Intracellular and membrane-damaging activities of methyl gallate isolated from Terminalia chebula against multidrug-resistant Shigella spp.

Abstract

Shigella spp. (Shigella dysenteriae, Shigella flexneri, Shigella boydii and Shigella sonnei ) cause bacillary dysentery (shigellosis), which is characterized by bloody mucous diarrhoea. Although a variety of antibiotics have been effective for treatment of shigellosis, options are becoming limited due to globally emerging drug resistance. In the present study, in vitro antibacterial activity of methyl gallate (MG) isolated from Terminalia chebula was determined by performing MIC, minimal bactericidal concentration (MBC) and time-kill kinetic studies. Bacterial membrane-damaging activity of MG was determined by membrane perturbation and transmission electron microscopy (TEM). Cellular drug accumulation, cell infection and assessment of intracellular activities of MG and reference antibiotics were performed using HeLa cell cultures. The bactericidal activity of MG against multidrug-resistant (MDR) Shigella spp. in comparison with other commonly used drugs including fluoroquinolone was demonstrated here. TEM findings in the present study revealed that MG caused the total disintegration of inner and outer membranes, and leakage of the cytoplasmic contents of S. dysenteriae. The level of accumulation of MG and tetracycline in HeLa cells incubated for 24 h was relatively higher than that of ciprofloxacin and nalidixic acid (ratio of intracellular concentration/extracellular concentration of antibiotic for MG and tetracycline.ciprofloxacin and nalidixic acid). The viable number of intracellular S. dysenteriae was decreased in a timedependent manner in the presence of MG (46MBC) and reduced to zero within 20 h. The significant intracellular activities of MG suggested that it could potentially be used as an effective antibacterial agent for the treatment of severe infections caused by MDR Shigella spp.

Antibacterial-guided isolation of constituents from <i>Senna alata </i>leaves with a particular reference against Multi-Drug-Resistant <i>Vibrio cholerae </i>and <i>Shigella flexneri</i>

“…The strains of Vibrio cholerae NB2, PC2 (Thakurta et al, 2007;Bag et al, 2008) and Shigella flexneri (Acharyya et al, 2015) included in the present study were MDR strains and these were resistant to commonly used drugs such as ampicillin, streptomycin, tetracycline, nalidixic acid, furazolidone, cotrimoxazole, etc. However, these bacterial strains were found to be sensitive to most of the tested samples, suggesting that their administration may represent an alternative treatment against the V. cholerae, the causative agent of dreadful disease cholera and S. flexneri, the causative agent of shigellosis.…”

Anti-quorum quenching activity of methyl gallate isolated from galls of Guiera senegalensis J. F. Gmel (Combretaceae)

“…The isolation permitted the obtention of potent antivirulence compound. Based on its significant antibacterial activity (Choi et al, 2008;Acharyya et al, 2015), its in vivo anti-inflammatory activity (Correa et al, 2016) and its anti-virulence activity associated to its low molecular weight, MG may be an active ingredient for pharmaceutical preparation used for treating infections caused by bacteria.…”

“…This compound possess anti-quorum sensing (Hossain et al, 2017) like inhibitory activity on Streptococcus mutans biofilm formation (Kacergius et al, 2017). Methyl gallate has also been reported to possess various biological activities including antioxidative, antitumor, anti-apoptotic, antiviral, anti-inflammatory, antiasthmastic, antibacterial, anti-platelet, vasodilatative, inhibition of melanin synthesis, anti-HIV-1 enzyme and anti-HIV-1 replication properties, protection against DNA damage and lung injury due to oxidative stress, and attenuation of diabetic oxidative stress (Chaubal et al, 2005;Choi et al, 2008;Acharyya et al, 2015;Kamatham et al, 2015;Farhoosh and Nyström, 2018;Ng et al, 2018). Many species of Combretaceae family already showed potent antiquorum sensing activity.…”

Complex secondary metabolites from <i>Ludwigia leptocarpa</i> with potent antibacterial and antioxidant activities

“…These strains are able to produce cholera toxin and hemolysin (24,25). The other strains used in this study were non-O1 and non-O139 strains of V. cholerae (strains CO6 and PC2) (24) and strains of Shigella flexneri (26). The non-O1 and non-O139 strains of V. cholerae were positive for hemolysin production but negative for cholera toxin production (24).…”

“…Accordingly, compound 3 had significant antibacterial activity against V. cholerae CO6, V. cholerae NB2, V. cholerae PC2, S. flexneri, and S. aureus while compound 6 had significant antibacterial activity against Shigella flexneri SDINT and Staphylococcus aureus ATCC 25923. The strains of V. cholerae NB2, PC2 (24,25) and Shigella flexneri (26) included in the present study were MDR clinical isolates and these were resistant to commonly used drugs such as ampicillin, streptomycin, tetracycline, nalidixic acid, furazolidone, and co-trimoxazole. However, most of the tested samples displayed antibacterial activity against these microbial strains, suggesting that their administration may represent an alternative treatment for V. cholerae, the cause of the dreadful disease cholera, and S. flexneri, the cause of shigellosis.…”