Beneficial effect of Mentha suaveolens essential oil in the treatment of vaginal candidiasis assessed by real-time monitoring of infection

<p>Abstract</p> <p>Background</p> <p>Vaginal candidiasis is a frequent and common distressing disease affecting up to 75% of the women of fertile age; most of these women have recurrent episodes. Essential oils from aromatic plants have been shown to have antimicrobial and antifungal activities. This study was aimed at assessing the anti-fungal activity of essential oil from <it>Mentha suaveolens </it>(EOMS) in an experimental infection of vaginal candidiasis.</p> <p>Methods</p> <p>The <it>in vitro </it>and <it>in vivo </it>activity of EOMS was assessed. The <it>in vitro </it>activity was evaluated under standard CLSI methods, and the <it>in vivo </it>analysis was carried out by exploiting a novel, non-invasive model of vaginal candidiasis in mice based on an <it>in vivo </it>imaging technique.</p> <p>Differences between essential oil treated and saline treated mice were evaluated by the non-parametric Mann-Whitney U-test. Viable count data from a time kill assay and yeast and hyphae survival test were compared using the Student's t-test (two-tailed).</p> <p>Results</p> <p>Our main findings were: i) EOMS shows potent candidastatic and candidacidal activity in an <it>in vitro </it>experimental system; ii) EOMS gives a degree of protection against vaginal candidiasis in an <it>in vivo </it>experimental system.</p> <p>Conclusions</p> <p>This study shows for the first time that the essential oil of a Moroccan plant <it>Mentha suaveolens </it>is candidastatic and candidacidal <it>in vitro</it>, and has a degree of anticandidal activity in a model of vaginal infection, as demonstrated in an <it>in vivo </it>monitoring imaging system. We conclude that our findings lay the ground for further, more extensive investigations to identify the active EOMS component(s), promising in the therapeutically problematic setting of chronic vaginal candidiasis in humans.</p

Chromatographic Analyses, In Vitro Biological Activities, and Cytotoxicity of Cannabis sativa L. Essential Oil: A Multidisciplinary Study

Due to renewed interest in the cultivation and production of Italian Cannabis sativa L., we proposed a multi-methodological approach to explore chemically and biologically both the essential oil and the aromatic water of this plant. We reported the chemical composition in terms of cannabinoid content, volatile component, phenolic and flavonoid pattern, and color characteristics. Then, we demonstrated the ethnopharmacological relevance of this plant cultivated in Italy as a source of antioxidant compounds toward a large panel of enzymes (pancreatic lipase, -amylase, -glucosidase, and cholinesterases) and selected clinically relevant, multidrug-sensible, and multidrug-resistant microbial strains (Staphylococcus aureus, Helicobacter pylori, Candida, and Malassezia spp.), evaluating the cytotoxic effects against normal and malignant cell lines. Preliminary in vivo cytotoxicity was also performed on Galleria mellonella larvae. The results corroborate the use of this natural product as a rich source of important biologically active molecules with particular emphasis on the role exerted by naringenin, one of the most important secondary metabolites

Surface-Associated Plasminogen Binding of Cryptococcus neoformans Promotes Extracellular Matrix Invasion

BACKGROUND:The fungal pathogen Cryptococcus neoformans is a leading cause of illness and death in persons with predisposing factors, including: malignancies, solid organ transplants, and corticosteroid use. C. neoformans is ubiquitous in the environment and enters into the lungs via inhalation, where it can disseminate through the bloodstream and penetrate the central nervous system (CNS), resulting in a difficult to treat and often-fatal infection of the brain, called meningoencephalitis. Plasminogen is a highly abundant protein found in the plasma component of blood and is necessary for the degradation of fibrin, collagen, and other structural components of tissues. This fibrinolytic system is utilized by cancer cells during metastasis and several pathogenic species of bacteria have been found to manipulate the host plasminogen system to facilitate invasion of tissues during infection by modifying the activation of this process through the binding of plasminogen at their surface. METHODOLOGY:The invasion of the brain and the central nervous system by penetration of the protective blood-brain barrier is a prerequisite to the establishment of meningoencephalitis by the opportunistic fungal pathogen C. neoformans. In this study, we examined the ability of C. neoformans to subvert the host plasminogen system to facilitate tissue barrier invasion. Through a combination of biochemical, cell biology, and proteomic approaches, we have shown that C. neoformans utilizes the host plasminogen system to cross tissue barriers, providing support for the hypothesis that plasminogen-binding may contribute to the invasion of the blood-brain barrier by penetration of the brain endothelial cells and underlying matrix. In addition, we have identified the cell wall-associated proteins that serve as plasminogen receptors and characterized both the plasminogen-binding and plasmin-activation potential for this significant human pathogen. CONCLUSIONS:The results of this study provide evidence for the cooperative role of multiple virulence determinants in C. neoformans pathogenesis and suggest new avenues for the development of anti-infective agents in the prevention of fungal tissue invasion

Synergistic activity of Pelargonium capitatum and Cymbopogon martini essential oils against C. albicans

The antifungal activity of Pelargonium capitatum essential oil (PCEO) and Cymbopogon martini essential oil (CMEO) against C.albicans were evaluated. The main components of essential oils were β-cytronellol 58.81% and geraniol 83.94% in PCEO and CMEO, respectively. PCEO was more activity than CMEO for all C.albicans strains tested with values MIC50 or MIC90 of 780 µg/ml. PCEO used in combination with fluconazole or CMEO shows synergistic effect with FICI values ≤ 0.5. Moreover both essential oils are able to inhibit the major virulence factor of C.albicans as the germ tube formation at sub-inhibitory concentration of 195 µg/ml. In conclusion, it is possible to hypothesize that PCEO can be used in combination with fluconazole or CMEO. Further studies are in due course to confirm these results

Antimicrobial and Antioxidant Activities of Natural Compounds

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Characterization of some virulence factors in Malassezia spp.

Objective: The main objectives of this work was to evaluate “in vitro” the hydrophobicity levels, the adherence on a plastic surface and the biofilm formation of 51 clinical isolates of Malassezia spp. Methods: 32 M. furfur, 10 M. sympodialis, 5 M. globosa, 2 M. slooffiae, 1 M. restricta and 1 M. pachydermatis, were all clinical isolates tested. M. furfur and M. sympodialis references strains were also included. In order to examine the adherence capacity to plastic surface, the yeasts were grown for 72 h at 32◦C in Leeming-Notman modified broth, washed twice with sterile PB and then resuspended at 37◦C in RPMI 1640 modified for Malassezia plus 10% FBS at 7.5 × 102 cells/ml. After incubation for 3 h at 37◦C in six-well polystyrene plates followed by extensive washing, 1 ml of Leeming-Notman Agar medium modified was poured into each well and let solidify. After incubation for 72 h at 37◦C, colonies were counted and the results were expressed as a percentage of the inoculum size. Cellular surface hydrophobicity (CSH) levels were determined by two-phase system. The biofilm formation was determined by tetrazolium salt (XTT) reduction assay. Results: All isolates of Malassezia spp. were hydrophobic, adherent and producers of biofilm on abiotic surfaces with different capacity. In particular, hydrophobicity was variable and ranged from 24 ± 0.1% for M. pachydermatis to 69.50 ± 14.6% for M. restricta. Similar values were observed for M. furfur and M. globosa. Adherences values also display variability, with ranges between 8.4 ± 1.1% for M. pachydermatis to 85.00 ± 2.3% for M. restricta. High values of adherence were obtained for M. globosa (65.22 ± 3.5). In addition, the no lipid-dependent yeast M. pachydermatis showed low values of adherence and hydrophobicity respect to the other Malassezia species. All Malassezia spp. were able to form biofilm on surface, ranged from 0.179 ± 0.13% for M. slooffiae to 0. 574 ± 0.20% for M. furfur. Except for M. pachydermatis, similar values were reported for the other Malassezia species tested. Conclusion: Our results suggest that all clinical isolates of Malassezia spp. were hydrophobic. Since the hydrophobicity is an important factor to adherence, varying degrees of success on abiotic surface were obtained. These characteristics are also involved in the high ability to form biofilm observed in this study. These important virulence factors could be responsible of this yeast changing from a commensal to a pathogenic status. The revision of the genus Malassezia has opened up new questions about the pathogenicity of Malassezia species

Induction of germ tube formation by N-acetyl-D-glucosamine in Candida albicans: uptake of inducer and germinative response.

A number of strains of Candida albicans were tested for germ tube formation after induction by N-acetyl-D-glucosamine (GlcNAc) and other simple (proline, glucose plus glutamine) or complex (serum) compounds. A proportion of strains (high responders) were induced to form germ tubes evolving to true hyphae by GlcNAc alone or by proline or glucose plus glutamine mixture. The majority of strains were low responders because they could be induced only by serum or GlcNAc-serum medium. Two strains were found to be nonresponders: they grew as pseudohyphae in serum. Despite minor quantitative differences, all strains efficiently utilized GlcNAc for growth under the yeast form at 28 degrees C. They also had comparable active, inducible, and constitutive uptake systems for GlcNAc. During germ tube formation in GlcNAc, the inducible uptake system was modulated, as expected from induction and decay of GlcNAc kinase. Uranyl acetate, at a concentration of 0.01 mM, inhibited both GlcNAc uptake and germ tube formation and was reversed by phosphates. Germinating and nongerminating cells differed in the rapidity and extent of GlcNAc incorporation into acid-insoluble and alkali-acid-insoluble cell fractions. During germ tube formation induced by proline, GlcNAc was almost totally incorporated into the acid-insoluble fraction after 60 min. Moreover, hyphal development on induction by either GlcNAc or proline was characterized by an apparent "uncoupling" between protein and polysaccharide metabolism, the ratio between the two main cellular constituents falling from more than 1 to less than 0.5 after 270 min of development. The data suggest that utilization of the inducer for wall synthesis is a determinant of germ tube formation C. albicans but that the nature and extent of inducer uptake is not a key event for this phenomenon to occur

Glucan synthesis and its inhibition by cilofungin in susceptible and resistante strains of Candida albicans.

The lipopeptide antimycotic agent, cilofungin, at a dose of 20 micrograms ml-1, inhibited beta 1-3 glucan synthesis in a drug-susceptible strain (3153; minimum inhibitory concentration (MIC) 50 micrograms ml-1). This was demonstrated for both whole cells under growing and non-growing conditions, and during protoplast regeneration. However, time-effect experiments, during growth of a CA-2 culture initially exposed to an inhibitory dose of cilofungin, showed that this strain was able to progressively regain both glucan synthesis and a growth rate comparable to that of cultures that had not been treated with the drug. This recovery was not attributable to cilofungin instability or degradation within the CA-2 culture. Our study suggests the existence of an as yet unknown drug-related and/or cell-related factor(s) modulating the inhibition of glucan synthesis, and then contributing to the actual inhibitory effects of cilofungin in C. albicans