scholarly journals Synthesis and Antibacterial Activity of Hydroxy and Chloro-Substituted Chalcone Derivatives

Author(s):  
Shaik Ammaji ◽  
Shaik Masthanamma

Chalcones are a class of natural products reported with a wide range of biological activities. Among them antibacterial is much promising and many potent chalcones have been emerged as useful antibacterial agents. In view of this, we synthesized 15 chalcones (3a-3o) containing both hydroxyl and chlorine substituents and studied them by using spectroscopic methods. The compounds were tested for antibacterial efficacy against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Proteus vulgaris, among other harmful microorganisms. The compounds have moderate to high antibacterial activity, among them heteroaromatic ring containing compounds  (3m, 3n, and 3o) elicited higher activity than the standard drug benzyl penicillin. The compound 3m having the pyridinyl compound displayed the maximum activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Proteus vulgaris, with zone of inhibition (in mm) values of 27.52±0.16, 28.85±0.11, 22.05±0.16, and 23.18±0.17, respectively. The synthesized compounds could be used as lead molecules in the development of novel antibacterial medicines.

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2278
Author(s):  
Mohammad Y. Alshahrani ◽  
Zeeshan Rafi ◽  
Nadiyah M. Alabdallah ◽  
Ambreen Shoaib ◽  
Irfan Ahmad ◽  
...  

Rauwolfia serpentina (R. serpentina), belonging to the family Apocynaceae, is a renowned medicinal herb for its different pharmacological activities such as antibacterial, antifungal, anti-inflammatory, and antiproliferative characteristics. This study has done a comparative assessment of the antibacterial, antioxidant, and anti-cancer activity of R. serpentina aqueous leaf extract (RSALE) with encapsulated gold nanoparticles (R-AuNPs). The R-AuNPs are prepared so that they are significant in size, monodispersed, and extremely stable. Their characterization was done by numerous parameters, including UV-visible spectroscopy (528 nm), transmission electron microscopy (~17 d. nm), dynamic light scattering (~68 d. nm), and zeta-potential (~−17 mV). Subsequently, a potent antibacterial activity was depicted via RSALE and R-AuNPs when examined by disc diffusion against various Gram-positive and Gram-negative bacterial strains. The obtained zones of inhibition of RSALE (100 mg/mL) were 34 ± 0.1, 35 ± 0.1, 28.4 ± 0.01, and 18 ± 0.01, although those of R-AuNPs (15 mg/mL) were 24.4 ± 0.12, 22 ± 0.07, 20 ± 0.16, and 17 ± 0.3 against Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Bacillus subtilis (MTCC 8114), and Streptococcus pyogenes (ATCC 19615), respectively. However, no zone of inhibition was obtained when tested against Proteus vulgaris (MTCC 1771). Furthermore, the obtained MIC values for Staphylococcus aureus were 0.91, 0.61, and 1.15 mg/mL; for Escherichia coli, 0.79, 0.36, and 1.02 mg/mL; for Bacillus subtilis 0.42, 0.27, and 0.474 mg/mL; and for Streptococcus pyogenes, 7.67, 3.86, and 8.5 mg/mL of pure RSALE, R-AuNPs, and Amoxicillin (control), respectively, incorporating that R-AuNPs have been shown to have a 1.4-fold, 2.1-fold, 1.5-fold, and 1.9-fold enhanced antibacterial activity in contrast to pure RSALE tested against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Streptococcus pyogenes, and Proteus vulgaris, respectively. Additionally, an enhanced antioxidant potential was detected in R-AuNPs compared to RSALE evaluated by the 2,2-Diphenyl-1-Picryl Hydrazyl Radical Scavenging (DPPH) Ferric reducing antioxidant power (FRAP) assay. The determined IC 50 values of RSALE and R-AuNPs were 0.131 ± 0.05 and 0.184 ± 0.02 mg/mL, and 0.110 ± 0.1 and 0.106 ± 0.24 mg/mL via the FRAP and DPPH assays, respectively. In addition, the anti-cancer activity against the human cervical cancer (Hela) cell line was evaluated, and the MTT assay results revealed that R-AuNPs (IC50 88.3 µg/mL) had an enhanced anti-cancer potential in contrast to RSALE (171.5 µg/mL). Subsequently, the findings of this study indicated that R. serpentina leaves and their nanoformulation can be used as a potent source for the treatment of the above-mentioned complications and can be used as a possible agent for novel target-based therapies for the management of different ailments.


2020 ◽  
Vol 15 (6) ◽  
pp. 665-679
Author(s):  
Alok K. Srivastava ◽  
Lokesh K. Pandey

Background: [1, 3, 4]oxadiazolenone core containing chalcones and nucleosides were synthesized by Claisen-Schmidt condensation of a variety of benzaldehyde derivatives, obtained from oxidation of substituted 5-(3/6 substituted-4-Methylphenyl)-1, 3, 4-oxadiazole-2(3H)-one and various substituted acetophenone. The resultant chalcones were coupled with penta-O-acetylglucopyranose followed by deacetylation to get [1, 3, 4] oxadiazolenone core containing chalcones and nucleosides. Various analytical techniques viz IR, NMR, LC-MS and elemental analysis were used to confirm the structure of the synthesised compounds.The compounds were targeted against Bacillus subtilis, Staphylococcus aureus and Escherichia coli for antibacterial activity and Aspergillus flavus, Aspergillus niger and Fusarium oxysporum for antifungal activity. Methods: A mixture of Acid hydrazides (3.0 mmol) and N, Nʹ- carbonyl diimidazole (3.3 mmol) in 15 mL of dioxane was refluxed to afford substituted [1, 3, 4]-oxadiazole-2(3H)-one. The resulted [1, 3, 4]- oxadiazole-2(3H)-one (1.42 mmol) was oxidized with Chromyl chloride (1.5 mL) in 20 mL of carbon tetra chloride and condensed with acetophenones (1.42 mmol) to get chalcones 4. The equimolar ratio of obtained chalcones 4 and β -D-1,2,3,4,6- penta-O-acetylglucopyranose in presence of iodine was refluxed to get nucleosides 5. The [1, 3, 4] oxadiazolenone core containing chalcones 4 and nucleosides 5 were tested to determined minimum inhibitory concentration (MIC) value with the experimental procedure of Benson using disc-diffusion method. All compounds were tested at concentration of 5 mg/mL, 2.5 mg/mL, 1.25 mg/mL, 0.62 mg/mL, 0.31 mg/mL and 0.15 mg/mL for antifungal activity against three strains of pathogenic fungi Aspergillus flavus (A. flavus), Aspergillus niger (A. niger) and Fusarium oxysporum (F. oxysporum) and for antibacterial activity against Gram-negative bacterium: Escherichia coli (E. coli), and two Gram-positive bacteria: Staphylococcus aureus (S. aureus) and Bacillus subtilis(B. subtilis). Result: The chalcones 4 and nucleosides 5 were screened for antibacterial activity against E. coli, S. aureus and B. subtilis whereas antifungal activity against A. flavus, A. niger and F. oxysporum. Compounds 4a-t showed good antibacterial activity whereas compounds 5a-t containing glucose moiety showed better activity against fungi. The glucose moiety of compounds 5 helps to enter into the cell wall of fungi and control the cell growth. Conclusion: Chalcones 4 and nucleosides 5 incorporating [1, 3, 4] oxadiazolenone core were synthesized and characterized by various spectral techniques and elemental analysis. These compounds were evaluated for their antifungal activity against three fungi; viz. A. flavus, A. niger and F. oxysporum. In addition to this, synthesized compounds were evaluated for their antibacterial activity against gram negative bacteria E. Coli and gram positive bacteria S. aureus, B. subtilis. Compounds 4a-t showed good antibacterial activity whereas 5a-t showed better activity against fungi.


2018 ◽  
Vol 42 (10) ◽  
pp. 512-514
Author(s):  
Rui-bo Xu ◽  
Xiao-tian Yang ◽  
Hai-nan Li ◽  
Peng-cheng Zhao ◽  
Jiao-jiao Li ◽  
...  

Two new bis-Schiff bases containing a piperazine ring, N,N‘-bis(4-chlorobenzylidene)- and N,N‘-bis(4-cyanobenzylidene)-1,4-bis(3-aminopropyl)piperazine, were prepared by the reaction of N,N‘-bis(3-aminopropyl)piperazine with 4-chloro- and 4-cyanobenzaldehyde, respectively. The dichloro compound was fully identified by X-ray crystallography and it exhibited good antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis.


Author(s):  
Haribhai Rabari ◽  
Hetal Vankar ◽  
Beenkumar Prajapati

The emergence of multidrug microbial resistance is the main challenges that the modern scientists have so far been facing in the recent era. In this respect, new series of drug classes having potential to give antimicrobial effect have been synthesized. A new series of 5- substituted-1,10 b-dihydroimidazole[1,2-c]quinazoline derivatives 8a-e have been synthesized and screened for antibacterial activity and antifungal activity. Synthesized derivatives were characterized by IR, MASS and 1H-NMR spectroscopy. Synthesized compounds show good activity, which was comparable to the standard drug and it can be useful for the further clinical study. Antibacterial activity was evaluated against four different pathogenic bacterial strains like Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudo-monas aeruginosa. Among the screened compounds, 8e show good antibacterial activity against Staphylococcus aureus and Escherichia coli with MIC of 50 and 100 μg/ml respectively. Antifungal activity was evaluated  against two strains of fungi. Among the synthesized derivates, compound 8c was emerged out as the potent antifungal compound against Candida albicans and Aspergillus niger with MIC of 25 μg/ml and 75μg/ml respectively. Compound 8e also shows good antifungal activity with MIC of 50 μg/ml against both Candida albicans and Aspergillus niger. The overall results of this study indicated that  synthesized quinazoline derivatives had the potential to act as an antibacterial and antifungal agent, hence further investigation is warranted.


2017 ◽  
Vol 901 ◽  
pp. 124-132
Author(s):  
Artania Adnin Tri Suma ◽  
Tutik Dwi Wahyuningsih ◽  
Deni Pranowo

Some novel N-phenylpyrazolines were synthesized and investigated for their antibacterial activitiy. Chalcones 2-4 which were prepared from acetophenone and veratraldehyde derivatives were reacted with phenylhydrazine to give N-phenylpyrazolines 5-7. All of the synthesized compounds were characterized using FTIR, GC-MS, and NMR spectrometers. Further, antibacterial activity of N-phenylpyrazolines were evaluated by agar well-diffusion method against Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Escherichia coli, and Shigella flexneri. The highest activity (highest inhibition zone) of compound 5 was 2.6 mm (at 1000 ppm) against B. subtillis, compound 6 was 7.25 mm (at 1000 ppm) against S. aureus, and compound 7 was 6.75 mm (at 500 ppm) against S. aureus. The results indicated that compound 6 and 7 exhibited promising antibacterial activity.


2000 ◽  
Vol 55 (9-10) ◽  
pp. 778-784 ◽  
Author(s):  
Josep Serra Bonvehí ◽  
Francesc Ventura Coll

Abstract The composition, bacteriostatic and ROO• -scavenging potential activities of fifteen propolis samples from various botanic and geographic origins were determined to obtain objective information related to propolis quality. Variance analysis showed significant differences (p ≤ 0.05) in the contents of polyphenols, flavonoids and active components between fresh and aged propolis. The state of the product (fresh or aged) could be differentiate by using flavonoid pattern and biological activities. A minimum propolis concentration of 80 μg/ml was required inhibit Bacillus subtilis and Staphylococcus aureus while 800 μg/ml was required to inhibit Escherichia coli using fresh propolis. Aged propolis inhibit B. subtilis and S. aureus at concentration of 100 μg/ml and E. coli at 1000 μg/ml. A minimum flavonoids percentage of 18 g/100 g and a maximum ROO• -scavenging potential activity of 4.3 μg/ml were determined in fresh propolis. Flavonoids levels in aged propolis were approximately 20% lower than in fresh propolis. A maximum flavonoids percentage of 19.8 g/100 g and a ROO•-scavenging potential activity between 5.7 to 6.4 μg/ml in aged propolis were quantified. Another objective was to assess the use of ROO•-scavenging potential activity in propolis quality.


2020 ◽  
Vol 32 (9) ◽  
pp. 2262-2266
Author(s):  
SHERAZ KHAN ◽  
SANIYA HASHIM KHAN ◽  
INAM ULLAH KHAN ◽  
WALI INAM ◽  
MUHAMMAD ASIM ◽  
...  

Herbal medicines has been the most cost-effective and valuable medical practice to cure diseases and emphasize modern health care treatment. The present research was conducted to assess the biological activities of 10 fractions obtained from methanolic extract which was derived from dried seeds of Sesamum indicum. Antioxidant activity was assessed using DPPH radical scavenging, total antioxidant capacity and total reducing power assays. Highest free radical scavenging activity (80.3 ± 1.36%), total antioxidant capacity (104.7 ± 4.04 μg AAE/mg) and ferric reducing power activity (238.76 ± 1.23 μg AAE/mg) was shown by fraction SE. Fraction SE showed the highest phenolic contents (63.72 ± 1.5 μg GAE/mg) while fraction SG sample showed highest flavonoid contents (54.62 ± 2.61 μg QE QE/mg). Antibacterial activity was performed against four selected bacterial strains including Staphylococcus aureus, Escherichia coli, Enterobacter aerogens and Bacillus subtilis. Highest inhibition was shown by fraction SD (11 ± 1.04 mm) against Staphylococcus aureus, fraction SH against Bacillus subtilis (11 ± 1.06 mm) and fraction SB against Escherichia coli. All fractions were found inactive against the selected fungal strains. While performing antileishmanial activity, fraction SC showed highest percent mortality (78%) of Leishmania tropica. In brine shrimp lethality bioassay, fraction SG showed significant LD50 value (23.48 μg/mL).


Author(s):  
Kaur M. ◽  
Sharma S. ◽  
Garg S. ◽  
Arora M.

This study describes the antibacterial activities of three different solvent extracts of leaves of Chenopodium album. Methanol, acetone and chloroform extracts of C. album were prepared. The antibacterial activity was assessed using well plate method and were examined for the size of zone of inhibition. Different extracts were investigated against the test organisms namely Lactobacillus, Bacillus subtilis and Escherichia coli. The maximum activity was observed at 100% concentration of different extracts of leaves. The maximum zone of inhibition for 100% concentration were observed as E. coli (19 mm) and Lactobacillus (19 mm) in diameter respectively. C. album did not show any antibacterial activity against B. subtilis. Antibacterial activity was compared with standard Amoxicillin and it was found to be 23 mm diameter for Lactobacillus and 25 mm for both E. coli and B. subtilis in terms of zone of inhibition.


2021 ◽  
Vol 251 ◽  
pp. 02061
Author(s):  
Xiaojuan Gao ◽  
Xiaoshi Lu ◽  
Zifeng Wang ◽  
Guangpeng Liu ◽  
Xinjun Li

Taking monascin as the research object, monascin was extracted from red kojic rice by ethanol extraction and extracted with 60%, 70% and 80% ethanol respectively. Finally, it was concluded that when the concentration of ethanol was 70%, the extraction rate of monascin was the highest, reached 75.68%. The bacteriostatic experiments of monascin extract and monascin fermentation showed that it had strong inhibitory effect on Staphylococcus aureus and Bacillus subtilis, weak inhibitory ability on Escherichia coli and Aspergillus niger, and no obvious inhibitory effect on the growth of Saccharomyces cerevisiae.


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