Inhibition of microbial growth by ajoene, a sulfur-containing compound derived from garlic

Abstract

Ajoene, a garlic-derived sulfur-containing compound that prevents platelet aggregation, exhibited broadspectrum antimicrobial activity. Growth of gram-positive bacteria, such as Bacillus cereus, Bacillus subtilis, Mycobacterium smegmatis, and Streptomyces griseus, was inhibited at 5 g of ajoene per ml. Staphylococcus aureus and Lactobacillus plantarum also were inhibited below 20 g of ajoene per ml. For gram-negative bacteria, such as Escherichia coli, Klebsiella pneumoniae, and Xanthomonas maltophilia, MICs were between 100 and 160 g/ml. Ajoene also inhibited yeast growth at concentrations below 20 g/ml. The microbicidal effect of ajoene on growing cells was observed at slightly higher concentrations than the corresponding MICs. B. cereus and Saccharomyces cerevisiae were killed at 30 g of ajoene per ml after 24 h of cultivation when cultivation was started at 10 5 cells per ml. However, the minimal microbicidal concentrations for resting cells were at 10 to 100 times higher concentrations than the corresponding MICs. The disulfide bond in ajoene appears to be necessary for the antimicrobial activity of ajoene, since reduction by cysteine, which reacts with disulfide bonds, abolished its antimicrobial activity.

Optimising chitosan–pectin hydrogel beads containing combined garlic and holy basil essential oils and their application as antimicrobial inhibitor

“…Furthermore, many studies suggested that DATTS provided a potent antimicrobial activity (Rattanachaikunsopon & Phumkhachorn, 2008). The antimicrobial potential of GEO has been demonstrated to increase with the number of disulphide groups, corresponding to relative MIC values of DATTS < DATS < DADS, in controlling B. cereus, L. monocytogenes, S. aureus and E. coli (Naganawa et al, 1996;Rattanachaikunsopon & Phumkhachorn, 2008). Therefore, chitosan-pectin hydrogel beads loaded with GEO+H-BEO at 1:1, v/v could expectedly inhibit a wide range of microorganisms.…”

Antimicrobia activity of garlic (Allium sativum L.) and holy basil (Ocimum sanctum L.) essential oils applied by liquid vs. vapour phases

“…GEO (sample A, B) was comprised of DADS (31.67%, 27.19%), DATS (31.56%, 42.49%) and DATTS (13.48%, 9.92%), respectively. Several works reported that garlic oil has strong antimicrobial potency due to its disulphide groups (Naganawa et al, 1996;Hyldgaard et al, 2012;Pirak et al, 2012;El-sayed et al, 2017). Antimicrobial activity of GEO increased with the number of disulphide groups, corresponding to relative MIC values of DATTS < DATS < DADS (Kim et al, 2004;Kyung, 2012).…”

“…GEO sample B showed a similar antimicrobial pattern, except a moderate inhibition against S. typhimurium (10.50 mm). Previous studies found Gram-positive bacteria, such as B. cereus and S. aureus, to be susceptible to EOs, while Gram-negative bacteria, such as E. coli and S. enterica, were more resistant (Naganawa et al, 1996;Boufadi et al, 2016;El-sayed et al, 2017;Trinetta et al, 2017). Gram-negative bacteria have an outer layer of hydrophilic lipopolysaccharide, which acts as a barrier between the cytoplasmic membrane and hydrophilic compounds, protecting the cell membrane from volatile diffusion (Burt, 2004).…”

“…When crushed, alliin is enzymatically hydrolysed to form allicin (2-propenyl-2-propene-thiosulphinate), which is unstable and rapidly converts to volatile sulphides-, mainly 2-propenyl (allyl) derivatives (Avato et al, 2000). These organosulphur compounds, including diallyl sulphide, diallyl disulphide and diallyl trisulphide (Naganawa et al, 1996;Kim et al, 2004;Avato et al, 2000), possess antimicrobial properties due to disulphide bond, against B. cereus, Cl. botulinum, E. coli, Lb plantarum, L. monocytogenes, P. auroginosa, S. typhymurium and S. aureus (Naganawa et al, 1996;Rattanachaikunsopon & Phumkhachorn, 2008;Fujisawa et al, 2009;Pirak et al, 2012;Fratianni et al, 2016).…”

Activities of Z‐ajoene against tumour and viral spreading in vitro

“…In the Middle Ages, it was used to treat plague and cholera and in the World War I for curing wounds. Anti-bacterial activity of garlic is known from Pasteur since 1858 and its anti-proliferative, proapoptotic, anti-tumoral, anti-viral and anti-platelet aggregation properties are known for 50 years [1][2][3][4][5][6][7][8][9][10][11]. Garlic's efficacy depends on the activity of products resulting from the breakage of alliin into allicin.…”