Antifungal Activity and Type of Interaction of Melissa officinalis Essential Oil with Antimycotics against Biofilms of Multidrug-Resistant Candida Isolates from Vulvovaginal Mucosa.

(1) Background: Vulvovaginal candidosis (VVC) is a major therapy issue due to its high resistance rate and virulence factors such as the ability to form biofilms. The possibility of combining commonly used antifungals with natural products might greatly improve therapeutic success. (2) Methods: A total of 49 vulvovaginal isolates, causative agents of recurrent VVC, were tested for their susceptibility to fluconazole, nystatin, and Melissa officinalis essential oil (MOEO). This examination included testing the antibiofilm potential of antifungals and MOEO and the determination of their types of interaction with mature biofilms. (3) Results: Antimicrobial testing showed that 94.4% of the Candida albicans isolates and all the Candida krusei isolates were resistant to fluconazole, while all strains showed resistance to nystatin. The same strains were susceptible to MOEO in 0.156-2.5 mg/mL concentrations. Additionally, the results revealed very limited action of fluconazole, while nystatin and MOEO reduced the amount of biofilm formed by as much as 17.7% and 4.6%, respectively. Testing of the combined effect showed strain-specific synergistic action. Furthermore, the lower concentrations exhibited antagonistic effects even in cases where synergism was detected. (4) Conclusions: This study showed that MOEO had a very good antibiofilm effect. However, combining MOEO with antimycotics demonstrated that the type of action depended on the choice of antifungal drugs as well as the applied concentration.

Bioisosteric ferrocenyl 1,3-thiazolidine-4-carboxylic acid derivatives: In vitro antiproliferative and antimicrobial evaluations.

To improve the antiproliferative effect of ALC67 (diastereomeric mixture of ethyl 2-phenyl-3-propioloyl-1,3-thiazolidine-4-carboxylate), its structure was modified via (i) bioisosteric substitution of the phenyl ring by the ferrocene unit and (ii) replacing the propiolamide side-chain in ACL67 with other acyl groups having differing electrophilicities. In this way, a small library of methyl N-acyl-2-ferrocenyl-1,3-thiazolidine-4-carboxylates (13 compounds in total) was created and characterized by spectral and crystallographic means. The last N-acylation step was highly diastereoselective toward the cis-diastereomer. In solution, most of the obtained compounds existed as a mixture of two rotamers and displayed a preference for the syn-orientation around the CN bond. A twisted 5T4 envelope conformation was adopted by the derivative containing the N-phenoxyacetyl group in the crystalline state. Two derivatives with chloroacetyl and bromoacetyl groups in the N-3 side chain were cytotoxic to fibroblasts and hepatocellular cancer cells in the low micromolar range (IC50(MRC5) = 9.0 and 11.8 µM, respectively, and IC50(HepG2) = 10.6 and 18.4 µM, respectively) causing an effect similar to the lead compound (IC50(HepG2) = 10.0 µM) and cisplatin (IC50(MRC5) = 4.0 µM and IC50(HepG2) = 7.7 µM). Several derivatives also manifested modest antimicrobial effects against the studied microbial strains (MICs in the range from 0.44 to 4.0 µmol/mL). Our findings demonstrated that the introduction of a ferrocene core facilitated the preparation of optically pure analogs of ALC67 and that the cytotoxicity of compounds may be enhanced by adding proper electrophilic centers to the N-acyl side-chain.

Coastal Halophytes: Potent Source of Bioactive Molecules from Saline Environment.

This study represents a comparative analysis of secondary metabolites content, antioxidant, and antimicrobial activity of 24 halophytes from coastal saline habitats of the Balkan Peninsula (Montenegro, Albania, and Greece). Total content of phenolics, flavonoids, tannins, anthocyanins, antioxidant, and antimicrobial activity was determined for dry methanolic (DME) and crude water extracts (CWE) and compared with well-known medicinal plants. The total phenolic content ranged from 13.23 to 376.08 mg of GA/g of DME, and from 33.68 to 511.10 mg/mL of CWE. The content of flavonoids ranged from 12.63 to 77.36 mg of RU/g of DME, and from 12.13 to 26.35 mg/mL of CWE. Total tannins and anthocyanins varied from 0.05 to 2.44 mg/mL, and from 1.31 to 39.81 µg/L, respectively. The antioxidant activity ranged from 1147.68 to 15.02 µg/mL for DME and from 1613.05 to 21.96 µg/mL for CWE. The best antioxidant properties, and the highest content of phenolic compounds, were determined for Polygonum maritimum and Limonium vulgare with values similar to or higher compared to the medicinal plants. Halophytes with significant antimicrobial potential were Limonium vulgare, L. angustifolium, and Artemisia maritima. Some of the analyzed coastal halophytes can be considered rich natural sources of phenolic compounds, with favorable antioxidative and antimicrobial properties.

New Iron Twist to Chloroquine─Upgrading Antimalarials with Immunomodulatory and Antimicrobial Features.

Herein, upgraded chloroquine (CQ) derivatives capable of overcoming Plasmodium resistance and, at the same time, suppressing excessive immune response and risk of concurrent bacteremia were developed. Twelve new ferrocene-CQ hybrids tethered with a small azathia heterocycle (1,3-thiazolidin-4-one, 1,3-thiazinan-4-one, or 5-methyl-1,3-thiazolidin-4-one) were synthesized and fully characterized. All hybrids were evaluated for their in vitro antiplasmodial, antimicrobial, and immunomodulatory activities. Additional assays were performed on selected hybrids to gain insights into their mode of action. Although only hybrid 4a was more potent than the parent drug toward CQ-resistant Dd2 Plasmodium falciparum strain, several other hybrids (such as 6b, 6c, and 6d) manifested substantially improved antimicrobial and immunomodulatory properties. Interesting structure-activity relationship data were obtained, hinting at future research for the development of new multitarget chemotherapies for malaria and other infectious diseases complicated by drug resistance, bacterial co-infection, and immune-driven pathology issues.

Pulicaria dysenterica (L.) Bernh.-Rightfully Earned Name? Identification and Biological Activity of New 3-Methoxycuminyl Esters from P. dysenterica Essential Oil.

Motivated by the ethnopharmacological use of Pulicaria dysenterica, in the present study, the antimicrobial potential of the extracted essential oil was investigated against a panel of eighteen microorganism strains. Additionally, anti-acetylcholinesterase and antispasmodic (isolated rat distal colon) activities, general acute toxicity (Artemia salina model), and immunomodulatory properties (cytotoxicity on isolated mouse macrophages) were studied. Detailed analyses of the essential oil led to the identification of 3-methoxycuminyl 2-methylbutanoate (a new natural product) and 3-methoxycuminyl 3-methylbutanoate (a rare natural product). The obtained esters and intermediates in the synthesis of the starting alcohol (3-methoxycuminol) were subjected to a battery of 1D- and 2D-NMR experiments. The synthesized esters were additionally characterized by GC-MS, IR, and UV-Vis. The synthesized compounds (ten in total) were biologically tested in the same way as the extracted P. dysenterica essential oil. The obtained low acute toxicity and promising antimicrobial potential suggest that the P. dysenterica essential oil might partially explain the ethnopharmacological application of P. dysenterica plant material for the treatment of gastrointestinal infections.

In vitro anti-clostridial action and potential of the spice herbs essential oils to prevent biofilm formation of hypervirulent Clostridioides difficile strains isolated from hospitalized patients with CDI.

BACKGROUND: Clostridioides difficile is the most common causative agent of antibiotic-acquired diarrhea in hospitalized patients associated with substantial morbidity and mortality. The global epidemic of CDI (Clostridioides difficile infection) began in the early 20th century with the emergence of the hypervirulent and resistant ribotype 027 strains, and requires an urgent search for new therapeutic agents. OBJECTIVE: The aim of this study is to investigate the antibacterial activity of the three essential oils isolated from spice herbs (wild oregano, garlic and black pepper) against C. difficile clinical isolates belonging to 6 different PCR ribotypes and their potential inhibitory effect on the biofilm production in in vitro conditions. RESULTS: Wild oregano essential oil showed strong inhibitory activity in concentrations 0.02-1.25 mg/mL and bactericidal activity in concentrations from 0.08 to 10 mg/mL. Garlic essential oil was effective in the concentration range of 0.02-40 mg/mL, and 0.16 - > 40 mg/mL. MIC and MBC for black pepper oil ranged from 0.04 to 40 mg/mL, and 0.08 - > 40 mg/mL, respectively. All the tested oils reduced in vitro biofilm production, with the best activity of oregano oil. CONCLUSION: Essential oils of wild oregano, black pepper and garlic are candidates for adjunctive therapeutics in the treatment of CDI. Oregano oil should certainly be preferred due to the lack of selectivity of action in relation to the ribotype, the strength of the produced biofilm and/or antibiotic-susceptibility patterns.

Essential Oils of Three Balkan Abies Species: Chemical Profiles, Antimicrobial Activity and Toxicity toward Artemia salina and Drosophila melanogaster.

This study focused on the essential oils (EOs) isolated from needles with twigs of three indigenous Balkan Abies species (A. alba, A. × borisii-regis and A. cephalonica) regarding their chemical composition, antimicrobial activity and toxicity toward crustaceans and insects. Even though distinct phytochemical profiles of dominant volatiles were revealed for each species, ß-pinene and α-pinene represented the first two major volatiles in all three EOs. Antimicrobial activity of EOs has shown inhibitory effect against all 17 studied strains (ATCC and respiratory isolates) in the range of 0.62-20.00 mg/mL (MICs). Further, all three EOs exhibited strong toxicity (LC50 <100 µg/mL) in Artemia salina lethality bioassay, but with significant differences that depended on the EO type. Additionally, tested EOs have shown a certain level of toxicity against Drosophila melanogaster, mostly at the highest tested concentration (3 %) which caused significant prolongation of developmental time, larvicidal effect and pupal mortality. In the three biological assays performed, there was no observed inhibitory effect or weakest activity for A. alba EO. Further, A. cephalonica EO has shown the highest levels of antimicrobial activity and toxicity toward A. salina, while in relation to the insecticidal potential, A. cephalonica and A. × borisii-regis EOs exhibited similar level of toxicity against D. melanogaster.

Clinical Presentations, Cluster Analysis and Laboratory-Based Investigation of Aspergillus Otomycosis-A Single Center Experience.

Species of Aspergillus (A.) niger complex and A. flavus complex are predominant molds that are causative agents of otomycoses. The goal of this study was to investigate the clinical presentation, diagnostic procedure, and appearance of relapse in patients with Aspergillus-otomycosis, as well as to determine the biofilm production ability of species isolated in relapse. Thirty patients with laboratory evidenced Aspergillus-otomycosis followed by two check-ups (30 and 60 days after initiation of treatment with antimycotics for local application) were included in the study. For isolation and identification of Aspergillus spp. the standard mycological procedure was applied. Results showed very high sensitivity of microscopy, but 16.7% Aspergillus species required the optimal temperature of 27-28 °C for cultivation. Applied statistical cluster analysis showed a defined specific cluster/group of patients with A. niger complex-otomycosis. Sixty days after diagnosis and treatment initiation, six patients had a relapse, with the same species of Aspergillus genus being the cause. To establish the ability of biofilm production, the modified method described by Pierce and Kvasnicková was performed, and all six species isolated in the relapse episode had the ability to produce biofilm. Official criteria and recommendations are needed due to the possibility of misdiagnosis, which leads to the prolongation and complication of the disease.

Essential Oils of Six Achillea Species: Chemical Profiles, Antimicrobial Potential and Toxicity toward Crustaceans.

This is the first comparative study on antimicrobial activity of essential oils (EOs) of six Achillea species (A. crithmifolia, A. distans, A. grandifolia, A. millefolium, A. nobilis, and A. lingulata) against ATCC and clinical microbial strains isolated from human swabs and on their toxicological potential on crustaceans. Oxygenated monoterpenes represented the major compound class in all six EOs, ranging from around 50 % (A. millefolium, A. nobilis, and A. lingulata) up to over 80 % (A. crithmifolia and A. grandifolia). Specific phytochemical profiles of the major volatiles were determined for each species. Still, borneol was the dominant compound in EOs of three yarrow species: A. distans, A. lingulata, and A. millefolium. Other major compounds were 1,8-cineole in A. crithmifolia, camphor in A. grandifolia, and artemisia ketone in A. nobilis EO. Antimicrobial activities of EOs were examined by a microdilution method revealing inhibitory action against all 15 studied strains in the range of 0.07-20.00 mg/mL (MICs). High toxicity (LC50 <100 µg/mL) in Artemia salina acute toxicity bioassay was a shared characteristic, appearing in five out of six tested EOs, i. e., those isolated from A. lingulata, A. millefolium, A. distans, A. nobilis, and A. grandifolia. In both types of biological tests, A. lingulata EO has shown the highest and A. crithmifolia EO the lowest potential. The strongest activities, recorded for EO of A. lingulata, which was the only studied species from the section Anthemoideae, may be explained by its somewhat unusual chemical composition. According to the obtained results, the second dominant compound of this EO is γ-palmitolactone, which may be a significant agent regarding the antimicrobial activity and toxicity to crustaceans, either on its own or in union with other components, and it may be a suitable topic for further research.

Linking the antimicrobial and anti-inflammatory effects of immortelle essential oil with its chemical composition - The interplay between the major and minor constituents.

Immortelle (Helichrysum italicum, Asteraceae) essential oil has been widely used in alternative medicine to accelerate wound healing, as well as in cosmetic products to stimulate skin regeneration and to reduce the appearance of wrinkles. It is also considered a natural and safe culinary spice that could also be applied in the food industry as a preservative in the future. The therapeutic efficacy of this oil changes with the natural variability of the composition. Herein we tested and mutually compared the antimicrobial and anti-inflammatory activities of four commercial immortelle oils differing in the relative amounts of marker compounds, i.e. neryl esters, α-pinene, γ- and ar-curcumenes, and ß-diketones. The anti-inflammatory effect of selected chromatographic fractions, enriched in the aforementioned constituents, was evaluated by studying toxicity toward rat peritoneal macrophages, their nitric oxide production, myeloperoxidase, and arginase activities. Subsequently, the compositional and activity data were subjected to a multivariate statistical treatment to reveal the possible correlation(s) between the percentage of essential-oil constituents and the observed activities. The obtained results imply that immortelle oil efficiency as an antimicrobial and/or anti-inflammatory agent is most plausibly a result of a synergistic action between its constituents, and/or, rather unexpectedly, the presence of some minor constituents.

Pseudotsuga menziesii (Pinaceae): Volatile Profiles, Antimicrobial Activity and Toxicological Evaluation of Its Essential Oil.

The present article investigates the chemical composition of volatiles of essential oil (EO) and headspace (HS) fraction, as well as biological activities of EO obtained from needles with twigs of Pseudotsuga menziesii var. menziesii cultivated in Serbia. The major class of compounds was monoterpene hydrocarbons with α-terpinolene, sabinene and ß-pinene (EO), and sabinene, α-terpinolene and ß-pinene (HS) as the dominant volatiles. Tested EO exhibited mostly low antimicrobial potential against investigated strains (ATCC and respiratory isolates), where MICs ranged 1.25-20.00 mg/mL. Nevertheless, based on presented results, where antimicrobial testing was done for the first time on human respiratory system isolates, there is a potential of this EO to be used as an adjuvant in the treatment of human respiratory infections, especially those caused by Pseudomonas aeruginosa or Candida albicans strains. Regarding toxicological evaluation, EO showed moderate toxicity in Artemia salina toxicity bioassay (LC50 =347.41, after 24 h) as well as week toxicity against Drosophila melanogaster with the ability only to moderately delay larval and pupal development.

Human microbiome and homeostasis: insights into the key role of prebiotics, probiotics, and symbiotics.

The interest in the study of the gut microbiome has grown exponentially. Indeed, its impact on health and disease has been increasingly reported, and the importance of keeping gut microbiome homeostasis clearly highlighted. However, and despite many advances, there are still some gaps, as well as the real discernment on the contribution of some species falls far short of what is needed. Anyway, it is already more than a solid fact of its importance in maintaining health and preventing disease, as well as in the treatment of some pathologies. In this sense, and given the existence of some ambiguous opinions, the present review aims to discuss the importance of gut microbiome in homeostasis maintenance, and even the role of probiotics, prebiotics, and symbiotics in both health promotion and disease prevention.

Synthesis and antimicrobial activity of (-)-cleistenolide and analogues.

Using the "chiral pool" approach, two modified total syntheses of the biologically active δ-lactone cleistenolide (1) have been achieved starting from d-glucose. These approaches also enabled the preparation of novel analogues and derivatives of natural product 1. The applied strategy for the synthesis of 1 involves: the initial degradation of the chiral precursor for a single C-atom, C2-fragment chain extension using Z-selective Wittig reaction, and the final δ-lactonization. All tested cleistenolide analogues displayed antimicrobial activity against a panel of nine microbial strains, most of them superseding the activity of cleistenolide itself, and, in some cases, coming close in value to the observed minimal inhibitory concentrations of chloramphenicol. Increased lipophilicity of the derivatives and the non-sterically congested conjugated lactone moiety were a prerequisite for analogues with high inhibitory activity against S. aureus and, in general, Gram-positive bacteria.

Probiotics: Versatile Bioactive Components in Promoting Human Health.

The positive impact of probiotic strains on human health has become more evident than ever before. Often delivered through food, dietary products, supplements, and drugs, different legislations for safety and efficacy issues have been prepared. Furthermore, regulatory agencies have addressed various approaches toward these products, whether they authorize claims mentioning a disease's diagnosis, prevention, or treatment. Due to the diversity of bacteria and yeast strains, strict approaches have been designed to assess for side effects and post-market surveillance. One of the most essential delivery systems of probiotics is within food, due to the great beneficial health effects of this system compared to pharmaceutical products and also due to the increasing importance of food and nutrition. Modern lifestyle or various diseases lead to an imbalance of the intestinal flora. Nonetheless, as the amount of probiotic use needs accurate calculations, different factors should also be taken into consideration. One of the novelties of this review is the presentation of the beneficial effects of the administration of probiotics as a potential adjuvant therapy in COVID-19. Thus, this paper provides an integrative overview of different aspects of probiotics, from human health care applications to safety, quality, and control.

Medicinal plants used in the treatment of tuberculosis - Ethnobotanical and ethnopharmacological approaches.

Tuberculosis is a highly infectious disease declared a global health emergency by the World Health Organization, with approximately one third of the world's population being latently infected with Mycobacterium tuberculosis. Tuberculosis treatment consists in an intensive phase and a continuation phase. Unfortunately, the appearance of multi drug-resistant tuberculosis, mainly due to low adherence to prescribed therapies or inefficient healthcare structures, requires at least 20 months of treatment with second-line, more toxic and less efficient drugs, i.e., capreomycin, kanamycin, amikacin and fluoroquinolones. Therefore, there exists an urgent need for discovery and development of new drugs to reduce the global burden of this disease, including the multi-drug-resistant tuberculosis. To this end, many plant species, as well as marine organisms and fungi have been and continue to be used in various traditional healing systems around the world to treat tuberculosis, thus representing a nearly unlimited source of active ingredients. Besides their antimycobacterial activity, natural products can be useful in adjuvant therapy to improve the efficacy of conventional antimycobacterial therapies, to decrease their adverse effects and to reverse mycobacterial multi-drug resistance due to the genetic plasticity and environmental adaptability of Mycobacterium. However, even if some natural products have still been investigated in preclinical and clinical studies, the validation of their efficacy and safety as antituberculosis agents is far from being reached, and, therefore, according to an evidence-based approach, more high-level randomized clinical trials are urgently needed.

Choosing the Right Essential Oil for a Mouthwash: Chemical, Antimicrobial and Cytotoxic Studies.

Thirteen commercial essential oils were assessed for their possible inclusion in a mouthwash formulation based on their inhibitory effect against potentially pathogenic anaerobic oral bacterial isolates from subgingival plaque, and their cytotoxicity towards gingival cells. The essential oils, originating from species belonging to seven major aromatic plant families, were chosen to provide the necessary diversity in chemical composition that was analyzed in detail by GC and GC/MS. Multivariate statistical analysis, performed using the in vitro microbiological/toxicological assays and compositional data, revealed that the major components of the essential oils were probably not the main carriers of the activities observed. A formulation of 'designer' mouthwashes is proposed based on the selective action of certain essential oils towards specific bacterial isolates (e. g., Citrus bergamia vs. Parvimonas micra), and non-toxicity to gingival cells at antimicrobially active concentrations.

Herbal remedies as alternative to conventional therapies for the treatment of pediatric infectious diseases.

Pediatric infections still represent a leading cause of mortality in many developing countries. Since ancient times, traditional healing systems provided some herbal remedies to treat pediatric diseases, only in some cases validated by an evidence-based approach. Therefore, this review covers the herbal remedies in Iranian traditional medicine and aims to assess the potential of phytotherapeutics as safe and effective alternatives to conventional therapies for the treatment of pediatric infectious diseases. Notably, pediatric patients may also benefit from adjuvant therapy, i.e., combined treatment with herbal remedies and conventional therapies, to improve the efficacy of conventional drugs, decrease their adverse effects at the cell-tissue-organ-organism level and reduce the occurrence of microbial strains resistant to antibiotics. Therefore, traditional healing systems still represent an unlimited source of active ingredients to be tested in preclinical assays as well as in humans in terms of efficacy and safety.

Anti-virulence potential of basil and sage essential oils: Inhibition of biofilm formation, motility and pyocyanin production of Pseudomonas aeruginosa isolates.

The effects of basil (Ocimum basilicum) and sage (Salvia officinalis) essential oils on selected virulence factors (biofilm formation, mature biofilm resistance, motility, and pyocyanin production) of Pseudomonas aeruginosa clinical isolates were evaluated in the present study for the first time. The two essential oils were chemically characterized by GC and GC-MS analyses. Linalool and (E)-anethole were found to be the main components of the investigated basil oil, while α-thujone and camphor were the major constituents of the studied sage essential oil. The oils inhibited biofilm formation up to 99.9% vs control, and significant reductions (74.7-99.9%) were also noted when the oils were applied to mature biofilms. Likewise, swimming, swarming, and twitching motility patterns were highly affected by both oils. The basil and sage oils reduced pyocyanin production by 13.32-55.6% and 5.0-58.7%, respectively. Thus, basil and sage essential oils are potentially highly efficient antipseudomonal agents that could be used against both acute and chronic infections.

Therapeutic Applications of Curcumin Nanomedicine Formulations in Cardiovascular Diseases.

Cardiovascular diseases (CVD) compromises a group of heart and blood vessels disorders with high impact on human health and wellbeing. Curcumin (CUR) have demonstrated beneficial effects on these group of diseases that represent a global burden with a prevalence that continues increasing progressively. Pre- and clinical studies have demonstrated the CUR effects in CVD through its anti-hypercholesterolemic and anti-atherosclerotic effects and its protective properties against cardiac ischemia and reperfusion. However, the CUR therapeutic limitation is its bioavailability. New CUR nanomedicine formulations are developed to solve this problem. The present article aims to discuss different studies and approaches looking into the promising role of nanotechnology-based drug delivery systems to deliver CUR and its derivatives in CVD treatment, with an emphasis on their formulation properties, experimental evidence, bioactivity, as well as challenges and opportunities in developing these systems.

The therapeutic potential of curcumin: A review of clinical trials.

Curcuma longa L., its derived extracts and even its major compound curcumin has a long history of use and doubtless effectiveness, reported through increasingly detailed in vitro, ex vivo, in vivo and even clinical trials. Regarding its biological effects, multiple health-promoting, disease-preventing and even treatment attributes has been remarkably highlighted. Clinical trials, although have increased in a progressive manner, significant disproportionalities have been stated in terms of biological effects assessment. In this sense, the present report aims to provide an extensive overview to curcumin therapeutic effects in human subjects. For that, clinical trials assessing the curcumin effect on inflammation, skin, eye, central nervous system, respiratory, cardiovascular, gastrointestinal, urogenital and metabolic disorders are here presented and discussed. A special emphasis was also given to curcumin activity on intoxications and multiple malignant diseases.