Anti-microbial Studies of Potential Cyclopentanone derived Spiropyrroidines

 

Karunakar Badaghu, D. Gavaskar*

Department of Chemistry, School of Basic Sciences – Vels Institute of Science, Technology & Advanced Studies (VISTAS), Pallavaram

 

ABSTRACT:

A Series of Various cyclopentanone derived spiro-pyrrolidines were synthesized using 1,3-dipolar cycloaddition methodology . The compounds found to have very good antimicrobial properties and some of the compounds shown properties greater than the reference compounds. The attachment of cyclopentanone moiety to spiropyrrolidines enhanced the antimicrobial properties and it is shown in the results.

 

 

INTRODUCTION:

Great attention has been paid for curing diseases caused by microorganisms. Many infectous of pathogenic microorganisms develop resistance against the prevailing drugs, and this situation has necessitated a search for new source of compounds. Heterocyclic compounds, particularly five- and six-membered ring compounds have occupied a prominent place among the organic compounds in view of their diverse biological activities. The spiro-pyrrolidine and oxindole ring systems have acquired a prominent place among various heterocyclic compounds owing to their specific structural motif in many pharmacologically relevant alkaloids, as typyfied by rhyncoohylline, cornoxeine, mitraphylline, horsifline and spirotryprostatins.^1,2 Cycloalkanone derivatives are also important synthetic precursors for biologically active materials. ³

 

Cycloalkanone based compounds turn out to be nontoxic, less vulnerable to multi-drug resistance (MDR) and highly bioavailable because of being capable of penetrating the cell wall^4,.5

 

Cycloalkanone find widespread application as anti-inflammatory, diuretic, anabolic, contraceptive, antiandrogenic, progestational and anticancer agents.⁶

 

Many of the cycloalkanone heterocycles have been found to exhibit potent biological activities, such as anti-inflammatory, anabolic, anti-cancer and anti-microbial activities.^7-15 Recently, heterocyclic cycloalkanone derivatives have been found to exhibit potential antibacterial, antifungal and antiproliferative activities.¹⁶

 

With this perspective we have carried out bioactivity studies on some of the spiro-pyrrolidines and the results are discussed

 

MATERIAL AND METHODS:

Clinical Bacterial isolates:

All the pathogenic bacterial and fungal isolates were obtained from Department of Clinical Medical Microbiology, Apollo Hospital at Chennai-06, India. All the clinical isolates were identified by standard methods. From this departmental culture collection unit, clinically important bacterial isolates were obtained namely Staphylcoccus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli strains were used. Screening of antimicrobial activity was performed by following the sequence as given below:

1)   Preparation of Nutrient agar,

2)   Preparation of McFerland standards,

3)   Inoculums preparation and

4)   In vitro Antimicrobial Sensitivity Determination by Agar well diffusion method.

 

Preparation of nutrient agar:

The nutrient agar was prepared by dissolving beef extract (1.5g), peptone (0.5g), yeast extract (1.5g),  sodium chloride (0.5g) and agar (1.5g) in 100mL of distilled water. The pH was adjusted to 7.2 followed by sterilization in an autoclave at 121oC/15 Lb for 15minutes. The sterile molten agar media was then cooled to 50oC. About 15ml of the media was poured on a sterile petriplate and allowed to cool at room temperature.

 

Preparation of 0.5 Mcferland standards:

0.5 mL of solution A (1.175g of barium chloride in 100mL of distilled water) was added to 99.5 mL of solution B (1mL of 0.36 N sulfuric acid in 100mL of distilled water) and mixed well with magnetic stirrer, then disturbed in test tubes with a screw cap of the same size as those containing the bacterial culture, the turbidity of which must be evaluated.

 

Preparation of bacterial inoculums:

The cooled sterile broth medium was poured into sterile petri-plates having a uniform depth of 4 mm; this is equivalent to approximately 25mL in a 90mm plate. Once the medium had solidified then the culture was inoculated on the medium. The turbidity of the culture was adjusted with sterile cotton swab was immersed in the bacterial/fungal suspension and then rotated and compressed against the wall of the test tube so as to remove the excess fluid.

 

RESULTS AND DISCUSSION:

Invitro Antimicrobial Sensitivity Determination Test by Well Diffusion Method:

The invitro antimicrobial sensitivity of the antibiotics and the test compounds synthesized were determined by well diffusion method⁹ as recommended by the National Committee for Clinical Laboratory Standards (NCCLS).¹⁰ The well diffusion test was performed using medium, as per the procedure described by Magaldi et al., 2004. A sterilized 10 mm cork borer was used to make agar wells on the sterile cotton swab.

 

Spiropyyrolidines derived cyclopentanone

Table 1

Compounds	Escherichia coli		Pseudomonas		Bacillus substills		Staphylococcus
			Aeruginosa				Auerus
	50 μg/ml	100 μg/ml	50 μg/ml	100 μg/ml	50 μg/ml	100 μg/ml	50 μg/ml	100 μg/ml
1a	13.47	17.73	13.34	15.47	·	·-	·	·-
1b	19.89	21.11	18.89	21.11	·	13.33	·	·14.22
1c	·-	14.33	·-	·-	·-	·	·-	·-
1d	13.33	17.77	13.33	17.78	·	·-	13.33	15.45
1e	·	12.24	·	·-	·	·-	·	·-

 

Table 2:  Antibacterial activity of Kanamycin (10 μg/ml) against human pathogens

Given values are mean values of triplicate and standard deviations (Mean ± SD)

 

Table 3: Minimum Inhibitory concentration (MIC) of compounds against   human pathogens

COMPOUNDS	Minimum  inhibitory concentration (µg/ml)
	Gram negative		Gram positive
	Escherichia coli	Pseudomonas aeruginosa	Bacillus subtilis	Staphylococcus aureus
27a	50	100	ND	ND
27b	50	50	50	50
27c	100	ND	ND	ND
27d	50	100	100	ND
27e	100	ND	ND	100

ND: Not Determined

 

Compounds were dissolved in DMSO solvent separately and poured in the wells with varying concentrations ranging from 50μL and 100 μL using a micropipette. Antibiotic kanamycin (10mg/ml) was used as a standard to compare the results. The percentage of inhibition was calculated by the formula.

 

CONCLUSIONS:

Five synthetic compounds were tested for antibacterial activity against four pathogens Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus. All the compounds showed moderate activity against the tested pathogens. The bioactivity was tested at two different concentrations 50 to 100 μg/ml with reference compound Kanamycin. For the compounds 1a, 1b and 1d MIC was found to be 50 μg/ml against E.coli. and 1b exhibited MIC 50 μg/ml against P.aeruginosa. 1b showed same MIC against B.subtilis and S.aureus. The compounds 1a and 1d exhibited MIC at 100 μg/ml against P.aeruginosa while the same MIC was showed by 1d against Bacillus subtilis and 1e against S.aureus. The remaining compounds did not show any antibacterial activity against the tested pathogens (Table 3).

 

ACKNOWLEDGEMENTS:

V.S thanks of Vels Institute of Science, Technology & Advanced Studies (VISTAS), Pallavaram for providing necessary facilities to carried this research work.

 

REFERENCES:

1.      Bristol, J. A., Ed.; Annual Reports in Medicinal Chemistry, Academic Press: San Diego, 1990; Vol. 25 and earlier volumes in this series.

2.      (a) Henrickson, J. B.; Silva, R. A. J. Am. Chem. Soc. 1962, 34, 643. (b) Shavel, J.; Zinnes, H.   J. Am. Chem. Soc. 1963, 35, 1320.

3.      Taylor R. In: Thiophene and Its Derivatives. part 1. Gronowitz S, editor. Vol. 44.  Wiley; New York: 1985. ch.3.

4.      (a) Ismail, M. A.; El-baily, S. A.; Brun, R.; Wenzler, T.; Nanjunda, R.; Wilson, W. D.; Boykin, D. W. Bioorg & Med. Chem Lett. 2011, 19, 978. (b) Chou, Y.; Lai, M.C.; Hwang, T.; Ong, C.W. Bioorg & Med. Chem Lett. 1999, 9, 2643.

5.      Pettit, R. K.; Cage, G. D.; Pettit, G. R.; Liebman, J. A. Int J Antimicrob Agents 2000, 15, 299.

6.      Savage, P. B. Eur. J. Org. Chem. 2002, 5, 759.

7.      Savage, P. B. Microbiol  Lett.  2002, 217, 1.

8.      Banday, A. H.; Mir, B. P.; Lone, I. H.; Suri, K. A.; Kumar, H. M. S. Steroids  2010, 75, 805.

9.      Shan, L. H.; Liu, H. M.; Huang, K. X, Dai, G. F, Cao, C. Bioorg. Med.Chem. Lett. 2009, 19, 6637.

10.   Lange, C.; Holzhey, N.; Scho¨necker, B.; Beckert, R.; Mollmann, U.; Dahse, H. M. Bioorg. Med. Chem. 2004, 12, 3357.

 

 

Accepted on 30.09.2019           © RJPT All right reserved

Research J. Pharm. and Tech 2020; 13(2):850-852.