Effect of antimicrobial photodynamic therapy with Chlorella and Curcuma extract on Streptococcus mutans biofilms

Natural Antimicrobial Compounds as Promising Preservatives: A Look at an Old Problem from New Perspectives

Antimicrobial compounds of natural origin are of interest because of the large number of reports regarding the harmfulness of food preservatives. These natural products can be derived from plants, animal sources, microorganisms, algae, or mushrooms. The aim of this review is to consider known antimicrobials of natural origin and the mechanisms of their action, antimicrobial photodynamic technology, and ultrasound for disinfection. Plant extracts and their active compounds, chitosan and chitosan oligosaccharide, bioactive peptides, and essential oils are highly potent preservatives. It has been experimentally proven that they possess strong antibacterial capabilities against bacteria, yeast, and fungi, indicating the possibility of their use in the future to create preservatives for the pharmaceutical, agricultural, and food industries.

Reduction of Streptococcus salivarius by Chlorella-Mediated Antimicrobial Photodynamic Therapy

Introduction: Nowadays, antimicrobial photodynamic therapy (aPDT) has been introduced as one of the minimally invasive methods for disinfection of the surfaces of dental implants. Being derived from seaweed, Chlorella has been used as a photosensitizer in this study. This study aimed to investigate the impacts of aPDT with Chlorella on the rate of reduction of Streptococcus salivarius in vitro. Methods: The minimum inhibitory concentration of Chlorella, the sublethal exposure to 660 nm diode laser irradiation, and the minimum sublethal dose of aPDT utilizing Chlorella against S. salivarius were determined. Finally, the CFU/mL value of each plate was calculated. Then, Tukey HSD and one-way ANOVA tests were utilized for comparison the number of colonies after the interventions. Results: A concentration of 250 µg/mL of Chlorella at an irradiation time of 3 minutes, was identified as a sublethal dose of aPDT for the reduction of S. salivarius. In contrast, the application of aPDT utilizing a 660 nm diode laser for 4 minutes in combination with Chlorella at a final concentration of 500 µg/mL, demonstrated significantly greater efficacy in reducing S. salivarius compared to the other experimental groups (P<0.001). Conclusion: Chlorella 500 µg/mL mediated aPDT (660 nm, 4 minutes) has a significant effect on reducing S. salivarius count.

Anti-biofilm activity of a novel nanoemulsion containing Curcuma xanthorrhiza oil

OBJECTIVES

We aimed to solubilize Curcuma xanthorrhiza oil (CXO) using nanoemulsification and evaluate its inhibitory effects against biofilm formation.

METHODS

The components of CXO were evaluated through high-performance liquid chromatography (HPLC) analysis. Healthy human saliva was inoculated onto hydroxyapatite discs to form microcosm biofilms for four days and treated six times with each antimicrobial agent: distilled water (DW), CXO emulsion (EM), CXO nanoemulsion (NE), and positive controls (Listerine and chlorhexidine). Biofilm fluorescence imaging was performed using quantitative light-induced fluorescence, and cell viability and dry-weight measurements were obtained. We compared the bacterial cell and extracellular polysaccharide (EPS) biovolume and thickness using confocal laser scanning microscopy (CLSM).

RESULTS

HPLC analysis revealed that CXO was composed of approximately 47% xanthorrhizol. Compared with DW, NE exhibited significantly lower red fluorescence intensity and area (42% and 37%, p < 0.001 and p < 0.001, respectively), and reduced total and aciduric bacterial cell viability (7.3% and 3.9%, p < 0.001, p = 0.01, respectively). Furthermore, the bacterial cell and EPS biovolume and thickness in NE decreased by 40-80% compared to DW, similar to chlorhexidine. Conversely, EM showed a significant difference only in cell viability against total bacteria when compared with DW (p = 0.003), with EPS biovolume and thickness exhibiting higher values than DW.

CONCLUSIONS

Nanoemulsification successfully solubilized CXO and demonstrated superior anti-biofilm effects compared to the emulsion form.

CLINICAL SIGNIFICANCE

These findings suggest the potential use of NE as a novel antimicrobial agent for preventing oral diseases.

Antimicrobial photodynamic therapy for the treatment of oral infections: A systematic review

Oral infection is a common clinical symptom. While antibiotics are widely employed as the primary treatment for oral diseases, the emergence of drug-resistant bacteria has necessitated the exploration of alternative therapeutic approaches. One such modality is antimicrobial photodynamic therapy (aPDT), which utilizes light and photosensitizers. Indeed, aPDT has been used alone or in combination with other treatment options dealing with periodontal disease for the elimination of biofilms from bacterial community to achieve bone formation and/or tissue regeneration. In this review article, in addition to factors affecting the efficacy of aPDT, various photosensitizers, the latest technology and perspectives on aPDT are discussed in detail. More importantly, the article emphasizes the novel design and clinical applications of photosensitizers, as well as the synergistic effects of chemical and biomolecules with aPDT to achieve the complete eradication of biofilms and even enhance the biological performance of tissues surrounding the treated oral area.

Smart dental materials for antimicrobial applications

Smart biomaterials can sense and react to physiological or external environmental stimuli (e.g., mechanical, chemical, electrical, or magnetic signals). The last decades have seen exponential growth in the use and development of smart dental biomaterials for antimicrobial applications in dentistry. These biomaterial systems offer improved efficacy and controllable bio-functionalities to prevent infections and extend the longevity of dental devices. This review article presents the current state-of-the-art of design, evaluation, advantages, and limitations of bioactive and stimuli-responsive and autonomous dental materials for antimicrobial applications. First, the importance and classification of smart biomaterials are discussed. Second, the categories of bioresponsive antibacterial dental materials are systematically itemized based on different stimuli, including pH, enzymes, light, magnetic field, and vibrations. For each category, their antimicrobial mechanism, applications, and examples are discussed. Finally, we examined the limitations and obstacles required to develop clinically relevant applications of these appealing technologies.

In Vitro Evaluation of Photodynamic Activity of Plant Extracts from Senna Species against Microorganisms of Medical and Dental Interest

Background: Bacterial resistance requires new treatments for infections. In this context, antimicrobial photodynamic therapy (aPDT) is an effective and promising option. Objectives: Three plant extracts (Senna splendida, Senna alata, and Senna macranthera) were evaluated as photosensitizers for aPDT. Methods: Cutibacterium acnes (ATCC 6919), Streptococcus mutans (ATCC 35668), Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), and Candida albicans (ATCC 90028) were evaluated. Reactive oxygen species production was also verified. Oral keratinocytes assessed cytotoxicity. LC-DAD-MS analysis identified the chemical components of the evaluated extracts. Results: Most species cultured in the planktonic phase showed total microbial reduction (>6 log10 CFU/mL/p < 0.0001) for all extracts. C. albicans cultured in biofilm showed total microbial reduction (7.68 log10 CFU/mL/p < 0.0001) for aPDT mediated by all extracts. Extracts from S. macranthera and S. alata produced the highest number of reactive oxygen species (p < 0.0001). The S. alata extract had the highest cell viability. The LC-DAD-MS analysis of active extracts showed one naphthopyrone and seven anthraquinones as potential candidates for photoactive compounds. Conclusion: This study showed that aPDT mediated by Senna spp. was efficient in microbial suspension and biofilm of microorganisms of medical and dental interest.

How Microalgae is Effective in Oxygen Deficiency Aggravated Diseases? A Comprehensive Review of Literature

Hypoxia can aggravate the conditions of many oxygen-deficiency-aggravated diseases (ODAD), such as cancer, ischemic heart disease, and chronic wounds. Photosynthetic microalgae can alleviate the hepatotoxicity of the local microenvironment by producing oxygen. In addition, microalgae extracts have antitumor, anti-inflammatory, antibacterial, and antioxidant effects. These properties make them attractive candidates for developing methods to treat ODAD. Although researchers have exploited the advantages of microalgae and developed a variety of microalgae-based biomaterials to treat ODAD, a comprehensive review of this topic has not been presented previously. Therefore, in this review, we summarize the development and progress made in the field of developing microalgae-based biomaterials toward the treatment of ODAD. The challenges and prospects of this field are also discussed.

The Potential Application of Natural Photosensitizers Used in Antimicrobial Photodynamic Therapy against Oral Infections

Oral health problems and the emergence of antimicrobial resistance among pathogenic bacterial strains have become major global challenges and are essential elements that negatively affect general well-being. Antimicrobial photodynamic therapy (APDT) is based on a light source and oxygen that activates a nontoxic photosensitizer, resulting in microbial destruction. Synthetic and natural products can be used to help the APDT against oral microorganisms. The undesirable consequences of conventional photosensitizers, including toxicity, and cost encourage researchers to explore new promising photosensitizers based on natural compounds such as curcumin, chlorella, chlorophyllin, phycocyanin, 5-aminolevulinic acid, and riboflavin. In this review, we summarize in vitro studies describing the potential use of APDT therapy conjugated with some natural products against selected microorganisms that are considered to be responsible for oral infections.