Enzymatic Synthesis and Antimicrobial Activity of Oligomer Analogues of Medicinal Biopolymers from Comfrey and Other Species of the Boraginaceae Family

This study reports the first enzymatic synthesis leading to several oligomer analogues of poly[3-(3,4-dihydroxyphenyl)glyceric acid]. This biopolymer, extracted from plants of the Boraginaceae family has shown a wide spectrum of pharmacological properties, including antimicrobial activity. Enzymatic ring opening polymerization of 2-methoxycarbonyl-3-(3,4-dibenzyloxyphenyl)oxirane (MDBPO) using lipase from Candida rugosa leads to formation of poly[2-methoxycarbonyl-3-(3,4-dibenzyloxyphenyl)oxirane] (PMDBPO), with a degree of polymerization up to 5. Catalytic debenzylation of PMDBPO using H2 on Pd/C yields poly[2-methoxycarbonyl-3-(3,4-dihydroxyphenyl)oxirane] (PMDHPO) without loss in molecular mass. Antibacterial assessment of natural polyethers from different species of Boraginaceae family Symhytum asperum, S. caucasicum,S. grandiflorum, Anchusa italica, Cynoglossum officinale, and synthetic polymers, poly[2-methoxycarbonyl-3-(3,4-dimethoxyphenyl)oxirane (PMDMPO) and PMDHPO, reveals that only the synthetic analogue produced in this study (PMDHPO) exhibits a promising antimicrobial activity against pathogenic strains S.aureus ATCC 25923 and E.coli ATCC 25922 the minimum inhibitory concentration (MIC) being 100 µg/mL.

Download Full-text

Antimicrobial Activity of Selected Antimicrobial Peptides Against Planktonic Culture and Biofilm of Acinetobacter baumannii

Probiotics and Antimicrobial Proteins ◽

10.1007/s12602-018-9444-5 ◽

2018 ◽

Vol 11 (1) ◽

pp. 317-324 ◽

Cited By ~ 9

Author(s):

Maciej Jaśkiewicz ◽

Damian Neubauer ◽

Kamil Kazor ◽

Sylwia Bartoszewska ◽

Wojciech Kamysz

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Peptides ◽

Acinetobacter Baumannii ◽

Reference Strain ◽

Inhibitory Concentration ◽

Wide Spectrum ◽

Selectivity Index ◽

Planktonic Culture

Abstract Acinetobacter baumannii is one of the most challenging pathogens, on account of its predisposition to develop resistance leading to severe, difficult-to-treat infections. As these bacteria are more usually isolated from nosocomial infections, the new therapeutic options are demanded. Antimicrobial peptides (AMPs) are compounds likely to find application in the treatment of A. baumannii. These compounds exhibit a wide spectrum of antimicrobial activity and were found to be effective against biofilm. In this study, eight AMPs, namely aurein 1.2, CAMEL, citropin 1.1., LL-37, omiganan, r-omiganan, pexiganan, and temporin A, were tested for their antimicrobial activity. A reference strain of A. baumannii ATCC 19606 was used. Antimicrobial assays included determination of the minimum inhibitory concentration and the minimum biofilm eradication concentration. Considering the fact that the majority of A. baumannii infections are associated with mechanical ventilation and the use of indwelling devices, the activity against biofilm was assessed on both a polystyrene surface and tracheal tube fragments. In addition, cytotoxicity (HaCaT) was determined and in vitro selectivity index was calculated.

Download Full-text

Sustainable Enzymatic Synthesis of a Solketal Ester—Process Optimization and Evaluation of Its Antimicrobial Activity

Catalysts ◽

10.3390/catal10020218 ◽

2020 ◽

Vol 10 (2) ◽

pp. 218 ◽

Cited By ~ 4

Author(s):

Patricia A. Mendoza-Ortiz ◽

Rafaela S. Gama ◽

Omar C. Gómez ◽

Jaine H. H. Luiz ◽

Roberto Fernandez-Lafuente ◽

...

Keyword(s):

Antimicrobial Activity ◽

Palmitic Acid ◽

Enzymatic Synthesis ◽

Candida Rugosa ◽

Thermomyces Lanuginosus ◽

Molar Ratio ◽

Nuclear Magnetic Resonance Analysis ◽

Ester Synthesis ◽

Mechanical Stirring ◽

Oil Hydrolysis

The present study aims the enzymatic synthesis of solketal palmitate by esterification between solketal and palmitic acid using heptane as solvent. Lipases from Thermomyces lanuginosus (TLL), Candida rugosa type VII (CRL), and Pseudomonas fluorescens (PFL) were immobilized via interfacial activation on rice husk silica functionalized with triethoxy(octyl)silane (Octyl–SiO2) and used as biocatalysts. A loading of 20–22 mg of lipase/g of support was immobilized independently of the studied enzyme. TLL–Octyl–SiO2 was the most active biocatalyst in oil hydrolysis (656.0 ± 23.9 U/g) and ester synthesis (productivity of 6.8 mmol/min.gbiocat), and it has been chosen for further ester synthesis optimization. The effect of some important parameters such as biocatalyst concentration, reaction temperature and acid:alcohol molar ratio on the reaction has been evaluated using a central composite rotatable design at fixed mechanical stirring (240 rpm) and reaction time (15 min). Subsequently, the effect of reactants concentration and molecular sieve concentration has also been examined. Under optimal conditions (56 °C, acid:alcohol molar ratio of 1:3 with a palmitic acid concentration of 1 M, and 20% wt. of TLL–Octyl–SiO2 per volume of reaction mixture), 83% acid conversion was obtained after 150 min of reaction. The biocatalyst retained 87% of its initial activity after seven successive reaction batches. The product was identified by nuclear magnetic resonance analysis. Antimicrobial activity studies showed that the synthesized ester demonstrated antifungal activity against Candida albicans and Candida parapsilosis, with minimum inhibitory concentration (MIC) between 200 and 400 µg/mL, and bacteriostatic/fungistatic action—minimum microbicial concentration (MMC) > 400 µg/mL.

Download Full-text

Green and Simple Synthesis of Silver Nanoparticles by Aqueous Extract of Perovskia abrotanoides: Characterization, Optimization and Antimicrobial Activity

Current Pharmaceutical Biotechnology ◽

10.2174/1389201020666190618121218 ◽

2020 ◽

Vol 21 (11) ◽

pp. 1129-1137 ◽

Cited By ~ 1

Author(s):

Somayeh Mirsadeghi ◽

Masoumeh F. Koudehi ◽

Hamid R. Rajabi ◽

Seied M. Pourmortazavi

Keyword(s):

Antimicrobial Activity ◽

Silver Nanoparticles ◽

Minimum Inhibitory Concentration ◽

Plant Extract ◽

Inhibitory Concentration ◽

Minimum Bactericidal Concentration ◽

Extraction Temperature ◽

Silver Particles ◽

Silver Nps ◽

Perovskia Abrotanoides

Background: Herein, we report the biosynthesis procedure to prepare silver nanoparticles as reduction and capping agents with the aqueous plant extract of Perovskia abrotanoides. Methods: The therapeutic application of silver nanoparticles entirely depends on the size and shape of the nanoparticles therefore, their control during the synthesis procedure is so important. The effects of synthesis factors, for example, silver ion concentration, the mass of plant extract, reaction time and extraction temperature, on the size of silver particles were considered and optimized. Several analytical methods were used for the characterization of silver NPs including FT-IR and UV–Vis spectrophotometer, XRD and SEM. Results: The results showed that the mean size of the silver particles was about 51 nm. Moreover, the antibacterial properties of biosynthesized silver NPs were investigated by the minimum inhibitory concentration, minimum bactericidal concentration, and Well-diffusion tests. The minimum inhibitory concentration/ minimum bactericidal concentration values of silver NPs and aqueous plant extract versus Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Gram-negative bacteria (E. coli) were 3.03/0.00, 1.20/0.01, 3.06/0.00, 0.98/1.04, 1.00/0.05 and 1.30/0.03 (mg/mL), respectively. Conclusion: The antimicrobial activity study displayed that the synthesized silver nanoparticles by plant extract have better antimicrobial properties compared to aqueous plant extract of Perovskia abrotanoides.

Download Full-text

Antimicrobial Metabolites against Methicillin-Resistant Staphylococcus aureus from the Endophytic Fungus Neofusicoccum australe

Molecules ◽

10.3390/molecules26041094 ◽

2021 ◽

Vol 26 (4) ◽

pp. 1094

Author(s):

Melissa M. Cadelis ◽

Soeren Geese ◽

Benedict B. Uy ◽

Daniel R. Mulholland ◽

Shara J. van de Pas ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Activity ◽

Natural Products ◽

Structure Elucidation ◽

Methicillin Resistant Staphylococcus Aureus ◽

Inhibitory Concentration ◽

Spectroscopic Methods ◽

Methicillin Resistant ◽

Bioassay Guided Fractionation ◽

Antimicrobial Metabolites

Antimicrobial bioassay-guided fractionation of the endophytic fungi Neofusicoccum australe led to the isolation of a new unsymmetrical naphthoquinone dimer, neofusnaphthoquinone B (1), along with four known natural products (2–5). Structure elucidation was conducted by nuclear magnetic resonance (NMR) spectroscopic methods, and the antimicrobial activity of all the natural products was investigated, revealing 1 to be moderately active towards methicillin-resistant Staphylococcus aureus (MRSA) with a minimum inhibitory concentration (MIC) of 16 µg/mL.

Download Full-text

Synergistic Effect of Plant Extracts on Endodontic Pathogens Isolated from Teeth with Root Canal Treatment Failure: An In Vitro Study

Antibiotics ◽

10.3390/antibiotics10050552 ◽

2021 ◽

Vol 10 (5) ◽

pp. 552

Author(s):

Suraj Arora ◽

Shahabe Saquib ◽

Youssef Algarni ◽

Mohammed Kader ◽

Irfan Ahmad ◽

...

Keyword(s):

Antimicrobial Activity ◽

Candida Albicans ◽

Synergistic Effect ◽

Enterococcus Faecalis ◽

Plant Extracts ◽

Azadirachta Indica ◽

Inhibitory Concentration ◽

Pathogenic Microorganisms ◽

Salvadora Persica ◽

Actinomyces Naeslundii

Background and objectives: This study aimed to evaluate the synergistic antimicrobial activity of extracts obtained from Salvadora persica (Miswak), Commiphora molmol (myrrh) and Azadirachta indica (neem) in combination with commercially available antimicrobial agents: penicillin, tetracycline, ofloxacin and fluconazole on endodontic pathogens such as Enterococcus faecalis, Streptococcus mitis, Actinomyces naeslundii and Candida albicans. Materials and Methods: Microbiological samples from the root canals of the teeth undergoing retreatment were taken using sterile paper points kept at full length in the canal for 30 seconds. The disc diffusion method was used to check the susceptibility of microbes to the plant extracts and antimicrobials by measuring the diameter of the inhibition zones. Against the microbes, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC) of the plant extracts were assessed. The fractional inhibitory concentration index (FICI) was used to estimate the synergistic effect of plant extracts combined with antimicrobials against the resistant endodontic microbes. Results: The findings clearly indicate the effectiveness of all the three plant extracts, Commiphora molmol, Azadirachta indica, Salvadora persica, against all the experimental pathogenic microorganisms except for the ineffectiveness of Azadirachta indica, Salvadora persica against Candida albicans. Maximum antimicrobial activity was displayed by Azadirachta indica against Enterococcus faecalis (MIC = 0.09 ± 1.2 mg/mL, MBC = 0.78 ± 1.25 mg/mL) and the minimum antimicrobial activity was displayed by Commiphora molmol against Actinomyces naeslundii (MIC = 12.5 ± 3.25 mg/mL, MBC = 100 ± 3.75 mg/mL). The best synergy was displayed by Commiphora molmol with fluconazole against Candida albicans (FICI = 0.45). Conclusions: The current study delineates the variable antimicrobial activity of plant extracts against the experimental endodontic pathogenic microorganisms. Plant extracts in conjunction with various antimicrobials can be valuable aids in combating relatively resistant endodontic microorganisms that have been the cause of worry in recent years, leading to failure even in treatment procedures following all required protocols.

Download Full-text

Evaluation of antimicrobial activity of the endophytic actinomycete R18(6) against multiresistant Gram-negative bacteria

Anais da Academia Brasileira de Ciências ◽

10.1590/0001-3765201620140655 ◽

2016 ◽

Vol 88 (1) ◽

pp. 155-163 ◽

Cited By ~ 2

Author(s):

Tiele Carvalho ◽

Sueli Van Der Sand

Keyword(s):

Antimicrobial Activity ◽

Inhibitory Concentration ◽

Proteolytic Enzymes ◽

Gram Negative Bacteria ◽

Bacteriostatic Activity ◽

Submerged Cultures ◽

Gram Negative ◽

Endophytic Actinomycete ◽

Endophytic Actinomycetes ◽

Antimicrobial Substances

Endophytic actinomycetes are promising sources of antimicrobial substances. This study evaluates the activity of metabolites produced by the endophytic actinomycete R18(6) against Gram-negative bacteria multiresistant to antimicrobials. R18(6) isolate was grown in submerged cultures under different conditions: carbon source, temperature, pH and incubation time to optimize antimicrobials production. The actinomycete grown in base medium supplemented with 1% glucose, pH 6.5 and incubation at 30 ºC for 96 h with shaking at 100 rpm, exhibited the highest activity against the used Gram-negative bacteria. Minimum inhibitory concentration (MIC) of the crude extract produced by the microorganism varied between 1/32 and 1/256. It had bactericide or bacteriostatic activity, depending on the Gram-negative organism. The active extract was stable at high temperatures, and unstable in medium containing proteolytic enzymes. Micromorphology of R18(6) was investigated by optical and scan microscopy, revealing that it was morphologically similar to the genusStreptomyces.

Download Full-text

Antimicrobial Activity of Leaves and Flowers of Cassia auriculata linn

Bangladesh Journal of Scientific and Industrial Research ◽

10.3329/bjsir.v46i4.9600 ◽

1970 ◽

Vol 46 (4) ◽

pp. 513-518 ◽

Cited By ~ 3

Author(s):

V Subhadradevi ◽

K Asokkumar ◽

M Umamaheswari ◽

AT Sivashanmugam ◽

JR Ushanandhini ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Agents ◽

Inhibitory Concentration ◽

Dominant Role ◽

Ethanolic Extract ◽

Diffusion Method ◽

Cassia Auriculata ◽

Potential Source ◽

Wide Range ◽

Ancient Times

Since ancient times plant as sources of medicinal compounds have continued to play a dominant role in the maintenance of human health. To treat chronic and infectious diseases plants used in traditional medicine contain a wide range of ingredients. In this regard, Cassia auriculata L. (Caesalpiniaceae) is widely used in Ayurvedic medicine as a tonic, astringent and as a remedy for diabetes, conjunctivitis, ulcers, leprosy, skin and liver diseases. The aim of present study was to evaluate the antimicrobial activity of ethanolic extract of Cassia auriculata leaves and flowers (CALE & CAFE). CALE and CAFE exhibited broad spectrum antimicrobial activity against standard strains of Staphylococcus aureus, Escherichia coli and Bacillus subtilis and exhibited no antifungal activity against standard strains of Candida albicans and Aspergillus niger. Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) was carried out for CALE and CAFE. The results obtained in the present study indicate that the CALE and CAFE can be a potential source of natural antimicrobial agents. Key words: Cassia auriculata; Antimicrobial activity; Agar well diffusion method. DOI: http://dx.doi.org/10.3329/bjsir.v46i4.9600 BJSIR 2011; 46(4): 513-518

Download Full-text

Antimicrobial Activity and Polyphenol Profiles of Hydroalcoholic Extracts of Thymus rasitatus Klokov and Thymus eremita Klokov

Open Access Macedonian Journal of Medical Sciences ◽

10.3889/oamjms.2021.6117 ◽

2021 ◽

Vol 9 (A) ◽

pp. 313-317

Author(s):

Svetlana Ivasenko ◽

Ainur Zhumabekova ◽

Agnieszka Ludwiczuk ◽

Krystyna Skalicka–Wozniak ◽

Alexandr Marchenko ◽

...

Keyword(s):

Antimicrobial Activity ◽

Chromatographic Analysis ◽

Antimicrobial Agents ◽

Raw Materials ◽

Wide Spectrum ◽

Raw Material ◽

Thymus Vulgaris ◽

Material Base ◽

Ultrasound Assisted Extraction ◽

Ethanol Extracts

BACKGROUND: A possible reduction in stocks of medicinal plant raw materials of Thymus serpyllum L. and Thymus vulgaris L. leads to the need to expand the raw material base of the official medicinal plants with using of endemic species of the flora of Kazakhstan, in particular, Thymus rasitatus Klokov, and Thymus eremita Klokov. AIM: The aim of the study was to study the possibility of using 70% ethanol extracts of T. rasitatus and T. eremita as antimicrobial agents. MATERIALS AND METHODS: The aerial parts of T. rasitatus and T. eremita were extracted with 70% ethanol using ultrasound assisted extraction. The qualitative and quantitative analyses of the 70% ethanol extracts were determined using the liquid chromatography-detection-ESI-mass spectrometry-(MS)/MS technique. The study of the antimicrobial activity of these extracts was performed for eight strains of Gram-positive bacteria, six strains of Gram-negative bacteria, and four cultures of fungi. RESULTS: Chromatographic analysis of hydroalcoholic extracts of both investigated Thymus species showed very similar phenolic compounds composition. In both cases, the major components are luteolin-7-O-glucoside and rosmarinic acid. About 70% ethanol extracts of T. rasitatus and T. eremita have a broad spectrum of antimicrobial activity, exhibit the bactericidal or bacteriostatic activity against all tested bacteria and fungi at concentration range of 0.0195–20 mg/ml, but differ in their potency against tested strains of microorganisms. CONCLUSION: About 70% ethanol extracts of T. rasitatus and T. eremita, endemic plants in the flora of Kazakhstan, can be considered as potential drugs with a wide spectrum of antimicrobial activity. The results of chromatographic analysis could be used for drug standardization.

Download Full-text

Antimicrobial Activity of Bauhinia Purpurea (L) by Minimum Inhibitory Concentration (MIC) Method

IOSR Journal of Pharmacy and Biological Sciences ◽

10.9790/3008-1201026971 ◽

2017 ◽

Vol 12 (01) ◽

pp. 69-71

Author(s):

Shamala T ◽

A.M. Krupanidhi ◽

Shanmukhappa S ◽

B.E. Basavarajappa ◽

Jayamma kulkarni

Keyword(s):

Antimicrobial Activity ◽

Minimum Inhibitory Concentration ◽

Inhibitory Concentration ◽

Bauhinia Purpurea

Download Full-text

Antimicrobial activity of Satureja hortensis L. essential oil against pathogenic microbial strains

Archives of Biological Sciences ◽

10.2298/abs1001159m ◽

2010 ◽

Vol 62 (1) ◽

pp. 159-166 ◽

Cited By ~ 20

Author(s):

Tatjana Mihajilov-Krstev ◽

Dragan Radnovic ◽

Dusanka Kitic ◽

Zorica Stojanovic-Radic ◽

Bojan Zlatkovic

Keyword(s):

Antimicrobial Activity ◽

Essential Oil ◽

Wide Spectrum ◽

Significant Activity ◽

Fungal Strains ◽

Satureja Hortensis ◽

Conservation Treatment ◽

Microbial Strains ◽

Editorial Decision ◽

Font Color

A hydro-distilled oil of Satureja hortensis L. was investigated for its antimicrobial activity against a panel of 11 bacterial and three fungal strains. The antimicrobial activity was determined using the disk-diffusion and broth microdilution methods. The essential oil of S. hortensis L. showed significant activity against a wide spectrum of Gram (-) bacteria (MIC/MBC=0.025-0.78/0.05-0.78 ?l/ml) and Gram (+) bacteria (MIC/MBC=0.05-0.39/0.05-0.78 ?l/ml), as well as against fungal strains (MIC/MBC=0.20/0.78 ?l/ml). The results indicate that this oil can be used in food conservation, treatment of different diseases of humans, and also for the treatment of plants infected by phytopathogens. Detected autoplagiarism. Link to the Editorial Decision <a href="http://dx.doi.org/10.2298/ABS1004251U">10.2298/ABS1004251U</a>

Download Full-text