and citral decreased the viability and induced apoptosis of GBM cells as demonstrated by DNA fragmentation and caspase-3 activation. Antioxidant prevented citral-induced death, indicating its dependence on the production of reactive oxygen species. Citral downmodulated the activity and inhibited the expression of multidrug resistance associated protein 1 (MRP1). These results show that EO, through its major component, citral, may be of potential interest for the treatment of GBM.
Cancer Investigation 04/2014; · 2.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Currently available leishmaniasis treatments are limited due to severe side effects. Arrabidaea chica is a medicinal plant used in Brazil against several diseases. In this study, we investigated the effects of 5 fractions obtained from the crude hexanic extract of A. chica against Leishmania amazonensis and L. infantum, as well as on the interaction of these parasites with host cells. Promastigotes were treated with several concentrations of the fractions obtained from A. chica for determination of their minimum inhibitory concentration (MIC). In addition, the effect of the most active fraction (B2) on parasite's ultrastructure was analyzed by transmission electron microscopy. To evaluate the inhibitory activity of B2 fraction on Leishmania peptidases, parasites lysates were treated with the inhibitory and subinhibitory concentrations of the B2 fraction. The minimum inhibitory concentration of B2 fraction was 37.2 and 18.6 μ g/mL for L. amazonensis and L. infantum, respectively. Important ultrastructural alterations as mitochondrial swelling with loss of matrix content and the presence of vesicles inside this organelle were observed in treated parasites. Moreover, B2 fraction was able to completely inhibit the peptidase activity of promastigotes at pH 5.5. The results presented here further support the use of A. chica as an interesting source of antileishmanial agents.
BioMed research international. 01/2014; 2014:985171.
[Show abstract][Hide abstract] ABSTRACT: Background
Visceral leishmaniasis is the most serious form of leishmaniasis and can be lethal if left untreated. Currently available treatments for these parasitic diseases are frequently associated to severe side effects. The leaves of Croton cajucara are used as an infusion in popular medicine to combat several diseases. Previous studies have demonstrated that the linalool-rich essential oil from C. cajucara (white sacaca) is extremely efficient against the tegumentary specie Leishmania amazonensis. In this study, we investigated the effects of the 7-hydroxycalamenene-rich essential oil from the leaves of C. cajucara (red sacaca) against Leishmania chagasi, as well as on the interaction of these parasites with host cells.
Promastigotes were treated with different concentrations of the essential oil for determination of its minimum inhibitory concentration (MIC). In addition, the effects of the essential oil on parasite ultrastructure were analyzed by transmission electron microscopy. To evaluate its efficacy against infected cells, mouse peritoneal macrophages infected with L. chagasi promastigotes were treated with the inhibitory and sub-inhibitory concentrations of the essential oil.
The minimum inhibitory concentrations of the essential oil and its purified component 7-hydroxycalamenene against L. chagasi were 250 and 15.6 mug/mL, respectively. Transmission electron microscopy analysis revealed important nuclear and kinetoplastic alterations in L. chagasi promastigotes. Pre-treatment of macrophages and parasites with the essential oil reduced parasite/macrophage interaction by 52.8%, while it increased the production of nitric oxide by L. chagasi-infected macrophages by 80%.
These results indicate that the 7-hydroxycalamenene-rich essential oil from C. cajucara is a promising source of leishmanicidal compounds.
BMC Complementary and Alternative Medicine 10/2013; 13(1):249. · 1.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The possible role of sialic acids in host cells-fungi interaction and their association with glycoproteins were evaluated using a clinical isolate of the dimorphic fungus Mucor polymorphosporus. Lectin-binding assays with spores and yeast cells denoted the presence of surface sialoglycoconjugates containing 2,3- and 2,6-linked sialylglycosyl groups. Western blotting with peroxidase-labeled Limulus polyphemus agglutinin revealed the occurrence of different sialoglycoprotein types in both cell lysates and cell wall protein extracts of mycelia, spores, and yeasts of M. polymorphosporus. Sialic acids contributed to the surface negative charge of spores and yeast forms as evaluated by adherence to a cationic substrate. Sialidase-treated spores were less resistant to phagocytosis by human neutrophils and monocytes from healthy individuals than control (untreated) fungal suspensions. The results suggest that sialic acids are terminal units of various glycoproteins of M. polymorphosporus, contributing to negative charge of yeasts and spore cells and protecting infectious propagules from destruction by host cells.
[Show abstract][Hide abstract] ABSTRACT: The anti-corrosion effect and the antimicrobial activity of lemongrass essential oil (LEO) against the planktonic and sessile growth of a sulfate reducing bacterium (SRB) were evaluated. Minimum inhibitory concentration (MIC) of LEO and its major component, the citral, was 0.17 mg ml-1. In addition, both LEO and citral showed an immediate killing effect against SRB in liquid medium, suggesting that citral is responsible for the antimicrobial activity of LEO against SRB. Transmission electron microscopy revealed that the MIC of LEO caused discernible cell membrane alterations and formed electron-dense inclusions. Neither biofilm formation nor corrosion was observed on carbon steel coupons after LEO treatment. LEO was effective for the control of the planktonic and sessile SRB growth and for the protection of carbon steel coupons against biocorrosion. The application of LEO as a potential biocide for SRB growth control in petroleum reservoirs and, consequently, for souring prevention, and/or as a coating protection against biocorrosion is of great interest for the petroleum industries.
[Show abstract][Hide abstract] ABSTRACT: For centuries, medicinal plants have been used as source of active principles for the treatment of many conditions. Ethnobotanical studies and bioassay guided isolation procedures have been successfully used in order to investigate and confirm their medicinal prescriptions. Traditionally used in Brazil, Cymbopogon citratus (lemongrass) is usually consumed as tea drink due to its calmative, anxyolitic as well as anti-hypertensive properties. Due to the similar lemongrass scent many species of Pectis genus have been used as infusion drinks for the same purposes as C. citratus. In Brazil, Pectis brevipedunculata, a sandy ornamental aromatic grass, is one of the "lemongrass odor" correlated species traditionally consumed. Chemical analysis of its essential oil was performed using GC-FID and GC-MS. Such essential oil was characterized by a high percentages of citral (81.8%: neral 35.6% and geranial 46.2%), followed by limonene (2.9%) and α-pinene (2.6%). Chemical and ethnobotanical investigations were performed involving one of the most commonly used Pectis species, known as lemongrass in order to confirm the medicinal indications compared to their chemical profile. The essential oil of P. brevipedunculata was tested against several clinical parasites. Our results were in agreement to the literature survey, suggesting the citral as the principal active constituent of the tested samples. Despite of the wide biological activities spectrum related to the major constituent presented in the essential oil of the most Pectis species, it is necessary to continue the phytochemical and pharmacological studies about the infusions constituents and validate the folk medicine.
Emirates Journal of Food and Agriculture. 06/2013; 25(10):798-808.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Teas from the husk fiber of Cocos nucifera are used in the folk medicine to treat arthritis and other inflammatory processes. Some works show that some varieties have biological activities. However, one of the main variety of the species, C. nucifera var. typica, known in Brazil as "gigante", was not studied yet. Thus, this study evaluates if this variety has the anti-inflammatory and antimicrobial activities already reported in other varieties. METHODS: C. nucifera aqueous crude extract (10, 50, and 100 mg/kg) and the reference drugs morphine (1 mg/kg) and acetylsalicylic acid (100 mg/kg) were evaluated in models of inflammation (formalin-induced licking and subcutaneous air pouch). The antioxidant activity was evaluated by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) photometric assay and compared with those of the standards (quercetin, rutin, and ascorbic acid). The extract was also screened against Candida albicans, Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA), in the agar diffusion method. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined by the broth micro-dilution assay. Activities of combinations of the extract and antibiotics (methicillin or vancomycin) against MRSA were evaluated using checkerboard assays. RESULTS: The extract significantly inhibited the time that the animals spent licking the formalin-injected paws (second phase). The extract also inhibited the inflammatory process induced by subcutaneous carrageenan injection by reducing cell migration, protein extravasation, and TNF-alpha production. Additionally, the extract showed an antioxidant potential in vitro as good as standards in their antioxidant activity. The extract was active only against S. aureus and MRSA. MIC and the bactericidal concentrations were identical (1,024 mug/ml). The extract and methicillin acted synergistically against the clinical MRSA isolate, whereas an indifferent effect was detected when the extract was combined with vancomycin. CONCLUSIONS: The extract exhibits anti-inflammatory activity through the inhibition of the cell migration. The mixture of extract constituents and methicillin could lead to the development of a new combination antibiotic against MRSA infections.
BMC Complementary and Alternative Medicine 05/2013; 13(1):107. · 1.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Lippia sidoides Cham., also known as pepper-rosmarin, produces an essential oil in its leaves that is currently used by the pharmaceutical, perfumery and cosmetic industries for its antimicrobial and aromatic properties. Because of the antimicrobial compounds (mainly thymol and carvacrol) found in the essential oil, we believe that the endophytic microorganisms found in L. sidoides are selected to live in different parts of the plant. RESULTS: In this study, the endophytic microbial communities from the stems and leaves of four L. sidoides genotypes were determined using cultivation-dependent and cultivation-independent approaches. In total, 145 endophytic bacterial strains were isolated and further grouped using either ERIC-PCR or BOX-PCR, resulting in 76 groups composed of different genera predominantly belonging to the Gammaproteobacteria. The endophytic microbial diversity was also analyzed by PCR-DGGE using 16S rRNA-based universal and group-specific primers for total bacteria, Alphaproteobacteria, Betaproteobacteria and Actinobacteria and 18S rRNA-based primers for fungi. PCR-DGGE profile analysis and principal component analysis showed that the total bacteria, Alphaproteobacteria, Betaproteobacteria and fungi were influenced not only by the location within the plant (leaf vs. stem) but also by the presence of the main components of the L. sidoides essential oil (thymol and/or carvacrol) in the leaves. However, the same could not be observed within the Actinobacteria. CONCLUSION: The data presented here are the first step to begin shedding light on the impact of the essential oil in the endophytic microorganisms in pepper-rosmarin.
[Show abstract][Hide abstract] ABSTRACT: Abstract Lippia alba (Miller) N.E. Brown is an aromatic plant known locally as "Erva-cidreira-do-campo" that has great importance in Brazilian folk medicine. The aim of our study was to evaluate the antidermatophytic potential of linalool-rich essential oil (EO) from L. alba and analyze the ability of this EO to inhibit peptidase and keratinase activities, which are important virulence factors in dermatophytes. The minimum inhibitory concentrations (MICs) of L. alba EO were 39, 156 and 312 µg/mL against Trichophyton rubrum, Epidermophyton floccosum and Microsporum gypseum, respectively. To evaluate the influence of L. alba EO on the proteolytic and keratinolytic activities of these dermatophytes, specific inhibitory assays were performed. The results indicated that linalool-rich EO from L. alba inhibited the activity of proteases and keratinases secreted from dermatophytes, and this inhibition could be a possible mechanism of action against dermatophytes. Due to the effective antidermatophytic activity of L. alba EO, further experiments should be performed to explore the potential of this linalool-rich EO as an alternative antifungal therapy.
Journal of Enzyme Inhibition and Medicinal Chemistry 01/2013; · 1.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Croton cajucara is a shrub native to the Amazon region locally known as "sacaca". Two morphotypes are known: white and red "sacaca". The essential oils (EO) obtained by hydrodistillation from leaves of the red morphotype were, in general, rich in 7-hydroxycalamenene (28.4%-37.5%). The effectiveness of these EO regarding the antimicrobial activity against pathogenic microorganisms was initially investigated by the drop test method, showing significant inhibition zones. Among the microorganisms tested, the essential oils rich in 7-hydroxycalamenene were more effective against methicillin resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Mycobacterium tuberculosis, M. smegmatis, Mucor circinelloides and Rhizopus oryzae. The minimum inhibitory concentrations (MIC) of the oils were determined using the broth dilution assay. It was possible to observe that 7-hydroxycalamenene-rich oils presented high antimicrobial activity, with MIC of 4.76 × 10-3 μg/mL for MRSA, 4.88 μg/mL for M. tuberculosis, 39.06 μg/mL for M. smegmatis, and 0.152 μg/mL for R. oryzae and 3.63 × 10-8 μg/mL for M. circinelloides. The antioxidant activity of this EO suggests that 7-hydroxycalamenene provides more antioxidant activity according with EC(50) less than 63.59 μg/mL. Considering the bioactive potential of EOs and 7-hydroxycalamenene could be of great interest for development of antimicrobials for therapeutic use in treatment of bacterial and fungal infections in humans and/or veterinary practice.
[Show abstract][Hide abstract] ABSTRACT: GBS serotypes III and V were the most prevalent in pregnant women and exhibited resistance to tetracycline, clindamycin and sulfamethoxazole/trimethoprim. Serotype III showed high sialic acid content and PFGE analysis discerned 33 heterogeneous profiles. Phenotypic and genotypic characterization could be relevant to control GBS infections unaffected by intra-partum chemoprophylaxis.
Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]. 01/2013; 44(3):869-72.
[Show abstract][Hide abstract] ABSTRACT: Species belonging to the Burseraceae family, especially of the genus Protium, are well known for producing fragrant oleoresins known in Brazil as breus. In this study, the physicochemical properties and antimicrobial activities of essential oils obtained from commercials samples of breu from the Brazilian Amazon were evaluated. Essential oils were extracted by hydrodistillation using a modified Clevenger apparatus and analyzed by gas chromatography/mass spectrometry (GC/MS) and GC/flame ionization detector (GC/FID). p-Cymene was the major constituent in all of the analyzed breu samples, with concentrations ranging from 21.9% to 51.9%, except for the white breu sample from Adolfo Lisboa Popular Market (ALPM), which contained α-pinene (22.7%). Other common monoterpenes were β-phellandrene, α-phellandrene, β-pinene, trans-dihydro-α-terpineol, α-terpineol and α-terpinene. The refractive indices ranged from 1.4769 to 1.4849 and the optical rotation ranged from −14.15° to +29.96°. The antimicrobial activity was low for all of the samples. The essential oil of black breu from ALPM was the only sample exhibiting antimycobacterial activity.
Journal of Essential Oil Research 12/2012; · 0.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fonsecaea pedrosoi, a dematiaceous fungus, is the main agent responsible for chromoblastomycosis, a chronic and progressive mycosis of the skin and subcutaneous tissues. This disease can cause different types of lesions depending on the immune status of the host. Its treatment is complicated by the toxicity of available antifungal agents as well as drug resistance. In this work, an ATP-binding cassette (ABC) transporter in this fungus was characterised, with the degree of expression related to the drug resistance of two strains (a patient isolated strain and a laboratory strain). A 150 kDa protein was detected by western blotting. The ATPase activity of membrane preparations was also evaluated. The F. pedrosoi transporter appears to behave like Pdr5p, a well-studied multidrug resistance transporter in Saccharomyces cerevisiae with the ability to hydrolyse different triphosphate nucleotides, as well as its response to classical inhibitors tested. Finally, a reverse transcription polymerase chain reaction (RT-PCR) approach was used and a 400 bp product was detected, corresponding to the highly conserved ATP-binding domain of ABC transporters. We suggest that an ABC transporter must be involved in F. pedrosoi multidrug resistance, and a complete understanding of this protein could bring an important contribution to antifungal treatment of this disease.
International Journal of Antimicrobial Agents 11/2012; 40(5):409-415. · 4.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Croton cajucara Benth. (Euphorbiaceae) is a shrub native to Amazon region and locally known as sacaca. Two morphotypes are known, namely white ‘sacaca’ and red ‘sacaca’. The essential oils from the leaves of these morphotypes are rich in linalool and 7-hydroxycalamenene, respectively. The effectiveness of the oils from forty individuals from a germplasm bank regarding the antimicrobial activity against Staphylococcus aureus and Candida albicans was investigated by drop diffusion (or agar diffusion) method. Expressive inhibition zones for both microorganisms tested were observed. Essential oils rich in 7-hydroxycalamenene were more effective against S. aureus while linalool-rich essential oils acted inhibiting C. albicans. The minimal inhibitory (MIC) and microbicidal concentrations of the main constituents of the oils were also determined, using broth dilution assay. It was observed that isolated 7-hydroxycalamenene presented high bactericidal activity, with a MIC of 0.3 μg/mL, while for fungicidal activity a MIC of 45 μg/mL was recorded. For S. aureus, the isolated 7-hydroxycalamenene was more active than the whole oil, whereas the linalool-rich essential oil presented higher bactericide activity than pure linalool. For C. albicans, however, pure linalool was more active than the whole essential oil.
Journal of Essential Oil Research 08/2012; 24(4):351-357. · 0.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fusarium species have emerged as one of the more outstanding groups of clinically important filamentous fungi, causing localized and life-threatening invasive infections with high morbidity and mortality. The ability to produce different types of hydrolytic enzymes is thought to be an important virulence mechanism of fungal pathogens and could be associated with the environment of the microorganism. Here, we have measured the production of two distinct lipolytic enzymes, phospholipase and esterase, by sixteen Fusarium isolates recovered from the hospital environment, immunocompromised patients' blood cultures, foot interdigital space scrapings from immunocompromised patients, and foot interdigital space scrapings from immunocompetent patients (4 isolates each). Fourteen of these 16 isolates were identified as Fusarium solani species complex (FSSC) and two were identified as F. oxysporum species complex (FOSC). Some relevant genus characteristics were visualized by light and electron microscopy such as curved and multicelled macroconidia with 3 or 4 septa, microconidia, phialides, and abundant chlamydospores. All Fusarium isolates were able to produce esterase and phospholipase under the experimental conditions. However, a negative correlation was observed between these two enzymes, indicating that a Fusarium isolate with high phospholipase activity has low esterase activity and vice versa. In addition, Fusarium isolated from clinical material produced more phospholipases, while environmental strains produced more esterases. These observations may be correlated with the different types of substrates that these fungi need to degrade during their nutrition processes.
Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas / Sociedade Brasileira de Biofisica ... [et al.] 03/2012; 45(5):411-6. · 1.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In a search for an antifungal substance with activity against the dermatophyte fungus Trichophyton rubrum, strain POC 115 was chosen among different Paenibacillus strains for its phenotypic and genetic characterization and for preliminary characterization of its antimicrobial substance. Strain POC 115 was identified as belonging to Paenibacillus kribbensis. Physico-chemical characterization of the antimicrobial substance showed that it was not stable during heat and organic solvents treatments, but its activity was preserved at a wide range of pH and after treatment with pronase E, trypsin and DNase I. The crude concentrated supernatant of POC 115 culture was partially purified and the fraction presenting antimicrobial activity was further analyzed by UPLC/Mass Spectrometry. Two peaks were observed at 2.02 (mass 1,207 D) and 2.71 (mass 1,014 D) min in the mass chromatogram. The antimicrobial substance produced by POC 115 was correlated to iturin family compounds based on a set of primers designed for the amplification of PKS operon in the POC 115 genome. As happens with the mode of action of the antibiotics of the iturin group, the AMS produced by POC 115 caused the disruption of cytoplasmic membrane of T. rubrum and the subsequent withdraw of the intracellular material. This is the first report on the production of antimicrobial substances in P. kribbensis, and it may be of great relevance as an alternative or supplementary substance to antifungal drugs currently used against dermatophytes.
World Journal of Microbiology and Biotechnology (Formerly MIRCEN Journal of Applied Microbiology and Biotechnology) 03/2012; 28(3):953-62. · 1.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Rhinocladiella aquaspersa is an etiologic agent of chromoblastomycosis, a subcutaneous chronic infectious disease. In the present work, we found that the three morphological forms of this fungus (conidia, mycelia and sclerotic bodies) expressed different levels of ecto-phosphatase activity. Our results demonstrated that surface conidial enzyme is an acid phosphatase, inhibited by sodium salts of molybdate, orthovanadate and fluoride and that the inhibition caused by orthovanadate and molybdate was irreversible. The conidial ecto-phosphatase efficiently released phosphate groups from different phosphorylated substrates, causing a higher rate of phosphate removal when p-nitrophenylphosphate was used as substrate. This ecto-enzyme of R. aquaspersa is modulated by Co(2 +) ions and inorganic phosphate (Pi). Accordingly, removal of Pi from the culture medium resulted in a marked (121-fold) increase of ecto-phosphatase activity. Surface phosphatase activity is apparently involved in fungal adhesive properties, since the attachment of R. aquaspersa to epithelial cells was reversed by the pre-treatment of the conidia with orthovanadate, molybdate and anti-phosphatase antibody. Corroborating this finding, conidia with greater ecto-phosphatase activity (grown in Pi-depleted medium) showed higher adherence to epithelial cells than fungi cultivated in the presence of Pi.
Medical mycology: official publication of the International Society for Human and Animal Mycology 02/2012; 50(6):570-8. · 2.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The antimicrobial activities of the isomers and enantiomers of pinene were evaluated against bacterial and fungal cells. The agar diffusion test showed that only the positive enantiomers of the α- and β-isomers of pinene were active. The minimal inhibitory concentration (MIC) and minimal microbicidal concentration (MMC) of these monoterpenes were also determined, confirming that the positive enantiomers exhibited microbicidal activity against all fungi and bacteria tested with MICs ranging from 117 to 4,150 μg/mL. However, no antimicrobial activity was detected with the negative enantiomers up to 20 mg/mL. Time-kill curves showed that (+)-α-pinene and (+)-β-pinene were highly toxic to Candida albicans, killing 100% of inoculum within 60 min. By contrast, the bactericidal effect occurred after 6 h in methicillin-resistant Staphylococcus aureus (MRSA). In combination with commercial antimicrobials, ciprofloxacin plus (+)-α-pinene or (+)-β-pinene presented synergistic activity against MRSA whereas an indifferent effect against all fungi was detected when amphotericin B was combined with the positive enantiomers of pinene. The potential of (+)-α-pinene and (+)-β-pinene to inhibit phospholipase and esterase activities was also evaluated, and the best inhibition results were obtained with Cryptococcus neoformans. C. albicans biofilm formation was prevented with the MIC concentration of (+)-α-pinene and twice the MIC value of (+)-β-pinene. Finally, the cytotoxicity of the positive enantiomers of pinene to murine macrophages was evaluated, and 250 μg/mL of (+)-α-pinene and (+)-β-pinene reduced the cell viability to 66.8% and 57.7%, respectively.