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

Quantification methods of Candida albicans are independent irrespective of fungal morphology

The ability of Candida albicans to switch its morphology from yeast to filaments, known as polymorphism, may bias the methods used in microbial quantification. Here, we compared the quantification methods [cell/mL, colony forming units (CFU)/mL, and the number of nuclei estimated by viability polymerase chain reaction (vPCR)] of three strains of C. albicans (one reference strain and two clinical isolates) grown as yeast, filaments, and biofilms. Metabolic activity (XTT assay) was also used for biofilms. Comparisons between the methods were evaluated by agreement analyses [Intraclass and Concordance Correlation Coefficients (ICC and CCC, respectively) and Bland-Altman Plot] and Pearson Correlation (α = 0.05). Principal Component Analysis (PCA) was employed to visualize the similarities and differences between the methods. Results demonstrated a lack of agreement between all methods irrespective of fungal morphology/growth, even when a strong correlation was observed. Bland-Altman plot also demonstrated proportional bias between all methods for all morphologies/growth, except between CFU/mL X vPCR for yeasts and biofilms. For all morphologies, the correlation between the methods were strong, but without linear relationship between them, except for yeast where vPCR showed weak correlation with cells/mL and CFU/mL. XTT moderately correlated with CFU/mL and vPCR and weakly correlated with cells/mL. For all morphologies/growth, PCA showed that CFU/mL was similar to cells/mL and vPCR was distinct from them, but for biofilms vPCR became more similar to CFU/mL and cells/mL while XTT was the most distinct method. As conclusions, our investigation demonstrated that CFU/mL underestimated cells/mL, while vPCR overestimated both cells/mL and CFU/mL, and that the methods had poor agreement and lack of linear relationship, irrespective of C. albicans morphology/growth.1.

Overview of Ethnobotanical-Pharmacological Studies Carried Out on Medicinal Plants from the Serra da Estrela Natural Park: Focus on Their Antidiabetic Potential

The Serra da Estrela Natural Park (NPSE) in Portugal stands out as a well-preserved region abundant in medicinal plants, particularly known for their pharmaceutical applications in diabetes prevention and treatment. This comprehensive review explores these plants' botanical diversity, traditional uses, pharmacological applications, and chemical composition. The NPSE boast a rich diversity with 138 medicinal plants across 55 families identified as traditionally and pharmacologically used against diabetes globally. Notably, the Asteraceae and Lamiaceae families are prevalent in antidiabetic applications. In vitro studies have revealed their significant inhibition of carbohydrate-metabolizing enzymes, and certain plant co-products regulate genes involved in carbohydrate metabolism and insulin secretion. In vivo trials have demonstrated antidiabetic effects, including glycaemia regulation, insulin secretion, antioxidant activity, and lipid profile modulation. Medicinal plants in NPSE exhibit various activities beyond antidiabetic, such as antioxidant, anti-inflammatory, antibacterial, anti-cancer, and more. Chemical analyses have identified over fifty compounds like phenolic acids, flavonoids, terpenoids, and polysaccharides responsible for their efficacy against diabetes. These findings underscore the potential of NPSE medicinal plants as antidiabetic candidates, urging further research to develop effective plant-based antidiabetic drugs, beverages, and supplements.

Exploring Plants with Flowers: From Therapeutic Nutritional Benefits to Innovative Sustainable Uses

Flowers have played a significant role in society, focusing on their aesthetic value rather than their food potential. This study's goal was to look into flowering plants for everything from health benefits to other possible applications. This review presents detailed information on 119 species of flowers with agri-food and health relevance. Data were collected on their family, species, common name, commonly used plant part, bioremediation applications, main chemical compounds, medicinal and gastronomic uses, and concentration of bioactive compounds such as carotenoids and phenolic compounds. In this respect, 87% of the floral species studied contain some toxic compounds, sometimes making them inedible, but specific molecules from these species have been used in medicine. Seventy-six percent can be consumed in low doses by infusion. In addition, 97% of the species studied are reported to have medicinal uses (32% immune system), and 63% could be used in the bioremediation of contaminated environments. Significantly, more than 50% of the species were only analysed for total concentrations of carotenoids and phenolic compounds, indicating a significant gap in identifying specific molecules of these bioactive compounds. These potential sources of bioactive compounds could transform the health and nutraceutical industries, offering innovative approaches to combat oxidative stress and promote optimal well-being.

Chemical Composition and Anti-Candida Activity of Mentha suaveolens Ehrh. Essential Oils Obtained by Different Distillation Processes

A comparative study on essential oils extracted from Mentha suaveolens Ehrh. from Italy is reported. Two extraction procedures were investigated: hydrodistillation and steam distillation, carried out as a continuous and fractionated procedure. Fresh and dried plant material from two harvests was used. The hydrodistillation method yielded a higher amount of essential oil. The dried plant was significantly richer in essential oil per kg of starting plant material. Gas chromatography-mass spectrometry analysis of 112 samples showed that the essential oils belong to the piperitenone oxide-rich chemotype. In addition, piperitenone, p-cymen-8-ol, and limonene were among the most abundant compounds in the different samples. A higher amount of piperitenone oxide was obtained by hydrodistillation, while steam distillation gave a higher percentage of piperitenone and limonene. The essential oils were characterized for their anti-Candida albicans activity; higher potency was observed for the samples rich in piperitenone oxide, with MIC values ranging from 0.39 to 0.78 mg·mL-1 (0.039% and 0.078% p/v). The results of this work provide a deep insight into the methodology of essential oil extraction and the associated chemical variability of M. suaveolens Ehrh. Some of the essential oils are potent against C. albicans and could be considered for potential use in therapy.

Synthetic bacterial consortia transplantation for the treatment of Gardnerella vaginalis-induced bacterial vaginosis in mice

Bacterial vaginosis (BV) is a disease caused by vaginal microbiota dysbiosis. Here, we propose the use of synthetic bacterial consortia transplantation (SBCT) for the treatment of Gardnerella vaginalis-induced BV mice. The results showed that SBCT significantly reduced vaginal tissue damage and restored the vaginal microbiota, decreased the secretion of pro-inflammatory cytokines (IL-1β and IL-8), and suppressed NF-κB activation. IL-17, iNOS, and COX-2 expression in vaginal tissue were also down-regulated. However, IL-10 and Foxp3 showed up-regulated expression in mice. Compared with vaginal microbiota transplantation (VMT), results indicated that VMT was more effective than SBCT in suppressing G. vaginalis-induced inflammation. The obtained results suggest that synthetic bacterial consortia might be used as a potential biotherapeutic agent for the treatment of G. vaginalis-induced bacterial vaginosis. Video Abstract.

Essential oil and nanocarrier-based formulations approaches for vaginal candidiasis

An exclusive site for local drug delivery is the vagina, especially for vaginal infections. The fungus Candida albicans causes vaginal infection known as vulvovaginal candidiasis, a highly prevalent and recurrent gynaecological disease among women. Vaginal candidiasis affects over 75% of women at a certain point in their life and has a recurrence rate of 40-50%. Medicinal plants provide some very effective phytoconstituents which when delivered as nanosystems have enhanced therapeutic action and efficacy by alteration in their characteristics. Antifungal drugs are used to treat these conditions, alternative medicine is required for prophylaxis and improved prognosis. The current review focuses on the research carried out on various nanocarrier-based approaches and essential oil-based formulations for vaginal candidiasis.

Recent Advances in the Application of Essential Oils as Potential Therapeutic Candidates for Candida-Related Infections

Candidiasis (oral, vulvovaginal, or systemic bloodstream infections) are important human fungal infections associated with a high global prevalence in otherwise healthy adults but are also opportunistic infections in immunocompromised patients. With the recent discovery of the multidrug resistant—and often difficult to treat—Candida auris, as well as the rising costs associated with hospitalisations and the treatment of infections caused by Candida species, there is an urgent need to develop effective therapeutics against these pathogenic yeasts. Essential oils have been documented for many years as treatments for different ailments and are widely known and utilised in alternative and complementary therapies, including treating microbial infections. This review highlights knowledge from research on the effects of medicinal plants, and in particular, essential oils, as potential treatments against different Candida species. Studies have been evaluated that describe the experimental approaches used in investigating the anticandidal effects of essential oils (in vivo and in vitro), the established mode of action of the different compounds against different Candida species, the effect of a combination of essential oils with other compounds as potential therapies, and the evidence from clinical trial studies.

Synergistic effects of carvacrol, α-terpinene, γ-terpinene, ρ-cymene and linalool against Gardnerella species

Bacterial vaginosis (BV) is the most common vaginal infection affecting women worldwide. This infection is characterized by the loss of the dominant Lactobacillus community in the vaginal microbiota and an increase of anaerobic bacteria, that leads to the formation of a polymicrobial biofilm, mostly composed of Gardnerella spp. Treatment of BV is normally performed using broad-spectrum antibiotics, such as metronidazole and clindamycin. However, the high levels of recurrence of infection after treatment cessation have led to a demand for new therapeutic alternatives. Thymbra capitata essential oils (EOs) are known to have a wide spectrum of biological properties, including antibacterial activity. Thus, herein, we characterized two EOs of T. capitata and tested their antimicrobial activity as well as some of their main components, aiming to assess possible synergistic effects. Our findings showed that carvacrol and ρ-cymene established a strong synergistic antimicrobial effect against planktonic cultures of Gardnerella spp. On biofilm, carvacrol and linalool at sub-MIC concentrations proved more efficient in eliminating biofilm cells, while showing no cytotoxicity observed in a reconstituted human vaginal epithelium. The antibiofilm potential of the EOs and compounds was highlighted by the fact cells were not able to recover culturability after exposure to fresh medium.

Native Iranian Medicinal Plants with Anti-Vaginal Infection Properties: A Systematic Review

BACKGROUND

The use of herbs has recently been considered an effective method in the treatment of infections. The purpose of this study was to introduce Iranian medicinal plants with an effect on vaginal infections.

METHODS

In our systematic review study, keywords including 'medicinal plants', 'Iranian medicinal plants', 'vaginal infection', 'essential oils', and 'extracts' were searched in PubMed, Web of Science Direct, Scopus, Scientific Information Database, and Google Scholar. This study focused on the articles published from 2000 to 2019.

RESULTS AND DISCUSSION

According to our investigation, Stachys lavandulifolia, Thymus vulgaris L., Origanum vulgare L., Allium jesdianum, Cichorium intybus, Trigonella foenum-graecum, Azadirachta Indica, Stachys lavandulifolia, Coriandrum sativum L., Rosmarinus officinalis, Ferula gummosa L., Origanum syriacum, Eucalyptus globulus, Myrtus communis, Zingiber officinale, Punica granatum, Vitex agnus-castus, Mentha suaveolens, Quercus Brantii Lindl, Zataria multiflora, Berberis vulgaris, Thymus vulgaris L., Echinophora platyloba, Stachys lavandulifolia, Viola odorata, Menthe piperita, Eucalyptus camaldulensis, Ziziphus mauritiana, Quercus infectoria, Hypericum perforatum, Glycyrrhiza glabra L., Calendula officinalis, Origanum vulgare, Ziziphus nummularia, Satureja Bachtiarica, Foeniculum vulgare, Nigella sativa, Anethum graveolens, Salvia officinalis, and Calendula officinalis are used to treat vaginal infections.

CONCLUSION

Therefore, native plants of Iran have been reported to have antimicrobial properties for the treatment of vaginal infections and can be used as a suitable and effective alternative to antibiotics in future research.

Coadministration of Ginger Extract and Fluconazole Shows a Synergistic Effect in the Treatment of Drug-Resistant Vulvovaginal Candidiasis

BACKGROUND

Azoles are the most common antifungal drugs used in the treatment of vulvovaginal candidiasis (VVC). The frequency of azole-resistant Candida isolates has increased dramatically in the last two decades. Here, we assessed the antifungal activity of a combination of fluconazole (FLZ) and methanolic extract of ginger (Meth-Gin) against drug-resistant vulvovaginal candidiasis (VVC) in a murine model.

METHODS

The in vitro activity of FLZ or a combination of FLZ and Meth-Gin was determined against Candida albicans by the agar well diffusion, macrodilution, time-kill and the biofilm eradication methods. The therapeutic efficacy of the formulations was assessed by analyzing the fungal load, pro-inflammatory cytokines, percent apoptotic cells and the histological changes in the vaginal tissues of the mice. Moreover, the renal toxicity the drug formulation was evaluated by analyzing the levels of the blood urea nitrogen (BUN) and creatinine.

RESULTS

The results of in vitro study demonstrated that FLZ did not show any activity against C. albicans, whereas a combination of FLZ and Meth-Gin demonstrated greater activity as shown by the data of the zone of growth inhibition, MIC and time-kill assay. FLZ or Meth-Gin treatment could not completely cure VVC, whereas a combination of FLZ and Meth-Gin was greatly effective in the treatment of VVC. The vaginal tissue from mice of the infected control group had the highest fungal load of 155370 ± 20617 CFUs. Treatment with FLZ at a dose of 40 mg/kg reduced the fungal load to 120863 ± 10723 CFUs. Interestingly, the mice treated with a combination of FLZ (40 mg/kg) and Meth-Gin (200 mg/kg) had a fungal load of 256 ± 152 CFUs. Besides, FLZ and Meth-Gin combination effectively reduced the pro-inflammatory cytokines (IL-1β, TNF-α and IL-17) and the percentage of apoptotic cells in the vaginal tissues. Likewise, the histological analysis revealed the epithelial necrosis, shedding and ulceration in the vaginal tissue, whereas treatment with FLZ and Meth-Gin combination reversed the histopathological changes in the vaginal epithelium and lamina propria.

CONCLUSION

The findings of the current study suggest that the co-administration of Meth-Gin and FLZ may have a potential therapeutic effect in the treatment of azole-resistant candidiasis.

Inhibitory Effect of Eugenol and trans-Anethole Alone and in Combination with Antifungal Medicines on Candida albicans Clinical Isolates

One of the most common pathogens among yeasts is Candida albicans, which presents a serious health threat. The study aimed to check the antifungal properties of trans-anethole and eugenol with selected antifungal medicines (AMs) against C. albicans clinical isolates. The checkerboard method was used to tests of interactions between these compounds. Achieved results indicated that eugenol showed synergistic and additive activities with miconazole and econazole against investigated clinical isolates, respectively. Moreover, the combination - trans-anethole - miconazole also showed an additive effect against two clinical isolate. We tried to relate the results to changes in C. albicans cell sheaths under the influence of essential oils compounds (EOCs) performing the Fourier transform infrared spectra analysis to confirm the presence of particular chemical moieties in C. albicans cells. Nevertheless, no strong relationships was observed between synergistic and additive actions of used EOC-AMs combinations and chemical moieties in C. albicans cells.

Improved in vitro and in vivo Anti-Candida albicans Activity of Cymbopogon nardus Essential Oil by Its Incorporation into a Microemulsion System

PURPOSE

Vulvovaginal candidiasis (VVC) is an opportunistic fungal infection that adversely affects a woman's health, due to unpleasant symptoms, therapeutic challenges, and the emergence of resistant strains. The association of natural products and nanotechnology is important to improve the antifungal potential of medicinal plants. We aimed to evaluate the in vitro and in vivo anti-Candida albicans activity of unloaded (EO) and loaded (ME+EO) essential oil of Cymbopogon nardus in the microemulsion (ME).

METHODS

The chemical analysis of the EO was performed by gas chromatography-mass spectrometry. The ME and ME+EO were characterized by scattering, zeta potential, polarized light microscopy, rheological assays, mucoadhesiveness and transmission electronic microscopy. The in vitro antifungal activity of the EO and ME+EO were evaluated by microdilution technique. The toxicity of EO and ME+EO was analyzed on human cell line HaCat and using alternative model assay with Artemia salina. The experimental in vivo VVC was performed in female mice (C57BL/6).

RESULTS

The main compounds of the EO were found to be citronellal, geranial, geraniol, citronellol, and neral. The formulations exhibited suitable size, homogeneity, negative charge, isotropic behavior, highly organized structure, and pseudoplastic behavior, for vaginal application. TEM photomicrographs showed possible EO droplets inside the spherical structures. The EO, when loaded into the ME, exhibited an improvement in its antifungal action against C. albicans. The EO was not toxic against brine shrimp nauplii. An in vivo VVC assay showed that the use of the ME significantly improved the action of the EO, since only the ME+EO promoted the eradication of the fungal vaginal infection on the third day of treatment.

CONCLUSION

The EO and ME+EO are promising alternatives for the control of fungal infections caused by C. albicans, once the use of nanotechnology significantly improved the antifungal action of the EO, especially in an in vivo model of VVC.

Use of Essential Oils in Veterinary Medicine to Combat Bacterial and Fungal Infections

Essential oils (EOs) are secondary metabolites of plants employed in folk medicine for a long time thanks to their multiple properties. In the last years, their use has been introduced in veterinary medicine, too. The study of the antibacterial properties of EOs is of increasing interest, because therapies with alternative drugs are welcome to combat infections caused by antibiotic-resistant strains. Other issues could be resolved by EOs employment, such as the presence of antibiotic residues in food of animal origin and in environment. Although the in vitro antimicrobial activity of EOs has been frequently demonstrated in studies carried out on bacterial and fungal strains of different origins, there is a lack of information about their effectiveness in treating infections in animals. The scientific literature reports some studies about in vitro EOs' activity against animal clinical bacterial and fungal isolates, but in vivo studies are very scanty. The use of EOs in therapy of companion and farm animals should follow careful studies on the toxicity of these natural products in relation to animal species and route of administration. Moreover, considering the different behavior of EOs in relation to both species and strain pathogen, before starting a therapy, an aromatogram should be executed to choose the oil with the best antimicrobial activity.

Assaying the effect of yeasts on growth of fungi associated with disease

Background

Pathogenic fungi often cause serious infections mainly in immunocompromised persons. The number of infections caused by the non-albicans Candida or other species has significantly increased over the last years. These infections present a major challenge in the health sector because these pathogenic fungi have strong virulence and often show resistance to the commonly used antifungal treatments. To solve the problems caused by the drug resistant pathogenic fungi, it is necessary to find new antifungal agents and their sources. The aim of this study was to give evidence that yeasts can effectively fight against strains which belong to pathogenic fungi and reveal those yeasts which are able to inhibit growth of Kodamaea ohmeri, Pichia kudriavzevii, Naganishia albida or Candida tropicalis. Furthermore, we wanted to determine the effects of certain culturing factors on the growth inhibition.

Results

Our screening revealed that although the strains belonging to pathogenic species were much more tolerant to the yeast-produced bioactive agents than the non-disease-associated yeasts, growth of Kodamaea ohmeri and Candida tropicalis could be inhibited by Metschnikowia andauensis, while Naganishia albida could be controlled by Pichia anomala or Candida tropicalis. Our data proved that the experimental circumstances could have a serious impact on the inhibitory capacity of the yeasts. Appearance of inhibition strongly depended on media, pH and temperature. Our data also shed some light on the fact that Pichia kudriavzevii must have high natural resistance to the yeast-produced agents, while other species, such as Saccharomycopsis crataegensis belonged to the easily inhibitable species.

Conclusions

Our study suggests that yeast-produced bioactive agents could be potential growth inhibitory agents against the disease-associated fungi and yeasts can also contribute to alternative approaches to combat against pathogenic fungi. Our data revealed an important role of the culturing factors in inhibition and pointed to the complex nature of antagonism.

Phytochemical Composition and In Vitro Antimicrobial Activity of Essential Oils from the Lamiaceae Family against Streptococcus agalactiae and Candida albicans Biofilms

The antimicrobial activity of different essential oils (EOs) from the Lamiaceae family was evaluated on Streptococcus agalactiae, Candida albicans, and lactobacilli. S. agalactiae is the main cause of severe neonatal infections, such as sepsis, meningitis, and pneumonia. C. albicans is a primary causative agent of vulvovaginal candidiasis, a multifactorial infectious disease of the lower female reproductive tract. Lactobacilli represent the dominant bacterial species of the vaginal flora and constitute the natural defense against pathogens. On the basis of the preliminary results, the attention was focused on the EOs from Lavandula x intermedia Emeric ex Loisel. and Mentha arvensis L. By using gas ghromatography (GS) retention data and mass spectra, it was possible to identify more than 90% of the total composition of the EO samples. The minimal inhibitory concentration (MIC) and anti-biofilm activity of the two EOs were determined against all isolated strains, using the EOs by themselves or in combination with each other and with drugs (erythromycin and fluconazole). The results showed a good antimicrobial and anti-biofilm activity of both EOs and a synergistic effect, leading to the best results against all the strains, resulted using the combinations EOs/EOs and antimicrobials/EOs.

Anti-Candida Activity of Essential Oils from Lamiaceae Plants from the Mediterranean Area and the Middle East

Extensive documentation is available on plant essential oils as a potential source of antimicrobials, including natural drugs against Candida spp. Yeasts of the genus Candida are responsible for various clinical manifestations, from mucocutaneous overgrowth to bloodstream infections, whose incidence and mortality rates are increasing because of the expanding population of immunocompromised patients. In the last decade, although C. albicans is still regarded as the most common species, epidemiological data reveal that the global distribution of Candida spp. has changed, and non-albicans species of Candida are being increasingly isolated worldwide. The present study aimed to review the anti-Candida activity of essential oils collected from 100 species of the Lamiaceae family growing in the Mediterranean area and the Middle East. An overview is given on the most promising essential oils and constituents inhibiting Candida spp. growth, with a particular focus for those natural products able to reduce the expression of virulence factors, such as yeast-hyphal transition and biofilm formation. Based on current knowledge on members of the Lamiaceae family, future recommendations to strengthen the value of these essential oils as antimicrobial agents include pathogen selection, with an extension towards the new emerging Candida spp. and toxicological screening, as it cannot be taken for granted that plant-derived products are void of potential toxic and/or carcinogenic properties.

Essential Oils of Lamiaceae Family Plants as Antifungals

The incidence of fungal infections has been steadily increasing in recent years. Systemic mycoses are characterized by the highest mortality. At the same time, the frequency of infections caused by drug-resistant strains and new pathogens e.g., Candida auris increases. An alternative to medicines may be essential oils, which can have a broad antimicrobial spectrum. Rich in the essential oils are plants from the Lamiaceae family. In this review are presented antifungal activities of essential oils from 72 Lamiaceae plants. More than half of these have good activity (minimum inhibitory concentrations (MICs) < 1000 µg/mL) against fungi. The best activity (MICs < 100) have essential oils from some species of the genera Clinopodium, Lavandula, Mentha, Thymbra, and Thymus. In some cases were observed significant discrepancies between different studies. In the review are also shown the most important compounds of described essential oils. To the chemical components most commonly found as the main ingredients include β-caryophyllene (41 plants), linalool (27 plants), limonene (26), β-pinene (25), 1,8-cineole (22), carvacrol (21), α-pinene (21), p-cymene (20), γ-terpinene (20), and thymol (20).

Exploration of Medicinal Plants as Sources of Novel Anticandidal Drugs

BACKGROUND

Human infections associated with skin and mucosal surfaces, mainly in tropical and sub-tropical parts of the world. During the last decade, there have been an increasing numbers of cases of fungal infections in immunocompromised patients, coupled with an increase in the number of incidences of drug resistance and toxicity to anti fungal agents. Hence, there is a dire need for safe, potent and affordable new antifungal drugs for the efficient management of candidal infections with minimum or no side effects.

INTRODUCTION

Candidiasis represents a critical problem to human health and a serious concern worldwide. Due to the development of drug resistance, there is a need for new antifungal agents. Therefore, we reviewed the different medicinal plants as sources of novel anticandidal drugs.

METHODS

The comprehensive and detailed literature on medicinal plants was carried out using different databases, such as Google Scholar, PubMed, and Science Direct and all the relevant information from the articles were analyzed and included.

RESULTS

Relevant Publications up to the end of November 2018, reporting anticandidal activity of medicinal plants has been included in the present review. In the present study, we have reviewed in the light of SAR and mechanisms of action of those plants whose extracts or phytomolecules are active against candida strains.

CONCLUSION

This article reviewed natural anticandidal drugs of plant origin and also summarized the potent antifungal bioactivity against fungal strains. Besides, mechanism of action of these potent active plant molecules was also explored for a comparative study. We concluded that the studied active plant molecules exhibit potential antifungal activity against resistant fungal strains.

The role of the miR1976/CD105/integrin αvβ6 axis in vaginitis induced by Escherichia coli infection in mice

Vaginitis is very common among women, especially women of childbearing age, and is associated with significantly increased risk of preterm birth and pelvic inflammatory diseases. An imbalance in the vaginal flora, the primary cause of vaginitis, promotes the initiation and progression of vaginal infections. However, the responsible mechanisms are still poorly understood. Using a murine vaginitis model of Escherichia coli infection, we demonstrated that decreased expression of microRNA1976 and increased expression of CD105 and integrin αvβ6 were closely associated with the progression of vaginal infection. Importantly, we demonstrated for the first time that the microRNA1976/CD105/integrin αvβ6 axis regulates E. coli-mediated vaginal infection in mice, as evidenced by the finding that E. coli-induced vaginal infection was reversed by microRNA1976 overexpression and exacerbated by CD105 overexpression. The regulation of CD105 and integrin αvβ6 by microRNA1976 was further confirmed in a murine model of vaginitis with adenoviral vector treatment. Taken together, our data suggested that microRNA1976 negatively regulates E. coli-induced vaginal infection in mice at least in part by suppressing CD105 and integrin αvβ6 expression. These findings may provide new insight into the mechanisms of E. coli-induced vaginitis, identify a novel diagnostic biomarker and a potential therapeutic target for flora imbalance-associated vaginitis.

Antioxidant, Antifungal, Antibiofilm, and Cytotoxic Activities of Mentha spp. Essential Oils

Since ancient times, plants have been used to preserve food, or for their health properties. Essential oils are complex mixtures of volatile compounds that are obtained from botanical material, specifically from aromatic plants. Lamiaceae is one of the most important families in the production of essential oils, as it has both antioxidant and antimicrobial properties. The essential oils of Mentha (the Lamiaceae family) have been extensively studied for their biological actions. In this review, we report the antioxidant, antifungal, antibiofilm, and cytotoxic properties of Mentha spp. essential oils. The first objective is to provide comprehensive information about the use of essential oils in the treatment of fungal infections, or as antioxidants and integrative anticancer therapy. The second is to explore the evidence supporting its effectiveness in treating diseases without causing any serious adverse reactions.

The Confrontation between Ethnopharmacology and Pharmacological Tests of Medicinal Plants Associated with Mental and Neurological Disorders

For neurological disorders, pharmacological tests have shown promising results in the reduction of side effects when using plants with known therapeutic effects in the treatment of some types of dementia. Therefore, the goals of this study are to gather data about the major medicinal plants used in the nervous system as described in ethnopharmacological surveys from South America and Brazil and to compare this data with the results from pharmacological tests on the active principles of those same plants found in the scientific literature. After collecting the data about each plant, their respective popular indication was compared with the results found through pharmacological tests. The discrepancy rate between the effects observed by ethnopharmacological and pharmacological methods in this study is greater than 50%. In conclusion, despite the importance of ethnopharmacological data, it is important to make comparisons with pharmacological tests for the same plants, since the pharmacological studies, although few, have shown a high rate of discrepancy in the results.

Antimicrobial Activity of Five Essential Oils against Bacteria and Fungi Responsible for Urinary Tract Infections

Urinary tract infections are frequently encountered in small animal practice. Escherichia coli and Enterococcus spp. are the most common agents associated to these infections, even though other bacteria and yeasts, such as Candida albicans and Candida famata, may be involved. In view of the increasing problem of the multi-drug resistance, the aim of this study was to investigate the antimicrobial activity of essential oils obtained from star anise (Illicium verum Hook.f.), basil (Ocimum basilicum L.), origanum (Origanum vulgare L.), clary sage (Salvia sclarea L.) and thymus (Thymus vulgaris L.) against multidrug-resistant strains of Escherichia coli, Enterococcus spp., Candida albicans and Candida famata previously isolated from dogs and cats with urinary tract infections. Enterococci were resistant to Illicium verum and Salvia sclarea, such as Candida to Salvia sclarea. Thymus vulgaris and Origanum vulgare essential oils showed the best activity against all the tested pathogens, so they could be proposed for the formulation of external and/or intravesical washes in small animals.

In vitro and in vivo effects of suloctidil on growth and biofilm formation of the opportunistic fungus Candida albicans

As the most frequent fungal pathogen in humans, Candida albicans can develop serious drug resistance because its biofilms are resistant to most antifungal agents; this leads to an urgent need to develop novel antifungals. Here, we evaluated the efficacy of an antithrombotic drug, suloctidil, against C. albicans biofilms in vitro and in vivo. We found that suloctidil is effective to inhibit C. albicans biofilm, with a minimum inhibitory concentration (MIC₈₀) of 4 μg/mL, a biofilm inhibiting concentration (BIC₈₀) of 16 μg/mL and a biofilm eradicating concentration (BEC₈₀) of 64 μg/mL. Furthermore, the concentration-dependent characteristics of suloctidil were shown by its time-kill curves. Scanning electron microscopy images clearly revealed the morphological effects of suloctidil on biofilm. Yeast-to-hyphal form switching is a key virulence factor of C. albicans; therefore, we performed hyphal growth tests and observed that suloctidil inhibited yeast-to-hyphal form switching. This result was consistent with the down-regulation of hypha-specific gene (HWP1, ALS3, and ECE1) expression levels after suloctidil treatment. In vivo, 256 μg/mL of suloctidil significantly reduced fungal counts (P<0.01) compared to that in groups without treatment; the treatment group induced a slight histological reaction, especially when the treatment lasted for 5 days (P<0.01). Taken together, our data suggest that suloctidil is a potential antifungal agent.

Genotoxicity assessment of piperitenone oxide: An in vitro and in silico evaluation

Piperitenone oxide, a natural flavouring agent also known as rotundifolone, has been studied for the genotoxicity assessment by an integrated in vitro and in silico experimental approach, including the bacterial reverse mutation assay, the micronucleus test, the comet assay and the computational prediction by Toxtree and VEGA tools. Under our experimental conditions, the monoterpene showed to induce both point mutations (i.e. frameshift, base-substitution and/or oxidative damage) and DNA damage (i.e. clastogenic or aneuploidic damage, or single-strand breaks). Computational prediction for piperitenone oxide agreed with the toxicological data, and highlighted the presence of the epoxide function and the α,β-unsaturated carbonyl as possible structural alerts for DNA damage. However, improving the toxicological libraries for natural occurring compounds is required in order to favour the applicability of in silico models to the toxicological predictions. Further in vivo evaluations are strictly needed in order to evaluate the role of the bioavailability of the substance and the metabolic fate on its genotoxicity profile. To the best of our knowledge, these data represent the first evaluation of the genotoxicity for this flavour compound and suggest the need of further studies to assess the safety of piperitenone oxide as a flavouring agent.

Calamintha nepeta (L.) Savi and its Main Essential Oil Constituent Pulegone: Biological Activities and Chemistry

Medicinal plants play an important role in the treatment of a wide range of diseases, even if their chemical constituents are not always completely recognized. Observations on their use and efficacy significantly contribute to the disclosure of their therapeutic properties. Calamintha nepeta (L.) Savi is an aromatic herb with a mint-oregano flavor, used in the Mediterranean areas as a traditional medicine. It has an extensive range of biological activities, including antimicrobial, antioxidant and anti-inflammatory, as well as anti-ulcer and insecticidal properties. This study aims to review the scientific findings and research reported to date on Calamintha nepeta (L.) Savi that prove many of the remarkable various biological actions, effects and some uses of this species as a source of bioactive natural compounds. On the other hand, pulegone, the major chemical constituent of Calamintha nepeta (L.) Savi essential oil, has been reported to exhibit numerous bioactivities in cells and animals. Thus, this integrated overview also surveys and interprets the present knowledge of chemistry and analysis of this oxygenated monoterpene, as well as its beneficial bioactivities. Areas for future research are suggested.

Essential Oil Extraction, Chemical Analysis and Anti-Candida Activity of Calamintha nepeta (L.) Savi subsp. glandulosa (Req.) Ball-New Approaches

A comprehensive study on essential oils extracted from different Calamintha nepeta (L.) Savi subsp. glandulosa (Req.) Ball samples from Tarquinia (Italy) is reported. In this study, the 24-h steam distillation procedure for essential oil preparation, in terms of different harvesting and extraction times, was applied. The Gas chromatography–mass spectrometry (GC/MS) analysis showed that C. nepeta (L.) Savi subsp. glandulosa (Req.) Ball essential oils from Tarquinia belong to the pulegone-rich chemotype. The analysis of 44 samples revealed that along with pulegone, some other chemicals may participate in exerting the related antifungal activity. The results indicated that for higher activity, the essential oils should be produced with at least a 6-h steam distillation process. Even though it is not so dependent on the period of harvesting, it could be recommended not to harvest the plant in the fruiting stage, since no significant antifungal effect was shown. The maximum essential oil yield was obtained in August, with the highest pulegone percentage. To obtain the oil with a higher content of menthone, September and October should be considered as the optimal periods. Regarding the extraction duration, vegetative stage material gives the oil in the first 3 h, while material from the reproductive phase should be extracted at least at 6 or even 12 h.

Anti-Candida albicans natural products, sources of new antifungal drugs: A review

INTRODUCTION

Candida albicans is the most prevalent fungal pathogen in humans. Due to the development of drug resistance, there is today a need for new antifungal agents for the efficient management of C. albicans infections. Therefore, we reviewed antifungal activity, mechanisms of action, possible synergism with antifungal drugs of all natural substances experimented to be efficient against C. albicans for future.

METHODS

An extensive and systematic review of the literature was undertaken and all relevant abstracts and full-text articles analyzed and included in the review.

REVIEW

A total of 111 documents were published and highlighted 142 anti-C. albicans natural products. These products are mostly are reported in Asia (44.37%) and America (28.17%). According to in vitro model criteria, from the 142 natural substances, antifungal activity can be considered as important for 40 (28.20%) and moderate for 24 (16.90%). Sixteen products have their antifungal activity confirmed by in vivo gold standard experimentation. Microbial natural products, source of antifungals, have their antifungal mechanism well described in the literature: interaction with ergosterol (polyenes), inhibition 1,3-β-d-glucan synthase (Echinocandins), inhibition of the synthesis of cell wall components (chitin and mannoproteins), inhibition of sphingolipid synthesis (serine palmitoyltransferase, ceramide synthase, inositol phosphoceramide synthase) and inhibition of protein synthesis (sordarins). Natural products from plants mostly exert their antifungal effects by membrane-active mechanism. Some substances from arthropods are also explored to act on the fungal membrane. Interestingly, synergistic effects were found between different classes of natural products as well as between natural products and azoles.

CONCLUSION

Search for anti-C. albicans new drugs is promising since the list of natural substances, which disclose activity against this yeast is today long. Investigations must be pursued not only to found more new anti-Candida compounds from plants and organisms but also to carried out details on molecules from already known anti-Candida compounds and to more elucidate mechanisms of action.

Chemical Composition and Bio-efficacy of Essential Oils from Italian Aromatic Plants: Mentha suaveolens, Coridothymus capitatus, Origanum hirtum and Rosmarinus officinalis

The chemical composition, antifungal, antioxidant and cytotoxic activities of the essential oils (EOs) of mint (Mentha suaveolens), thyme (Coridothymus capitatus), oregano (Origanum hirtum) and rosemary (Rosmarinus officinalis) were investigated. The antifungal properties of the EOs were investigated against four species of Candida by a microdilution method. Cytotoxicity was tested on human keratinocyte (HaCaT) and lung cancer (A549) cell lines using the MTT test. DPPH• and ABTS•+ spectrophotometric assays and DPPH•- ABTS•+(HP)TLC-bioautographic assays were used to evaluate the antioxidant activity. The main compounds of thyme and oregano EOs were carvacrol and thymol, respectively; piperitenone oxide and γ-terpinene were the most abundant compounds of mint and rosemary EOs, respectively. All EOs showed activity against all Candida species in a range between 760 ± 290 to 3120 ± 0.0 μg/mL. Among the EOs, that of M. suaveolens showed a stronger cytotoxic activity on HaCaT cells. Thyme, oregano and rosemary EOs exhibited important antioxidant activities by ABTS•+ assay compared with trolox.

Activity of crude extracts from Brazilian cerrado plants against clinically relevant Candida species

Background

Medicinal plants have traditionally been used in many parts of the world as alternative medicine. Many extracts and essential oils isolated from plants have disclosed biological activity, justifying the investigation of their potential antimicrobial activity. In this study, the in vitro antifungal activity of six Brazilian Cerrado medicinal plant species were evaluated against clinically relevant Candida species.

Methods

The crude extract plants were evaluated against American Type Culture Collection (ATCC) standard strains of Candida spp. using disk diffusion method and determining the minimum inhibitory concentration (MIC). The chemical study results were confirmed by HPLC method.

Results

All six plant species showed antifungal activity. Among the species studied, Eugenia dysenterica and Pouteria ramiflora showed significant inhibitory activity against C. tropicalis at lowest MIC value of 125 and 500 μg/disc, respectively. The Eugenia dysenterica also disclosed MIC value of 125 μg/disc against C. famata, 250 μg/disc against C. krusei and 500 μg/disc against C. guilliermondii and C. parapsilosis. Pouteria torta, Bauhinia rufa, Erythroxylum daphnites and Erythroxylum subrotundum showed activity against the yeast strains with MIC value of 1000 μg/disc. The chemical study of the most bioactive extracts of Eugenia dysenterica and Pouteria ramiflora revealed catechin derivatives and flavonoids as main components.

Conclusions

All six evaluated plant species showed good antifungal potential against several Candida strains. However, E .dysenterica and P. ramiflora showed the higher inhibitory effect against the non-albicans Candida species. Our results may contribute to the continuing search of new natural occurring products with antifungal activity.

Multidisciplinary Approach to Determine the Optimal Time and Period for Extracting the Essential Oil from Mentha suaveolens Ehrh

A comprehensive study on essential oils (EOs) extracted from some Mentha suaveolens L. samples, collected in the countryside of Tarquinia, is reported. In this study, the procedure for essential oil preparation, in terms of harvesting and extraction time, was analyzed in detail for the first time. The GC/MS analysis, carried out on 18 samples, revealed that piperitenone oxide (PO), the main essential oils' chemical constituent, is primarily responsible for the related antifungal activity. Nevertheless, EOs with lower PO content indicate that other chemicals, such as para-cymenene, may participate in exerting the EOs' antifungal effect. Furthermore, the bacterial reverse mutation assay highlighted lack of mutagenic effect in all tested samples. Analysis of the results indicated that for higher activity, the essential oils should be produced with 3 h maximum hydrodistillation, regardless of the harvesting time. Differently, the maximum essential oil yield can be obtained in August and the highest piperitenone oxide percentage is obtainable in July.

Mentha suaveolens Ehrh. (Lamiaceae) Essential Oil and Its Main Constituent Piperitenone Oxide: Biological Activities and Chemistry

Since herbal medicines play an important role in the treatment of a wide range of diseases, there is a growing need for their quality control and standardization. Mentha suaveolens Ehrh. (MS) is an aromatic herb with fruit and a spearmint flavor, used in the Mediterranean areas as a traditional medicine. It has an extensive range of biological activities, including cytotoxic, antimicrobial, antioxidant, anti-inflammatory, hypotensive and insecticidal properties, among others. This study aims to review the scientific findings and research reported to date on MS that prove many of the remarkable various biological actions, effects and some uses of this species as a source of bioactive natural compounds. On the other hand, piperitenone oxide (PO), the major chemical constituent of the carvone pathway MS essential oil, has been reported to exhibit numerous bioactivities in cells and animals. Thus, this integrated overview also surveys and interprets the present knowledge of chemistry and analysis of this oxygenated monoterpene, as well as its beneficial bioactivities. Areas for future research are suggested.

Effects of Mentha suaveolens essential oil on Chlamydia trachomatis

Chlamydia trachomatis, the most common cause of sexually transmitted bacterial infection worldwide, has a unique biphasic developmental cycle alternating between the infectious elementary body and the replicative reticulate body. C. trachomatis is responsible for severe reproductive complications including pelvic inflammatory disease, ectopic pregnancy, and obstructive infertility. The aim of our study was to evaluate whether Mentha suaveolens essential oil (EOMS) can be considered as a promising candidate for preventing C. trachomatis infection. Specifically, we investigated the in vitro effects of EOMS towards C. trachomatis analysing the different phases of chlamydial developmental cycle. Our results demonstrated that EOMS was effective towards C. trachomatis, whereby it not only inactivated infectious elementary bodies but also inhibited chlamydial replication. Our study also revealed the effectiveness of EOMS, in combination with erythromycin, towards C. trachomatis with a substantial reduction in the minimum effect dose of antibiotic. In conclusion, EOMS treatment may represent a preventative strategy since it may reduce C. trachomatis transmission in the population and, thereby, reduce the number of new chlamydial infections and risk of developing of severe sequelae.

Evaluation of anti-Candida activity of Vitis vinifera L. seed extracts obtained from wine and table cultivars

For the first time, grape seed extracts (GSEs), obtained from wine and table cultivars of Vitis vinifera L., cultured in experimental fields of Lazio and Puglia regions of Italy and grown in different agronomic conditions, have been tested on 43 Candida species strains. We demonstrated a significant correlation between the content of the flavan-3-ols in GSEs extracts, with a polymerization degree ≥4, and anti-Candida activity. Moreover, we demonstrated that GSEs, obtained from plants cultured with reduced irrigation, showed a content of polymeric flavan-3-ols >250 mg/g with geometric mean MIC values between 5.7 and 20.2 mg/L against Candida albicans reference strains. GSE, showing 573 mg/g of polymeric flavan-3-ols, has been tested in an experimental murine model of vaginal candidiasis by using noninvasive in vivo imaging technique. The results pointed out a significant inhibition of Candida albicans load 5 days after challenge. These findings indicate that GSEs with high content of polymeric flavan-3-ols can be used in mucosal infection as vaginal candidiasis.

Effects of Mentha suaveolens Essential Oil Alone or in Combination with Other Drugs in Candida albicans

Candidosis is the most important cause of fungal infections in humans. The yeast Candida albicans can form biofilms, and it is known that microbial biofilms play an important role in human diseases and are very difficult to treat. The prolonged treatment with drugs has often resulted in failure and resistance. Due to the emergence of multidrug resistance, alternatives to conventional antimicrobial therapy are needed. This study aims to analyse the effects induced by essential oil of Mentha suaveolens Ehrh (EOMS) on Candida albicans and its potential synergism when used in combination with conventional drugs. Morphological differences between control and EOMS treated yeast cells or biofilms were observed by scanning electron microscopy and transmission electron microscopy (SEM and TEM resp.,). In order to reveal the presence of cell cycle alterations, flow cytometry analysis was carried out as well. The synergic action of EOMS was studied with the checkerboard method, and the cellular damage induced by different treatments was analysed by TEM. The results obtained have demonstrated both the effects of EOMS on C. albicans yeast cells and biofilms and the synergism of EOMS when used in combination with conventional antifungal drugs as fluconazole (FLC) and micafungin (MCFG), and therefore we can hypothesize on its potential use in therapy. Further studies are necessary to know its mechanism of action.

Antimicrobial activity against beneficial microorganisms and chemical composition of essential oil of Mentha suaveolens ssp. insularis grown in Sardinia

The aim of this work was to determine the chemical constituents and in vitro antimicrobial activity of the essential oil (EO) of the aerial parts of Mentha sueveolens spp. insularis grown in Sardinia (Italy) against probiotic and starter microorganisms. The gas chromatography-mass spectrometry (GC-MS) analysis allowed to identified 34 compounds, most of oxygenated monoterpene compounds (82.5%) and among them, pulegone was found as major compound (46.5%). The agar diffusion test carried out employing the EO of Mentha suaveolens spp. insularis showed a low antibacterial activity, in particular no action was noticed for probiotic bacteria belonging to lactic acid bacteria groups, whereas almost all yeasts strains tested were inhibited. The automated microtitter dilution assay showed a clear effect at increasing concentration of EO on the specific growth rate (μ) and extension of the lag phase (λ) only for S. xylosus SA23 among bacteria and for Saccharomyces cerevisiae, Tetrapisispora phaffii CBS 4417, Metschnikowia pulcherrima, and Candida zemplinina among yeasts. Results obtained in this work allow us to broaden the knowledge on the effect of EOs on probiotic and food-related microorganisms.

PRACTICAL APPLICATION

Mentha suaveolens spp. insularis may be used in combination with probiotic bacteria into the food matrix or encapsulated in coating and edible films for food preservation.

Medicinal plants, human health and biodiversity: a broad review

Biodiversity contributes significantly towards human livelihood and development and thus plays a predominant role in the well being of the global population. According to WHO reports, around 80 % of the global population still relies on botanical drugs; today several medicines owe their origin to medicinal plants. Natural substances have long served as sources of therapeutic drugs, where drugs including digitalis (from foxglove), ergotamine (from contaminated rye), quinine (from cinchona), and salicylates (willow bark) can be cited as some classical examples.Drug discovery from natural sources involve a multifaceted approach combining botanical, phytochemical, biological, and molecular techniques. Accordingly, medicinal-plant-based drug discovery still remains an important area, hitherto unexplored, where a systematic search may definitely provide important leads against various pharmacological targets.Ironically, the potential benefits of plant-based medicines have led to unscientific exploitation of the natural resources, a phenomenon that is being observed globally. This decline in biodiversity is largely the result of the rise in the global population, rapid and sometimes unplanned industrialization, indiscriminate deforestation, overexploitation of natural resources, pollution, and finally global climate change.Therefore, it is of utmost importance that plant biodiversity be preserved, to provide future structural diversity and lead compounds for the sustainable development of human civilization at large. This becomes even more important for developing nations, where well-planned bioprospecting coupled with nondestructive commercialization could help in the conservation of biodiversity, ultimately benefiting mankind in the long run.Based on these findings, the present review is an attempt to update our knowledge about the diverse therapeutic application of different plant products against various pharmacological targets including cancer, human brain, cardiovascular function, microbial infection, inflammation, pain, and many more.

Plant-derived antimicrobial compounds: alternatives to antibiotics

The increasing incidence of drug-resistant pathogens has drawn the attention of the pharmaceutical and scientific communities towards studies on the potential antimicrobial activity of plant-derived substances, an untapped source of antimicrobial chemotypes, which are used in traditional medicine in different countries. The aim of this review is to provide recent insights regarding the possibilities of the most important natural antimicrobial compounds derived from plant sources containing a wide variety of secondary metabolites, which are useful as alternative strategies to control infectious diseases. This review will focus on natural plant products as a useful source of antimicrobial molecules, active in particular, on bacteria and fungi. When considering that many of these compounds, which have been used for centuries, are a source of new drugs and that there are ever-increasing technical breakthroughs, it can be envisaged that in the next years some different molecules discovered by ingenious screening programs and obtained from different plant oils and extracts will become useful therapeutic tools.

Mouse strain-dependent differences in estrogen sensitivity during vaginal candidiasis

The animal models available for studying the immune response to genital tract infection require induction of a pseudo estrous state, usually achieved by administration of 17-β-estradiol. In our experimental model of vaginal candidiasis, under pseudo estrus, different strains of mice were used. We observed major differences in the clearance of Candida albicans infection among the different strains, ascribable to differing susceptibility to estradiol treatment. In the early phase of infection CD1, BALB/c, C57BL/6 albino and C57BL/6 mice were colonized to similar levels, while in the late phase of infection, BALB/c mice, which are considered genetically resistant to C. albicans infection, exhibited greater susceptibility to vaginal candidiasis than CD1 and C57BL/6 albino strains of mice. This was because estradiol induced "per se" enlarged and fluid-filled uteri, more pronounced in infected mice and consistently more evident in BALB/c and C57BL/6 mice than in CD1 mice. Unlike CD1, BALB/c and C57BL/6 mice showed a heavy fungal colonization of the uterus, even though C57BL/6 mice apparently cleared C. albicans from the vagina. The presence of C. albicans in the vagina and uterus was accompanied by a heavy bacterial load. Collectively these observations prompted us to carry out a careful analysis of estradiol effects in a mouse model of vaginal infection.

Shedding natural light on fungal infections

Bioluminescence imaging allows the visualization of the temporal and spatial progression of biological phenomena, in particular infection, by non-invasive methods in vivo. This nature-borrowed technology has been successfully used to monitor bacterial infections but recent studies have also succeeded in tracking fungal infections such as those caused by the two major opportunistic fungal pathogens Candida albicans and Aspergillus fumigatus. The findings of Donat and collaborators published in this issue now show that by combining the sensitivity of the Gaussia princeps luciferase with a surface display expression system it is possible to perform longitudinal infection studies on cutaneous forms of aspergillosis with a small number of animals. Besides providing new and valuable information in the field of aspergillosis, the findings of Donat et al. offer a new perspective on the general applicability of bioluminescence methodologies for eukaryotic pathogens where the bacterial lux operon cannot be exploited.