Extracts of Emblica officinalis seeds prepared by Microwave Assisted Extraction (MAE) method were evaluated for their antimicrobial property against planktonic form of certain human/plant pathogenic microbes. Additionally, seed extracts of E. officinalis, Tamarindus indica, Manilkara zapota, Phoenix sylvestris, Syzygium cumini, and selected phytocompounds were tested against multi-drug resistant Streptococcus mutans (a major pathogen associated with human dental caries) in its planktonic as well as biofilm form. Ability of these extracts to eradicate and kill S. mutans biofilm was investigated. E. officinalis extracts exerted bactericidal action against S. mutans, Pseudomonas aeruginosa, and Vibrio cholerae. Acetone extract of S. cumini, and curcumin were able to inhibit S. mutans at appreciably low concentrations of 50 µg/mL and 20 µg/mL respectively. T. indica and S. cumini seed extracts were able to kill ≥ 80% cells of S. mutans in biofilm, in the concentration range of 500-1000 µg/mL. These extracts were able to achieve ≥ 95% killing of S. mutans biofilm at concentrations ranging from 600-2000 µg/mL. Ability of the potent extracts to kill S. mutans biofilm did not seem to be much dependent on eradication of the biofilm. Extraction efficiency was found to have a good correlation with antibacterial activity.
Table of Contents
1. Introduction
2. Review of Literature
2.1. Biofilm formation
2.2. Mechanisms of antibiotic resistance among biofilms
2.3. Problems associated with biofilm
2.3.1. Biofilm in public health
2.3.2. Biofilm in industry
2.3.3. Biofilm in agriculture
2.4. Applications of biofilm
2.5. Plant Materials
2.5.1. Embalica officinalis
2.5.2. Tamarindus indica
2.5.3. Syzygium cumini
2.5.4. Phoenix sylvestris
2.5.5. Manilkara zapota
2.6. Test Microorganisms
2.6.1. Streptococcus mutans
2.6.2. Streptococcus pyogenes
2.6.3. Staphylococcus aureus
2.6.4. Staphylococcus epidermidis
2.6.5. Pseudomonas aeruginosa
2.6.6. Vibrio cholerae
2.6.7. Salmonella paratyphi A
2.6.8. Candida albicans
2.6.9. Escherichia coli
2.6.10. Xanthomonas campestris
2.6.11. Agrobacterium tumefaceins
2.6.12. Pectobacterium caratovorum
2.6.13. Pseudomonas syringae
2.7. Extraction of Plant material
2.7.1. Microwave assisted extraction (MAE)
2.8. Antimicrobial susceptibility testing
2.8.1. Antibacterial susceptibility testing
2.8.1.1 Broth dilution assay
2.8.2. Antifungal susceptibility testing
2.9. Time required to kill
2.10. Methods for the study of biofilm
2.10.1 Tissue culture plate (TCP) method
2.11. The ‘Eagle effect’
3. Materials and Methods
3.1 Plant materials
3.2 Test organisms
3.3 Microwave assisted extraction
3.4. Inoculum standardization
3.5 Antimicrobial susceptibility testing with planktonic cell (Microbroth dilution method)
3.5.1 Plant extracts.
3.5.2 Pure compounds
3.6 Minimum bactericidal concentration (MBC)
3.7 Determination of time required to kill
3.8 Disc diffusion assay with antibiotics
3.9 Antimicrobial susceptibility testing with biofilm
3.9.1 Biofilm formation by tissue culture plate (TCP) method
3.9.2 Antimicrobial susceptibility testing of organism in biofilm.
3.9.3 Determination of viability in biofilm
3.9.3.1. Determination of viability by tube method
3.9.3.2 Determination of viability by viable plate count
3.9.4. Estimation of biofilm Eradication by crystal violet assay
3.10 Stastical analysis
3.11 Events during biofilm assay
4. Results and Discussion
4.1 Microwave assisted extraction (MAE)
4.2 Antimicrobial susceptibility testing (AST) with planktonic cells
4.2.1 AST of human pathogens
4.2.2 AST of plant pathogen
4.2.3 Final result table of microbroth dilution assay (E. officinalis)
4.2.4 AST of S. mutans
4.2.5 Final result table of microbroth dilution assay (S. mutans)
4.3 Total activity of verious seed extracts against different organisms
4.4 Time required to kill
4.5 Disc diffusion assay of standard antibiotics against S. mutans
4.6 Effect of verious seed extracts on planktonic form of different organisms
4.7 Biofilm formation
4.8 Antimicrobial susceptibility testing with biofilm
4.8.1 Antimicrobial susceptibility testing for biofilm
4.8.2 Final result table of antimicrobial susceptibility testing for biofilm (S. mutans)
4.9 Some interesting observations of biofilm assay
5. Conclusion
6. Appendices
7. Bibliography
Objectives and Research Themes
The research focuses on evaluating the antimicrobial and anti-biofilm potential of specific plant seeds—Emblica officinalis, Tamarindus indica, Syzygium cumini, Phoenix sylvestris, and Manilkara zapota—against various human and phytopathogenic microorganisms, with a primary objective to determine if these natural extracts can effectively combat bacterial infections in both planktonic and biofilm growth states.
- Screening of crude seed extracts for antimicrobial efficacy against selected bacterial pathogens.
- Determination of Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentrations (MBC) for plant extracts and pure compounds.
- Assessment of the biofilm eradication potential of plant extracts against Streptococcus mutans.
- Comparison of the antimicrobial effectiveness of plant-based extracts against conventional antibiotics.
- Analysis of the relationship between extraction efficiency and the total biological activity of the seed extracts.
Excerpt from the Book
2.1. Biofilm formation
Biofilm formation is a multistage process (Fig 1). The initial step in biofilm formation involves reversible attachment of planktonic (freely moving individual cell) bacteria to a surface (colonization) by using adhesins (Donlan and Costerton, 2002; De Beer and Stoodley, 2006; Høiby et al. 2011). For example, polysaccharide adhesin (PS/A) of S. epidermidis initiates adhesion on naked or coated polymer surface (expression is controlled by the inter-cellular adhesion operon (Ica) (Li Chen, 2011; Tojo et al., 1988; Zhang et al., 2003). In Streptococcus pyogenes, various cell surface molecules such as proteins and lipoteichoic acid are important for adherence on cultured human cells (Nobbs, 2009). The adhesin SpaP (PAc) in Streptococcus mutans is important for adhesion on teeth surfaces, and its expression is enhanced by sucrose or preexisting biofilm (Li Chen, 2011). In Vibrios, lateral flagella provide mechanism for attachment on surfaces (Atlas and Bartha, 1998). In P. aeruginosa, one of the virulence determinants, alginate plays important role in the adherence of the organism on trachael epithelium (Anwer et al., 1992; Marcus et al., 1989). In S. aureus, SasC protein factor plays important role in colonization during infection (Schroeder et al., 2009). The adhesion process is also affected by physiological state of the organism; in some organisms attachment is high in log phase, while in others attachment is high in stationary phase (Fletcher, 1999). The bacteria are still susceptible to antibiotics at this stage.
Summary of Chapters
1. Introduction: This chapter highlights the rising challenge of antimicrobial resistance and introduces the significance of microbial biofilms in medical and industrial contexts, setting the stage for the study of plant-derived alternatives.
2. Review of Literature: This section provides a comprehensive overview of biofilm biology, the mechanisms of resistance, specific challenges in public health and agriculture, and a detailed pharmacological background of the selected plant materials and test organisms.
3. Materials and Methods: This chapter details the experimental protocols used, including microwave-assisted extraction, antimicrobial susceptibility testing (microbroth dilution), and methods specifically designed for quantifying biofilm formation and eradication.
4. Results and Discussion: This section presents the analytical findings regarding extraction efficiency, the antimicrobial activity of various extracts against different pathogens, and detailed assessments of biofilm inhibition, supported by statistical analysis and correlation studies.
5. Conclusion: The final chapter summarizes the key findings of the study, noting the successful identification of potent plant seed extracts and their potential as alternatives for oral hygiene and therapeutic applications.
Keywords
Biofilm, Antimicrobial activity, Streptococcus mutans, Emblica officinalis, Plant extracts, Minimum Inhibitory Concentration (MIC), Microwave Assisted Extraction (MAE), Bacterial resistance, Dental caries, Phytopathogens, Antibiofilm, Seed extracts, Biofilm eradication, Natural products, Bacterial adhesion
Frequently Asked Questions
What is the core focus of this scientific research?
The research primarily evaluates the potential of various plant seed extracts—specifically Emblica officinalis, Tamarindus indica, Syzygium cumini, Phoenix sylvestris, and Manilkara zapota—to act as antimicrobial and anti-biofilm agents against human and plant pathogens.
What are the central thematic areas of this publication?
The core themes include microbial biofilm formation, the mechanisms of antibiotic resistance in biofilms, the pharmacological screening of plant-based antimicrobial compounds, and the optimization of extraction techniques like microwave-assisted extraction.
What is the primary research goal or main research question?
The study aims to determine whether specific plant extracts can inhibit the growth of pathogenic bacteria in both planktonic and biofilm states, and specifically to evaluate their effectiveness against the cariogenic pathogen Streptococcus mutans.
Which scientific methods are applied in this work?
The authors employ various standard microbiological techniques, including microbroth dilution assays for MIC/MBC determination, tissue culture plate (TCP) assays for biofilm quantification, crystal violet staining, and statistical significance testing using Student's t-test.
What topics are covered in the main body of the text?
The main body covers the theoretical background of biofilms, detailed botanical profiles of the selected plants, experimental procedures for extraction and susceptibility testing, and an extensive analysis of the results including activity indices and correlation between extraction efficiency and antimicrobial potency.
Which keywords best characterize the study?
Key terms include Biofilm, Antimicrobial activity, Streptococcus mutans, Plant extracts, MIC, MAE, Bacterial resistance, Dental caries, and Phytopathogens.
How does the biofilm-forming ability of S. mutans compare to other tested organisms?
The study confirms that S. mutans exhibits high adherence and strong biofilm-forming capacity, making it a critical focus for testing eradication potential compared to other organisms like V. cholerae or P. aeruginosa, which showed no or weak biofilm formation under the same conditions.
What role does the 'Eagle effect' play in the findings of this research?
The 'Eagle effect' (or paradoxical effect) refers to the phenomenon where antibacterial activity decreases at higher concentrations of the extract, an observation documented by the authors for certain extracts like those of E. officinalis, which helps in understanding the non-linear dose-response of some natural plant products.
- Arbeit zitieren
- Assistant Professor Vijay Kothari (Autor:in), Ina Patel (Autor:in), Vaibhavi Patel (Autor:in), Asha Thakkar (Autor:in), 2013, Plant Products in Dental Health, München, GRIN Verlag, https://www.grin.com/document/267909
