scholarly journals In vitro antibacterial activity of several plant extracts against fish bacterial pathogens

2021 ◽  
Vol 13 (Aquaculture) ◽  
pp. 106-112
Author(s):  
Thi My Duyen Tran ◽  
Trong Tuan Nguyen ◽  
Thi Tuyet Hoa Tran

Crude methanol extract of 9 Vietnamese plants were in vitro screened for their antibacterial activity against three common freshwater fish pathogens including Aeromonas hydrophila, Edwardsiella ictaluri, and Streptococcus agalactiae. Agar disc diffusion method was used to evaluate the antibacterial activity, then solvent extract was performed for the extracts which exhibited the strongest and a broad-spectrum antibacterial activity. Minimal inhibitory concentration (MIC) was conducted for effective plant extracts using broth dilution method. The results indicated that most of the plant extracts exhibited antibacterial propeties to at least one tested bacterium. Headache tree (Premna corymbosa), bushwillows (Combretum quadrangulare) and Celandine spider flower (Cleome chelidonii) showed a broad-spectrum antibacterial activity. The largest inhibitory zones of 35 mm and 21 mm were observed  for the extract of Premna corymbosa against E. ictaluri and S. agalactiae, respectively. E. ictaluri was found to be the most susceptible for all of the extracts while A. hydrophila was the most resistant. The MIC of effective plant extracts against tested bacteria ranged between 0.39 mg/mL and 3.125 mg/mL. The result can be considered for further investigation of the development of an alternative therapy against bacterial infection in aquaculture.

2017 ◽  
Vol 1 ◽  
pp. 13
Author(s):  
G. Bachir Raho

The purpose of this research was to evaluate the in vitro antibacterial activity of the essential oils from the resin of Pistacia lentiscus against Staphylococcus aureus (Gram–positive bacteria) and Escherichia coli (Gram–negative bacteria). The agar disc diffusion method was used for microbial growth inhibition at various dilutions of the oils. Results showed that the tested essential oils possess antibacterial activity against S. aureus but inactive on E. coli. These results may have significant implications for the future development of resin oils of P. lentiscus as an antimicrobial agent for the treatment of the infections caused by S. aureus. 


2021 ◽  
Author(s):  
Filippo Fratini ◽  
Margherita Giusti ◽  
Simone Mancini ◽  
Francesca Pisseri ◽  
Basma Najar ◽  
...  

AbstractStaphylococcus aureus and coagulase-negative staphylococci are among the major causes of mastitis in sheep. The main goal of this research was to determine the in vitro antibacterial activity of several essential oils (EOs, n 30), then five of them were chosen and tested alone and in blends against staphylococci isolates. Five bacteria were isolated from episodes of ovine mastitis (two S. aureus and three S. xylosus). Biochemical and molecular methods were employed to identify the isolates and disk diffusion method was performed to determine their antimicrobial-resistance profile. The relative percentage of the main constituents in the tested essential oils and their blends was detected by GC-EIMS analysis. Antibacterial and bactericidal effectiveness of essential oils and blends were evaluated through minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). All of them showed sensitivity to the used antimicrobials. The EOs with the highest antibacterial activity were those belonging to the Lamiaceae family characterized by high concentrations of thymol, carvacrol and its precursor p-cymene, together with cinnamon EO, rich in cinnamaldehyde. In terms of both MIC and MBC values, the blend composed by Thymus capitatus EO 40%, Cinnamomum zeylanicum EO 20%, Thymus serpyllum EO 20% and Satureja montana EO 20% was found to be the most effective against all the isolates. Some essential oils appear to represent, at least in vitro, a valid tool against ovine mastitis pathogens. Some blends showed a remarkable effectiveness than the single oils, highlighting a synergistic effect in relation to the phytocomplex.


1970 ◽  
Vol 1 (4) ◽  
pp. 82-88 ◽  
Author(s):  
MJ Foysal ◽  
MM Rahman ◽  
M Alam

Studies were conducted to identify Pseudomonas fluorescens isolates from a collection of bacteria isolated from bacterial haemorrhagic septicaemia infected carp and catfish, evaluate their antibiotic sensitivity pattern and screen the antibacterial activity of some medicinal plant extracts against the isolates.. A total of 10 isolates were identified as P. fluorescens by morphological, physiological and biochemical tests. In vitro antibiotic sensitivity test of the P. fluorescens isolates were conducted by disc diffusion method for seven antibiotics where, all of the isolates were found to be sensitive only against streptomycin and gentamycin but, most of the isolates (80%) were found resistant to chloramphenicol (C). Moreover, eighty percent of the isolates showed resistance to multiple antibiotics. A total of 118 plant extracts were screened for their antibacterial activity against the P. fluorescens isolates where the isolates exhibited sensitivity to 30 samples. Leaf extracts of Tamarindus indicus, Terminalia chebula, Citrus aurantifolia, Eugenia caryophyllata and Spondias pinnata were found to inhibit the growth of all of the P. fluorescens isolates. DOI: http://dx.doi.org/10.3329/ijns.v1i4.9733 IJNS 2011 1(4): 82-88


2018 ◽  
Vol 5 ◽  
pp. 69-76
Author(s):  
Mamata Adhikari ◽  
Anil Kumar Sah ◽  
Dev Raj Joshi

Objectives: In order to investigate alternate therapeutic option, this study was carried out to assess the in vitro antibacterial activity of gel extract of Aloe barbadensis against multiple antibiotic resistant Pseudomonas aeruginosa isolated from wound specimens. Methods: A total of 180 different wound specimens collected in a hospital, were subjected to isolate and identify P. aeruginosa by cultural methods. Antibiotic susceptibility testing was done by Kirby- Bauer disc diffusion method to screen multidrug resistant isolates. A. barbadensis extracts were prepared using aqueous and organic solvents and their in vitro inhibitory action was evaluated by agar well diffusion methods. Results: Out of total, 38 (21.1%) of the wound specimens showed the occurrence of P. aeruginosa, among which 15 (39%) isolates were multi-drug resistant. Organic extracts of various concentrations (0.2 - 0.8 v/v %) inhibited 66.7% of MDR and all non-MDR (n = 23) P. aeruginosa with zone of inhibition ranging from 9.5 ±1.0 to 21.3 ± 2.2 mm but not by aqueous extract. A positive Pearson’s correlation (r=0.983) was found between antibacterial effect and concentrations of the extracts. The antibacterial activity of organic extracts was statistically associated with antibiotic resistance profile of the organism (p<0.05). Conclusion: Organic extracts of A. barbadensis revealed variable in vitro inhibitory action against both MDR and non-MDR P. aeruginosa isolated from wound specimens. Although further confirmation is needed, aloe gel extract may be applied as an alternate treatment option.


Infection ◽  
1980 ◽  
Vol 8 (S3) ◽  
pp. S330-S333 ◽  
Author(s):  
R. Skalova ◽  
D. Hajsig ◽  
V. Muic ◽  
D. Kapun

Author(s):  
Samira Hsaine ◽  
Reda Charof ◽  
Khadija Ounine

Objective: Streptococcus oralis plays an important role in the biofilm formation of dental plaque and the occurrence of periodontal disease. Thepresent study was conducted to evaluate in vitro antibacterial activity of three essential oils, namely, Cinnamomum zeylanicum, Eugenia caryophyllata,and Rosmarinus officinalis against S. oralis.Methods: The antibacterial activity of essential oils was investigated by diffusion method using sterile discs (or aromatograms). The minimuminhibitory concentration (MIC) of essential oils showing important antibacterial activity was measured using the broth dilution method.Results: Evaluation of the antibacterial activity of three essential oils as determined by the aromatogram technique showed that the essential oilof R. officinalis had no effect on S. oralis, while the latter was extremely sensitive to the other two essential oils, but with a higher efficiency of theessential oil of C. zeylanicum (42 mm diameter) than E. caryophyllata (20 mm diameter). Similarly, the MIC and minimum bactericidal concentration(MBC) were higher for the essential oil of C. zeylanicum than the essential oil of E. caryophyllata. The MBC/MIC ratio is of the order of 2. The essentialoils studied therefore appear to exert bactericidal activity against S. oralis.Conclusion: The findings suggest that essential oils of C. zeylanicum and E. caryophyllata may be used as an alternative to synthetic antibiotics.Keywords: Essential oil, Cinnamomum zeylanicum, Eugenia caryophyllata, Rosmarinus officinalis, Antimicrobial activity, Streptococcus oralis.


Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1553 ◽  
Author(s):  
Na Li ◽  
Dan Liu ◽  
Jiang-Kun Dai ◽  
Jin-Yi Wang ◽  
Jun-Ru Wang

Background: Based on our previous work, we found that 10-methoxycanthin-6-one displayed potential antibacterial activity and quaternization was an available method for increasing the antibacterial activity. Here, we explored the antibacterial activity of quaternized 10-methoxy canthin-6-one derivatives. Methods and Results: Twenty-two new 3-N-benzylated 10-methoxy canthin-6-ones were designed and synthesized through quaternization reaction. The in vitro antibacterial activity against three bacteria was evaluated by the double dilution method. Moreover, the structure–activity relationships (SARs) were carefully summarized in order to guide the development of antibacterial canthin-6-one agents. Two highly active compounds (6p and 6t) displayed 8-fold superiority (MIC = 3.91 µg/mL) against agricultural pathogenic bacteria R. solanacearum and P. syringae compared to agrochemical streptomycin sulfate, and showed potential activity against B. cereus. Moreover, these two compounds exhibited good “drug-like” properties, low cytotoxicity, and no inhibition on seed germination. Conclusions: This work provides two new effective quaternized canthin-6-one derivatives as candidate bactericide, promoting the development of natural-sourced bactericides and preservatives.


1993 ◽  
Vol 46 (1) ◽  
pp. 71-87 ◽  
Author(s):  
YASUHIRO MINE ◽  
YUJI WATANABE ◽  
HIROSHI SAKAMOTO ◽  
KAZUO HATANO ◽  
KYOICHIRO KUNO ◽  
...  

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