Development of New Antimicrobial Oleanonic Acid Polyamine Conjugates

A series of oleanolic acid derivatives holding oxo- or 3-N-polyamino-3-deoxy-substituents at C3 as well as carboxamide function at C17 with different long chain polyamines have been synthesized and evaluated for antimicrobial activities. Almost all series presented good to moderate activity against Gram-positive S. aureus, S. faecalis and B. cereus bacteria with minimum inhibitory concentration (MIC) values from 3.125 to 200 µg/mL. Moreover, compounds possess important antimicrobial activities against Gram-negative E. coli, P. aeruginosa, S. enterica, and EA289 bacteria with MICs ranging from 6.25 to 200 µg/mL. The testing of ability to restore antibiotic activity of doxycycline and erythromycin at a 2 µg/mL concentration in a synergistic assay showed that oleanonic acid conjugate with spermine spacered through propargylamide led to a moderate improvement in terms of antimicrobial activities of the different selected combinations against both P. aeruginosa and E. coli. The study of mechanism of action of the lead conjugate 2i presenting a N-methyl norspermidine moiety showed the effect of disruption of the outer bacterial membrane of P. aeruginosa PA01 cells. Computational ADMET profiling renders this compound as a suitable starting point for pharmacokinetic optimization. These results give confidence to the successful outcome of bioconjugation of polyamines and oleanane-type triterpenoids in the development of antimicrobial agents.

Download Full-text

DPPH-Scavenging and Antimicrobial Activities of Asteraceae Medicinal Plants on Uropathogenic Bacteria

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2020/7807026 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Phan-Canh Trinh ◽

Le-Thi-Thanh Thao ◽

Hoang-Tran-Viet Ha ◽

TuAnh Nguyen

Keyword(s):

Antimicrobial Agents ◽

Natural Antioxidants ◽

Ethyl Acetate Fraction ◽

Antimicrobial Activities ◽

Chrysanthemum Morifolium ◽

Bacterial Strains ◽

Ageratum Conyzoides ◽

Potent Effect ◽

E Coli ◽

Dpph Scavenging

Asteraceae species were widely applied in traditional medicines in Asian countries as sources of natural antioxidants and antimicrobial agents. This study aimed to evaluate DPPH-scavenging capacities and antimicrobial activities of nine Asteraceae species collected from Southern Vietnam. Antioxidant and antimicrobial activities were determined by standard protocols. Essential oils from Ageratum conyzoides, Helianthus annuus, and Artemisia vulgaris indicated significant inhibitory effects on Staphylococcus aureus and Candida spp. Crude extracts and fractions from Taraxacum officinale, Chrysanthemum morifolium, A. conyzoides, and Tagetes erecta showed inhibitory ability on at least one testing bacterial strains including S. aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. In a study on clinical isolates, ethyl acetate fraction from A. conyzoides flower displayed the most potent effect on uropathogenic E. coli and K. pneumoniae with MIC at 1.25–10 mg/ml and 5–12.5 mg/ml, respectively. DPPH-scavenging assay indicated that T. erecta extract had the lowest IC50 (17.280 μg/ml) and is 2.4 times higher than vitamin C (7.321 μg/ml). This study revealed that A. conyzoides has good potential against uropathogenic E. coli and K. pneumoniae, and therefore could be applied for prophylactic treatment of urinary infection.

Download Full-text

Structure-activity relationships of 3-substituted-5,5- diphenylhydantoins as potential antiproliferative and antimicrobial agents

Journal of the Serbian Chemical Society ◽

10.2298/jsc110314143t ◽

2011 ◽

Vol 76 (12) ◽

pp. 1597-1606 ◽

Cited By ~ 9

Author(s):

Nemanja Trisovic ◽

Bojan Bozic ◽

Ana Obradovic ◽

Olgica Stefanovic ◽

Snezana Markovic ◽

...

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antimicrobial Agents ◽

Human Colon ◽

Antibacterial Activities ◽

E Coli ◽

Structure Activity Relationships ◽

Structure Activity ◽

Almost All

A series of twelve 3-substituted-5,5-diphenylhydantoins was synthesized, including some whose anticonvulsant activities have already been reported in the literature. Their antiproliferative activities against HCT-116 human colon carcinoma cells were evaluated to determine structure-activity relationships. Almost all of the compounds exhibited statistically significant antiproliferative effects at a concentration of 100 ?M, while the derivative bearing a benzyl group was active even at lower concentrations. Moreover, their in vitro antibacterial activities against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and clinical isolates of Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus were evaluated. Only the 3-iso-propyl and 3-benzyl derivatives showed weak antibacterial activities against the Gram-positive bacterium E. faecalis and the Gram-negative bacteria E. coli ATCC 25922 and E. coli.

Download Full-text

Synthesis, Characterization, and Thermal and Antimicrobial Activities of Some Novel Organotin(IV): Purine Base Complexes

Journal of Chemistry ◽

10.1155/2013/568195 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 3

Author(s):

Reena Jain ◽

Rajeev Singh ◽

N. K. Kaushik

Keyword(s):

Antimicrobial Agents ◽

Rhizopus Oryzae ◽

Antimicrobial Activities ◽

Spectral Studies ◽

Purine Base ◽

Mass Spectral ◽

E Coli ◽

Kinetic And Thermodynamic Parameters ◽

C Nmr

A new series of organotin(IV) complexes with purine bases theophylline (HL1) and theobromine (L2) of the types R3Sn(L1), R2Sn(L1)Cl, R3Sn(L2)Cl, and R2Sn(L2)Cl2(R = C6H5CH2–;p-ClC6H4CH2–) have been synthesized in anhydrous THF. The complexes were characterized by elemental analysis, conductance measurements, molecular weight determinations, UV-vis, IR,1H,13C NMR, and mass spectral studies. Various kinetic and thermodynamic parameters of these complexes have also been determined using TG/DTA technique. The thermal decomposition techniques indicate the formation of SnO2as a residue. The results show that the ligands act as bidentate, forming a five-member chelate ring. All the complexes are 1 : 1 metal-ligand complexes. In order to assess their antimicrobial activity, the ligands and their corresponding complexes have also been testedin vitroagainst bacteria (E. coli, S. aureus, andP. pyocyanea) and fungi (Rhizopus oryzaeandAspergillus flavus). All the complexes exhibit remarkable activity, and the results provide evidence that the studied complexes might indeed be a potential source of antimicrobial agents.

Download Full-text

Antimicrobial Resistance Pilot Surveillance of Pigs and Chickens in Vietnam, 2017–2019

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.618497 ◽

2021 ◽

Vol 8 ◽

Author(s):

C. V. Tuat ◽

P. T. Hue ◽

N. T. P. Loan ◽

N. T. Thuy ◽

L. T. Hue ◽

...

Keyword(s):

Public Health ◽

Antimicrobial Resistance ◽

Antimicrobial Agents ◽

Multidrug Resistant ◽

Surveillance Program ◽

E Coli ◽

The North ◽

Disk Diffusion Assay ◽

Almost All ◽

The Impact

Antimicrobial use (AMU) and antimicrobial resistance (AMR) are a growing public health and economic threat in Vietnam. We conducted a pilot surveillance programme in five provinces of Vietnam, two in the south and three in the north, to identify antimicrobial resistance (AMR) in rectal swab samples from pigs and fecal samples from chickens at slaughter points during three different points in time from 2017 to 2019. Escherichia coli (E. coli) and non-typhoidal Salmonella (NTS) isolates were tested for antimicrobial susceptibility using disk diffusion assay for 19 antimicrobial agents belonging to nine antimicrobial classes and Etest for colistin (polymyxin). Almost all E. coli (99%; 1029/1042) and NTS (96%; 208/216) isolates were resistant to at least one antimicrobial agent; 94% (981/1042) of E. coli and 89% (193/216) of NTS isolates were multidrug-resistant (MDR). Higher proportions of E. coli and NTS isolated from chickens were resistant to all antimicrobial classes than those isolates from pigs. There was a significantly higher proportion of MDR NTS isolates from the southern provinces of Ho Chi Minh City and Long An (p = 0.008). Although there were increasing trends of NTS in proportion of resistance to fluoroquinolone over the three surveillance rounds, there was a significant decreasing trend of NTS in proportion of resistance to polymyxin (p = 0.002). It is important to establish an annual AMR surveillance program for livestock in Vietnam to assess the impact of interventions, observe trends and drive decision making that ultimately contributes to reducing AMR public health threat.

Download Full-text

SYNTHESIS CHARACTERIZATION AND ANTIMICROBIAL ACTIVITIES STUDIES OF N-{2-(4-CHLOROPHENYL) ACETYL} AMINO ALCOHOLS DERIVED FROM α-AMINO ACIDS

International Journal of Pharmaceutical Sciences and Drug Research ◽

10.25004/ijpsdr.2020.120102 ◽

2020 ◽

pp. 11-16

Author(s):

G. Venkateshappa ◽

G. Shivaraju ◽

P. Raghavendra Kumar

Keyword(s):

Amino Acids ◽

Amino Alcohols ◽

Antimicrobial Activities ◽

Docking Studies ◽

Moderate Activity ◽

E Coli ◽

Synthetic Drugs ◽

Antimicrobial Studies ◽

Ft Ir ◽

Derivatives Of

Amino acids play important roles in organisms to sustain in living state and perform as body constituents, enzymes and antibodies. At insalubrious situations, use of amino acids derivatives as drugs in the maintenance of normal health is better choice than common unnatural synthetic drugs. This is due to the fact that the amino acids derivatives may be more bio-compatible, biodegradable and eliminate easily than others. In this sense we have made an effort and report herein the synthesis of N-{2-(4-chlorophenyl) acetyl} amino alcohols synthesised by reduction of N-{2-(4-chlorophenyl)acetyl} derivatives of (S)-amino acids such as (S)-phenylalanine, (S)-alanine, (S)-methionine, (S)-leucine, (S)-tryptophan and (S)-proline. These newly synthesized amino acids derivatives were analysed by proton, carbon-13 NMR and FT-IR spectroscopy. The composition of solid derivatives was determined by elemental analysis. Further, antimicrobial activities of these derivatives were assessed on usual bacteria K. aerogenes, E. coli, S. aureus and P. desmolyticum and fungi A. flavus and C. albicans. The compounds were witnessed moderate activity than authorised antibacterial and fungal agents Ciprofloxacin and Fluconazole respectively. The antimicrobial studies also revealed that, these derivatives could be better antifungal agents than antibacterial agents. Finally we compared the experimental results of antimicrobial activities with docking studies.

Download Full-text

Synthesis of sulfonamides bearing 1,3,5-triarylpyrazoline and 4-thiazolidinone moieties as novel antimicrobial agents

Journal of the Serbian Chemical Society ◽

10.2298/jsc180621057t ◽

2020 ◽

Vol 85 (2) ◽

pp. 155-162

Author(s):

Thi-Dan Thach ◽

Thi Le ◽

Thien-Annguyen Nguyen ◽

Chi-Hien Dang ◽

Van-Su Dang ◽

...

Keyword(s):

Antimicrobial Agents ◽

Antimicrobial Activities ◽

Significant Inhibition ◽

Mercaptoacetic Acid ◽

Bacterial Strains ◽

Reference Drug ◽

E Coli ◽

Yeast Strains ◽

Microbial Strains

Two series of sulfonamides were synthesized from 4-hydrazinylbenzenesulfonamide as the key starting material. 1,3,5-Triarylpyrazoline sulfonamides (2a?i) were obtained by cyclocondensation of various chalcones in 53? ?64 % yields, while 4-thiazolidinone derivatives (4a?e) were synthesized by cyclocondensation between mercaptoacetic acid and different phenylhydrazones in 43?62 % yields. The synthesized compounds were characterized based on FTIR, 1H-NMR, 13C-NMR and HRMS data. The sulfonamides were evaluated for their in vitro antimicrobial activities against four bacterial strains (E. coli, P. aeruginosa, B. subtillis and S aureus), two filamentous fungal strains (A. niger and F. oxysporum) and two yeast strains (C. albicans and S. cerevisiae). Seven pyrazolines, 2a?c and 2e?h, exhibited significant inhibition of different microbial strains. Among them, compound 2b displayed good antifungal activity against A. niger (MIC value at 12.5 ?g mL-1) over the reference drug.

Download Full-text

Synthesis, antimicrobial activities and GAPDH docking of novel 1, 2, 3-triazole derivatives

Tropical Journal of Pharmaceutical Research ◽

10.4314/tjpr.v18i5.27 ◽

2021 ◽

Vol 18 (5) ◽

pp. 1101-1108

Author(s):

Abdulsalam A.M. Alkhaldi ◽

Mohamed A. Abdelgawad ◽

Bahaa G.M. Youssif ◽

Ahmed O. El-Gendy ◽

Harry P. De Koning

Keyword(s):

Staphylococcus Epidermidis ◽

Antimicrobial Agents ◽

Leishmania Major ◽

Antimicrobial Activities ◽

Docking Studies ◽

Moderate Activity ◽

Triazole Derivatives ◽

Lead Compounds ◽

Compound Ii

Purpose: To synthesize new triazole derivatives in order to overcome the problem of side effects of antimicrobial agents and microbial resistance, while broadening the spectrum of antimicrobial activity. Methods: The starting triazole, compound 1, was prepared through click chemistry and reacted with chloroacetyl chloride to yield compound II. Triazole 1 was reacted with acids and aldehydes to produce oxadiazole (III) and azomethine (IV) which cyclized in acetic anhydride to give a new acetylated oxadiazole (V). Minimum inhibitory concentration (MIC) and resorufin assays were used for antibacterial and anti-parasitic screening, respectively. Compounds II and IVb were subjected to molecular docking studies using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) Molecular Operating Environment (MOE) program. Results: Novel oxazole-triazole derivative (III) showed high activity against Pseudomonas aeruginosa and moderate activity against Staphylococcus epidermidis, whereas compound IVc showed moderate activity against Staphylococcus epidermidis. Chloro-acetyl-triazole II and 2-hydroxyphenyl-triazole Schiff base (Ivb) showed pronounced activity against the kinetoplastid parasites, Leishmania major, Leishmania mexicana and Trypanosoma brucei. Conclusion: The new synthesized triazoles represent a new antimicrobial scaffold and identifies potential new lead compounds for follow-up and for further mechanistic studies.

Download Full-text

Efficiency of Basil Essential Oil Antimicrobial Agents under Different Shading Treatments and Harvest Times

Agronomy ◽

10.3390/agronomy11081574 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1574

Author(s):

Zoran S. Ilić ◽

Lidija Milenković ◽

Ljubomir Šunić ◽

Nadica Tmušić ◽

Jasna Mastilović ◽

...

Keyword(s):

Antimicrobial Activity ◽

Essential Oil ◽

Essential Oils ◽

Antimicrobial Agents ◽

Antimicrobial Activities ◽

Plant Production ◽

Exposure Control ◽

Harvest Time ◽

E Coli ◽

Growing Conditions

The aim of this study was to determine the antimicrobial activity of essential oils obtained from sweet basil (Ocimum basilicum L. cv. ‘Genovese’) cultivated in the open field under different shading conditions (red, blue, and pearl nets with a shade index of 50% and full sunlight exposure (control plants)), harvested at different times. The antimicrobial activity of basil essential oils (BEOs) obtained from all samples was determined for four microorganisms, while determinations for an additional five microorganisms included samples from non-shaded plants, plants grown under red and pearl nets, and second harvest of plants grown under blue net. Basil essential oil exhibited antimicrobial activity surpassing the activity of relevant commercial antibiotics regardless of growing conditions in the case of B. cereus, K. pneumoniae and C. albicans, while superior antimicrobial activity was exhibited in the case of essential oils from plants grown under blue nets in the case of S. aureus, E. coli and P. vulgaris. The influence of the application of colored shading nets was highly significant (p < 0.01) in the cases of all analyzed microorganisms except C. albicans and P. aeruginosa, while the influence of harvest time was proven in the cases of all microorganisms except K. pneumoniae. ANOVA proved that antimicrobial activities are highly dependent on the methods of plant production, shading treatment, and harvest time. Obtained results are discussed in relation to previously determined composition and yield of essential oils from basil grown under shade nets and harvested in different periods.

Download Full-text

Synthesis and Biological Evaluation of Novel Aminochalcones as Potential Anticancer and Antimicrobial Agents

Molecules ◽

10.3390/molecules24224129 ◽

2019 ◽

Vol 24 (22) ◽

pp. 4129 ◽

Cited By ~ 3

Author(s):

Joanna Kozłowska ◽

Bartłomiej Potaniec ◽

Dagmara Baczyńska ◽

Barbara Żarowska ◽

Mirosław Anioł

Keyword(s):

Antimicrobial Activity ◽

Cell Lines ◽

Antimicrobial Agents ◽

Human Colon ◽

Biological Properties ◽

Biological Evaluation ◽

Human Colon Cancer ◽

E Coli ◽

Almost All ◽

Ht 29

A series of 18 aminochalcone derivatives were obtained in yields of 21.5–88.6% by applying the classical Claisen-Schmidt reaction. Compounds 4–9, 14 and 16–18 with 4-ethyl, 4-carboxy-, 4-benzyloxy- and 4-benzyloxy-3-methoxy groups were novel, not previously described in the scientific literature. To determine the biological properties of the synthesized compounds, anticancer and antimicrobial activity assays were performed. Antiproliferative potential was evaluated on four different human colon cancer cell lines—HT-29, LS180, LoVo and LoVo/DX —using the SRB assay and compared with green monkey kidney fibroblasts COS7. Anticancer activity was described as the IC50 value. The best results were observed for 2′-aminochalcone (1), 3′-aminochalcone (2) and 4′-aminochalcone (3) (IC50 = 1.43–1.98 µg·mL−1) against the HT-29 cell line and for amino-nitrochalcones 10–12 (IC50 = 2.77–3.42 µg·mL−1) against the LoVo and LoVo/DX cell lines. Moreover, the antimicrobial activity of all derivatives was evaluated on two strains of bacteria: Escherichia coli ATCC10536 and Staphylococcus aureus DSM799, the yeast strain Candida albicans DSM1386 and three strains of fungi: Alternaria alternata CBS1526, Fusarium linii KB-F1 and Aspergillus niger DSM1957. In the case of E. coli ATCC10536 almost all derivatives hindered the bacterial growth (∆OD = 0). Furthermore, the best results were observed in the presence of 4′-aminochalcone (3), that completely limited the growth of all tested strains at the concentration range of 0.25–0.5 mg·mL−1. The strongest bacteriostatic activity was exhibited by novel 3′-amino-4-benzyloxychalcone (14), that prevented the growth of E. coli ATCC10536 with MIC = 0.0625 mg·mL−1.

Download Full-text

New Oxadiazole Derivatives: Synthesis and Appraisal of Their Potential as Antimicrobial Agents

Letters in Drug Design & Discovery ◽

10.2174/1570180814666170425160545 ◽

2018 ◽

Vol 15 (1) ◽

pp. 21-30

Author(s):

Deboleena Dhara ◽

Dhanya Sunil ◽

Pooja R. Kamath ◽

K. Ananda ◽

S. Shrilakshmi ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Agents ◽

Drug Resistant ◽

Bacterial Strains ◽

Spectral Techniques ◽

Docking Simulations ◽

E Coli ◽

Oxadiazole Derivatives ◽

Bacteria And Fungi ◽

Almost All

Introduction: The escalating threat due to dwindling effect of antibiotics and challenge of tackling rising drug-resistant infections has gathered high focus in current medicinal research. Methods: In an attempt to find new molecules that can defeat microbial resistance, two new series of 2-[2-substituted ethenyl]-5-(substituted methoxy)-1,3,4-oxadiazole derivatives were synthesized. Various aromatic hydrazides were allowed to undergo cyclization to substituted oxadiazole-2- amines in the presence of cyanogen bromide and further condensed with different heterocyclic aldehydes to give new oxadiazole derivatives. The synthesized molecules were fully characterized by various spectral techniques and tested for antimicrobial activity. Results: Almost all the newly synthesized compounds especially (5g-5l) displayed remarkable growth inhibition against three bacterial strains: M. smegmatis, S. aureus, E. coli and fungi C. albicans. The antimicrobial activity was further confirmed by MIC assay against the same microorganisms. Oxadiazole 5g displayed promising activity with a MIC value of 0.025 mM for two bacteria and fungi, whereas MIC of this compound for E. coli was 0.1 mM. Other active compounds (5h-5l) also exhibited good MIC ranging between 0.313 to 5.0 mM against the selected microorganisms. Docking simulations were generated to explore the potential binding approaches of ligand 5g at the D-alanine:d-alanine ligase (Ddl) protein of E. coli and S. aureus. Conclusion: Molecule 5g was active even at a lower concentration and could probably act as a prospective lead molecule for targeting the drug resistant microorganisms.

Download Full-text