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21 pages, 6437 KiB

Open AccessArticle

Phenolic Content and Antimicrobial and Anti-Inflammatory Effects of Solidago virga-aurea, Phyllanthus niruri, Epilobium angustifolium, Peumus boldus, and Ononis spinosa Extracts

by Claudio Ferrante, Annalisa Chiavaroli, Paola Angelini, Roberto Venanzoni, Giancarlo Angeles Flores, Luigi Brunetti, Massimiliano Petrucci, Matteo Politi, Luigi Menghini, Sheila Leone, Lucia Recinella, Gokhan Zengin, Gunes Ak, Massimo Di Mascio, Francesco Bacchin and Giustino Orlando

Antibiotics 2020, 9(11), 783; https://doi.org/10.3390/antibiotics9110783 - 6 Nov 2020

Cited by 47 | Viewed by 6033

Abstract

Prostatitis is an inflammatory condition that is related to multiple infectious agents, including bacteria and fungi. Traditional herbal extracts proved efficacious in controlling clinical symptoms associated with prostatitis. In this context, the aim of the present study was to explore the efficacy of [...] Read more.

Prostatitis is an inflammatory condition that is related to multiple infectious agents, including bacteria and fungi. Traditional herbal extracts proved efficacious in controlling clinical symptoms associated with prostatitis. In this context, the aim of the present study was to explore the efficacy of extracts from Solidago virga-aurea, Ononis spinosa, Peumus boldus, Epilobium angustifolium, and Phyllanthus niruri against bacterial (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus) and fungi strains (Candida albicans; C. tropicalis) involved in prostatitis. Additionally, anti-mycotic effects were tested against multiple species of dermatophytes (Trichophyton rubrum, T. tonsurans, T. erinacei, Arthroderma crocatum, A. quadrifidum, A. gypseum, A. currey, and A. insingulare). Antioxidant effects were also evaluated in isolated rat prostates challenged with lipopolysaccharide (LPS), and phytochemical analyses were conducted to identify and quantify selected phenolic compounds, in the extracts. Finally, a bioinformatics analysis was conducted to predict putative human and microbial enzymes targeted by extracts’ phytocompounds and underlying the observed bio-pharmacological effects. The phytochemical analysis highlighted that rutin levels could be crucial for explaining the highest antibacterial activity of P. boldus extract, especially against E. coli and B. cereus. On the other hand, in the E. angustifolium extract, catechin concentration could partially explain the highest efficacy of this extract in reducing lipid peroxidation, in isolated rat prostates stimulated with LPS. Concluding, the results of the present study showed moderate antimicrobial and anti-inflammatory effects induced by water extracts of S. virga-aurea, P. boldus, E. angustifolium, P. niruri, and O. spinosa that could be related, at least partially, to the phenolic composition of the phytocomplex. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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20 pages, 1827 KiB

Open AccessArticle

MeJA Elicitation of Chicory Hairy Roots Promotes Efficient Increase of 3,5-diCQA Accumulation, a Potent Antioxidant and Antibacterial Molecule

by Guillaume Bernard, Harmony Alves Dos Santos, Audrey Etienne, Jennifer Samaillie, Christel Neut, Sevser Sahpaz, Jean-Louis Hilbert, David Gagneul, Nathalie Jullian, Ali Tahrioui, Sylvie Chevalier, Céline Rivière and Caroline Rambaud

Antibiotics 2020, 9(10), 659; https://doi.org/10.3390/antibiotics9100659 - 30 Sep 2020

Cited by 11 | Viewed by 3708

Abstract

Cichorium intybus L. (Asteraceae) is an important industrial crop, as well as a medicinal plant which produces some bioactive compounds implicated in various biological effects with potential applications in human health. Particularly, roots produce hydroxycinnamic acids like 5-caffeoyquinic acid and 3,5-dicaffeoylquinic [...] Read more.

Cichorium intybus L. (Asteraceae) is an important industrial crop, as well as a medicinal plant which produces some bioactive compounds implicated in various biological effects with potential applications in human health. Particularly, roots produce hydroxycinnamic acids like 5-caffeoyquinic acid and 3,5-dicaffeoylquinic acid (di-CQA). The present investigation relates to the use of methyl jasmonate for enhancing phenolic compounds accumulation and production in hairy root cultures of C. intybus. Elicitated hairy root growth rate increased 13.3 times compared with the initial inoculum in a period of 14 days and di-CQA production represented about 12% of DW. The elicitation has also promoted the production of tricaffeoylquinic acid never described in the chicory roots and identified as 3,4,5-tricaffeoyquinic acid by means of nuclear magnetic resonance. Our study confirmed the strong anti-oxidant effect of di-CQA. Our results also confirmed globally a selectivity of action of di-CQA against Gram-positive bacteria, in particular against some strains of Staphylococcus and Streptococcus. However, a non-negligible antibacterial activity of di-CQA against Pseudomonas aeruginosa was also underlined (MIC = 0.156 mg.mL⁻¹ against some P. aeruginosa strains). The influence of di-CQA has been explored to evaluate its impact on the physiology of P. aeruginosa. Di-CQA showed no effect on the biofilm formation and the production of extracellular pyocyanin. However, it demonstrated an effect on virulence through the production of pyoverdine with a dose-dependent manner by more than 7-fold when treated at a concentration of 128 µg·mL⁻¹, thus suggesting a link between di-CQA and iron sequestration. This study shows that elicitated hairy root cultures of chicory can be developed for the production of di-CQA, a secondary metabolite with high antibacterial potential. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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15 pages, 2904 KiB

Open AccessArticle

Antimicrobial, Antioxidant, and Antiproliferative Effects of Coronilla minima: An Unexplored Botanical Species

by Claudio Ferrante, Paola Angelini, Roberto Venanzoni, Giancarlo Angeles Flores, Bruno Tirillini, Lucia Recinella, Annalisa Chiavaroli, Luigi Brunetti, Sheila Leone, Simonetta Cristina Di Simone, Maria Chiara Ciferri, Gokhan Zengin, Gunes Ak, Luigi Menghini and Giustino Orlando

Antibiotics 2020, 9(9), 611; https://doi.org/10.3390/antibiotics9090611 - 17 Sep 2020

Cited by 16 | Viewed by 4016

Abstract

Coronilla species, belonging to the Coronilla genus (Fabaceae), have long been used in traditional medicine for treating cold, diabetes, pain, and as cardiotonics. The goal of the present study was to explore the phytochemical composition and pharmaco-toxicological properties of C. minima. In this [...] Read more.

Coronilla species, belonging to the Coronilla genus (Fabaceae), have long been used in traditional medicine for treating cold, diabetes, pain, and as cardiotonics. The goal of the present study was to explore the phytochemical composition and pharmaco-toxicological properties of C. minima. In this regard, phenolic content, scavenging/reducing properties and antimicrobial activity toward pathogen bacterial (Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus aureus) and fungal strains (Candida albicans, C. tropicalis, Aspergillus tubigensis and A. minutus) were investigated. Extract effects on human colon cancer HCT116 cell viability were also assayed. Finally, a bioinformatics approach was conducted with the aim to identify putative microbial and human protein targets underlying antibacterial, antimycotic, and antiproliferative effects. Phytochemical investigation suggested that water extract is richer in terms of total flavonoid and phenol content, whereas the hydroalcoholic extract was revealed to be more potent as antioxidant agent. According to bioinformatics analysis, the antibacterial activity of the hydroalcoholic extract could be related to its content in resveratrol. The presence of resveratrol could also explain the hydroalcoholic extract efficacy in reducing HCT116 cell viability. In conclusion, the present study represents the first phytochemical and bio-pharmacological investigation about C. minima. Like other plants belonging to the Fabaceae family, C. minima revealed a good source of resveratrol, which could explain, albeit partially, the efficacy of the hydroalcoholic extract as antimicrobial, antioxidant, and antiproliferative agent. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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16 pages, 1966 KiB

Open AccessArticle

Evaluation of Antioxidant, Antimicrobial and Tyrosinase Inhibitory Activities of Extracts from Tricholosporum goniospermum, an Edible Wild Mushroom

by Paola Angelini, Roberto Venanzoni, Giancarlo Angeles Flores, Bruno Tirillini, Giustino Orlando, Lucia Recinella, Annalisa Chiavaroli, Luigi Brunetti, Sheila Leone, Simonetta Cristina Di Simone, Maria Chiara Ciferri, Gokhan Zengin, Gunes Ak, Luigi Menghini and Claudio Ferrante

Antibiotics 2020, 9(8), 513; https://doi.org/10.3390/antibiotics9080513 - 13 Aug 2020

Cited by 46 | Viewed by 5266

Abstract

Tricholosporum goniospermum (Bres.) Guzmán ex T.J. Baroni is an excellent edible mushroom whose compounds and biological properties are still unknown. In this study, n-hexane, ethyl acetate and methanol extracts from fruiting bodies and liquid-cultured mycelia were compared for the analysis of phenolic compounds, [...] Read more.

Tricholosporum goniospermum (Bres.) Guzmán ex T.J. Baroni is an excellent edible mushroom whose compounds and biological properties are still unknown. In this study, n-hexane, ethyl acetate and methanol extracts from fruiting bodies and liquid-cultured mycelia were compared for the analysis of phenolic compounds, the evaluation of scavenger (DPPH, ABTS) and reducing (CUPRAC, FRAP) activities, and the enzyme inhibition of α-amylase, acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase. Additionally, T. goniospermum extracts were evaluated for antibacterial and antimycotic activities against Gram+ and Gram− bacteria, and clinical yeast and fungal dermatophytes. Finally, based on the extract content in phenolic compounds, in silico studies, including the docking approach, were conducted to predict the putative targets (namely tyrosinase, lanosterol-14-α-demethylase, the multidrug efflux system transporters of E. coli (mdtK) and P. aeruginosa (pmpM), and S. aureus β-lactamase (ORF259)) underlying the observed bio-pharmacological and microbiological effects. The methanolic extract from mycelia was the richest in gallic acid, whereas the ethyl acetate extract from fruiting bodies was the sole extract to show levels of catechin. Specifically, docking runs demonstrated an affinity of catechin towards all docked proteins, in the micromolar range. These in silico data are consistent, at least in part, with the highest activity of ethyl acetate extract as an antimicrobial and anti-tyrosinase (554.30 mg KAE/g for fruiting bodies and 412.81 mg KAE/g for mycelia) agent. The ethyl acetate extracts were also noted as being the most active (2.97 mmol ACAE/g for fruiting bodies and 2.25 mmol ACAE/g for mycelia) on α-amylase. BChE inhibitory activities varied from 2.61 to 26.78 mg GALAE/g, while the tested extracts were not active on AChE. In conclusion, all mushroom extracts tested in this study had potent antimicrobial activities. Particularly, among the tested extracts, the ethyl acetate extract showed the highest efficacy as both an antimicrobial and anti-tyrosinase agent. This could be related, albeit partially, to its content of catechin. In this regard, the bioinformatics analyses showed interactions of catechin with tyrosinase and specific microbial proteins involved in the resistance to chemotherapeutic drugs, thus suggesting innovative pharmacological applications of T. goniospermum extracts. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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14 pages, 1547 KiB

Open AccessArticle

In Vitro Evaluation of the Antimicrobial and Immunomodulatory Activity of Culinary Herb Essential Oils as Potential Perioceutics

by Marcela Popa, Luminița Măruțescu, Eliza Oprea, Coralia Bleotu, Crina Kamerzan, Mariana Carmen Chifiriuc and Grațiela Grădișteanu Pircalabioru

Antibiotics 2020, 9(7), 428; https://doi.org/10.3390/antibiotics9070428 - 21 Jul 2020

Cited by 22 | Viewed by 4127

Abstract

Due to their antimicrobial, immunomodulatory, antioxidant, and regenerative activities, culinary herbs have multiple medicinal uses, among which to prevent and treat oral diseases. The whole essential oils (EOs) have multiple advantages over purified components, such as a low probability to select for antimicrobial [...] Read more.

Due to their antimicrobial, immunomodulatory, antioxidant, and regenerative activities, culinary herbs have multiple medicinal uses, among which to prevent and treat oral diseases. The whole essential oils (EOs) have multiple advantages over purified components, such as a low probability to select for antimicrobial resistance, synergic effects of different components, and multi-pharmacological activities. In this study, we aimed to evaluate essential oils from Salvia officinalis (sage), Satureja hortensis (summer savory), and Anethum graveolens (dill) using an in vitro analysis of their antimicrobial activity against Gram-positive and Gram-negative bacterial strains isolated from the oral cavity of patients with periodontitis; the assays addressed both the planktonic and biofilm growth states and used culture-based approaches. Some of the tested EOs exhibited excellent bactericidal and antibiofilm activity, being active at concentrations as low as 0.08–1.36 mg/mL. Flow cytometry was used to investigate the potential mechanisms of their antibacterial activity and confirmed that the tested EOs act by permeabilizing the bacterial membrane and by inhibiting the activity of the efflux pumps. The immunomodulatory effect of the three EOs was determined by analyzing the gene expression profiles for pro- and anti-inflammatory cytokines of the THP-1 cells. The summer savory EO induced a clear proinflammatory effect, while the others did not significantly influence the cytokines profile of the tested cells. Taken together, our results indicate that summer savory EO and, to a lesser extent, sage and dill EOs could be used to inhibit bacteria involved in oral plaque formation and to reduce the expression of genes known to contribute to the inflammatory response using cell culture assessment. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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12 pages, 911 KiB

Open AccessArticle

Ocotea glomerata (Nees) Mez Extract and Fractions: Chemical Characterization, Anti-Candida Activity and Related Mechanism of Action

by Mayara Nunes Vitor Anjos, Luiz Nascimento de Araújo-Neto, Maria Daniela Silva Buonafina, Rejane Pereira Neves, Edson Rubhens de Souza, Isabelle Cristinne Ferraz Bezerra, Magda Rhayanny Assunção Ferreira, Luiz Alberto Lira Soares, Henrique Douglas Melo Coutinho, Natália Martins, Márcia Vanusa da Silva and Maria Tereza dos Santos Correia

Antibiotics 2020, 9(7), 394; https://doi.org/10.3390/antibiotics9070394 - 9 Jul 2020

Cited by 3 | Viewed by 2802

Abstract

Background: Opportunistic fungal infections are increasingly common, with Candida albicans being the most common etiological agent; however, in recent years, episodes of candidiasis caused by non-albicans Candida species have emerged. Plants belonging to the Lauraceae family have shown remarkable antifungal effects. This [...] Read more.

Background: Opportunistic fungal infections are increasingly common, with Candida albicans being the most common etiological agent; however, in recent years, episodes of candidiasis caused by non-albicans Candida species have emerged. Plants belonging to the Lauraceae family have shown remarkable antifungal effects. This study assessed the anti-Candida activity of Ocotea glomerata extracts and fractions, time of death and the synergistic effects with conventional antifungals. The possible mechanism of action was also addressed. Methods: Minimal inhibitory concentrations (MIC) were determined by broth microdilution technique, and the mechanism of action was assessed by ergosterol, sorbitol, cell viability, reactive oxygen species (ROS) generation and phosphatidylserine externalization tests. Results: All the tested extracts evidenced antifungal activity, but the methanol extract was revealed to be the most effective (MIC = 3.12 μg/mL) on C. krusei. The combination of methanol extract with ketoconazole and fluconazole revealed a synergistic effect for C. krusei and C. albicans, respectively. Fractions 1 and 5 obtained from the methanol extract had fungicidal activity, mainly against C. krusei. Methanol extract did not reveal effects by ergosterol and sorbitol assays; however, it led to an increase in intracellular ROS levels, decreased cell viability, and consequently, cell death. Conclusion: O. glomerata methanol extract may be viewed as a rich source of biomolecules with antifungal activity against Candida spp. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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17 pages, 1291 KiB

Open AccessArticle

Acacia senegal Extract Rejuvenates the Activity of Phenicols on Selected Enterobacteriaceae Multi Drug Resistant Strains

by René Dofini Magnini, Adama Hilou, Helana Millogo-Koné, Jean-Marie Pagès and Anne Davin-Regli

Antibiotics 2020, 9(6), 323; https://doi.org/10.3390/antibiotics9060323 - 13 Jun 2020

Cited by 9 | Viewed by 3677

Abstract

This study reported the phytochemical composition of two hydroethanolic extracts of Acacia senegal and Acacia seyal trees from Burkina Faso and their activities, alone or in combination with selected antibiotics, against multidrug resistant bacteria. High performance thin layer chromatography (HPTLC) method was used [...] Read more.

This study reported the phytochemical composition of two hydroethanolic extracts of Acacia senegal and Acacia seyal trees from Burkina Faso and their activities, alone or in combination with selected antibiotics, against multidrug resistant bacteria. High performance thin layer chromatography (HPTLC) method was used for phytochemical screening. Total phenolic and total flavonoid ant tannins in leaves extracts contents were assessed by spectrophotometric method. The minimal inhibitory concentrations (MICs) of plant extracts and antibiotics were determined using the microdilution method and p-iodonitrotetrazolium chloride. Combinations of extracts and antibiotics were studied using checkerboard assays. Screening revealed the presence of phenolic compounds, flavonoids, and tannins in the hydroethanolic extract (HE) of the leaves. The HE of A. seyal showed the highest total phenolic (571.30 ± 6.97 mg GAE/g), total flavonoids (140.41 ± 4.01 mg RTE/g), and tannins (24.72 ± 0.14%, condensed; 35.77 ± 0.19%, hydrolysable tannins). However, the HE of A. senegal showed the lowest total phenolic (69.84 ± 3.54 mg GAE/g), total flavonoids (27.32 ± 0.57 mg RTE/g), and tannins (14.60 ± 0.01%, condensed; 3.09 ± 0.02%, hydrolysable). The MICs for HE and antibiotics were in the range of 2–512 and 0.008–1024 mg/L, respectively. All tested HE presented an MIC greater than 512 mg/L except HE of A. senegal. The lowest MIC value (128 mg/L) was obtained with HE of A. senegal against Klebsiella aerogenes EA298 and Escherichia coli AG100A. Interesting restoring effects on chloramphenicol and florphenicol activity were detected with alcoholic extracts of A. senegal against resistant E. coli and K. aerogenes strains that overproduce AcrAB or FloR pumps. The adjuvant effect of HE of A. senegal suggests that the crude extract of leaves could be a potential source of molecules for improving the susceptibility of bacteria to phenicols antibiotics. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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13 pages, 2337 KiB

Open AccessArticle

The Inhibitory Effect of Plant Extracts on Growth of the Foodborne Pathogen, Listeria monocytogenes

by Marina Ceruso, Jason A. Clement, Matthew J. Todd, Fangyuan Zhang, Zuyi Huang, Aniello Anastasio, Tiziana Pepe and Yanhong Liu

Antibiotics 2020, 9(6), 319; https://doi.org/10.3390/antibiotics9060319 - 11 Jun 2020

Cited by 30 | Viewed by 5493

Abstract

Listeria monocytogenes is a foodborne pathogen responsible for about 1600 illnesses each year in the United States (US) and about 2500 confirmed invasive human cases in European Union (EU) countries. Several technologies and antimicrobials are applied to control the presence of L. monocytogenes [...] Read more.

Listeria monocytogenes is a foodborne pathogen responsible for about 1600 illnesses each year in the United States (US) and about 2500 confirmed invasive human cases in European Union (EU) countries. Several technologies and antimicrobials are applied to control the presence of L. monocytogenes in food. Among these, the use of natural antimicrobials is preferred by consumers. This is due to their ability to inhibit the growth of foodborne pathogens but not prompt negative safety concerns. Among natural antimicrobials, plant extracts are used to inactivate L. monocytogenes. However, there is a large amount of these types of extracts, and their active compounds remain unexplored. The aim of this study was to evaluate the antibacterial activity against L. monocytogenes of about 800 plant extracts derived from plants native to different countries worldwide. The minimal inhibitory concentrations (MICs) were determined, and scanning electron microscopy (SEM) was used to verify how the plant extracts affected L. monocytogenes at the microscopic level. Results showed that 12 of the plant extracts had inhibitory activity against L. monocytogenes. Future applications of this study could include the use of these plant extracts as new preservatives to reduce the risk of growth of pathogens and contamination in the food industry from L. monocytogenes. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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12 pages, 526 KiB

Open AccessArticle

Anti-Infectious Plants of the Thai Karen: A Meta-Analysis

by Methee Phumthum and Henrik Balslev

Antibiotics 2020, 9(6), 298; https://doi.org/10.3390/antibiotics9060298 - 2 Jun 2020

Cited by 15 | Viewed by 5702

Abstract

Pharmacology has developed many drugs to treat infections, but many people, especially in developing countries, cannot afford to purchase them, and still depend on traditional knowledge and local medicinal plants to fight off infections. In addition, numerous microbes have developed resistance to the [...] Read more.

Pharmacology has developed many drugs to treat infections, but many people, especially in developing countries, cannot afford to purchase them, and still depend on traditional knowledge and local medicinal plants to fight off infections. In addition, numerous microbes have developed resistance to the pharmaceutical drugs developed to fight them, and for many, such as Covid-19, effective drugs remain to be found. Ethnomedicinal knowledge is useful, not only for local people as a source of medicine for primary health care, but also for new pharmacological discoveries. This study aimed to identify the plants that the Karen, the largest hill-tribe ethnic minority in northern and western Thailand, use for treatments of infectious diseases. We present a meta-analysis of data from 16 ethnobotanical studies of 25 Karen villages with the aim of understanding traditional knowledge and treatments and point to potential plants for further pharmacological development. The Karen used 127 plant species from 59 plant families to treat infections and infectious diseases. The Cultural Important Index (CI) showed that the Leguminosae, Euphorbiaceae, Asteraceae, Lauraceae, Apocynaceae, Menispermaceae, and Lamiaceae were the most commonly used families. As for species, Cleidion javanicum, Tinospora crispa, Litsea cubeba, Aesculus assamica, Tadehagi triquetrum, Senna alata, Tithonia diversifolia, Embelia sessiliflora, and Combretum indicum were the most commonly used in treatments of infectious diseases. We suggest that these plant species should be the first to be pharmacologically tested for possible development of medicines, and the remaining species registered should subsequently undergo testing. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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12 pages, 1331 KiB

Open AccessArticle

Satureja montana L. and Origanum majorana L. Decoctions: Antimicrobial Activity, Mode of Action and Phenolic Characterization

by Fernanda Gomes, Maria Inês Dias, Ângela Lima, Lillian Barros, Maria Elisa Rodrigues, Isabel C.F.R. Ferreira and Mariana Henriques

Antibiotics 2020, 9(6), 294; https://doi.org/10.3390/antibiotics9060294 - 31 May 2020

Cited by 31 | Viewed by 5051

Abstract

Medicinal and aromatic plants are known to have a wide range of uses and health benefits, and should be exploited for their bioactivity. Here we evaluated the antimicrobial activity of decoctions of Satureja montana L. and Origanum majorana L. against Gram-positive and Gram-negative [...] Read more.

Medicinal and aromatic plants are known to have a wide range of uses and health benefits, and should be exploited for their bioactivity. Here we evaluated the antimicrobial activity of decoctions of Satureja montana L. and Origanum majorana L. against Gram-positive and Gram-negative bacteria and Candida spp. as well as their mechanism of action and phenolic characterization. The Satureja montana and Origanum majorana extracts were effective against a broad set of species, including the Gram-positive Staphylococcus aureus, Enterococcus faecalis, and Streptococcus dysgalactiae and the Gram-negative Klebsiella pneumoniae and Pseudomonas aeruginosa. Both extracts were found to have rosmarinic acid as the main phenolic compound and to exert their antimicrobial activity at the level of the cell membrane. Membrane perturbations by the extracts impaired cell membrane integrity only a few hours after exposure. This study confirms the bioactive potential of Satureja montana and Origanum majorana decoctions, and supports the development of novel formulations with wide antimicrobial properties based on these medicinal and aromatic herbs. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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10 pages, 1613 KiB

Open AccessArticle

Structural Elucidation of Antibiotic TKR2999, an Antifungal Lipodepsipeptide Isolated from the Fungus Foliophoma fallens

by Gloria Crespo, Ignacio Pérez-Victoria, Francisco Javier Ortiz-López, Víctor González-Menéndez, Mercedes de la Cruz, Bastien Cautain, Pilar Sánchez, Francisca Vicente, Olga Genilloud and Fernando Reyes

Antibiotics 2020, 9(6), 278; https://doi.org/10.3390/antibiotics9060278 - 26 May 2020

Cited by 1 | Viewed by 4363

Abstract

An antifungal lipodepsipeptide was obtained from cultures of the fungus Foliophoma fallens CF-236885. Its structure, elucidated by HRMS and NMR spectroscopy, contained Gly, Thr, Asn, β-Ala, Orn, Ala, two Ser residues, and 3-hydroxy-4-methylhexadecanoic acid. The absolute configuration of its amino acid residues was [...] Read more.

An antifungal lipodepsipeptide was obtained from cultures of the fungus Foliophoma fallens CF-236885. Its structure, elucidated by HRMS and NMR spectroscopy, contained Gly, Thr, Asn, β-Ala, Orn, Ala, two Ser residues, and 3-hydroxy-4-methylhexadecanoic acid. The absolute configuration of its amino acid residues was determined using Marfey’s analysis and J-based configuration analysis helped to establish the relative configuration of the 3-hydroxy-4-methylhexadecanoic acid moiety. A literature search retrieved a patent describing antibiotic TKR2999 (1), whose non-disclosed structure was confirmed to be identical to that found for our compound, according to its physicochemical properties and NMR spectra. Compound 1 displayed potent antifungal activity against Aspergillus fumigatus and a panel of Candida strains. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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14 pages, 1726 KiB

Open AccessArticle

whISOBAX^TM Inhibits Bacterial Pathogenesis and Enhances the Effect of Antibiotics

by Reuven Rasooly, Hwang-Yong Choi, Paula Do, Gianluca Morroni, Lucia Brescini, Oscar Cirioni, Andrea Giacometti and Emmanouil Apostolidis

Antibiotics 2020, 9(5), 264; https://doi.org/10.3390/antibiotics9050264 - 19 May 2020

Cited by 10 | Viewed by 4514

Abstract

As bacteria are becoming more resistant to commonly used antibiotics, alternative therapies are being sought. whISOBAX (WH) is a witch hazel extract that is highly stable (tested up to 2 months in 37 °C) and contains a high phenolic content, where 75% of [...] Read more.

As bacteria are becoming more resistant to commonly used antibiotics, alternative therapies are being sought. whISOBAX (WH) is a witch hazel extract that is highly stable (tested up to 2 months in 37 °C) and contains a high phenolic content, where 75% of it is hamamelitannin and traces of gallic acid. Phenolic compounds like gallic acid are known to inhibit bacterial growth, while hamamelitannin is known to inhibit staphylococcal pathogenesis (biofilm formation and toxin production). WH was tested in vitro for its antibacterial activity against clinically relevant Gram-positive and Gram-negative bacteria, and its synergy with antibiotics determined using checkerboard assays followed by isobologram analysis. WH was also tested for its ability to suppress staphylococcal pathogenesis, which is the cause of a myriad of resistant infections. Here we show that WH inhibits the growth of all bacteria tested, with variable efficacy levels. The most WH-sensitive bacteria tested were Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecium and Enterococcus faecalis, followed by Acinetobacter baumannii, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Streptococcus agalactiae and Streptococcus pneumoniae. Furthermore, WH was shown on S. aureus to be synergistic to linezolid and chloramphenicol and cumulative to vancomycin and amikacin. The effect of WH was tested on staphylococcal pathogenesis and shown here to inhibit biofilm formation (tested on S. epidermidis) and toxin production (tested on S. aureus Enterotoxin A (SEA)). Toxin inhibition was also evident in the presence of subinhibitory concentrations of ciprofloxacin that induces pathogenesis. Put together, our study indicates that WH is very effective in inhibiting the growth of multiple types of bacteria, is synergistic to antibiotics, and is also effective against staphylococcal pathogenesis, often the cause of persistent infections. Our study thus suggests the benefits of using WH to combat various types of bacterial infections, especially those that involve resistant persistent bacterial pathogens. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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13 pages, 3101 KiB

Open AccessArticle

New Peptaibiotics and a Cyclodepsipeptide from Ijuhya vitellina: Isolation, Identification, Cytotoxic and Nematicidal Activities

by Ashaimaa Y. Moussa, Christopher Lambert, Theresia E.B. Stradal, Samad Ashrafi, Wolfgang Maier, Marc Stadler and Soleiman E. Helaly

Antibiotics 2020, 9(3), 132; https://doi.org/10.3390/antibiotics9030132 - 22 Mar 2020

Cited by 14 | Viewed by 4975

Abstract

Fungal associations with nematodes have attracted scientific attention because of the need to develop new biocontrol agents. In this context, Ijuhya vitellina, an antagonistic fungus previously isolated from the plant parasitic cyst nematode Heterodera filipjevi, was selected to carry out an [...] Read more.

Fungal associations with nematodes have attracted scientific attention because of the need to develop new biocontrol agents. In this context, Ijuhya vitellina, an antagonistic fungus previously isolated from the plant parasitic cyst nematode Heterodera filipjevi, was selected to carry out an in-depth metabolomic study for its active metabolites. Herein, three new nonapeptide peptaibols with leucinostatin based sequences were isolated and identified by 1, 2D NMR, and HR-ESI-MS-MS. The absolute configuration was assigned based on Marfay’s analysis and Mosher ester formation. The new leucinostatins manifested moderate nematicidal effect against the plant pathogenic nematode Pratylenchus penetrans with LD₉₀ values ranging from 5 to 7 µg/mL. Furthermore, a cyclodepsipeptide, named arthrichitin D, with five amino acid residues attached to a 3-hydroxy-2,4-dimethylhexadeca-4,6-dienoic fatty acid chain was discovered and showed weak nematicidal effect against Caenorhabditis elegans. Chaetoglobosin B and its 19-O-acetyl derivative were also obtained as minor metabolites, and the activity of chaetoglobosin B on the actin cytoskeleton of mammalian cells was assessed. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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12 pages, 2657 KiB

Open AccessArticle

Susceptibility of Multidrug-Resistant and Biofilm-Forming Uropathogens to Mexican Oregano Essential Oil

by Karen Arely Zapién-Chavarría, Alejandro Plascencia-Terrazas, María Georgina Venegas-Ortega, Mauricio Varillas-Torres, Blanca Estela Rivera-Chavira, Jaime Raúl Adame-Gallegos, María Olga González-Rangel and Guadalupe Virginia Nevárez-Moorillón

Antibiotics 2019, 8(4), 186; https://doi.org/10.3390/antibiotics8040186 - 15 Oct 2019

Cited by 11 | Viewed by 6577

Abstract

Antibiotic resistance along with biofilm formation increases the difficulty for antibiotic therapy in urinary tract infections. Bioactive molecules derived from plants, such as those present in essential oils, can be used to treat bacterial infections. Oregano is one of the spices to have [...] Read more.

Antibiotic resistance along with biofilm formation increases the difficulty for antibiotic therapy in urinary tract infections. Bioactive molecules derived from plants, such as those present in essential oils, can be used to treat bacterial infections. Oregano is one of the spices to have antimicrobial activity. Therefore, three Mexican oregano essential oils (two Lippia berlandieri Schauer and one Poliomintha longiflora) were tested for antimicrobial capacity against multidrug-resistant, biofilm-forming bacterial isolates. Clinical isolates from urinary tract infections were tested for antibiotic resistance. Multidrug-resistant isolates were evaluated for biofilm formation, and Mexican oregano antimicrobial effect was determined by the minimal inhibitory (CMI) and minimal bactericidal concentrations (CMB). The selected isolates were identified by molecular phylogenetic analysis. Sixty-one isolates were included in the study; twenty were characterized as multidrug-resistant and from those, six were strong biofilm formers. Three isolates were identified as Escherichia coli, two as Pseudomonas aeruginosa and one as Enterococcus faecalis based on the phylogenetic analysis of 16 S rRNA gene sequences. The antimicrobial effect was bactericidal; E. faecalis was the most susceptible (<200 mg/L CMI/CMB), and P. aeruginosa was the most resistant (>2,000 mg/L CMI/CMB). There was a range of 500-1000 mg/L (CMI/CMB) for the E. coli isolates. Mexican oregano essential oils demonstrated antimicrobial efficacy against multidrug-resistant clinical isolates. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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10 pages, 783 KiB

Open AccessReview

The Antimicrobial Activity of Cannabinoids

by John A. Karas, Labell J. M. Wong, Olivia K. A. Paulin, Amna C. Mazeh, Maytham H. Hussein, Jian Li and Tony Velkov

Antibiotics 2020, 9(7), 406; https://doi.org/10.3390/antibiotics9070406 - 13 Jul 2020

Cited by 72 | Viewed by 14280

Abstract

A post-antibiotic world is fast becoming a reality, given the rapid emergence of pathogens that are resistant to current drugs. Therefore, there is an urgent need to discover new classes of potent antimicrobial agents with novel modes of action. Cannabis sativa is an [...] Read more.

A post-antibiotic world is fast becoming a reality, given the rapid emergence of pathogens that are resistant to current drugs. Therefore, there is an urgent need to discover new classes of potent antimicrobial agents with novel modes of action. Cannabis sativa is an herbaceous plant that has been used for millennia for medicinal and recreational purposes. Its bioactivity is largely due to a class of compounds known as cannabinoids. Recently, these natural products and their analogs have been screened for their antimicrobial properties, in the quest to discover new anti-infective agents. This paper seeks to review the research to date on cannabinoids in this context, including an analysis of structure–activity relationships. It is hoped that it will stimulate further interest in this important issue. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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26 pages, 1047 KiB

Open AccessReview

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

by Giulia Potente, Francesca Bonvicini, Giovanna Angela Gentilomi and Fabiana Antognoni

Antibiotics 2020, 9(7), 395; https://doi.org/10.3390/antibiotics9070395 - 9 Jul 2020

Cited by 14 | Viewed by 3906

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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27 pages, 3445 KiB

Open AccessReview

Alkaloids from Marine Fungi: Promising Antimicrobials

by Thomas Willems, Maarten L. De Mol, Aleksandar De Bruycker, Sofie L. De Maeseneire and Wim K. Soetaert

Antibiotics 2020, 9(6), 340; https://doi.org/10.3390/antibiotics9060340 - 18 Jun 2020

Cited by 31 | Viewed by 6654

Abstract

Resistance of pathogenic microorganisms against antimicrobials is a major threat to contemporary human society. It necessitates a perpetual influx of novel antimicrobial compounds. More specifically, Gram⁻ pathogens emerged as the most exigent danger. In our continuing quest to search for novel antimicrobial [...] Read more.

Resistance of pathogenic microorganisms against antimicrobials is a major threat to contemporary human society. It necessitates a perpetual influx of novel antimicrobial compounds. More specifically, Gram⁻ pathogens emerged as the most exigent danger. In our continuing quest to search for novel antimicrobial molecules, alkaloids from marine fungi show great promise. However, current reports of such newly discovered alkaloids are often limited to cytotoxicity studies and, moreover, neglect to discuss the enigma of their biosynthesis. Yet, the latter is often a prerequisite to make them available through sufficiently efficient processes. This review aims to summarize novel alkaloids with promising antimicrobial properties discovered in the past five years and produced by marine fungi. Several discovery strategies are summarized, and knowledge gaps in biochemical production routes are identified. Finally, links between the structure of the newly discovered molecules and their activity are proposed. Since 2015, a total of 35 new antimicrobial alkaloids from marine fungi were identified, of which 22 showed an antibacterial activity against Gram⁻ microorganisms. Eight of them can be classified as narrow-spectrum Gram⁻ antibiotics. Despite this promising ratio of novel alkaloids active against Gram⁻ microorganisms, the number of newly discovered antimicrobial alkaloids is low, due to the narrow spectrum of discovery protocols that are used and the fact that antimicrobial properties of newly discovered alkaloids are barely characterized. Alternatives are proposed in this review. In conclusion, this review summarizes novel findings on antimicrobial alkaloids from marine fungi, shows their potential as promising therapeutic candidates, and hints on how to further improve this potential. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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33 pages, 17494 KiB

Open AccessReview

The Revaluation of Plant-Derived Terpenes to Fight Antibiotic-Resistant Infections

by Floriana Cappiello, Maria Rosa Loffredo, Cristina Del Plato, Silvia Cammarone, Bruno Casciaro, Deborah Quaglio, Maria Luisa Mangoni, Bruno Botta and Francesca Ghirga

Antibiotics 2020, 9(6), 325; https://doi.org/10.3390/antibiotics9060325 - 13 Jun 2020

Cited by 41 | Viewed by 6820

Abstract

The discovery of antibiotics has revolutionized the medicine and treatment of microbial infections. However, the current scenario has highlighted the difficulties in marketing new antibiotics and an exponential increase in the appearance of resistant strains. On the other hand, research in the field [...] Read more.

The discovery of antibiotics has revolutionized the medicine and treatment of microbial infections. However, the current scenario has highlighted the difficulties in marketing new antibiotics and an exponential increase in the appearance of resistant strains. On the other hand, research in the field of drug-discovery has revaluated the potential of natural products as a unique source for new biologically active molecules and scaffolds for the medicinal chemistry. In this review, we first contextualized the worldwide problem of antibiotic resistance and the importance that natural products of plant origin acquire as a source of new lead compounds. We then focused on terpenes and their potential development as antimicrobials, highlighting those studies that showed an activity against conventional antibiotic-resistant strains. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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26 pages, 2312 KiB

Open AccessReview

Omics for Bioprospecting and Drug Discovery from Bacteria and Microalgae

by Reuben Maghembe, Donath Damian, Abdalah Makaranga, Stephen Samwel Nyandoro, Sylvester Leonard Lyantagaye, Souvik Kusari and Rajni Hatti-Kaul

Antibiotics 2020, 9(5), 229; https://doi.org/10.3390/antibiotics9050229 - 4 May 2020

Cited by 39 | Viewed by 10516

Abstract

“Omics” represent a combinatorial approach to high-throughput analysis of biological entities for various purposes. It broadly encompasses genomics, transcriptomics, proteomics, lipidomics, and metabolomics. Bacteria and microalgae exhibit a wide range of genetic, biochemical and concomitantly, physiological variations owing to their exposure to biotic [...] Read more.

“Omics” represent a combinatorial approach to high-throughput analysis of biological entities for various purposes. It broadly encompasses genomics, transcriptomics, proteomics, lipidomics, and metabolomics. Bacteria and microalgae exhibit a wide range of genetic, biochemical and concomitantly, physiological variations owing to their exposure to biotic and abiotic dynamics in their ecosystem conditions. Consequently, optimal conditions for adequate growth and production of useful bacterial or microalgal metabolites are critically unpredictable. Traditional methods employ microbe isolation and ‘blind’-culture optimization with numerous chemical analyses making the bioprospecting process laborious, strenuous, and costly. Advances in the next generation sequencing (NGS) technologies have offered a platform for the pan-genomic analysis of microbes from community and strain downstream to the gene level. Changing conditions in nature or laboratory accompany epigenetic modulation, variation in gene expression, and subsequent biochemical profiles defining an organism’s inherent metabolic repertoire. Proteome and metabolome analysis could further our understanding of the molecular and biochemical attributes of the microbes under research. This review provides an overview of recent studies that have employed omics as a robust, broad-spectrum approach for screening bacteria and microalgae to exploit their potential as sources of drug leads by focusing on their genomes, secondary metabolite biosynthetic pathway genes, transcriptomes, and metabolomes. We also highlight how recent studies have combined molecular biology with analytical chemistry methods, which further underscore the need for advances in bioinformatics and chemoinformatics as vital instruments in the discovery of novel bacterial and microalgal strains as well as new drug leads. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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32 pages, 2891 KiB

Open AccessReview

Testing the Antimicrobial Characteristics of Wood Materials: A Review of Methods

by Muhammad Tanveer Munir, Hélène Pailhories, Matthieu Eveillard, Mark Irle, Florence Aviat, Laurence Dubreil, Michel Federighi and Christophe Belloncle

Antibiotics 2020, 9(5), 225; https://doi.org/10.3390/antibiotics9050225 - 1 May 2020

Cited by 29 | Viewed by 11916

Abstract

Some wood species have antimicrobial properties, making them a better choice over inert surfaces in certain circumstances. However, the organic and porous nature of wood raises questions regarding the use of this material in hygienically important places. Therefore, it is reasonable to investigate [...] Read more.

Some wood species have antimicrobial properties, making them a better choice over inert surfaces in certain circumstances. However, the organic and porous nature of wood raises questions regarding the use of this material in hygienically important places. Therefore, it is reasonable to investigate the microbial survival and the antimicrobial potential of wood via a variety of methods. Based on the available literature, this review classifies previously used methods into two broad categories: one category tests wood material by direct bacterial contact, and the other tests the action of molecules previously extracted from wood on bacteria and fungi. This article discusses the suitability of these methods to wood materials and exposes knowledge gaps that can be used to guide future research. This information is intended to help the researchers and field experts to select suitable methods for testing the hygienic safety and antimicrobial properties of wood materials. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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19 pages, 1424 KiB

Open AccessReview

Plant Secondary Metabolites in the Battle of Drugs and Drug-Resistant Bacteria: New Heroes or Worse Clones of Antibiotics?

by Cyrill L. Gorlenko, Herman Yu. Kiselev, Elena V. Budanova, Andrey A. Zamyatnin, Jr. and Larisa N. Ikryannikova

Antibiotics 2020, 9(4), 170; https://doi.org/10.3390/antibiotics9040170 - 10 Apr 2020

Cited by 159 | Viewed by 12418

Abstract

Infectious diseases that are caused by bacteria are an important cause of mortality and morbidity in all regions of the world. Bacterial drug resistance has grown in the last decades, but the rate of discovery of new antibiotics has steadily decreased. Therefore, the [...] Read more.

Infectious diseases that are caused by bacteria are an important cause of mortality and morbidity in all regions of the world. Bacterial drug resistance has grown in the last decades, but the rate of discovery of new antibiotics has steadily decreased. Therefore, the search for new effective antibacterial agents has become a top priority. The plant kingdom seems to be a deep well for searching for novel antimicrobial agents. This is due to the many attractive features of plants: they are readily available and cheap, extracts or compounds from plant sources often demonstrate high-level activity against pathogens, and they rarely have severe side effects. The huge variety of plant-derived compounds provides very diverse chemical structures that may supply both the novel mechanisms of antimicrobial action and provide us with new targets within the bacterial cell. In addition, the rapid development of modern biotechnologies opens up the way for obtaining bioactive compounds in environmentally friendly and low-toxic conditions. In this short review, we ask the question: do antibacterial agents derived from plants have a chance to become a panacea against infectious diseases in the “post-antibiotics era”. Full article

(This article belongs to the Special Issue Natural Antimicrobial Products from Plants and Fungi: Current Knowledge and Future Prospects)

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