Determination Method of Antimicrobial Activity of Plant Substances, Extracts and Essential Oils

A special issue of Antibiotics (ISSN 2079-6382). This special issue belongs to the section "Plant-Derived Antibiotics".

Deadline for manuscript submissions: closed (31 January 2024) | Viewed by 9190

Special Issue Editors


E-Mail Website
Guest Editor
Department of Biological Chemistry, Laboratory of Microbiology and Molecular Biology, Program of Post-Graduation in Molecular Bioprospection, Regional University of Cariri, Crato 63105-000, Brazil
Interests: mechanisms of bacterial resistance; substances with antibacterial potential

E-Mail Website
Guest Editor
Graduate Program in Health Sciences, Universidade Federal do Cariri—UFCA, Barbalha 63180-000, Brazil
Interests: bacterial biofilms; substances with antibacterial potential

E-Mail Website
Guest Editor
Department of Biological Chemistry, Laboratory of Microbiology and Molecular Biology, Program of Post-Graduation in Molecular Bioprospection, Regional University of Cariri, Crato 63105-000, Brazil
Interests: mechanisms of bacterial resistance; substances with antibacterial potential

E-Mail Website
Guest Editor
Department of Pathology and Legal Medicine, Federal University of Ceará, Fortaleza, Brazil
Interests: fungal and bacterial pathogens; bacterial and fungal resistance mechanisms and virulence

Special Issue Information

Dear Colleagues,

The evaluation of the antibacterial activity of substances with antimicrobial potential is carried out through several well-known in vitro or vivo assays. In recent years, new alternatives have been proposed to assess the antimicrobial potential of a substance. Many of the new alternatives improve on existing methods, and others use completely new approaches. In this sense, this Special Issue seeks studies that show new methods of evaluating antimicrobial activity, with a focus on products and substances of natural origin. In addition, associated studies of existing antibiotics with new substances of natural origin are also sought. Approaches used the following methods: potentiation methods of antibiotics and antifungals; methods of gaseous contact with essential oils and volatile compounds; methods of inhibition of resistance mechanisms; methods of inhibition of biofilms by products of natural origin; synergistic testing methods with drugs and substances of natural origin; inhibition of pathogenic fungal dimorphism; methods of antibacterial activity by photodynamics.

Dr. Saulo Relison Tintino
Dr. Jacqueline Cosmo Andrade Pinheiro
Dr. Cícera Datiane Morais Oliveira-Tintino
Dr. Glaucia Morgana de Melo Guedes
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Antibiotics is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • antimicrobial
  • methods of inhibition
  • natural products
  • antibiotics

Published Papers (6 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

12 pages, 684 KiB  
Article
Antibacterial Effect of Eight Essential Oils against Bacteria Implicated in Bovine Mastitis and Characterization of Primary Action Mode of Thymus capitatus Essential Oil
by Chedia Aouadhi, Ahlem Jouini, Karima Maaroufi and Abderrazak Maaroufi
Antibiotics 2024, 13(3), 237; https://doi.org/10.3390/antibiotics13030237 - 05 Mar 2024
Viewed by 1015
Abstract
During the current investigation, eight essential oils (EOs) were tested for their antimicrobial activity against six species, belonging to the genus of staphylococcus, multi-resistant to antibiotics (S. epidermidis, S. cohni, S. wareneri, S. scuiri, S. chromogenes, [...] Read more.
During the current investigation, eight essential oils (EOs) were tested for their antimicrobial activity against six species, belonging to the genus of staphylococcus, multi-resistant to antibiotics (S. epidermidis, S. cohni, S. wareneri, S. scuiri, S. chromogenes, S. pasteuri), three methicillin-resistant Staphylococcus aureus strains (MRSA) and two strains of Escherichia coli, producing extended-spectrum β-lactamase (ESBL) responsible for bovine mastitis. Our results indicated that the antimicrobial activities of eight EOs varied significantly among the types of EOs and bacterial species. Thymus capitatus and Trachyspermum ammi EOs display important antibacterial activity against all tested strains, with the inhibition zone diameters situated between 20 and 45 mm, while EOs of Artemisia absinthium, Eucalyptus globulus, Eucalyptus camaldulensis, Myrtus communis and Mentha pulegium exerted an intermediate activity. For Cymbopogon citratus, this effect depends on bacteria species. In fact, an important effect was observed against S. warneri, S. epidermidis, S. cohenii, S. pasteuri and MRSA (EC 39+) strains. In addition, the important lytic effect was observed against MRSA strains, showing that Gram-positive bacteria were more sensitive to T. capitatus EO than Gram-negative ones. Concerning the characterization of the mode action of T. capitatus, experiments of kill-time, bacteriolytic, loss of salt tolerance and loss of cytoplasmic material showed that the used EO was able to destroy cell walls and membranes followed by the loss of vital intracellular materials. In addition, it inhibits the normal synthesis of DNA, causing the bacterial death of E. coli and MRSA strains. This study shows the potential of using of EOs, particularly T. capitaus, to inhibit the growth of Gram-positive and Gram-negative bacteria multi-resistant to antibiotics causing bovine mastitis. Full article
Show Figures

Figure 1

17 pages, 2787 KiB  
Article
Study of the Antibacterial Activity of Rich Polyphenolic Extracts Obtained from Cytisus scoparius against Foodborne Pathogens
by Lorena G. Calvo, Aly Castillo, Rosa-Antía Villarino, José Luis R. Rama, Ana G. Abril and Trinidad de Miguel
Antibiotics 2023, 12(11), 1645; https://doi.org/10.3390/antibiotics12111645 - 20 Nov 2023
Cited by 1 | Viewed by 1296
Abstract
Natural extracts containing high polyphenolic concentrations may act as good antimicrobials for their antibacterial and antibiofilm activity. The present research characterizes two hydro-organic extracts with high polyphenolic content, obtained from the shrub Cytisus scoparius as antipathogenic candidates. As a result of their own [...] Read more.
Natural extracts containing high polyphenolic concentrations may act as good antimicrobials for their antibacterial and antibiofilm activity. The present research characterizes two hydro-organic extracts with high polyphenolic content, obtained from the shrub Cytisus scoparius as antipathogenic candidates. As a result of their own composition, both extracts, LE050 and PG050, have shown pronounced bioactivities with potential uses, especially in agricultural, livestock production, food manufacturing, and pharmaceutical industries. Polyphenolic compounds were extracted by using adjusted hydro-organic solvent mixtures. These extracts’ in vitro antimicrobial activity was evaluated on Gram-positive and Gram-negative pathogenic bacteria, giving special attention to those involved in food contamination. Due to this, the biofilm dispersion was assessed on Listeria monocytogenes, Staphylococcus aureus and Pseudomonas aeruginosa. The extracts showed antimicrobial activity against the pathogenic species tested, presenting IC50 values between 0.625–20% v/v. Different behaviors have been detected between both extracts, probably linked to their distinct polyphenol composition, being LE050 extract the one with most promising bioactive applications. Finally, the results from the biofilm dispersion assays reveal that the extracts exhibit a good antibiofilm activity against the pathogenic bacteria tested. Full article
Show Figures

Figure 1

15 pages, 1092 KiB  
Article
Terminalia petiolaris A.Cunn ex Benth. Extracts Have Antibacterial Activity and Potentiate Conventional Antibiotics against β-Lactam-Drug-Resistant Bacteria
by Muhammad Jawad Zai, Matthew James Cheesman and Ian Edwin Cock
Antibiotics 2023, 12(11), 1643; https://doi.org/10.3390/antibiotics12111643 - 20 Nov 2023
Cited by 2 | Viewed by 977
Abstract
Terminalia petiolaris A. Cunn. Ex Benth. (genus: Terminalia, family: Combretaceae) is native to Australia. Terminalia spp. have traditionally been used to treat various ailments, including bacterial infections. Solvents of varying polarity were used to extract compounds from leaves of this species, and [...] Read more.
Terminalia petiolaris A. Cunn. Ex Benth. (genus: Terminalia, family: Combretaceae) is native to Australia. Terminalia spp. have traditionally been used to treat various ailments, including bacterial infections. Solvents of varying polarity were used to extract compounds from leaves of this species, and the extracts were tested against a panel of bacteria, including antibiotic-resistant strains. The methanolic and water extracts showed substantial inhibitory activity against several bacteria, including antibiotic-resistant strains in both disc diffusion and liquid dilution assays. Combining these extracts with selected conventional antibiotics enhanced the inhibition of bacterial growth for some combinations, while others showed no significant interaction. In total, two synergistic, twenty-five additive, twenty-three non-interactive and one antagonistic interaction were observed. The methanolic and ethyl acetate plant extracts were found to be non-toxic in Artemia franciscana nauplii toxicity assays. A liquid chromatography–mass spectrometry metabolomics analysis identified several flavonoid compounds, including miquelianin, trifolin and orientin, which might contribute to the observed activities. The potential modes of these active extracts are further discussed in this study. Full article
Show Figures

Figure 1

14 pages, 2349 KiB  
Article
Enhancing the Antifungal Efficacy of Fluconazole with a Diterpene: Abietic Acid as a Promising Adjuvant to Combat Antifungal Resistance in Candida spp.
by Maria Gabriely de Lima Silva, Luciene Ferreira de Lima, Victor Juno Alencar Fonseca, Lucas Yure Santos da Silva, Ana Cecília Calixto Donelardy, Ray Silva de Almeida, Cícera Datiane de Morais Oliveira-Tintino, Anita Oliveira Brito Pereira Bezerra Martins, Jaime Ribeiro-Filho, Maria Flaviana Bezerra Morais-Braga, Saulo Relison Tintino and Irwin Rose Alencar de Menezes
Antibiotics 2023, 12(11), 1565; https://doi.org/10.3390/antibiotics12111565 - 26 Oct 2023
Cited by 1 | Viewed by 1181
Abstract
The increasing antifungal resistance rates against conventional drugs reveal the urgent need to search for new therapeutic alternatives. In this context, natural bioactive compounds have a critical role in antifungal drug development. Since evidence demonstrates that abietic acid, a diterpene found in Pinus [...] Read more.
The increasing antifungal resistance rates against conventional drugs reveal the urgent need to search for new therapeutic alternatives. In this context, natural bioactive compounds have a critical role in antifungal drug development. Since evidence demonstrates that abietic acid, a diterpene found in Pinus species, has significant antimicrobial properties, this study aimed to evaluate the antifungal activity of abietic acid against Candida spp and its ability to potentiate the activity of fluconazole. Abietic acid was tested both individually and in combination with fluconazole against Candida albicans (CA INCQS 40006), Candida krusei (CK INCQS 40095), and Candida tropicalis (CT INCQS 40042). The microdilution method was used to determine the IC50 and the cell viability curve. Minimum Fungicidal Concentration (MFC) was determined by subculture in a solid medium. The plasma membrane permeability was measured using a fluorescent SYTOX Green probe. While the IC50 of the drugs alone ranged between 1065 and 3255 μg/mL, the IC50 resulting from the combination of abietic acid and fluconazole ranged between 7563 and 160.1 μg/mL. Whether used in combination with fluconazole or isolated, abietic acid exhibited Minimum Fungicidal Concentration (MFC) values exceeding 1024 μg/mL against Candida albicans, Candida krusei and Candida tropicalis. However, it was observed that the antifungal effect of fluconazole was enhanced when used in combination with abietic acid against Candida albicans and Candida tropicalis. These findings suggest that while abietic acid alone has limited inherent antifungal activity, it can enhance the effectiveness of fluconazole, thereby reducing antifungal resistance. Full article
Show Figures

Figure 1

13 pages, 1335 KiB  
Article
Antioxidant, Anti-Tyrosinase, and Anti-Skin Pathogenic Bacterial Activities and Phytochemical Compositions of Corn Silk Extracts, and Stability of Corn Silk Facial Cream Product
by Raenu Yucharoen, Pawalee Srisuksomwong, Jakaphun Julsrigival, Lapatrada Mungmai, Thida Kaewkod and Yingmanee Tragoolpua
Antibiotics 2023, 12(9), 1443; https://doi.org/10.3390/antibiotics12091443 - 13 Sep 2023
Cited by 3 | Viewed by 1834
Abstract
Zea mays L. Poaceae stigma (corn silk, CS) is a byproduct of agricultural waste and is used as a traditional herb in many countries. CS is rich in chemical compounds known to benefit human health and is also a remedy for infectious diseases [...] Read more.
Zea mays L. Poaceae stigma (corn silk, CS) is a byproduct of agricultural waste and is used as a traditional herb in many countries. CS is rich in chemical compounds known to benefit human health and is also a remedy for infectious diseases and has anti-proliferative effects on human cancer cell lines. In the present study, CS extract has been evaluated for its antioxidant, antibacterial, and anti-tyrosinase activities and its phytochemical composition. The higher total phenolic and flavonoid contents were found in the ethanolic extract of corn silk (CSA), at 28.27 ± 0.86 mg gallic acid equivalent/g extract and 4.71 ± 0.79 mg quercetin equivalent/g extract, respectively. Moreover, the antioxidant content of CSA was found at 5.22 ± 0.87 and 13.20 ± 0.42 mg gallic acid equivalent/g extract using DPPH and reducing power assays. Furthermore, the ethanolic extract of corn silk showed tyrosinase inhibition with an IC50 value of 12.45 µg/mL. The bacterial growth inhibition of CSA was tested using agar disc diffusion and broth dilution assays against Cutibacterium acnes and Staphylococcus epidermidis. It was found that CSA inhibited C. acnes and S. epidermidis with an inhibition zone of 11.7 ± 1.2 and 9.3 ± 0.6 mm, respectively. Moreover, the CSA showed MIC/MBC of 15.625 mg/mL against C. acnes. The following phytochemical compounds were detected in CSA: cardiac glycosides; n-hexadecanoic acid; hexadecanoic acid, ethyl ester; oleic acid; and 9,12-octadecadienoic acid, ethyl ester. After the corn silk cream product was formulated, the product demonstrated stability without phase separation. This research is beneficial for promoting effective ways to use agricultural waste while utilizing the antioxidant, anti-tyrosinase, and antibacterial activities of corn silk. Moreover, the use of technology and innovation to obtain high-value CS extract will benefit the development of commercial cosmetic products by providing safe, natural, and quality ingredients to the consumer. Full article
Show Figures

Figure 1

13 pages, 1870 KiB  
Article
Inhibitory Activity of Essential Oils of Mentha spicata and Eucalyptus globulus on Biofilms of Streptococcus mutans in an In Vitro Model
by Guillermo Ernesto Landeo-Villanueva, María Elena Salazar-Salvatierra, Julio Reynaldo Ruiz-Quiroz, Noemi Zuta-Arriola, Benjamín Jarama-Soto, Oscar Herrera-Calderon, Josefa Bertha Pari-Olarte and Eddie Loyola-Gonzales
Antibiotics 2023, 12(2), 369; https://doi.org/10.3390/antibiotics12020369 - 10 Feb 2023
Cited by 5 | Viewed by 2231
Abstract
The aim of this study was to evaluate the inhibitory activity of the commercially available essential oils of Mentha spicata (spearmint) and Eucalyptus globulus (eucalyptus) on Streptococcus mutans ATCC 25175 biofilms in vitro, emulating dental plaque conditions. The composition of the essential oils [...] Read more.
The aim of this study was to evaluate the inhibitory activity of the commercially available essential oils of Mentha spicata (spearmint) and Eucalyptus globulus (eucalyptus) on Streptococcus mutans ATCC 25175 biofilms in vitro, emulating dental plaque conditions. The composition of the essential oils (EOs) was determined using gas chromatography coupled with mass spectrometry (GC-MS), with the main metabolites being Carvone (57.93%) and Limonene (12.91%) for Mentha spicata and 1,8-Cineole (Eucalyptol) (65.83%) for Eucalyptus globulus. The inhibitory activity was evaluated using the methods of agar-well diffusion and colorimetric microdilution. The inhibition halos were 18.3 ± 0.47 mm and 27.0 ± 0.82 mm, and the MICs were 1.8484 mg/mL and 1.9168 mg/mL for the EOs of Mentha spicata and Eucalyptus globulus, respectively. The activity against the biofilms was evaluated on a substrate of bovine enamel pieces using a basal mucin medium (BMM) in anaerobic conditions with daily sucrose exposition cycles in order to emulate oral cavity conditions. The EOs were applied in a concentration of 0.5% in a sterile saline vehicle with 1% polysorbate 20. After 72 h of cultivation, a significant reduction was observed (p < 0.001%) on the biofilm biomass, which was evaluated by its turbidity in suspension and using a count of the recoverable organisms with regards to the control. The effects of the Eos were not significantly distinct from each other. The EOs showed antimicrobial activity against both the Streptococcus mutans planktonic and biofilm cultures. Thus, EOs may have great potential for the development of pharmaceutical and sanitary products for oral health. Full article
Show Figures

Figure 1

Back to TopTop