Study on Antibacterial Activity of Radix isatidis Extracts and Preliminary Investigation of Their Antibacterial Mechanism

Abstract Background Plant secondary metabolites and phytochemicals that exhibit strong bioactivities have potential to be developed as safe and efficient natural antimicrobials against food contamination and addressing antimicrobial resistance caused by the overuse of chemical synthetic preservative. In this study, the chemical composition, antibacterial activities and related mechanism of the extracts of the valonia and the shell of Quercus variabilis Blume were studied to determine its potential as a safe and efficient natural antimicrobial. Methods The phenolic compositions of valonia and shell extracts were determined by folin-ciocalteau colourimetric method, sodium borohydride/chloranil-based assay and the aluminium chloride method and then further identified by the reverse-phase HPLC analysis. The antibacterial activities of valonia and shell extracts were evaluated by the agar disk diffusion method and agar dilution method. The related antibacterial mechanism was explored successively by the membrane of pathogens effect, phosphorous metabolism, whole-cell proteins and the microbial morphology under scanning electron microscopy. Results The n-butanol fraction and water fraction of valonia along with n-butanol fraction of the shell contains enrich phenolics including ellagic acid, theophylline, caffeic acid and tannin acid. The n-butanol fraction and ethanol crude extracts of valonia exhibited strong antibacterial activities against Salmonella paratyphi A (S. paratyphi A) and Staphylococcus aureus (S. aureus) with the DIZ values ranged from 10.89 ± 0.12 to 15.92 ± 0.44, which were greater than that of the Punica granatum (DIZ: 10.22 ± 0.18 and 10.30 ± 0.21). The MIC values of the n-butanol fraction and ethanol crude extracts of valonia against S. paratyphi A and S. aureus were 1.25 mg/ml and 0.625 mg/ml. The related antibacterial mechanism of n-butanol fraction and ethanol crude extracts of valonia may be attributed to their strong impact on membrane permeability and cellular metabolism. Those extracts exhibited strong antibacterial activity according to inhibit the synthesis of bacterial proteins and seriously change morphological structure of bacterial cells. Conclusions The n-butanol fraction and ethanol crude extracts of valonia had reasonably good antibacterial activities against S. paratyphi A and S. aureus. This study suggests possible application of valonia and shell as natural antimicrobials or preservatives for food and medical application.

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On the Mechanism of Berberine–INF55 (5-Nitro-2-phenylindole) Hybrid Antibacterials

Australian Journal of Chemistry ◽

10.1071/ch14426 ◽

2014 ◽

Vol 67 (10) ◽

pp. 1471 ◽

Cited By ~ 9

Author(s):

Naveen K. Dolla ◽

Chao Chen ◽

Jonah Larkins-Ford ◽

Rajmohan Rajamuthiah ◽

Sakthimala Jagadeesan ◽

...

Keyword(s):

Drug Resistance ◽

Antibacterial Activity ◽

Multidrug Resistance ◽

Inhibitory Activity ◽

Antibacterial Drug ◽

Antibacterial Mechanism ◽

Antibacterial Effects ◽

Antibacterial Drug Resistance

Berberine–INF55 hybrids are a promising class of antibacterials that combine berberine and the NorA multidrug resistance pump inhibitor INF55 (5-nitro-2-phenylindole) together in one molecule via a chemically stable linkage. Previous studies demonstrated the potential of these compounds for countering efflux-mediated antibacterial drug resistance but they didn’t establish whether the compounds function as originally intended, i.e. with the berberine moiety providing antibacterial activity and the attached INF55 component independently blocking multidrug resistance pumps, thereby enhancing the activity of berberine by reducing its efflux. We hypothesised that if the proposed mechanism is correct, then hybrids carrying more potent INF55 pump inhibitor structures should show enhanced antibacterial effects relative to those bearing weaker inhibitors. Two INF55 analogues showing graded reductions in NorA inhibitory activity compared with INF55 were identified and their corresponding berberine–INF55 hybrids carrying equivalent INF55 inhibitor structures synthesised. Multiple assays comparing the antibacterial effects of the hybrids and their corresponding berberine–INF55 analogue combinations showed that the three hybrids all show very similar activities, leading us to conclude that the antibacterial mechanism(s) of berberine–INF55 hybrids is different from berberine–INF55 combinations.

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Preliminary Investigation of the Antibacterial Activity of Psidium guajava Extracts

European Journal of Medicinal Plants ◽

10.9734/ejmp/2015/14307 ◽

2015 ◽

Vol 7 (1) ◽

pp. 26-30 ◽

Cited By ~ 1

Author(s):

Iroha Ifeanyichukwu ◽

Ejikeugwu Chika ◽

Nwakaeze Emmanuel ◽

Oji Anthonia ◽

Afiukwa Ngozi ◽

...

Keyword(s):

Antibacterial Activity ◽

Preliminary Investigation ◽

Psidium Guajava

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The antibacterial activity and antibacterial mechanism of a polysaccharide from Cordyceps cicadae

Journal of Functional Foods ◽

10.1016/j.jff.2017.09.047 ◽

2017 ◽

Vol 38 ◽

pp. 273-279 ◽

Cited By ~ 45

Author(s):

Yu Zhang ◽

Yu-Ting Wu ◽

Wei Zheng ◽

Xiao-Xuan Han ◽

Yao-Huang Jiang ◽

...

Keyword(s):

Antibacterial Activity ◽

Antibacterial Mechanism ◽

Cordyceps Cicadae

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Size-controlled growth and antibacterial mechanism for Cu:C nanocomposite thin films

Physical Chemistry Chemical Physics ◽

10.1039/c6cp06955j ◽

2017 ◽

Vol 19 (1) ◽

pp. 237-244 ◽

Cited By ~ 26

Author(s):

Amjed Javid ◽

Manish Kumar ◽

Seokyoung Yoon ◽

Jung Heon Lee ◽

Jeon Geon Han

Keyword(s):

Thin Films ◽

Antibacterial Activity ◽

Volume Fraction ◽

Size Reduction ◽

Antibacterial Mechanism ◽

Cu Nanoparticles ◽

Plasma Energy ◽

Fixed Volume ◽

Nanocomposite Thin Films ◽

Size Controlled

Plasma energy induced size reduction of Cu nanoparticles (at fixed volume fraction) in C matrix demonstrated effective antibacterial activity.

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A Preliminary Investigation on the In-Vitro Antibacterial Activities of Cave Actinomycetes

Journal of Mountain Research ◽

10.51220/jmr.v16i3.41 ◽

2021 ◽

Vol 16 (3) ◽

Author(s):

Asifa Mushtaq ◽

Musharaf Gul ◽

Seema Rawat ◽

Jay Krishan Tiwari

Keyword(s):

Antibacterial Activity ◽

Secondary Metabolites ◽

Scientific Community ◽

Preliminary Investigation ◽

Antibacterial Properties ◽

Antibacterial Activities ◽

Industrial Applications ◽

Gram Positive Bacteria ◽

Streptomyces Genus

Actinomycetes are prolific producers of secondary metabolites majority of which have phenomenal industrial applications. Actinomycetes recovered from cave habitats have generated a considerable interest among the scientific community with respect to their adaptability under such unique environmental conditions. Garhwal Himalaya, Uttarakhand abodes several pristine caves which have not been previously explored for the presence of actinomycetes. The present study has been undertaken to assess the in vitro antibacterial properties of actinomycetes recovered from some of the caves located in Garhwal Himalayan region. In the present study, a total of 127 actinomycetes were isolated from three distinct caves. Majority of the isolates exhibited antibacterial activity against gram-positive bacteria. Actinomycetes isolates RCM1 and SCMM1 were observed to evince promising antibacterial activities. Members of Streptomyces genus were found to be predominant in all the samples.

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Investigation of the Antibacterial Mechanism of Aflatoxins in the BioArena System

Natural Product Communications ◽

10.1177/1934578x1100600517 ◽

2011 ◽

Vol 6 (5) ◽

pp. 1934578X1100600

Author(s):

Ágnes M. Móricz ◽

Péter G. Ott ◽

Klára H. Otta ◽

Ernő Tyihák

Keyword(s):

Amino Acids ◽

Antibacterial Activity ◽

Toxic Effect ◽

Antibacterial Effect ◽

Indigo Carmine ◽

Antibacterial Mechanism ◽

Phytopathogenic Bacterium ◽

Toxic Activity ◽

Basic Amino Acids ◽

Inhibition Zones

The influence of monomethylated basic amino acids [NG-monomethyl-L-arginine (MMA) and Nε-monomethyl-L-lysine (MML)] and ozone capturers (indigo carmine, d-limonene) on the antibacterial effect of the mycotoxins aflatoxins B1, B2, G1 and G2 was studied in BioArena, which is a complex bioautographic system especially suitable for investigating biochemical interactions. In the presence of the formaldehyde precursors MMA or MML, the antibacterial-toxic activity of all the aflatoxins against the phytopathogenic bacterium Pseudomonas savastanoi pv. phaseolicola was enhanced dose-dependently. Indigo carmine and d-limonene, in appropriate concentrations, decreased the inhibition zones of aflatoxins. These results support the original idea that HCHO and its derivative O3 may be involved in the antibacterial activity of aflatoxins and so, potentially, in their known toxic effect.

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Preliminary Investigation of the Antibacterial Activity of Antitumor Drug 3-Amino-1,2,4-Benzotriazine-1,4-Dioxide (Tirapazamine) and its Derivatives

Applied Sciences ◽

10.3390/app10124062 ◽

2020 ◽

Vol 10 (12) ◽

pp. 4062 ◽

Cited By ~ 1

Author(s):

Evelina Polmickaitė-Smirnova ◽

Jonas Šarlauskas ◽

Kastis Krikštopaitis ◽

Živilė Lukšienė ◽

Zita Staniulytė ◽

...

Keyword(s):

Antibacterial Activity ◽

Density Functional ◽

Preliminary Investigation ◽

Structural Features ◽

Antitumor Drug ◽

Additive Effects ◽

Bacterial Strains ◽

Functional Theory ◽

Inhibitory Activities

The antitumor drug 3-amino-1,2,4-benzotriazine-1,4-dioxide (tirapazamine, TPZ (1)) along with a number of newly synthesized tirapazamine derivatives (TPZs) bearing substitutions at the 3-amine position of TPZ (1) were estimated for their antibacterial activity against representative Gram-negative Escherichia coli (ATCC 25922) and Salmonella enterica (SL 5676), as well as Gram-positive Staphylococcus aureus (ATCC 25923) bacterial strains. Their activities in terms of minimum inhibitory concentrations (MICs) varied in the range of 1.1 µM (0.25 µg/mL)–413 µM (128 µg/mL). Amongst the most potent derivatives (1–6), acetyl- and methoxycarbonyl-substituted TPZs (2 and 4) were the strongest agents, which exhibited approximately 4–30 fold greater activities compared to those of TPZ (1) along with the reference drugs chloramphenicol (CAM) and nitrofurantoin (NFT). The inhibitory activities of the compounds were highly impacted by their structural features. No reliable relationships were established between activities and the electron-accepting potencies of the whole set of studied compounds, while the activities of TPZ drug (1) and the structurally uniform set of molecules (2–6) were found to increase with an increase in their electron-accepting potencies obtained by means of density functional theory (DFT) computation. A greater steric, lipophilic and polar nature of the substituents led to a lower activity of the compounds. The combined antibacterial in vitro trial gave clear evidence that TPZs coupled with the commonly utilized antibiotics ciprofloxacin (Cipro) and nitrofurantoin (NFT) could generate enhanced (suggestive of partial and virtually complete synergistic) and additive effects. The strongest effects were defined for TPZs–NFT combinations, which resulted in a notable reduction in the MICs of di-N-oxides. These preliminary findings suggest that the synthesized novel di-N-oxides might be used as sole agents or applied as antibiotic complements.

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