scholarly journals Bioactive Compounds from the Bornean Endemic Plant Goniothalamus longistipetes

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 913
Author(s):  
Stephen P. Teo ◽  
Sanjib Bhakta ◽  
Paul Stapleton ◽  
Simon Gibbons
Keyword(s):  
Bioactive Compounds ◽  
Antibacterial Activities ◽  
Chloroform Extract ◽  
Spectroscopic Techniques ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Endemic Plant ◽  
Gram Positive ◽  
Gram Negative ◽  
Inhibitory Activities

The present study aimed to screen plants for bioactive compounds with potential antibacterial activities. In our efforts to evaluate plants from Borneo, we isolated and elucidated the structures of four natural products from the bioactive fraction of a chloroform extract of Goniothalamus longistipetes using various chromatographic and spectroscopic techniques. The bioactive compounds were identified as a known styryllactone, (+)-altholactone ((2S,3R,3aS,7aS)-3-hydroxy-2-phenyl-2,3,3a,7a-tetrahydrobenzo-5(4H)-5-one) (1), a new styryllactone, (2S,3R,3aS,7aS)-3-hydroxy-2-phenyl-2,3,3a,7a-tetrahydrobenzo-5(4H)-5-one) (2) as well as a new alkaloid, 2,6-dimethoxyisonicotinaldehyde (3) and a new alkenyl-5-hydroxyl-phenyl benzoic acid (4). 1 and 4 showed broad-spectrum anti-bacterial activities against Gram-positive and Gram-negative bacteria as well as acid-fast model selected for this study. Compound 2 only demonstrated activities against Gram-positive bacteria whilst 3 displayed selective inhibitory activities against Gram-positive bacterial strains. Additionally, their mechanisms of anti-bacterial action were also investigated. Using Mycobacterium smegmatis as a fast-growing model of tubercle bacilli, compounds 1, 2 and 4 demonstrated inhibitory activities against whole-cell drug efflux and biofilm formation; two key intrinsic mechanisms of antibiotic resistance. Interestingly, the amphiphilic compound 4 exhibited inhibitory activity against the conjugation of plasmid pKM101 in Escherichia coli using a plate conjugation assay. Plasmid conjugation is a mechanism by which Gram-positive and Gram-negative-bacteria acquire drug resistance and virulence. These results indicated that bioactive compounds isolated from Goniothalamus longistipetes can be potential candidates as ‘hits’ for further optimisation.

scholarly journals Synthesis and antimicrobial activity of some new N-(aryl-oxo-alkyl)-5-arylidene-thiazolidine-2,4-diones

2014 ◽  
Vol 79 (2) ◽  
pp. 115-123 ◽  
Author(s):  
Anca Stana ◽  
Brînduşa Tiperciuc ◽  
Mihaela Duma ◽  
Adrian Pîrnău ◽  
Philippe Verité ◽  
...  
Keyword(s):  
Antimicrobial Activities ◽  
Fungal Strain ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Reference Drug ◽  
Gram Negative ◽  
E Coli ◽  
Inhibitory Activities

A series of new 5-(2,6-dichlorobenzylidene)thiazolidine-2,4-dione and 5-(4-methoxy-benzylidene)thiazolidine-2,4-dione derivatives (3a-h and 5a-h) were synthesized starting from 5-arylidene-thiazolidine-2,4-dione and ?-halo-ketones. The structural elucidation of the newly synthesized compounds was based on elemental analysis and spectroscopic data (MS, 1H-NMR, 13C-NMR). The synthesized compounds were screened for their antimicrobial activities against several pathogenic strains of Gram-positive and Gram-negative bacteria and one fungal strain (Candida albicans), assessed in vitro as growth inhibition diameters. Some of them displayed better inhibitory activities than that of the reference drug against the Gram-positive S. aureus, B. cereus, L. monocytogenes bacterial strains, and showed good antifungal activity against C. albicans, while the antibacterial activity against Gram-negative E. coli and S. typhimurium bacterial strains was moderate.

scholarly journals Antibacterial activity of cobalt(II) complexes with some benzimidazole derivatives

2008 ◽  
Vol 73 (12) ◽  
pp. 1153-1160 ◽  
Author(s):  
S.O. Podunavac-Kuzmanovic ◽  
V.M. Leovac ◽  
D.D. Cvetkovic
Keyword(s):  
Antibacterial Activity ◽  
Chemical Structure ◽  
Antibacterial Activities ◽  
Benzimidazole Derivatives ◽  
Wall Structure ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative

The antibacterial activities of cobalt(II) complexes with two series of benzimidazoles were evaluated in vitro against three Gram-positive bacterial strains (Bacillus cereus, Staphylococcus aureus, and Sarcina lutea) and one Gram-negative isolate (Pseudomonas aeruginosa). The minimum inhibitory concentration was determined for all the complexes. The majority of the investtigated complexes displayed in vitro inhibitory activity against very persistent bacteria. They were found to be more active against Gram-positive than Gram-negative bacteria. It may be concluded that the antibacterial activity of the compounds is related to the cell wall structure of the tested bacteria. Comparing the inhibitory activities of the tested complexes, it was found that the 1-substituted- -2-aminobenzimidazole derivatives were more active than complexes of 1-substituted- 2-amino-5,6-dimethylbenzimidazoles. The effect of chemical structure on the antibacterial activity is discussed.

Antimicrobial Activity of Iron-Halide Complexes Against Gram-Positive and Gram-Negative Bacteria

2020 ◽  
Author(s):  
Nusrat Abedin ◽  
Abdullah Hamed A Alshehri ◽  
Ali M A Almughrbi ◽  
Olivia Moore ◽  
Sheikh Alyza ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Resistance ◽  
Extracellular Dna ◽  
Antibiofilm Activity ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Antimicrobial Substances ◽  
Mammalian Cell Lines

Antimicrobial resistance (AMR) has become one of the more serious threats to the global health. The emergence of bacteria resistant to antimicrobial substances decreases the potencies of current antibiotics. Consequently, there is an urgent and growing need for the developing of new classes of antibiotics. Three prepared novel iron complexes have a broad-spectrum antimicrobial activity with minimum bactericidal concentration (MBC) values ranging from 3.5 to 10 mM and 3.5 to 40 mM against Gram-positive and Gram-negative bacteria with antimicrobial resistance phenotype, respectively. Time-kill studies and quantification of the extracellular DNA confirmed the bacteriolytic mode of action of the iron-halide compounds. Additionally, the novel complexes showed significant antibiofilm activity against the tested pathogenic bacterial strains at concentrations lower than the MBC. The cytotoxic effect of the complexes on different mammalian cell lines show sub-cytotoxic values at concentrations lower than the minimum bactericidal concentrations.

scholarly journals In Vitro and In Vivo Antibacterial Activities of DW-224a, a New Fluoronaphthyridone

2006 ◽  
Vol 50 (6) ◽  
pp. 2261-2264 ◽  
Author(s):  
Hee-Soo Park ◽  
Hyun-Joo Kim ◽  
Min-Jung Seol ◽  
Dong-Rack Choi ◽  
Eung-Chil Choi ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
The Other ◽  
Vitro Activity ◽  
Gram Negative Bacteria ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.

scholarly journals Ultrasonic Irradiation: Synthesis, Characterization, and Preliminary Antimicrobial Activity of Novel Series of 4,6-Disubstituted-1,3,5-triazine Containing Hydrazone Derivatives

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hessa H. Al-Rasheed ◽  
Monirah Al Alshaikh ◽  
Jamal M. Khaled ◽  
Naiyf S. Alharbi ◽  
Ayman El-Faham
Keyword(s):  
Antimicrobial Activity ◽  
Ultrasonic Irradiation ◽  
New Products ◽  
Conventional Heating ◽  
Pyridine Derivative ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Antimicrobial And Antifungal Activities

Novel series of 4,6-disubstituted-1,3,5-triazines containing hydrazone derivatives were synthesized employing ultrasonic irradiation and conventional heating. The ultrasonication gave the target products in higher yields and purity in shorter reaction time compared with the conventional method. IR, NMR (H 1 and C 13), elemental analysis, and LC-MS confirmed the structures of the new products. The antimicrobial and antifungal activities were evaluated for all the prepared compounds against some selected Gram-positive and Gram-negative bacterial strains. The results showed that only two compounds 7i (pyridine derivative) and 7k (4-chlorobenzaldehyde derivative) displayed biological activity against some Gram-positive and Gram-negative bacteria, while the rest of the tested compounds did not display any antifungal activity.

scholarly journals Antibacterial and Cytotoxic Activities of the Sesquiterpene Lactones Cnicin and Onopordopicrin

2011 ◽  
Vol 6 (2) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
Sandra M. Bach ◽  
Mario A. Fortuna ◽  
Rodgoun Attarian ◽  
Juliana T. de Trimarco ◽  
César A. N. Catalán ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Sesquiterpene Lactones ◽  
Antibacterial Activities ◽  
Chloroform Extract ◽  
Cytotoxic Activities ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
High Cytotoxicity

The antimicrobial and cytotoxic activities of chloroform extracts from the weeds Centaurea tweediei and C. diffusa, and the main sesquiterpene lactones isolated from these species, onopordopicrin and cnicin, respectively, were assayed. Results show that the chloroform extracts from both Centaurea species possess antibacterial activities against a panel of Gram-positive and Gram-negative bacteria. Remarkable antibacterial activity against methicillin-resistant Staphylococcus aureus was also measured. Both the extracts and the purified sesquiterpene lactones show high cytotoxicity against human-derived macrophages. Despite this cytotoxicity, C. diffusa chloroform extract and cnicin are attractive candidates for evaluation as antibiotics in topical preparations against skin-associated pathogens.

scholarly journals Antibacterial Compounds from Glycosmis puberula Twigs

2014 ◽  
Vol 9 (12) ◽  
pp. 1934578X1400901
Author(s):  
Cholpisut Tantapakul ◽  
Tawanun Sripisut ◽  
Wisanu Maneerat ◽  
Thunwadee Ritthiwigrom ◽  
Surat Laphookhieo
Keyword(s):  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Isolation And Identification ◽  
Gram Positive ◽  
Antibacterial Compounds ◽  
Gram Negative ◽  
Spectroscopic Analyses ◽  
Phytochemical Investigation ◽  
Reported Data

The first phytochemical investigation of Glycosmis puberula twigs led to the isolation and identification of a new quinolone alkaloid, glycosmispuberulone (1), along with ten known compounds (2–11). The structures were elucidated by spectroscopic analyses and comparison with previously reported data. Their antibacterial activities against Gram-positive and Gram-negative bacteria were also evaluated.

scholarly journals Antibacterial Potential of Aloe weloensis (Aloeacea) Leaf Latex against Gram-Positive and Gram-Negative Bacteria Strains

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Yohannes Kelifa Emiru ◽  
Ebrahim Abdela Siraj ◽  
Tekleab Teka Teklehaimanot ◽  
Gedefaw Getnet Amare
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Infections ◽  
Inhibition Zone ◽  
Antibacterial Activities ◽  
Maximum Activity ◽  
New Drugs ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative

Objective. To evaluate the antibacterial effects of the leaf latex of Aloe weloensis against infectious bacterial strains. Methods. The leaf latex of A. weloensis at different concentrations (400, 500, and 600 mg/ml) was evaluated for antibacterial activities using the disc diffusion method against some Gram-negative species such as Escherichia coli (ATCC 14700) and Pseudomonas aeruginosa (ATCC 35619) and Gram-positive such as Staphylococcus aureus (ATCC 50080) and Enterococcus fecalis (ATCC 4623). Results. The tested concentrations of the latex ranging between 400 and 600 mg·mL−1 showed significant antibacterial activity against bacterial strain. The highest dose (600 mg/ml) of A. weloensis leaf latex revealed the maximum activity (25.93 ± 0.066 inhibition zone) followed by the dose 500 mg/ml against S. aureus. The lowest antibacterial activity was observed by the concentration 400 mg/ml (5.03 ± 0.03) against E. coli. Conclusion. The results of the present investigation suggest that the leaf latex of A. weloensis can be used as potential leads to discover new drugs to control some bacterial infections.

scholarly journals Hybrid Approach for Synthesis and Antimicrobial Activity of Heterocyclic Compounds

2018 ◽  
Vol 77 ◽  
pp. 35-52 ◽  
Author(s):  
Nisheeth C. Desai ◽  
Darshita V. Vaja
Keyword(s):  
Antimicrobial Activity ◽  
Heterocyclic Compounds ◽  
Hybrid Approach ◽  
Spectroscopic Techniques ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Microbial Strains

We have synthesized novel series of N-(1-(2-(1-phenyl-3-(p-tolyl)-1H-pyrazol-4-yl)-5-(pyridin-4-yl)-1,3,4-oxadiazol-3(2H)-yl)ethylidene)arylaniline and their derivatives. The structures of synthesized compounds were well characterized by spectroscopic techniques. Antimicrobial activity of the newly synthesized derivatives was evaluated against gram positive (S. aureus and S. pyogenes), gram negative bacteria (E. coli and P. aeruginosa), and strains of fungi (C. albicans, A. niger and A. clavatus). Among the screened derivatives 5c, 5f, 5i, 5l and 5t demonstrated superior antimicrobial activity against microbial strains.

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