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17 pages, 2501 KiB

Open AccessArticle

Phytochemical Analysis, Antimicrobial Screening and In Vitro Pharmacological Activity of Artemisia vestita Leaf Extract

by Shivani Dogra, Bhupendra Koul, Joginder Singh, Meerambika Mishra and Dhananjay Yadav

Molecules 2024, 29(8), 1829; https://doi.org/10.3390/molecules29081829 - 17 Apr 2024

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Abstract

Artemisia vestita Wall. Ex Besser is a folklore medicinal plant that belongs to Asteraceae family and a treasure trove of drugs. The aim of this research study was to investigate the phytoconstituents, antimicrobial activity, antioxidant, anti-inflammatory, cytotoxicity and wound healing potential of A. [...] Read more.

Artemisia vestita Wall. Ex Besser is a folklore medicinal plant that belongs to Asteraceae family and a treasure trove of drugs. The aim of this research study was to investigate the phytoconstituents, antimicrobial activity, antioxidant, anti-inflammatory, cytotoxicity and wound healing potential of A. vestita leaf extract (ALE). Phytochemical analysis of the ALE was carried out by Soxhlet extraction and GCMS (gas chromatography–mass spectrometry) analysis. Antimicrobial activity was performed by the agar well diffusion method against selected bacterial and fungal strains. Free radical scavenging potential was evaluated by DPPH (2,2-Diphenyl-1-picrylhydrazyl), ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and FRAP (Ferric reducing antioxidant power) assays. Anti-inflammatory activity was performed by enzyme inhibition assay–COXII. The cytotoxicity of ALE on HaCaT cells was studied via MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. An in vitro scratch assay was performed for the evaluation of the wound healing property of ALE. It showed satisfactory antimicrobial activity against Staphylococcus aureus (14.2 ± 0.28 mm), Escherichia coli (17.6 ± 0.52 mm), Bacillus subtilis (13.1 ± 0.37 mm), Streptococcus pyogenes (17.3 ± 0.64 mm), Proteus mirabilis (9.4 ± 0.56 mm), Aspergillus niger (12.7 ± 0.53 mm), Aspergilus flavus (15.3 ± 0.25 mm) and Candida albicans (17.6 ± 0.11 mm). In ALE, 36 phytochemicals were detected by GCMS analysis, but 22 were dominant. Moreover, the ALE was effective in scavenging free radicals with different assays and exhibited reasonable anti-inflammatory activity. The MTT assay revealed that ALE had a cytotoxic effect on the HaCaT cells. The scratch assay showed 94.6% wound closure (after 24 h incubation) compared to the positive control Cipladine, which is remarkable wound healing activity. This is the first report on the wound healing property of A. vestita, which can serve as a potential agent for wound healing and extends knowledge on its therapeutic potential. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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21 pages, 10860 KiB

Open AccessArticle

Discovery of Potential Anti-Microbial Molecules and Spectrum Correlation Effect of Ardisia crenata Sims via High-Performance Liquid Chromatography Fingerprints and Molecular Docking

by Chunli Zhao, Changbin Wang, Yongqiang Zhou, Tao Hu, Yan Zhang, Xiang Lv, Jiaxin Li and Ying Zhou

Molecules 2024, 29(5), 1178; https://doi.org/10.3390/molecules29051178 - 06 Mar 2024

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Abstract

Ardisia crenata Sims, an important ethnic medicine, is recorded in the Chinese Pharmacopoeia for treating laryngeal diseases and upper respiratory tract infections. This study aimed to evaluate the antimicrobial effect of extracts and potential antimicrobial compounds of A. crenata Sims. It was found [...] Read more.

Ardisia crenata Sims, an important ethnic medicine, is recorded in the Chinese Pharmacopoeia for treating laryngeal diseases and upper respiratory tract infections. This study aimed to evaluate the antimicrobial effect of extracts and potential antimicrobial compounds of A. crenata Sims. It was found that the roots of A. crenata Sims have a potential inhibitory effect on Candida albicans and Aspergillus flavus, with MICs of 1.56 mg/mL and 0.39 mg/mL, and the leaves of A. crenata Sims have a potential inhibitory effect on Pseudomonas aeruginosa and Staphylococcus aureus, with MICs of 3.12 mg/mL and 6.77 mg/mL, respectively. Meanwhile, five compounds including one catechin and four bergenins were obtained from roots. These components were identified on the fingerprint spectrum, representing chromatographic peaks 16, 21, 22, 23, and 25, respectively. Among these, 11-β-d-glucopyranosyl-bergenin and (−)-gallocatechin showed potential inhibition for Staphylococcus aureus and Pseudomonas aeruginosa with MIC of 0.26 and 0.33 mg/mL, respectively. The roots, stems, and leaves of A. crenata Sims are very similar in chemical composition, with large differences in content. Principal component analysis (PCA) and Hierarchical cluster analysis (HCA) showed that 16 batches of A. crenata Sims could be divided into four main production areas: Guizhou, Jiangsu, Guangxi, and Jiangxi. Furthermore, molecular docking results showed that 11-β-d-glucopyranosyl-bergenin had a better affinity for Casein lytic proteinase P (ClpP), and (−)-gallocatechin possessed a strong affinity for LasA hydrolysis protease and LasB elastase. These findings suggest catechin and bergenins from A. crenata Sims can be used as antimicrobial activity molecules. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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22 pages, 7412 KiB

Open AccessArticle

Evaluation of the Antimicrobial Activity of Geraniol and Selected Geraniol Transformation Products against Gram-Positive Bacteria

by Anna Fajdek-Bieda, Joanna Pawlińska, Agnieszka Wróblewska and Agnieszka Łuś

Molecules 2024, 29(5), 950; https://doi.org/10.3390/molecules29050950 - 21 Feb 2024

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Abstract

Both geraniol and the products of its transformation, thanks to their beneficial properties, find a variety of applications in cosmetics. Due to their antioxidant and moisturizing properties, these compounds can be added to skin care products such as face creams, lotions, oils, and [...] Read more.

Both geraniol and the products of its transformation, thanks to their beneficial properties, find a variety of applications in cosmetics. Due to their antioxidant and moisturizing properties, these compounds can be added to skin care products such as face creams, lotions, oils, and masks. In addition, these compounds show some antibacterial and antifungal properties, making them suitable for application in skin care products to help fight against bacteria or fungi. This study determined the antimicrobial activity of geraniol and the compounds which were formed during its transformation in relation to selected Gram-positive bacteria, and the preliminary assessment was made whether these compounds can act as ingredients of preparations with potential antimicrobial activity in the treatment of various human diseases (for example diseases of the skin, digestive system, or urinary tract). In addition, this work presents studies on the microbiological purity of cream samples obtained with different contents of geraniol and its transformation products (contents of the tested compounds: 0.5%, 1.5%, 2.5%, 4%, 8%, and 12%). Antibacterial activity tests were performed using the disc diffusion method against Gram-positive cocci, including the reference strains Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212, and against the clinical strains Staphylococcus aureus MRSA, Staphylococcus epidermidis, Enterococcus faecalis VRE VanB, Enterococcus faecium VRE VanA, and Enterococcus faecium VRE VanB. The most active ingredient against bacteria of the Staphylococcus genus was citral, followed by linalool and then geraniol. During our tests, in the case of bacteria of the Enterococcus genus, citral also showed the highest activity, but linalool, ocimenes, and geraniol showed a slightly lower activity. Moreover, this study examined the microbiological purity of cream samples obtained with various contents of geraniol and its transformation products. In the tests of the microbiological purity of cream samples, no growth of aerobic bacteria and fungi was found, which proves the lack of microbiological contamination of the obtained cosmetic preparations. On this basis, it was assessed that these compounds have preservative properties in the prepared creams. The addition of the analyzed compounds also had influence on the durability of the creams and had no effect on the change in their consistency, did not negatively affect the separation of phases during storage, and even had a positive effect on organoleptic sensations by enriching the smell of the tested samples. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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15 pages, 2150 KiB

Open AccessArticle

Antibacterial and Antibiofilm Effects of Photodynamic Treatment with Curcuma L. and Trans-Cinnamaldehyde against Listeria monocytogenes

by Aleksandra Zimińska, Izabela Lipska, Joanna Gajewska, Anna Draszanowska, Manuel Simões and Magdalena A. Olszewska

Molecules 2024, 29(3), 685; https://doi.org/10.3390/molecules29030685 - 01 Feb 2024

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Abstract

Photodynamic inactivation (PDI) is a highly effective treatment that can eliminate harmful microorganisms in a variety of settings. This study explored the efficacy of a curcumin-rich extract, Curcuma L., (Cur)- and essential oil component, trans-cinnamaldehyde, (Ca)-mediated PDI against Listeria monocytogenes ATCC 15313 [...] Read more.

Photodynamic inactivation (PDI) is a highly effective treatment that can eliminate harmful microorganisms in a variety of settings. This study explored the efficacy of a curcumin-rich extract, Curcuma L., (Cur)- and essential oil component, trans-cinnamaldehyde, (Ca)-mediated PDI against Listeria monocytogenes ATCC 15313 (Lm) including planktonic cells and established biofilms on silicone rubber (Si), polytetrafluoroethylene (PTFE), stainless steel 316 (SS), and polyethylene terephthalate (PET). Applying Ca- and Cur-mediated PDI resulted in planktonic cell reductions of 2.7 and 6.4 log CFU/cm², respectively. Flow cytometric measurements (FCMs) coupled with CFDA/PI and TOTO^®-1 staining evidenced that Ca- doubled and Cur-mediated PDI quadrupled the cell damage. Moreover, the enzymatic activity of Lm cells was considerably reduced by Cur-mediated PDI, indicating its superior efficacy. Photosensitization also affected Lm biofilms, but their reduction did not exceed 3.7 log CFU/cm². Cur-mediated PDI effectively impaired cells on PET and PTFE, while Ca-mediated PDI caused no (TOTO^®-1) or only slight (PI) cell damage, sparing the activity of cells. In turn, applying Ca-mediate PDI to Si largely diminished the enzymatic activity in Lm. SS contained 20% dead cells, suggesting that SS itself impacts Lm viability. In addition, the efficacy of Ca-mediated PDI was enhanced on the SS, leading to increased damage to the cells. The weakened viability of Lm on Si and SS could be linked to unfavorable interactions with the surfaces, resulting in a better effect of Ca against Lm. In conclusion, Cur demonstrated excellent photosensitizing properties against Lm in both planktonic and biofilm states. The efficacy of Ca was lower than that of Cur. However, Ca bears potent antibiofilm effects, which vary depending on the surface on which Lm resides. Therefore, this study may help identify more effective plant-based compounds to combat L. monocytogenes in an environmentally sustainable manner. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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15 pages, 2350 KiB

Open AccessCommunication

Effects of Roasting Conditions on Antibacterial Properties of Vietnamese Turmeric (Curcuma longa) Rhizomes

by Hai Thanh Nguyen, Siyuan Wu, Tomoki Ootawa, Hieu Chi Nguyen, Hong Thi Tran, Pitchaya Pothinuch, Hang Thi Thu Pham, Anh Thi Hong Do, Hao Thanh Hoang, Md. Zahorul Islam, Atsushi Miyamoto and Ha Thi Thanh Nguyen

Molecules 2023, 28(21), 7242; https://doi.org/10.3390/molecules28217242 - 24 Oct 2023

Cited by 2 | Viewed by 1312

Abstract

Processing with heat treatment has been reported to alter several therapeutic effects of turmeric. In Vietnamese traditional medicine, turmeric has been long used for bacterial infections, and roasting techniques are sometimes applied with this material. However, there have been no studies investigating the [...] Read more.

Processing with heat treatment has been reported to alter several therapeutic effects of turmeric. In Vietnamese traditional medicine, turmeric has been long used for bacterial infections, and roasting techniques are sometimes applied with this material. However, there have been no studies investigating the effects of these thermal processes on the plant’s antibacterial properties. Our study was therefore performed to examine the changes that roasting produced on this material. Slices of dried turmeric were further subjected to light-roasting (80 °C in 20 min) or dark-roasting (160 °C in 20 min) processes. Broth dilution and agar-well diffusion methods were applied to examine and compare the effects of ethanol extracts obtained from non-roasted, light-roasted and dark-roasted samples, on a set of 6 gram-positive and gram-negative bacteria. In both investigations, dark-roasted turmeric was significantly less antibacterial than non-roasted and light-roasted materials, as evident by the higher values of minimum inhibitory concentrations and the smaller diameters of induced inhibitory zones. In addition, dark-roasting was also found to clearly reduce curcumin contents, total polyphenol values and antioxidant activities of the extracts. These results suggest that non-roasting or light-roasting might be more suitable for the processing of turmeric materials that are aimed to be applied for bacterial infections. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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12 pages, 959 KiB

Open AccessArticle

Comparison of Phytochemical Composition, Antibacterial, and Antifungal Activities of Extracts from Three Organs of Pistacia lentiscus from Saudi Arabia

by Maha Al-Zaben, Mayasar Al Zaban, Souheila Naghmouchi, Albandary Nasser Alsaloom, Nada Al-Sugiran and Ahlam Alrokban

Molecules 2023, 28(13), 5156; https://doi.org/10.3390/molecules28135156 - 01 Jul 2023

Cited by 2 | Viewed by 898

Abstract

This in vitro study focused on the antimicrobial activity of methanolic and aqueous extracts of three organs (stems, roots, and leaves) of Pistacia lentiscus against nine bacterial species, two fungal, and one yeast strain. A comparative study of the yield, high-performance liquid chromatography [...] Read more.

This in vitro study focused on the antimicrobial activity of methanolic and aqueous extracts of three organs (stems, roots, and leaves) of Pistacia lentiscus against nine bacterial species, two fungal, and one yeast strain. A comparative study of the yield, high-performance liquid chromatography (HPLC) composition, and polyphenol content of the different extracts was conducted. The obtained data showed that the yield of the methanolic extracts (between 13% and 33.3%) was greater than that of the aqueous extracts (between 10% and 18%). The highest yield recorded was in the presence of the methanolic leaf extract, followed by the stem and root extracts. Methanolic extracts are richer in polyphenols than aqueous extracts. Indeed, the highest content was observed in the leaf methanolic extract (28.4 mg GAE/g), followed by the stem (2.96 mg GAE/g), and then the root (2.62 mg GAE/g). HPLC revealed variability in the chemical compositions of the different methanolic extracts. The leaf extract was richer in phenolic acids and flavonoids than the stem and root extracts. Regarding antimicrobial activity, it was concluded that the different methanolic extracts of lentisk were more active than the aqueous extracts. In addition, the different methanolic extracts exhibited antimicrobial activity against all tested strains, despite their morphology and Gram-staining. Indeed, the maximum inhibition zones and the minimum inhibitory concentrations for the bacterial strains sensitive to the different methanolic extracts of the mastic tree were in the range of 7 to 11 mm and 12.5 to 25 µg/mL, respectively. In addition, these extracts showed greater inhibitory activity against the tested fungal strains (A. niger and A. flavus) and yeast (C. albicans) than against the bacterial strains. These extracts can be used to treat antimicrobial infections and as food preservatives. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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19 pages, 4150 KiB

Open AccessArticle

BotCl, the First Chlorotoxin-like Peptide Inhibiting Newcastle Disease Virus: The Emergence of a New Scorpion Venom AMPs Family

by Abir Jlassi, Marwa Mekni-Toujani, Asma Ferchichi, Charfeddine Gharsallah, Christian Malosse, Julia Chamot-Rooke, Mohamed ElAyeb, Abdeljelil Ghram, Najet Srairi-Abid and Salma Daoud

Molecules 2023, 28(11), 4355; https://doi.org/10.3390/molecules28114355 - 26 May 2023

Cited by 1 | Viewed by 1792

Abstract

Newcastle disease virus (NDV) is one of the most serious contagions affecting domestic poultry and other avian species. It causes high morbidity and mortality, resulting in huge economic losses to the poultry industry worldwide. Despite vaccination, NDV outbreaks increase the need for alternative [...] Read more.

Newcastle disease virus (NDV) is one of the most serious contagions affecting domestic poultry and other avian species. It causes high morbidity and mortality, resulting in huge economic losses to the poultry industry worldwide. Despite vaccination, NDV outbreaks increase the need for alternative prevention and control means. In this study, we have screened fractions of Buthus occitanus tunetanus (Bot) scorpion venom and isolated the first scorpion peptide inhibiting the NDV multiplication. It showed a dose dependent effect on NDV growth in vitro, with an IC₅₀ of 0.69 µM, and a low cytotoxicity on cultured Vero cells (CC50 > 55 µM). Furthermore, tests carried out in specific pathogen-free embryonated chicken eggs demonstrated that the isolated peptide has a protective effect on chicken embryos against NDV, and reduced by 73% the virus titer in allantoic fluid. The N-terminal sequence, as well as the number of cysteine residues of the isolated peptide, showed that it belongs to the scorpion venom Chlorotoxin-like peptides family, which led us to designate it “BotCl”. Interestingly, at 10 µg/mL, BotCl showed an inhibiting effect three times higher than its analogue AaCtx, from Androctonus australis (Aa) scorpion venom, on NDV development. Altogether, our results highlight the chlorotoxin-like peptides as a new scorpion venom AMPs family. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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20 pages, 4623 KiB

Open AccessArticle

Chemical Profile, Antibacterial, Antibiofilm, and Antiviral Activities of Pulicaria crispa Most Potent Fraction: An In Vitro and In Silico Study

by Fatma Abo-Elghiet, Areej Rushdi, Mona H. Ibrahim, Sara H. Mahmoud, Mohamed A. Rabeh, Saad Ali Alshehri and Nagwan Galal El Menofy

Molecules 2023, 28(10), 4184; https://doi.org/10.3390/molecules28104184 - 19 May 2023

Cited by 5 | Viewed by 1590

Abstract

Infectious diseases caused by viruses and bacteria are a major public health concern worldwide, with the emergence of antibiotic resistance, biofilm-forming bacteria, viral epidemics, and the lack of effective antibacterial and antiviral agents exacerbating the problem. In an effort to search for new [...] Read more.

Infectious diseases caused by viruses and bacteria are a major public health concern worldwide, with the emergence of antibiotic resistance, biofilm-forming bacteria, viral epidemics, and the lack of effective antibacterial and antiviral agents exacerbating the problem. In an effort to search for new antimicrobial agents, this study aimed to screen antibacterial and antiviral activity of the total methanol extract and its various fractions of Pulicaria crispa (P. crispa) aerial parts. The P. crispa hexane fraction (HF) was found to have the strongest antibacterial effect against both Gram-positive and Gram-negative bacteria, including biofilm producers. The HF fraction reduced the expression levels of penicillin binding protein (PBP2A) and DNA gyrase B enzymes in Staphylococcus aureus and Pseudomonas aeruginosa, respectively. Additionally, the HF fraction displayed the most potent antiviral activity, especially against influenza A virus, affecting different stages of the virus lifecycle. Gas chromatography/mass spectrometry (GC/MS) analysis of the HF fraction identified 27 compounds, mainly belonging to the sterol class, with β-sitosterol, phytol, stigmasterol, and lupeol as the most abundant compounds. The in silico study revealed that these compounds were active against influenza A nucleoprotein and polymerase, PBP2A, and DNA gyrase B. Overall, this study provides valuable insights into the chemical composition and mechanism of action of the P. crispa HF fraction, which may lead to the development of more effective treatments for bacterial and viral infections. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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18 pages, 1607 KiB

Open AccessArticle

Evaluation of the Cytotoxic, Antioxidative and Antimicrobial Effects of Dracocephalum moldavica L. Cultivars

by Ștefania Simea, Irina Ielciu, Daniela Hanganu, Mihaela Niculae, Emoke Pall, Ramona Flavia Burtescu, Neli-Kinga Olah, Mihai Cenariu, Ilioara Oniga, Daniela Benedec and Marcel Duda

Molecules 2023, 28(4), 1604; https://doi.org/10.3390/molecules28041604 - 07 Feb 2023

Cited by 2 | Viewed by 1391

Abstract

The aim of the present study was to correlate the antioxidant, antimicrobial, and cytotoxic activities of hydroalcoholic extracts obtained from the aerial parts of three Dracocephalum moldavica L. cultivars with their polyphenolic compositions. The polyphenols were identified and quantified using spectrophotometrical methods and [...] Read more.

The aim of the present study was to correlate the antioxidant, antimicrobial, and cytotoxic activities of hydroalcoholic extracts obtained from the aerial parts of three Dracocephalum moldavica L. cultivars with their polyphenolic compositions. The polyphenols were identified and quantified using spectrophotometrical methods and LC–MS analysis. Their antioxidant capacities were assessed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. Their in vitro antimicrobial efficacies were assessed using the agar well diffusion and broth microdilution methods. Their cytotoxicity was investigated on normal diploid foreskin fibroblasts (BJ) and on colorectal adenocarcinoma (DLD-1) cell lines. The results pointed out significant amounts of polyphenolic compounds in the compositions of the tested cultivars, with rosmarinic acid as the main compound (amounts ranging between 5.337 ± 0.0411 and 6.320 ± 0.0535 mg/mL). All three cultivars displayed significant antioxidant (IC₅₀ ranging between 35.542 ± 0.043 and 40.901 ± 0.161 µg/mL for the DPPH assay, and for the FRAP assay 293.194 ± 0.213 and 330.165 ± 0.754 µmol Trolox equivalent/mg dry vegetal material) and antimicrobial potential (especially towards the Gram-positive bacteria), as well as a selective toxicity towards the tumoral line. A significant positive correlation was found between antioxidant activity and the total phenolic acids (r² = 0.987) and polyphenols (r² = 0.951). These findings bring further arguments for strongly considering D. moldavica cultivars as promising vegetal products, which warrants further investigation. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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12 pages, 2274 KiB

Open AccessArticle

Antibacterial Effect of Cell-Free Supernatant from Lactobacillus pentosus L-36 against Staphylococcus aureus from Bovine Mastitis

by Gengchen Wang and Hong Zeng

Molecules 2022, 27(21), 7627; https://doi.org/10.3390/molecules27217627 - 07 Nov 2022

Cited by 3 | Viewed by 2037

Abstract

This study sought to analyze the main antibacterial active components of Lactobacillus pentosus (L. pentosus) L-36 cell-free culture supernatants (CFCS) in inhibiting the growth of Staphylococcus aureus (S. aureus), to explore its physicochemical properties and anti-bacterial mechanism. Firstly, the [...] Read more.

This study sought to analyze the main antibacterial active components of Lactobacillus pentosus (L. pentosus) L-36 cell-free culture supernatants (CFCS) in inhibiting the growth of Staphylococcus aureus (S. aureus), to explore its physicochemical properties and anti-bacterial mechanism. Firstly, the main antibacterial active substance in L-36 CFCS was peptides, which inferred by adjusting pH and enzyme treatment methods. Secondly, the physicochemical properties of the antibacterial active substances in L-36 CFCS were studied from heat, pH, and metal ions, respectively. It demonstrated good antibacterial activity when heated at 65 °C, 85 °C and 100 °C for 10 and 30 min, indicating that it had strong thermal stability. L-36 CFCS had antibacterial activity when the pH value was 2–6, and the antibacterial active substances became stable with the decrease in pH value. After 10 kinds of metal ions were treated, the antibacterial activity did not change significantly, indicating that it was insensitive to metal ions. Finally, scanning electron microscopy, transmission electron microscopy and fluorescence probe were used to reveal the antibacterial mechanism of S. aureus from the aspects of cell morphology and subcellular structure. The results demonstrated that L-36 CFCS could form 1.4–2.3 nm pores in the cell membrane of S. aureus, which increased the permeability of the bacterial cell membrane, resulting in the depolarization of cell membrane potential and leakage of nucleic acid protein and other cell contents. Meanwhile, a large number of ROS are produced and accumulated in the cells, causing damage to DNA, and with the increase in L-36 CFCS concentration, the effect is enhanced, and finally leads to the death of S. aureus. Our study suggests that the main antibacterial active substances of L-36 CFCS are peptides. L-36 CFCS are thermostable, active under acidic conditions, insensitive to metal ions, and exhibit antibacterial effects by damaging cell membranes, DNA and increasing ROS. Using lactic acid bacteria to inhibit S. aureus provides a theoretical basis for the discovery of new antibacterial substances, and will have great significance in the development of antibiotic substitutes, reducing bacterial resistance and ensuring animal food safety. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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22 pages, 10175 KiB

Open AccessArticle

In Silico Studies on Zinc Oxide Based Nanostructured Oil Carriers with Seed Extracts of Nigella sativa and Pimpinella anisum as Potential Inhibitors of 3CL Protease of SARS-CoV-2

by Awatif A. Hendi, Promy Virk, Manal A. Awad, Mai Elobeid, Khalid M. O. Ortashi, Meznah M. Alanazi, Fatemah H. Alkallas, Maha Mohammad Almoneef and Mohammed Aly Abdou

Molecules 2022, 27(13), 4301; https://doi.org/10.3390/molecules27134301 - 04 Jul 2022

Cited by 8 | Viewed by 2241

Abstract

Coming into the second year of the pandemic, the acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants continue to be a serious health hazard globally. A surge in the omicron wave, despite the discovery of the vaccines, has shifted the attention of [...] Read more.

Coming into the second year of the pandemic, the acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants continue to be a serious health hazard globally. A surge in the omicron wave, despite the discovery of the vaccines, has shifted the attention of research towards the discovery and use of bioactive compounds, being potential inhibitors of the viral structural proteins. The present study aimed at the green synthesis of zinc oxide (ZnO) nanoparticles with seed extracts of Nigella sativa and Pimpinella anisum—loaded nanostructured oil carriers (NLC)—using a mixture of olive and black seed essential oils. The synthesized ZnO NLC were extensively characterized. In addition, the constituent compounds in ZnO NLC were investigated as a potential inhibitor for the SARS-CoV-2 main protease (3CLpro or Mpro) where 27 bioactive constituents, along with ZnO in the nanostructure, were subjected to molecular docking studies. The resultant high-score compounds were further validated by molecular dynamics simulation. The study optimized the compounds dithymoquinone, δ-hederin, oleuropein, and zinc oxide with high docking energy scores (ranging from −7.9 to −9.9 kcal/mol). The RMSD and RMSF data that ensued also mirrored these results for the stability of proteins and ligands. RMSD and RMSF data showed no conformational change in the protein during the MD simulation. Histograms of every simulation trajectory explained the ligand properties and ligand–protein contacts. Nevertheless, further experimental investigations and validation of the selected candidates are imperative to take forward the applicability of the nanostructure as a potent inhibitor of COVID-19 (Coronavirus Disease 2019) for clinical trials. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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Review

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14 pages, 1463 KiB

Open AccessReview

Efflux Pump Inhibitors in Controlling Antibiotic Resistance: Outlook under a Heavy Metal Contamination Context

by Thi Huyen Thu Nguyen, Hai Dang Nguyen, Mai Huong Le, Thi Thu Hien Nguyen, Thi Dua Nguyen, Duc Long Nguyen, Quang Huy Nguyen, Thi Kieu Oanh Nguyen, Serge Michalet, Marie-Geneviève Dijoux-Franca and Hoang Nam Pham

Molecules 2023, 28(7), 2912; https://doi.org/10.3390/molecules28072912 - 24 Mar 2023

Cited by 7 | Viewed by 2706

Abstract

Multi-drug resistance to antibiotics represents a growing challenge in treating infectious diseases. Outside the hospital, bacteria with the multi-drug resistance (MDR) phenotype have an increased prevalence in anthropized environments, thus implying that chemical stresses, such as metals, hydrocarbons, organic compounds, etc., are the [...] Read more.

Multi-drug resistance to antibiotics represents a growing challenge in treating infectious diseases. Outside the hospital, bacteria with the multi-drug resistance (MDR) phenotype have an increased prevalence in anthropized environments, thus implying that chemical stresses, such as metals, hydrocarbons, organic compounds, etc., are the source of such resistance. There is a developing hypothesis regarding the role of metal contamination in terrestrial and aquatic environments as a selective agent in the proliferation of antibiotic resistance caused by the co-selection of antibiotic and metal resistance genes carried by transmissible plasmids and/or associated with transposons. Efflux pumps are also known to be involved in either antibiotic or metal resistance. In order to deal with these situations, microorganisms use an effective strategy that includes a range of expressions based on biochemical and genetic mechanisms. The data from numerous studies suggest that heavy metal contamination could affect the dissemination of antibiotic-resistant genes. Environmental pollution caused by anthropogenic activities could lead to mutagenesis based on the synergy between antibiotic efficacy and the acquired resistance mechanism under stressors. Moreover, the acquired resistance includes plasmid-encoded specific efflux pumps. Soil microbiomes have been reported as reservoirs of resistance genes that are available for exchange with pathogenic bacteria. Importantly, metal-contaminated soil is a selective agent that proliferates antibiotic resistance through efflux pumps. Thus, the use of multi-drug efflux pump inhibitors (EPIs) originating from natural plants or synthetic compounds is a promising approach for restoring the efficacy of existing antibiotics, even though they face a lot of challenges. Full article

(This article belongs to the Special Issue Antimicrobial Activity of Natural Extracts)

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