scholarly journals Antibacterial Effects of Leaf Extract of Nandina domestica and the Underlined Mechanism

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Zhao-Yu Guo ◽  
Zhuo-Yang Zhang ◽  
Jia-Qi Xiao ◽  
Jin-Hong Qin ◽  
Wei Zhao
Keyword(s):  
Chronic Bronchitis ◽  
Leaf Extract ◽  
Solid Phase ◽  
Safety Issue ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Mice Model ◽  
Active Components ◽  
Bacterial Morphology ◽  
Guinea Pig Model

Aim. The study was conducted to investigate the antibacterial and antiasthmatic effects of Nandina domestica leaf extract, to find out its active components, and to assess its safety issue. Methods. (1) Solid-phase agar dilution method was used for antibacterial activity test of nandina leaf extract and the change of bacterial morphology after treatment was observed under the transmission microscope; (2) guinea pig model of asthma was used to test the asthma prevention effect of nandina leaf extract; (3) alkaloids and flavones were separated from nandina leaf extract and were further analyzed with HPLC-MS; (4) mice model was used to assessment of the safety issue of nandina leaf extract. Results. (1) Nandina leaf extract inhibited the growth of bacteria and destroyed bacterial membrane; (2) nandina leaf extract alleviated animal allergy and asthma; (3) the components reextracted by ethyl acetate were active, in which alkaloids inhibited Gram-positive bacteria and prevented asthma and flavones inhibited Gram-negative bacteria; (4) nandina leaf extract had no toxic effect on mice. Conclusion. Nandina leaves inhibit bacterial growth and prevent asthma through alkaloids and flavones, which had integrated function against chronic bronchitis. This study provided theoretical basement for producing new Chinese medicine against chronic bronchitis.

scholarly journals Antibacterial Activity of Guyabano, Ulasimang Bato, Sambong, and Tsaang Gubat Leaf Extracts against Common Drug-resistant Bacteria

2020 ◽  
Vol 54 (1) ◽  
Author(s):  
Cecilia C. Maramba-Lazarte ◽  
Lolita L. Cavinta ◽  
Ma. Carmelita L. Sara
Keyword(s):  
Antibacterial Activity ◽  
Leaf Extract ◽  
Resistant Bacteria ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Moderate Activity ◽  
Alcoholic Extract ◽  
Drug Resistant ◽  
Leaf Extracts ◽  
E Coli

Background. Using plants as antimicrobials has long been a practice of traditional healers and validating these customs may lead to the discovery and development of useful herbal medicines. Objective. This study aimed to determine the antibacterial activity of guyabano, tsaang gubat, sambong, and ulasimang bato against common pathogens. Methods. Aqueous or alcoholic leaf extracts of the different medicinal plants were prepared. The solid agar dilution method was used to determine the MIC of guyabano, tsaang gubat, sambong, and ulasimang bato against common pathogens including Staphylococcus aureus, Echerichia coli, Streptococcus pneumoniae, Hemophilus influenzae, Pseudomonas aeruginosa, Salmonella typhi, and Shigella flexneri. Results. The alcoholic leaf extract of guyabano showed moderate activity against oxacillin-sensitive S. aureus with an MIC of 5-6.3 mg/mL. However, tsaang gubat did not exhibit any antibacterial activity for drug-resistant enteric organisms (S. typhi, S. flexneri, and E. coli) and S. aureus at a concentration of 25 mg/mL. Even at a concentration of 100mg/mL, ulasimang bato failed to show any antibacterial activity against drug-resistant S. aureus, S. pneumonia, H. influenzae, E. coli, and P. aeruginosa. Sambong alcoholic extract had some antibacterial activity against penicillin-resistant S. pneumoniae with an MIC of 12.5 mg/mL. Conclusions. Guyabano alcoholic leaf extract showed moderate antibacterial activity against oxacillin-sensitive S. aureus. Sambong alcoholic extract likewise exhibited inhibitory activity against S. pneumoniae. However, tsaang gubat and ulasimang bato aqueous extracts failed to show significant antibacterial activity for the pathogens tested.

Effects of Piper betle Leaf Extract on Biofilm and Rhamnolipid Formation of Pseudomonas aeruginosa

2021 ◽  
pp. 5182-5186
Author(s):  
Irene Ratridewi ◽  
Shod A. Dzulkarnain ◽  
Andreas B. Wijaya ◽  
John T. R. Huwae ◽  
Daniel S. M. Putra ◽  
...  
Keyword(s):  
Leaf Extract ◽  
Linear Regression Analysis ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Piper Betle ◽  
Betel Leaf ◽  
Polystyrene Plate ◽  
Beta Coefficient ◽  
Agar Dilution ◽  
Adherence Test

High mortality rate and antimicrobial resistance are still becoming world-wide problems, due to Pseudomonas aeruginosa’s (P. aeruginosa) virulence and its ability to form biofilm. Biofilm’s formation is affected by the presence of rhamnolipid, whose production is regulated by quorum sensing systems. Piper betle (P. betle) possesses antimicrobial, antioxidant, anti-inflammatory and immunomodulatory properties. The aim of our study is to investigate the effects of P. betle leaf’s extract against biofilm formation and rhamnolipid production of P. aeruginosa. Active compounds of P. betle were identified using plate chromatography. Agar dilution method was used to determine the minimum biofilm inhibitory concentration (MBIC) of methanolic leaf extract of P. betle. A biofilm-producing P. aeruginosa isolate in the polystyrene plate adherence test was selected for confirmation of biofilm production by Scanning Electron Microscopy (SEM), after P. betle administration. Rhamnolipid detection and evaluation were performed by interpreting halo formed around the well. After administration of various concentrations of P. betle leaf extract on the microplate well, it was concluded that the MBIC of P. betle leaf extract on P. aeruginosa was 0.4%. Methanolic extract of P. betle leaf extract at concentration of 0.4% showed that P. aeruginosa could not form biofilm at all, although the bacteria could still aggregate and form a matrix. After linear regression analysis, beta-coefficient was obtained at -0.931 for P. betle leaf extract. It can be concluded that P. betle leaf extract was effective in inhibiting the growth of biofilm and formation of rhamnolipid by P. aeruginosa. The increase in concentration of P. betle leaf extract was inversely proportional to the diameter of the halo rhamnolipid formed. The higher the level of P. betel leaf extract, the smaller the diameter of the halo rhamnolipid formed.

scholarly journals In vitro Assessment of Euclea crispa (Thunb.) Leaf Extracts against Campylobacter spp. and Escherichia coli - Common Diarrhoeal Agents

2018 ◽  
Vol 6 (4) ◽  
Author(s):  
Kazeem Adekunle Alayande ◽  
Carolina (H) Pohl ◽  
Anofi Omotayo Tom Ashafa
Keyword(s):  
Escherichia Coli ◽  
Mortality Rate ◽  
Ethyl Acetate ◽  
Leaf Extract ◽  
Total Mortality ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Leaf Extracts ◽  
Time Kill

Diarrhoea is a common childhood disease with high mortality rate. This study thus aimed at assessing effect of Euclea crispa leaf extract and its fractions against diarrhoea causing bacterial isolates and determining time-kill dynamics by each of the potent fractions. Susceptibility of each isolates was determined by agar well diffusion while the minimum bacteriostatic and bactericidal concentrations were determined by agar dilution method. Time-Kill dynamics was evaluated over a period of 120 min against Escherichia coli (1323) representing Gram negative isolates. The zones of inhibition exhibited by the leaf extract at 20 mg/ml range between 17±0.28 and 22±0.00 mm while that of the partitioned fractions at 10 mg/ml are between 14±0.00 and 22±0.00 mm. MICs of the leaf extract range between 0.31 and 2.50 mg/ml. The lowest MIC (0.08 mg/ml) is exhibited by the fractions partitioned into ethyl acetate, n-butanol and water while that of n-hexane and chloroform is 0.16 mg/ml. The lowest MBC exhibited by all the fractions is 0.31 mg/ml except that of the chloroform (1.25 mg/ml). Total mortality was achieved by the ethyl acetate fraction at a concentration of 2 × MIC after 120 min of contact time, meanwhile the mortality rate achieved by n-butanol, n-hexane, aqueous and chloroform fractions were 98, 94.6, 91.8 and 83.7% respectively under similar condition. This study showcase significant antidiarrhoeal potential of Euclea crispa leaf extracts and equally indicates a source of readily available therapeutic agent against diarrhoeal infection in South Africa and environs.

scholarly journals Antibacterial Activity and Comparison of the Volatile Constituents Obtained by Several Extraction Methods from the Flowers, Stems and Leaves of Astrodaucus orientalis

2012 ◽  
Vol 7 (2) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Marzieh Torabbeigi ◽  
Parviz Abroomand Azar ◽  
Anousheh Sharifan ◽  
Zahra Aghaei Meibodi
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Extraction Methods ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Volatile Constituents ◽  
Head Space ◽  
Agar Dilution ◽  
Stems And Leaves ◽  
Escherichia Coli Bacteria

The oils of the flowers, stems and leaves of Astrodaucus orientalis L. were separately extracted using hydrodistillation (HD), head-space solid-phase microextraction (HS-SPME) and microwave assisted head-space solid-phase microextraction (MA-HS-SPME). The volatile constituents were analyzed by GC and GC/MS. Temperature and time of extraction, microwave power and exposure time of extraction were optimized. Polydimethylsiloxane (PDMS) fiber was used as the solid phase for SPME methods. The main constituents of the flower, stem and leaf oils isolated by HD, HS-SPME and MA-HS-SPME are as follows, respectively: β-pinene (20.5%, 13.9% and 30.4%), α-thujene (8.7%, 16.2% and 10.9%) and α-pinene (7.6%, 14.3% and 10.9%) for the flowers, sabinene (11.8%, 32.3% and 11.8%), α-pinene (8.7%, 28.8% and 6.1%) and p-mycrene (2.5%, 12% and 8.5%) for the stem, and α-pinene (9.4%, 37.1% and 22.5%), sabinene (13.5%, 26.3% and 23.5%), β-pinene (6.3%, 9.8% and 10%) and p-mycrene (3.2%, 2.5% and 15.6%) for the leaf. The minimum inhibitory concentrations (MIC) were determined for all essential oils obtained by HD against both Gram-positive ( Bacillus subtilis) and Gram-negative ( Escherichia coli) bacteria using the agar dilution method. These oils showed the good activities against the both bacteria (0.5 – 1.5 mg/mL).

Development of Ultrasensitive and Arsenic (III) Selective Upconverting (NaYF4: Yb3+, Er3+) Platform

2020 ◽  
Author(s):  
Suman Duhan ◽  
Kedar Sahoo ◽  
Sudhir Kumar Singh ◽  
Manoj Kumar
Keyword(s):  
Heavy Ions ◽  
Leaf Extract ◽  
Moringa Oleifera ◽  
Solid Phase ◽  
Selective Detection ◽  
Arsenic Pollution ◽  
Apparent Effect ◽  
Safe Limit ◽  
Interfering Ions ◽  
Resonance Transfer

The development of a sensitive alpha-NaYF4:Yb3+, Er3+ solid-phase upconverting platform (UCP) has been realized using Moringa oleifera leaf extract for selective detection of arsenic (As III) contamination in drinking water. The presence of polyphenols in the leaves extract is shown to induce luminescence resonance transfer (LRET), diminishing thereby the Er3+ upconverting red and green emissions activated by 980 nm excitation. However, addition of As3+ species interrupts the LRET process and restores emission proportionately. This feature allows platform to selectively detect arsenic pollution in water below the safe limit of 10 ppt. The uniqueness of UCP lies in monitoring the As3+ contamination in samples containing heavy ions (Cd2+, Hg2+) as well, without apparent effect on the signal reproducibility. UCP is also found to be insensitive to other interfering ions like Pb2+, H2PO4-, F-, Cl-, Ca2+, Mg2+, Sn2+, Cr6+, Fe2+ and Co2+, if present.<br><br>

scholarly journals e-Pharmacophore model-guided design of potential DprE1 inhibitors: synthesis, in vitro antitubercular assay and molecular modelling studies

2021 ◽  
Author(s):  
Avinash Kumar ◽  
Revathi Rajappan ◽  
Suvarna G. Kini ◽  
Ekta Rathi ◽  
Sriram Dharmarajan ◽  
...  
Keyword(s):  
Pharmacophore Model ◽  
Antitubercular Activity ◽  
Stable Complex ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Standard Drug ◽  
Docking Score ◽  
Mycobacterium Tuberculosis H37rv ◽  
Cytotoxicity Studies

AbstractTuberculosis continues to wreak havoc worldwide and caused around 1.4 million deaths in 2019. Hence, in our pursuit of developing novel antitubercular compounds, we are reporting the e-Pharmacophore-based design of DprE1 (decaprenylphosphoryl-ribose 2′-oxidase) inhibitors. In the present work, we have developed a four-feature e-Pharmacophore model based on the receptor–ligand cavity of DprE1 protein (PDB ID 4P8C) and mapped our previous reported library of compounds against it. The compounds were ranked on phase screen score, and the insights obtained from their alignment were used to design some novel compounds. The designed compounds were docked with DprE1 protein in extra-precision mode using Glide module of Maestro, Schrodinger. Some derivatives like B1, B2, B4, B5 and B12 showed comparable docking score (docking score > − 6.0) with respect to the co-crystallized ligand. The designed compounds were synthesized and characterized. In vitro antitubercular activity was carried out on Mycobacterium tuberculosis H37Rv (ATCC27294) strain using the agar dilution method, and minimum inhibitory concentration (MIC) was determined. The compound B12 showed a MIC value of 1.56 μg/ml which was better than the standard drug ethambutol (3.125 μg/ml). Compounds B7 and B11 were found to be equipotent with ethambutol. Cytotoxicity studies against Vero cell lines proved that these compounds were non-cytotoxic. Molecular dynamic simulation study also suggests that compound B12 will form a stable complex with DprE1 protein and will show the crucial H-bond interaction with LYS418 residue. Further in vitro enzyme inhibition studies are required to validate these findings.

scholarly journals Evaluation of the Antimicrobial Activity of Some Components of the Essential Oils of Plants Used in the Traditional Medicine of the Tehuacán-Cuicatlán Valley, Puebla, México

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 295
Author(s):  
Sebastián Candelaria-Dueñas ◽  
Rocío Serrano-Parrales ◽  
Marisol Ávila-Romero ◽  
Samuel Meraz-Martínez ◽  
Julieta Orozco-Martínez ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oils ◽  
Qualitative Evaluation ◽  
Bactericidal Effect ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Diffusion Technique ◽  
Agar Dilution

In Tehuacán-Cuicatlán valley (Mexico), studies have been carried out on the essential oils of medicinal plants with antimicrobial activity and it was found that they present compounds in common such as: α-pinene, β-pinene, carvacrol, eugenol, limonene, myrcene, ocimene, cineole, methyl salicylate, farnesene, and thymol. The goal of this study was to assess the antimicrobial activity of essential oils’ compounds. The qualitative evaluation was carried out by the Kirby Baüer agar diffusion technique in Gram-positive bacteria (11 strains), Gram-negative bacteria (18 strains), and yeasts (8 strains). For the determination of the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), the agar dilution method was used. All the evaluated compounds presented antimicrobial activity. The compounds eugenol and carvacrol showed the largest inhibition zones. Regarding yeasts, the compounds ocimene, cineole, and farnesene did not show any activity. The compounds eugenol, carvacrol, and thymol presented the lowest MIC; bactericidal effect was observed at MIC level for S. aureus 75MR, E. coli 128 MR, and C albicans CUSI, for different compounds, eugenol, carvacrol, and thymol. Finally, this study shows that the essential oils of plants used by the population of Tehuacán-Cuicatlán valley share compounds and some of them have antibacterial and fungicidal activity.

scholarly journals 1456. Resistance Mechanisms of Tigecycline in Enterococcus faecalis

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S730-S731
Author(s):  
Bing Bai ◽  
Zewen Wen ◽  
Zhiwei Lin ◽  
Tam Vincent H ◽  
Zhijian Yu
Keyword(s):  
Enterococcus Faecalis ◽  
Molecular Mechanisms ◽  
Genetic Mutations ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Whole Genome ◽  
Synonymous Mutations ◽  
Target Sites ◽  
Parental Isolate ◽  
Resistant Strains

Abstract Background Enterococcus faecalis have been regarded as one of the leading causes of the nosocomial infections worldwide. Tigecycline (TGC) is considered as a choice of last resort for the treatment of infections caused by multidrug-resistant E. faecalis, however, the emergence of TGC non-susceptibility has posted the therapeutic challenge. Non-susceptibility in clinical strains could be due to resistance (MIC &gt;0.5 mg/l) or heteroresistance. Therefore, this study aimed to understand the underlying molecular mechanisms of TGC resistance and heteroresistance in E. faecalis. Methods In vitro induction experiments were carried out under TGC pressure with two TGC- sensitive E. faecalis strains. Heteroresistance was evaluated by population analysis profiling (PAP) in 270 clinical TGC- sensitive E. faecalis strains. TGC susceptibility was determined by the agar dilution method. Resistance and heteroresistance mechanisms were investigated by identifying genetic mutations in tetracycline (Tet) target sites and susceptibility testing in the presence of the efflux protein inhibitors phenylalanine-arginine-β-naphthylamide (PaβN) and carbonyl cyanide m chlorophenylhydrazine (CCCP). Comparison of single nucleotide polymorphism in the whole genome between the parental isolate and two TGC-resistant strains were investigated by next-generation sequencing. Results No mutations in Tet target sites in seven TGC heteroresistant strains were present, whereas the mutations in Tet target sites of seven TGC-resistant E. faecalis were frequently found (Table 1). TGC MICs in heteroresistant strains were reduced by CCCP (Table 2). Whole genome sequencing revealed the same non-synonymous mutations and transcoding deletions in the exons of several genes encoding for various enzymes or transfer systems (Table 3). Table 1. The characteristics of the antimicrobial susceptibility, resistance mechanism of TGC-induced resistant isolates Table 2. Characteristics of clinical heteroresistant mother E. faecalis strains and heteroresistance-derived E. faecalis clones Table 3. List of mutation-related genes, amino acids and proteins by comparison of whole genome between the parental isolate and the TGC-induced resistant strains Conclusion Our data indicated that the main mechanism of TGC heteroresistance in E. faecalis might be associated with the efflux pumps. TGC resistance in E. faecalis was associated with mutations in the 16SrRNA site or 30S ribosome protein S10. The genetic mutations in several enzymes and transfer systems might also participate in the resistance development to TGC in E. faecalis. Disclosures All Authors: No reported disclosures

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