Study of the antibacterial and antifungal activities of synthetic benzyl bromides, ketones, and corresponding chalcone derivatives

Figures & data

Figure 1 General structure of chalcone.

Figure 2 Synthesized chalcones used in the present study; benzyl bromides (1a–c), substituted ketones (2a–c), and substituted chalcone derivatives (3a–c), where A: n=2, B: n=3, C: n=4.

Table 1 Pathogenic bacteria and fungi used for the antimicrobial assays

Bacterial strain	Fungal strain
Staphylococcus aureus	Candida albicans
Enterococcus faecalis	Candida krusei
Streptococcus pyogenes	Aspergillus niger
Pseudomonas aeruginosa
Escherichia coli
Shigella dysenteriae
Salmonella typhi
Citrobacter freundii
Enterobacter aerogenes
Klebsiella pneumoniae
Acinetobacter species

Table 2 The antibacterial activity of the prepared synthetic compounds, the inhibition zone is measured in millimeter

Compound names		Tested strains
		Gram-negative bacteria inhibition zone (mm)								Gram-positive bacteria inhibition zone (mm)
		Citrobacter freundii	Salmonella typhi	Acinetobacter species	Klebsiella pneumonia	Escherichia coli	Enterobacter aerogenes	Pseudomonas aeruginosa	Shigella dysenteriae inhibition zone	Enterococcus faecalis	Staphylococcus aureus	Streptococcus pyogenes
1	Bromo 1a	7	7	–	7	7	–	–	–	10	17	11
2	Bromo 1b	–	–	–	–	–	–	–	–	9	8	15
3	Bromo 1c	–	–	–	–	–	–	–	–	8	9	–
4	Ketone 2a	–	–	–	–	–	–	–	–	–	–	–
5	Ketone 2b	–	–	–	–	–	–	–	–	–	–	–
6	Ketone 2c	–	–	–	–	–	–	–	–	–	–	–
7	Chalcone 3a	–	–	–	–	–	–	–	–	–	–	–
8	Chalcone 3b	–	–	–	–	–	–	–	–	–	–	–
9	Chalcone 3c	–	–	–	–	–	–	–	–	–	–	–
+ve	Amoxicillin	–	24	13	–	10	–	–	–	25	35	30
−ve	Sterile DW	–	–	–	–	–	–	–	–	–	–	–

Notes: No inhibition (–), positive control (+ve), and negative control (−ve).

Abbreviation: DW, distilled water.

Table 3 The antifungal activity of the nine prepared synthetic compounds, the inhibition zone is measured in millimeter

Compound names		Tested pathogenic fungal strains
		Candida albicans	Candida krusei	Aspergillus niger
1	Bromo 1a	35	20	14
2	Bromo 1b	9	10	–
3	Bromo 1c	10	10	–
4	Ketone 2a	–	–	–
5	Ketone 2b	–	–	–
6	Ketone 2c	7	–	–
7	Chalcone 3a	–	–	–
8	Chalcone 3b	–	–	–
9	Chalcone 3c	–	–	–
+ve	Amoxicillin	14	14	13
−ve	Sterile DW	–	–	–

Notes: No inhibition (–), positive control (+ve), and negative control (−ve).

Abbreviation: DW, distilled water.

Table 4 The MIC values of benzyl bromides against pathogenic bacterial strains

Gram-positive bacteria	Bromo 1a, MIC (mg/mL)	Bromo 1b,MIC (mg/mL)	Bromo 1c, MIC (mg/mL)
Streptococcus pyogenes	2	–	0.5
Staphylococcus aureus	1	–	4
Enterococcus faecalis	2	–	2
Gram-negative bacteria
Klebsiella pneumoniae	2	–	4
Acinetobacter spp.	–	–	–
Enterobacter aerogenes	–	–	–
Salmonella typhi	2	–	4
Shigella dysenteriae	–	–	–
Escherichia coli	2	–	2
Citrobacter freundii	2.5	–	4
Pseudomonas aeruginosa	–	–	–

Note: Not detected (–).

Abbreviation: MIC, minimum inhibitory concentration.

Table 5 The MIC values of benzyl bromides against pathogenic fungal strains

Fungi	Bromo 1a (mg/mL)	Bromo 1b (mg/mL)	Bromo 1c (mg/mL)	Ketone 2c (mg/mL)
Candida albicans	0.25	–	1	–
Candida krusei	1	–	0.5	–
Aspergillus niger	1	–	–	–

Note: Not detected: (–).

Abbreviation: MIC, minimum inhibitory concentration.