Antimicrobial and Anti-infective Activity of Natural Products

A special issue of Antibiotics (ISSN 2079-6382). This special issue belongs to the section "Novel Antimicrobial Agents".

Deadline for manuscript submissions: closed (30 November 2022) | Viewed by 48362

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Centro de Ciências Biológicas e da Saúde, Universidade Federal do Maranhão, São Luís 65080-805, MA, Brazil
Interests: antimicrobial activity; bioactive compounds; mechanisms of action; natural products
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Instituto de Pesquisa Pelé Pequeno Príncipe, Faculdades Pequeno Príncipe, Curitiba 80250-060, PR, Brazil
Interests: antimicrobial compounds; models of infection
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Antimicrobial drugs represent one of the great scientific advances in the medical field. However, a dramatic increase in antimicrobial resistance has compromised the effectiveness of these drugs. Thus, there is an increased need to search for new antimicrobial compounds. A growing area of research in this regard is the investigation of antimicrobial activities in natural products from different sources, including plants, microorganisms, and animals. Another important area of research in combating resistant microorganisms is the investigation of compounds that neutralize or inactivate bacterial resistance mechanisms—for example, compounds that inhibit efflux pumps or beta-lactamases. Furthermore, there are molecules that can interfere with bacterial virulence properties. The main advantage claimed for antivirulence therapy is the reduced selective pressure on the pathogen and, consequently, the lower possibility of the emergence of resistance. This Special Issue aims to highlight the recent advances in the discovery of new antimicrobial compounds from natural products, mechanisms of action of pure compounds, in silico evidence of antimicrobial activity, synergistic associations with antibiotics, and compounds with antivirulence activity or capable of neutralizing bacterial resistance. We also welcome the submission of research papers that study alternative methods of demonstrating the in vivo efficacy of compounds or natural extracts.

Dr. Valério Monteiro-Neto
Dr. Elizabeth S. Fernandes
Guest Editors

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Keywords

  • antimicrobial activity
  • antivirulence activity
  • natural compounds and extracts
  • antimicrobial resistance inhibition
  • beta-lactamase inhibition
  • efflux pump inhibition
  • synergistic associations
  • models of infection
  • clinical assays

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Published Papers (20 papers)

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Editorial

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8 pages, 250 KiB  
Editorial
Antimicrobial and Anti-Infective Activity of Natural Products—Gaining Knowledge from Novel Studies
by Elizabeth S. Fernandes, Isabella F. da Silva Figueiredo, Cinara R. A. V. Monteiro and Valério Monteiro-Neto
Antibiotics 2023, 12(6), 1051; https://doi.org/10.3390/antibiotics12061051 - 15 Jun 2023
Cited by 1 | Viewed by 1478
Abstract
Despite advances in the development of antimicrobial drugs in the last centuries, antimicrobial resistance has consistently raised in the last decades, compromising their effectiveness. Novel antimicrobial compounds, especially from natural sources, including plants, microorganisms, and animals, have since become a growing area of [...] Read more.
Despite advances in the development of antimicrobial drugs in the last centuries, antimicrobial resistance has consistently raised in the last decades, compromising their effectiveness. Novel antimicrobial compounds, especially from natural sources, including plants, microorganisms, and animals, have since become a growing area of research. In this context, studies covering the investigation of their ability to combat resistant microorganisms, either by neutralization or inactivation of pathogen resistance mechanisms and virulence properties, have gained attention. Herein, a collection of 19 manuscripts focused on the antimicrobial and anti-infective activity of natural products, including their mechanisms of action, in silico evidence of antimicrobial activity, synergistic associations with antibiotics, and other aspects, will be discussed. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)

Research

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11 pages, 2011 KiB  
Article
Antimicrobial Activity of Apis mellifera Bee Venom Collected in Northern Peru
by Orlando Pérez-Delgado, Abraham Omar Espinoza-Culupú and Elmer López-López
Antibiotics 2023, 12(4), 779; https://doi.org/10.3390/antibiotics12040779 - 19 Apr 2023
Cited by 2 | Viewed by 2274
Abstract
Due to the emergence of microorganisms resistant to antibiotics and the failure of antibiotic therapies, there is an urgent need to search for new therapeutic options, as well as new molecules with antimicrobial potential. The objective of the present study was to evaluate [...] Read more.
Due to the emergence of microorganisms resistant to antibiotics and the failure of antibiotic therapies, there is an urgent need to search for new therapeutic options, as well as new molecules with antimicrobial potential. The objective of the present study was to evaluate the in vitro antibacterial activity of Apis mellifera venom collected in the beekeeping areas of the city of Lambayeque in northern Peru against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Bee venom extraction was performed by electrical impulses and separated using the Amicon ultra centrifugal filter. Subsequently, the fractions were quantified by spectrometric 280 nm and evaluated under denaturant conditions in SDS-PAGE. The fractions were pitted against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853. A purified fraction (PF) of the venom of A. mellifera and three low molecular weight bands of 7 KDa, 6 KDa, and 5 KDa were identified that showed activity against E. coli with a MIC of 6.88 µg/mL, while for P. aeruginosa and S. aureus, it did not present a MIC. No hemolytic activity at a concentration lower than 15.6 µg/mL and no antioxidant activity. The venom of A. mellifera contains a potential presence of peptides and a predilection of antibacterial activity against E. coli. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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16 pages, 3686 KiB  
Article
Antiparasitic Activities of Compounds Isolated from Aspergillus fumigatus Strain Discovered in Northcentral Nigeria
by Oluwatofunmilayo A. Diyaolu, Gagan Preet, Adeshola A. Fagbemi, Frederick Annang, Guiomar Pérez-Moreno, Cristina Bosch-Navarrete, Olusoji O. Adebisi, Emmanuel T. Oluwabusola, Bruce F. Milne, Marcel Jaspars and Rainer Ebel
Antibiotics 2023, 12(1), 109; https://doi.org/10.3390/antibiotics12010109 - 6 Jan 2023
Cited by 3 | Viewed by 2251
Abstract
In this study, we explored a fungal strain UIAU-3F identified as Aspergillus fumigatus isolated from soil samples collected from the River Oyun in Kwara State, Nigeria. In order to explore its chemical diversity, the fungal strain UIAU-3F was cultured in three different fermentation [...] Read more.
In this study, we explored a fungal strain UIAU-3F identified as Aspergillus fumigatus isolated from soil samples collected from the River Oyun in Kwara State, Nigeria. In order to explore its chemical diversity, the fungal strain UIAU-3F was cultured in three different fermentation media, which resulted in different chemical profiles, evidenced by LC-ESI-MS-based metabolomics and multivariate analysis. The methanolic extract afforded two known compounds, fumitremorgin C (1) and pseurotin D (2). The in vitro antiparasitic assays of 1 against Trypanosoma cruzi and Plasmodium falciparum showed moderate activity with IC50 values of 9.6 µM and 2.3 µM, respectively, while 2 displayed IC50 values > 50 µM. Molecular docking analysis was performed on major protein targets to better understand the potential mechanism of the antitrypanosomal and antiplasmodial activities of the two known compounds. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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18 pages, 2120 KiB  
Article
In Silico and In Vitro Analysis of Sulforaphane Anti-Candida Activity
by Bruna L. R. Silva, Gisele Simão, Carmem D. L. Campos, Cinara R. A. V. Monteiro, Laryssa R. Bueno, Gabriel B. Ortis, Saulo J. F. Mendes, Israel Viegas Moreira, Daniele Maria-Ferreira, Eduardo M. Sousa, Flávia C. B. Vidal, Cristina de Andrade Monteiro, Valério Monteiro-Neto and Elizabeth S. Fernandes
Antibiotics 2022, 11(12), 1842; https://doi.org/10.3390/antibiotics11121842 - 19 Dec 2022
Cited by 3 | Viewed by 2506
Abstract
Oropharyngeal candidiasis/candidosis is a common and recurrent opportunistic fungal infection. Fluconazole (FLZ), one of the most used and effective antifungal agents, has been associated with a rise of resistant Candida species in immunocompromised patients undergoing prophylactic therapy. Sulforaphane (SFN), a compound from cruciferous [...] Read more.
Oropharyngeal candidiasis/candidosis is a common and recurrent opportunistic fungal infection. Fluconazole (FLZ), one of the most used and effective antifungal agents, has been associated with a rise of resistant Candida species in immunocompromised patients undergoing prophylactic therapy. Sulforaphane (SFN), a compound from cruciferous vegetables, is an antimicrobial with yet controversial activities and mechanisms on fungi. Herein, the in silico and antifungal activities of SFN against C. albicans were investigated. In silico analyzes for the prediction of the biological activities and oral bioavailability of SFN, its possible toxicity and pharmacokinetic parameters, as well as the estimates of its gastrointestinal absorption, permeability to the blood-brain barrier and skin, and similarities to drugs, were performed by using different software. SFN in vitro anti-Candida activities alone and in combination with fluconazole (FLZ) were determined by the broth microdilution method and the checkerboard, biofilm and hyphae formation tests. Amongst the identified probable biological activities of SFN, nine indicated an antimicrobial potential. SFN was predicted to be highly absorbable by the gastrointestinal tract, to present good oral availability, and not to be irritant and/or hepatotoxic. SFN presented antifungal activity against C. albicans and prevented both biofilm and hyphae formation by this microorganism. SFN was additive/synergistic to FLZ. Overall, the data highlights the anti-Candida activity of SFN and its potential to be used as an adjuvant therapy to FLZ in clinical settings. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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24 pages, 3892 KiB  
Article
The Anti-Virulence Effect of Vismia guianensis against Candida albicans and Candida glabrata
by Elizangela Pestana Motta, Josivan Regis Farias, Arthur André Castro da Costa, Anderson França da Silva, Alberto Jorge Oliveira Lopes, Maria do Socorro Sousa Cartágenes, Roberto Nicolete, Afonso Gomes Abreu, Elizabeth Soares Fernandes, Flavia Raquel Fernandes Nascimento, Cláudia Quintino da Rocha, Cristina Andrade Monteiro and Rosane Nassar Meireles Guerra
Antibiotics 2022, 11(12), 1834; https://doi.org/10.3390/antibiotics11121834 - 16 Dec 2022
Cited by 2 | Viewed by 1758
Abstract
In folk medicine, Vismia guianensis is used to treat skin diseases and mycoses in the Amazon region. We evaluated the anti-Candida activity of the hydroalcoholic extract from the leaves of Vismia guianensis (EHVG). HPLC-PDA and FIA-ESI-IT-MSn were used to chemically characterize [...] Read more.
In folk medicine, Vismia guianensis is used to treat skin diseases and mycoses in the Amazon region. We evaluated the anti-Candida activity of the hydroalcoholic extract from the leaves of Vismia guianensis (EHVG). HPLC-PDA and FIA-ESI-IT-MSn were used to chemically characterize EHVG. The anti-Candida activity was determined in vitro by the minimum inhibitory concentrations (MIC) against Candida glabrata (ATCC-2001); Candida albicans (ATCC-90028, ATCC-14053, and ATCC-SC5314), and C. albicans clinical isolates. EHVG effects on adhesion, growth, and biofilm formation were also determined. Molecular docking was used to predict targets for EHVG compounds. The main compounds identified included anthraquinone, vismione D, kaempferol, quercetin, and vitexin. EHVG was fungicidal against all tested strains. C. albicans ATCC 14053 and C. glabrata ATCC 2001 were the most sensitive strains, as the extract inhibited their virulence factors. In silico analysis indicated that vismione D presented the best antifungal activity, since it was the most effective in inhibiting CaCYP51, and may act as anti-inflammatory and antioxidant agent, according to the online PASS prediction. Overall, the data demonstrate that EHVG has an anti-Candida effect by inhibiting virulence factors of the fungi. This activity may be related to its vismione D content, indicating this compound may represent a new perspective for treating diseases caused by Candida sp. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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16 pages, 5246 KiB  
Article
Effects of Coleus amboinicus L. Essential Oil and Ethanolic Extracts on Planktonic Cells and Biofilm Formation of Microsporum canis Isolated from Feline Dermatophytosis
by Arpron Leesombun, Karnchanarat Thanapakdeechaikul, Jiraporn Suwannawiang, Pipada Mukto, Sivapong Sungpradit, Norasuthi Bangphoomi, Tanasak Changbunjong, Orathai Thongjuy, Thekhawet Weluwanarak and Sookruetai Boonmasawai
Antibiotics 2022, 11(12), 1734; https://doi.org/10.3390/antibiotics11121734 - 1 Dec 2022
Cited by 4 | Viewed by 2081
Abstract
Microsporum canis is an important zoonotic fungus that causes dermatophytosis in domestic animals and their owners. Domestic cats are the primary reservoir for M. canis. Antifungal drugs frequently produce adverse effects on the host animal, increasing the demand for novel alternative treatments [...] Read more.
Microsporum canis is an important zoonotic fungus that causes dermatophytosis in domestic animals and their owners. Domestic cats are the primary reservoir for M. canis. Antifungal drugs frequently produce adverse effects on the host animal, increasing the demand for novel alternative treatments derived from nature. We evaluated the antifungal activity of Coleus amboinicus essential oil (CEO) and ethanolic extracts (CEE) against M. canis in planktonic and biofilm growth. Twelve clinical isolates of M. canis were identified in feline dermatophyte samples. Using GC-MS, 18 compounds were identified in CEO, with carvacrol being the major constituent. HPLC analysis of CEE revealed that it contained rosmarinic acid, apigenin, and caffeic acid. The planktonic growth of all M. canis isolates was inhibited by C. amboinicus extracts. The minimum inhibitory concentration at which ≥50% of the isolates were inhibited (MIC50) was 128 µg/mL (32–256 µg/mL) for both CEO and CEE. The MIC90 values of CEO and CEE were 128 and 256 µg/mL, respectively. CEO at MIC (128 µg/mL) and 2× MIC (256 µg/mL) significantly inhibited the biofilm formation of weak, moderate, and strong biofilm-producing M. canis. CEE at 2× MIC (256 µg/mL) significantly inhibited the biofilm formation of all isolates. Overall, C. amboinicus extracts inhibited planktonic growth and exhibited a significant antibiofilm effect against M. canis. Thus, C. amboinicus is a potential source of natural antifungal compounds. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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21 pages, 6465 KiB  
Article
Phytochemical Profile of the Ethanol Extract of Malvaviscus arboreus Red Flower and Investigation of the Antioxidant, Antimicrobial, and Cytotoxic Activities
by Hanaa S. S. Gazwi, Nagwa A. Shoeib, Magda E. Mahmoud, Osama I. A. Soltan, Moaz M. Hamed and Amany E. Ragab
Antibiotics 2022, 11(11), 1652; https://doi.org/10.3390/antibiotics11111652 - 18 Nov 2022
Cited by 14 | Viewed by 2319
Abstract
Flowers are rich sources of bioactive antimicrobial, antioxidant, and anticancer components. This study aimed to determine the constituents of the ethanol extract of Malvaviscus arboreus red flower (ERF) by GC-MS analysis and HPLC identification of phenolic compounds and flavonoids, in addition to the 1 [...] Read more.
Flowers are rich sources of bioactive antimicrobial, antioxidant, and anticancer components. This study aimed to determine the constituents of the ethanol extract of Malvaviscus arboreus red flower (ERF) by GC-MS analysis and HPLC identification of phenolic compounds and flavonoids, in addition to the 1HNMR fingerprint. The antimicrobial, antioxidant, and cytotoxic activities of the ERF were investigated. The GC-MS analysis revealed twenty-one components, while HPLC analysis revealed the presence of phenolic and flavonoid compounds. The ERF showed antifungal and antibacterial activity. The highest antibacterial activity was found against Vibrio damsela where a time-kill assay revealed a decline in the amount of viable V. damsela. For fungi, the highest activity was observed against Aspergillus terreus. Using the SRB test on HepG2, the anti-proliferative efficacy of the ERF was evaluated. Cell cycle analysis was utilized to determine autophagic cell death. The ERF prevented the proliferation of the HepG2 cell line with an IC50 of 67.182 µg/µL. The extract primarily promoted apoptosis in HepG2 cells by accumulating hypodiploid cells in the sub-G0/G1 phase, increased caspase 3/7 activity, and caused considerable autophagic cell death in apoptosis-deficient cells. Finally, the observed elevation of cancer cell death indicated that ERF had substantial anticancer potential against HepG2 cells. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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14 pages, 2353 KiB  
Article
In-Vitro and In-Vivo Antibacterial Effects of Frankincense Oil and Its Interaction with Some Antibiotics against Multidrug-Resistant Pathogens
by Megren Bin Faisal Almutairi, Mohammed Alrouji, Yasir Almuhanna, Mohammed Asad and Babu Joseph
Antibiotics 2022, 11(11), 1591; https://doi.org/10.3390/antibiotics11111591 - 10 Nov 2022
Cited by 6 | Viewed by 2207
Abstract
Frankincense (Boswellia sacra oleo gum resin) is reported to possess antimicrobial activity against several pathogens in-vitro. The antimicrobial effects of frankincense oil and its interaction with imipenem and gentamicin against methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant P. aeruginosa were determined through in-vitro [...] Read more.
Frankincense (Boswellia sacra oleo gum resin) is reported to possess antimicrobial activity against several pathogens in-vitro. The antimicrobial effects of frankincense oil and its interaction with imipenem and gentamicin against methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant P. aeruginosa were determined through in-vitro methods and an in-vivo study using a rat pneumonia model. Frankincense oil was subjected to GC-MS analysis to determine the different volatile components. Antibacterial effects against MRSA and MDR-P. aeruginosa was evaluated and its MIC and MBC were determined. For the rat pneumonia model (in-vivo), oil was administered at a dose of 500 mg/kg and 1000 mg/kg followed by determination of CFU in lung tissue and histological studies. Frankincense oil did not show a very potent inhibitory effect against MRSA or MDR-P. aeruginosa; the oil did not affect the zone of inhibition or FIC when combined with imipenem or gentamicin indicating a lack of interaction between the oil and the antibiotics. Furthermore, there was no interaction between the antibiotics and the frankincense oil in the in-vivo model. The result of the study revealed that frankincense oil has a weak inhibitory effect against MRSA and MDR-P. aeruginosa, and it did not show any interaction with imipenem or gentamicin. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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17 pages, 1705 KiB  
Article
Isolation and Characterization of a Novel Actinomycete Isolated from Marine Sediments and Its Antibacterial Activity against Fish Pathogens
by Haimanti Mondal and John Thomas
Antibiotics 2022, 11(11), 1546; https://doi.org/10.3390/antibiotics11111546 - 3 Nov 2022
Cited by 9 | Viewed by 4083
Abstract
Marine habitats are especially complex, with a varied diversity of living organisms. Marine organisms, while living in such intense conditions, have developed great physiological and metabolic potential to survive. This has led them to produce several potent metabolites, which their terrestrial counterparts are [...] Read more.
Marine habitats are especially complex, with a varied diversity of living organisms. Marine organisms, while living in such intense conditions, have developed great physiological and metabolic potential to survive. This has led them to produce several potent metabolites, which their terrestrial counterparts are unable to produce. Over the past few years, marine Actinomycetes have been considered one of the most abundant sources of diverse and novel metabolites. In this work, an attempt was made to isolate Actinomycetes from marine sediments in terms of their ability to produce several novel bioactive compounds. A total of 16 different Actinomycete colonies were obtained from marine sediment samples. Among the 16 Actinomycete isolates, 2 isolates demonstrated in vitro antibacterial activity against Aeromonas hydrophila and Vibrio parahemolyticus. However, among them, only one isolate was found to have potent antibacterial activity, and hence, was taken for further analysis. This isolate was designated as Beijerinickia fluminensis VIT01. The bioactive components obtained were extracted and later subjected to Fourier transform infrared spectroscopy (FTIR) and gas chromatography–mass spectroscopy (GC-MS) analyses for identification. Several novel bioactive compounds were reported from the data obtained and were found to have potent antibacterial activity. Hence, they could be used as an alternative to antibiotics for treating several fish pathogens in the aquaculture industry. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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20 pages, 2017 KiB  
Article
In Vitro Antibacterial Activity of Green Synthesized Silver Nanoparticles Using Mangifera indica Aqueous Leaf Extract against Multidrug-Resistant Pathogens
by Yahya S. Alqahtani, Amal Bahafi, Kiran K. Mirajkar, Rakshith Rudrapura Basavaraju, Susweta Mitra, Shailaja S, Sunil S. More, Uday M. Muddapur, Aejaz Abdullatif Khan, P. Renuka Sudarshan and Ibrahim Ahmed Shaikh
Antibiotics 2022, 11(11), 1503; https://doi.org/10.3390/antibiotics11111503 - 28 Oct 2022
Cited by 5 | Viewed by 2078
Abstract
An estimated 35% of the world’s population depends on wheat as their primary crop. One fifth of the world’s wheat is utilized as animal feed, while more than two thirds are used for human consumption. Each year, 17–18% of the world’s wheat is [...] Read more.
An estimated 35% of the world’s population depends on wheat as their primary crop. One fifth of the world’s wheat is utilized as animal feed, while more than two thirds are used for human consumption. Each year, 17–18% of the world’s wheat is consumed by China and India. In wheat, spot blotch caused by Bipolaris sorokiniana is one of the major diseases which affects the wheat crop growth and yield in warmer and humid regions of the world. The present work was conducted to evaluate the effect of green synthesized silver nanoparticles on the biochemical constituents of wheat crops infected with spot blotch disease. Silver nanoparticles (AgNPs) were synthesized using Mangifera indica leaf extract and their characterization was performed using UV-visible spectroscopy, SEM, XRD, and PSA. Characterization techniques confirm the presence of crystalline, spherical silver nanoparticles with an average size of 52 nm. The effect of green synthesized nanoparticles on antioxidative enzymes, e.g., Superoxide dismutase (SOD), Catalase (CAT), Glutathione Reductase (GR), Peroxidase (POX), and phytochemical precursor enzyme Phenylalanine Ammonia-Lyase (PAL), and on primary and secondary metabolites, e.g., reducing sugar and total phenol, in Bipolaris sorokiniana infected wheat crop were studied. Inoculation of fungal spores was conducted after 40 days of sowing. Subsequently, diseased plants were treated with silver nanoparticles at different concentrations. Elevation in all biochemical constituents was recorded under silver nanoparticle application. The treatment with a concentration of nanoparticles at 50 pp min diseased plants showed the highest resistance towards the pathogen. The efficacy of the green synthesized AgNPs as antibacterial agents was evaluated against multi drug resistant (MDR) bacteria comprising Gram-negative bacteria Escherichia coli (n = 6) and Klebsiella pneumoniae (n = 7) and Gram-positive bacteria Methicillin resistant Staphylococcus aureus (n = 2). The results show promising antibacterial activity with significant inhibition zones observed with the disc diffusion method, thus indicating green synthesized M. indica AgNPs as an active antibacterial agent against MDR pathogens. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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10 pages, 1359 KiB  
Article
Potentiation of Antibiotic Action and Efflux Pump Inhibitory Effect on Staphylococcus aureus Strains by Solasodine
by Ana Raquel Pereira da Silva, Maria do Socorro Costa, Nara Juliana Santos Araújo, Thiago Sampaio de Freitas, Ray Silva de Almeida, José Maria Barbosa Filho, Josean Fechine Tavares, Erlânio Oliveira de Souza, Pablo Antonio Maia de Farias, Jacqueline Cosmo Andrade Pinheiro and Henrique Douglas Melo Coutinho
Antibiotics 2022, 11(10), 1309; https://doi.org/10.3390/antibiotics11101309 - 27 Sep 2022
Cited by 1 | Viewed by 1559
Abstract
A worrisome fact is the increase in microbial resistance, which has as its main cause the indiscriminate use of antibiotics. Scientific studies have investigated bioactive compounds such as steroidal sapogenins, in the perspective of new beneficial alternatives for the control of bacterial resistance. [...] Read more.
A worrisome fact is the increase in microbial resistance, which has as its main cause the indiscriminate use of antibiotics. Scientific studies have investigated bioactive compounds such as steroidal sapogenins, in the perspective of new beneficial alternatives for the control of bacterial resistance. Therefore, the objective of this work was to verify the antibacterial activity as well as the modifying action of antibiotics associated with solasodine and its ability to inhibit the efflux pump mechanism in strains of Staphylococcus aureus. Tests were performed to verify the minimum inhibitory concentration (MIC). In addition, the action-modifying potential of antibiotics and the inhibitory capacity of the efflux pump NorA and MepA through synergistic effects on the antibiotic and ethidium bromide were evaluated. Solasodine showed significant results for the standard bacteria with an MIC of 512 μg/mL, and when associated with the antibiotics gentamicin and nofloxacin for the multidrug-resistant bacteria S. aureus 10, Escherichia coli 06, and Pseudomonas aeruginosa 24, it showed a 50% reduction in MIC. The association of solasodine with the antibiotic ciprofloxacin against S. aureus K2068 (MepA) showed synergism, with a reduction in the MIC of the antibiotic from 64 μg/mL to 40 μg/mL, and also a reduction in the MIC when the antibiotic was used in conjunction with the efflux pump inhibitors. Solasodine may be acting on the mechanism of action of the antibiotic, as it has shown a potentiating effect when associated with antibiotics, inducing a reduction in the MIC against Gram-positive and Gram-negative bacteria. Therefore, this study demonstrated significant results for the potentiating action of solasodine when associated with antibiotics of clinical importance. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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15 pages, 1707 KiB  
Article
In Vitro Biological Activity of Natural Products from the Endophytic Fungus Paraboeremia selaginellae against Toxoplasma gondii
by Flaminia Mazzone, Viktor E. Simons, Lasse van Geelen, Marian Frank, Attila Mándi, Tibor Kurtán, Klaus Pfeffer and Rainer Kalscheuer
Antibiotics 2022, 11(9), 1176; https://doi.org/10.3390/antibiotics11091176 - 31 Aug 2022
Cited by 2 | Viewed by 2468
Abstract
Toxoplasma gondii is an apicomplexan pathogen able to infect a wide range of warm-blooded animals, including humans, leading to toxoplasmosis. Current treatments for toxoplasmosis are associated with severe side-effects and a lack efficacy to eradicate chronic infection. Thus, there is an urgent need [...] Read more.
Toxoplasma gondii is an apicomplexan pathogen able to infect a wide range of warm-blooded animals, including humans, leading to toxoplasmosis. Current treatments for toxoplasmosis are associated with severe side-effects and a lack efficacy to eradicate chronic infection. Thus, there is an urgent need for developing novel, highly efficient agents against toxoplasmosis with low toxicity. For decades, natural products have been a useful source of novel bioactive compounds for the treatment of infectious pathogens. In the present study, we isolated eight natural products from the crude extract of the endophytic fungus Paraboeremia selaginellae obtained from the leaves of the plant Philodendron monstera. The natural products were tested for inhibiting Toxoplasma gondii proliferation, and their cytotoxicity was evaluated in different human cell lines. Six natural products showed antitoxoplasma activity with low or no cytotoxicity in human cell lines. Together, these findings indicate that biphenyl ethers, bioxanthracenes, and 5S,6S-phomalactone from P. selaginellae are potential candidates for novel anti-toxoplasma drugs. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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12 pages, 1827 KiB  
Article
The Array of Antibacterial Action of Protocatechuic Acid Ethyl Ester and Erythromycin on Staphylococcal Strains
by Maria Miklasińska-Majdanik, Małgorzata Kępa, Monika Kulczak, Maciej Ochwat and Tomasz J. Wąsik
Antibiotics 2022, 11(7), 848; https://doi.org/10.3390/antibiotics11070848 - 24 Jun 2022
Cited by 5 | Viewed by 1799
Abstract
The spread of antibiotic resistance among bacteria has become one of the major health problems worldwide. Methicillin-resistant staphylococcal strains are especially dangerous because they are often resistant to other antibiotics. The increasing insensitivity to macrolides, lincosamides and streptogramin B antibiotics of methicillin-resistant staphylococcal [...] Read more.
The spread of antibiotic resistance among bacteria has become one of the major health problems worldwide. Methicillin-resistant staphylococcal strains are especially dangerous because they are often resistant to other antibiotics. The increasing insensitivity to macrolides, lincosamides and streptogramin B antibiotics of methicillin-resistant staphylococcal isolates has limited the use of these drugs in therapy. The combination of natural compounds and antibiotics can be considered as an alternative tool to fight multi-drug-resistant pathogen infections. The aim of the presented study was to examine the antibacterial activity of protocatechuic acid ethyl ester–erythromycin combination towards Staphylococcus aureus and Staphylococcus epidermidis strains with various resistance profiles to methicillin and macrolides, lincosamides and streptogramin B (MLSB) antibiotics. The in-vitro antibacterial potential of the above combination was investigated by minimum inhibitory concentration assays and checkerboard testing. The observed effects were strain dependent, with 8 of 12 tested staphylococcal strains showing an indifferent effect on the natural compound and erythromycin; for 2 strains, the tested combination had an additive effect, while for another 2, the effect was synergistic. Interestingly, the multi-drug-resistant strains were more sensitive to the cooperative action of the protocatechuic acid ethyl ester and the antibiotic. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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20 pages, 2886 KiB  
Article
Ethyl Acetate Fraction of Bixa orellana and Its Component Ellagic Acid Exert Antibacterial and Anti-Inflammatory Properties against Mycobacterium abscessus subsp. massiliense
by Roberval Nascimento Moraes-Neto, Gabrielle Guedes Coutinho, Ana Caroline Santos Ataíde, Aline de Oliveira Rezende, Camila Evangelista Carnib Nascimento, Rafaela Pontes de Albuquerque, Cláudia Quintino da Rocha, Adriana Sousa Rêgo, Maria do Socorro de Sousa Cartágenes, Ana Lúcia Abreu-Silva, Igor Victor Ferreira dos Santos, Cleydson Breno Rodrigues dos Santos, Rosane Nassar Meireles Guerra, Rachel Melo Ribeiro, Valério Monteiro-Neto, Eduardo Martins de Sousa and Rafael Cardoso Carvalho
Antibiotics 2022, 11(6), 817; https://doi.org/10.3390/antibiotics11060817 - 17 Jun 2022
Cited by 5 | Viewed by 2484
Abstract
Mycobacterium abscessus subsp. massiliense (Mabs) causes chronic infections, which has led to the need for new antimycobacterial agents. In this study, we investigated the antimycobacterial and anti-inflammatory activities of the ethyl acetate fraction of Bixa orellana leaves (BoEA) and ellagic acid [...] Read more.
Mycobacterium abscessus subsp. massiliense (Mabs) causes chronic infections, which has led to the need for new antimycobacterial agents. In this study, we investigated the antimycobacterial and anti-inflammatory activities of the ethyl acetate fraction of Bixa orellana leaves (BoEA) and ellagic acid (ElAc). In silico analysis predicted that ElAc had low toxicity, was not mutagenic or carcinogenic, and had antimicrobial and anti-inflammatory activities. Apparently, ElAc can interact with COX2 and Dihydrofolate reductase (DHFR) enzymes, which could explain both activities. In vitro analysis showed that BoEA and ElAc exerted antimicrobial activity against Mabs (minimum inhibitory concentration of 1.56, 1.56 mg/mL and bactericidal concentration of 6.25, 3.12 mg/mL, respectively. Clarithromycin showed MIC and MBC of 1 and 6 µg/mL). Treatment with BoEA or ElAc increased survival of Tenebrio molitor larvae after lethal infection with Mabs and reduced carrageenan-induced paw edema in mice, around 40% of edema volume after the fourth hour, similarly to diclofenac. In conclusion, BoEA and ElAc exert antimicrobial effects against Mabs and have anti-inflammatory effects, making them potential sources of antimycobacterial drugs. The biological activities of ElAc may be due to its high binding affinities predicted for COX2 and DHFR enzymes. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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14 pages, 3041 KiB  
Article
Cinnamaldehyde Increases the Survival of Mice Submitted to Sepsis Induced by Extraintestinal Pathogenic Escherichia coli
by Isabella F. S. Figueiredo, Lorena G. Araújo, Raissa G. Assunção, Itaynara L. Dutra, Johnny R. Nascimento, Fabrícia S. Rego, Carolina S. Rolim, Leylane S. R. Alves, Mariana A. Frazão, Samilly F. Cadete, Luís Cláudio N. da Silva, Joicy C. de Sá, Eduardo M. de Sousa, Waldir P. Elias, Flávia R. F. Nascimento and Afonso G. Abreu
Antibiotics 2022, 11(3), 364; https://doi.org/10.3390/antibiotics11030364 - 9 Mar 2022
Cited by 8 | Viewed by 2264
Abstract
Several natural products have been investigated for their bactericidal potential, among these, cinnamaldehyde. In this study, we aimed to evaluate the activity of cinnamaldehyde in the treatment of animals with sepsis induced by extraintestinal pathogenic E. coli. Initially, the E. coli F5 [...] Read more.
Several natural products have been investigated for their bactericidal potential, among these, cinnamaldehyde. In this study, we aimed to evaluate the activity of cinnamaldehyde in the treatment of animals with sepsis induced by extraintestinal pathogenic E. coli. Initially, the E. coli F5 was incubated with cinnamaldehyde to evaluate the minimum inhibitory and minimum bactericidal concentration. Animal survival was monitored for five days, and a subset of mice were euthanized after 10 h to evaluate histological, hematological, and immunological parameters, as well as the presence of bacteria in the organs. On the one hand, inoculation of bacterium caused the death of 100% of the animals within 24 h after infection. On the other hand, cinnamaldehyde (60 mg/kg) was able to keep 40% of mice alive after infection. The treatment significantly reduced the levels of cytokines in serum and peritoneum and increased the production of cells in both bone marrow and spleen, as well as lymphocytes at the infection site. Cinnamaldehyde was able to reduce tissue damage by decreasing the deleterious effects for the organism and contributed to the control of the sepsis and survival of animals; therefore, it is a promising candidate for the development of new drugs. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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17 pages, 2780 KiB  
Article
Ethyl Acetate Fraction of Punica granatum and Its Galloyl-HHDP-Glucose Compound, Alone or in Combination with Fluconazole, Have Antifungal and Antivirulence Properties against Candida spp.
by Aline Michelle Silva Mendonça, Cristina de Andrade Monteiro, Roberval Nascimento Moraes-Neto, Andrea Souza Monteiro, Renata Mondego-Oliveira, Camila Evangelista Carnib Nascimento, Luís Cláudio Nascimento da Silva, Lidio Gonçalves Lima-Neto, Rafael Cardoso Carvalho and Eduardo Martins de Sousa
Antibiotics 2022, 11(2), 265; https://doi.org/10.3390/antibiotics11020265 - 18 Feb 2022
Cited by 6 | Viewed by 2450
Abstract
Candidiasis is the most common fungal infection among immunocompromised patients. Its treatment includes the use of antifungals, which poses limitations such as toxicity and fungal resistance. Plant-derived extracts, such as Punica granatum, have been reported to have antimicrobial activity, but their antifungal [...] Read more.
Candidiasis is the most common fungal infection among immunocompromised patients. Its treatment includes the use of antifungals, which poses limitations such as toxicity and fungal resistance. Plant-derived extracts, such as Punica granatum, have been reported to have antimicrobial activity, but their antifungal effects are still unknown. We aimed to evaluate the antifungal and antiviral potential of the ethyl acetate fraction of P. granatum (PgEA) and its isolated compound galloyl-hexahydroxydiphenoyl-glucose (G-HHDP-G) against Candida spp. In silico analyses predicted the biological activity of G-HHDP-G. The minimum inhibitory concentrations (MIC) of PgEA and G-HHDP-G, and their effects on biofilm formation, preformed biofilms, and phospholipase production were determined. In silico analysis showed that G-HHDP-G has antifungal and hepatoprotective effects. An in vitro assay confirmed the antifungal effects of PgEA and G-HHDP-G, with MIC in the ranges of 31.25–250 μg/mL and 31.25 ≥ 500 μg/mL, respectively. G-HHDP-G and PgEA synergistically worked with fluconazole against planktonic cells. The substances showed antibiofilm action, alone or in combination with fluconazole, and interfered with phospholipase production. The antifungal and antibiofilm actions of PgEA and G-HHDP-G, alone or in combination with fluconazole, in addition to their effects on reducing Candida phospholipase production, identify them as promising candidates for therapeutics. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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Review

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19 pages, 670 KiB  
Review
An Assessment of the In Vitro Models and Clinical Trials Related to the Antimicrobial Activities of Phytochemicals
by Jonathan Kopel, Julianna McDonald and Abdul Hamood
Antibiotics 2022, 11(12), 1838; https://doi.org/10.3390/antibiotics11121838 - 17 Dec 2022
Cited by 8 | Viewed by 2205
Abstract
An increased number antibiotic-resistant bacteria have emerged with the rise in antibiotic use worldwide. As such, there has been a growing interest in investigating novel antibiotics against antibiotic-resistant bacteria. Due to the extensive history of using plants for medicinal purposes, scientists and medical [...] Read more.
An increased number antibiotic-resistant bacteria have emerged with the rise in antibiotic use worldwide. As such, there has been a growing interest in investigating novel antibiotics against antibiotic-resistant bacteria. Due to the extensive history of using plants for medicinal purposes, scientists and medical professionals have turned to plants as potential alternatives to common antibiotic treatments. Unlike other antibiotics in use, plant-based antibiotics have the innate ability to eliminate a broad spectrum of microorganisms through phytochemical defenses, including compounds such as alkaloids, organosulfur compounds, phenols, coumarins, and terpenes. In recent years, these antimicrobial compounds have been refined through extraction methods and tested against antibiotic-resistant strains of Gram-negative and Gram-positive bacteria. The results of the experiments demonstrated that plant extracts successfully inhibited bacteria independently or in combination with other antimicrobial products. In this review, we examine the use of plant-based antibiotics for their utilization against antibiotic-resistant bacterial infections. In addition, we examine recent clinical trials utilizing phytochemicals for the treatment of several microbial infections. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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18 pages, 385 KiB  
Review
Surface-Active Compounds Produced by Microorganisms: Promising Molecules for the Development of Antimicrobial, Anti-Inflammatory, and Healing Agents
by Jéssica Araujo, Joveliane Monteiro, Douglas Silva, Amanda Alencar, Kariny Silva, Lara Coelho, Wallace Pacheco, Darlan Silva, Maria Silva, Luís Silva and Andrea Monteiro
Antibiotics 2022, 11(8), 1106; https://doi.org/10.3390/antibiotics11081106 - 16 Aug 2022
Cited by 12 | Viewed by 2211
Abstract
Surface-active compounds (SACs), biomolecules produced by bacteria, yeasts, and filamentous fungi, have interesting properties, such as the ability to interact with surfaces as well as hydrophobic or hydrophilic interfaces. Because of their advantages over other compounds, such as biodegradability, low toxicity, antimicrobial, and [...] Read more.
Surface-active compounds (SACs), biomolecules produced by bacteria, yeasts, and filamentous fungi, have interesting properties, such as the ability to interact with surfaces as well as hydrophobic or hydrophilic interfaces. Because of their advantages over other compounds, such as biodegradability, low toxicity, antimicrobial, and healing properties, SACs are attractive targets for research in various applications in medicine. As a result, a growing number of properties related to SAC production have been the subject of scientific research during the past decade, searching for potential future applications in biomedical, pharmaceutical, and therapeutic fields. This review aims to provide a comprehensive understanding of the potential of biosurfactants and emulsifiers as antimicrobials, modulators of virulence factors, anticancer agents, and wound healing agents in the field of biotechnology and biomedicine, to meet the increasing demand for safer medical and pharmacological therapies. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
37 pages, 3288 KiB  
Review
Marine Actinobacteria a New Source of Antibacterial Metabolites to Treat Acne Vulgaris Disease—A Systematic Literature Review
by Maria Clara De La Hoz-Romo, Luis Díaz and Luisa Villamil
Antibiotics 2022, 11(7), 965; https://doi.org/10.3390/antibiotics11070965 - 18 Jul 2022
Cited by 9 | Viewed by 3986
Abstract
Acne vulgaris is a multifactorial disease that remains under-explored; up to date it is known that the bacterium Cutibacterium acnes is involved in the disease occurrence, also associated with a microbial dysbiosis. Antibiotics have become a mainstay treatment generating the emergence of antibiotic-resistant [...] Read more.
Acne vulgaris is a multifactorial disease that remains under-explored; up to date it is known that the bacterium Cutibacterium acnes is involved in the disease occurrence, also associated with a microbial dysbiosis. Antibiotics have become a mainstay treatment generating the emergence of antibiotic-resistant bacteria. In addition, there are some reported side effects of alternative treatments, which indicate the need to investigate a different therapeutic approach. Natural products continue to be an excellent option, especially those extracted from actinobacteria, which represent a prominent source of metabolites with a wide range of biological activities, particularly the marine actinobacteria, which have been less studied than their terrestrial counterparts. Therefore, this systematic review aimed to identify and evaluate the potential anti-infective activity of metabolites isolated from marine actinobacteria strains against bacteria related to the development of acne vulgaris disease. It was found that there is a variety of compounds with anti-infective activity against Staphylococcus aureus and Staphylococcus epidermidis, bacteria closely related to acne vulgaris development; nevertheless, there is no report of a compound with antibacterial activity or quorum-sensing inhibition toward C. acnes, which is a surprising result. Since two of the most widely used antibiotics for the treatment of acne targeting C. acnes were obtained from actinobacteria of the genus Streptomyces, this demonstrates a great opportunity to pursue further studies in this field, considering the potential of marine actinobacteria to produce new anti-infective compounds. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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Other

6 pages, 470 KiB  
Brief Report
Bactericidal Activity of Sodium Bituminosulfonate against Staphylococcus aureus
by Elisa Heuser, Karsten Becker and Evgeny A. Idelevich
Antibiotics 2022, 11(7), 896; https://doi.org/10.3390/antibiotics11070896 - 5 Jul 2022
Cited by 4 | Viewed by 2073
Abstract
Antibiotic resistance is increasing worldwide making it necessary to search for alternative antimicrobials. Sodium bituminosulfonate is a long-known substance, whose antimicrobial inhibitory activity has recently been re-evaluated. However, to the best of our knowledge, the bactericidal mode of action of this substance has [...] Read more.
Antibiotic resistance is increasing worldwide making it necessary to search for alternative antimicrobials. Sodium bituminosulfonate is a long-known substance, whose antimicrobial inhibitory activity has recently been re-evaluated. However, to the best of our knowledge, the bactericidal mode of action of this substance has not been systematically characterized. The aim of this study was to investigate the in vitro bactericidal activity of sodium bituminosulfonate by determining the minimal bactericidal concentrations (MBC), as well as the rapidity of bactericidal effect by time-kill curves. Clinical isolates of methicillin-susceptible (MSSA, n = 20) and methicillin-resistant (mecA/mecC-MRSA, n = 20) Staphylococcus aureus were used to determine MBC by a broth microdilution method. Sodium bituminosulfonate (Ichthyol® light) was tested in double-dilution concentration steps ranging from 0.03 g/L to 256 g/L. For time-kill analysis, two reference and two clinical S. aureus strains were tested with different concentrations of sodium bituminosulfonate (1× minimal inhibitory concentration (MIC), 2× MIC, 4× MIC, 16× MIC and 256× MIC). For MSSA isolates, MBC50, MBC90 and the MBC range were 0.5 g/L, 1.0 g/L and 0.125–1.0 g/L; (MBC/MIC ratio)50, (MBC/MIC ratio)90 and the range of the MBC/MIC ratio were 4, 4 and 1–8, respectively. Among MRSA isolates, MBC50, MBC90 and the MBC range amounted to 0.5 g/L, 1.0 g/L and 0.06–1.0 g/L; (MBC/MIC ratio)50, (MBC/MIC ratio)90 and the range of the MBC/MIC ratio were 2, 4 and 1–8, respectively. Time-kill kinetics revealed a bactericidal effect after 30 min for sodium bituminosulfonate concentrations of 16× MIC and 256× MIC. The bactericidal activity against MSSA and MRSA was demonstrated for sodium bituminosulfonate. The killing was very rapid with the initial population reduced by 99.9% after only short incubation with concentrations of 16× MIC and higher. Full article
(This article belongs to the Special Issue Antimicrobial and Anti-infective Activity of Natural Products)
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