Biological Activities of Virgin Coconut and Virgin Olive Oil Mixture against Oral Primary Colonizers: An In Vitro Study.

AIM AND BACKGROUND: This study aimed to explore the potential synergistic interaction of virgin coconut oil (VCO) and virgin olive oil (VOO) mixture against Streptococcus sanguinis, Streptococcus mutans, and Lactobacillus casei in a single and mixture species through the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), antiadherence, and antibiofilm activities. MATERIALS AND METHODS: The broth microdilution technique was used to individually determine the MIC of both oils and an oil mixture (in the ratio of 1:1) in a 96-well microtiter plate. As for the MBC, the subcultured method was used. The fractional inhibitory concentration index (ΣFIC) was determined to identify the interaction types between both oils. The oil mixture at its MIC was then tested on its antibiofilm and antiadherence effect. RESULTS: The MIC of the oil mixture against the tested microbiota was 50-100%. The oil mixture was bactericidal at 100% concentration for all the mentioned microbes except S. mutans. The ΣFIC value was 2 to 4, indicating that the VCO and VOO acted additively against the microbiota. Meanwhile, the oil mixture at MIC (50% for S. sanguinis and L. casei; 100% for S. mutans and mixture species) exhibited antiadherence and antibiofilm activity toward the microbiota in mixture species. CONCLUSION: The oil mixture possesses antibacterial, antibiofilm, and antiadherence properties toward the tested microbiota, mainly at 50-100% concentration of oil mixture. There was no synergistic interaction found between VCO and VOO. CLINICAL SIGNIFICANCE: Children and individuals with special care may benefit from using the oil mixture, primarily to regulate the biofilm formation and colonization of the bacteria. Furthermore, the oil mixture is natural and nontoxic compared to chemical-based oral healthcare products. How to cite this article: Ng YM, Sockalingam SNMP, Shafiei Z, et al. Biological Activities of Virgin Coconut and Virgin Olive Oil Mixture against Oral Primary Colonizers: An In Vitro Study. J Contemp Dent Pract 2024;25(3):260-266.

Antibacterial Activity of Epigallocatechin-3-gallate (EGCG) Loaded Lipid-chitosan Hybrid Nanoparticle against Planktonic Microorganisms.

Epigallocatechin-3-gallate (EGCG), a polyphenol derived from Green Tea, is one of the sources of natural bioactive compounds which are currently being developed as medicinal ingredients. Besides other biological activities, this natural compound exhibits anti-cariogenic effects. However, EGCG has low physical-chemical stability and poor bioavailability. Thus, the purpose of this study was to develop and characterize lipid-chitosan hybrid nanoparticle with EGCG and to evaluate its in vitro activity against cariogenic planktonic microorganisms. Lipid-chitosan hybrid nanoparticle (LCHNP-EGCG) were prepared by emulsion and sonication method in one step and characterized according to diameter, polydispersity index (PdI), zeta potential (ZP), encapsulation efficiency (EE), mucoadhesion capacity and morphology. Strains of Streptococcus mutans, Streptococcus sobrinus and Lactobacillus casei were treated with LCHNP- EGCG, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated. LCHNP-EGCG exhibited a size of 217.3 ± 5.1 nm with a low polydispersity index (0.17) and positive zeta potential indicating the presence of chitosan on the lipid nanoparticle surface (+33.7 mV). The LCHNP-EGCG showed a spherical morphology, high stability and a mucoadhesive property due to the presence of chitosan coating. In addition, the EGCG encapsulation efficiency was 96%. A reduction of almost 15-fold in the MIC and MBC against the strains was observed when EGCG was encapsulated in LCHNP, indicating the potential of EGCG encapsulation in lipid-polymer hybrid nanoparticles. Taking the results together, the LCHNP-EGCG could be an interesting system to use in dental care due to their nanometric size, mucoadhesive properties high antibacterial activity against relevant planktonic microorganisms.

Antibacterial effect of diode laser on different cariogenic bacteria: An In-vitro study.

AIMS: The authors have used an in vitro model to appraise the antimicrobial efficacy of diode lasers with two different power outputs on Streptococcus mutans (SM), Lactobacillus casei (LC), and Actinomyces naeslundii (AN). METHODS AND MATERIALS: The coronal dentin of thirty human mandibular third molars was prepared with four cylindrical cavities left in contact with SM, LC, and AN for 72 h to facilitate bacterial penetration. Diode laser (810 nm for 30 s in two cycles) with 1.5 W (group I), 1 W (group II), and 2% chlorhexidine gluconate solution for 60 s (group III) was applied on three cavities and the fourth cavity was not subjected to any treatment (control). Similar amounts of dentin debris were collected from the cavity into sterile tubes. The bacterial count was determined by serial dilution and plate count method. Percentage of killing was calculated for comparative analysis. RESULTS: The percentage of SM killed after exposure was 73.68 ± 23.37, 51.75 ± 25.45, and 26.78 ± 21.8 in three groups, respectively, (P = 0.002; Kruskal-Wallis) with no significant difference between group I and group II (P = 0.089; Mann-Whitney). The percentage of AN killed after exposure was 37.77 ± 49.52, 22 ± 19.48, and 56.86 ± 23.93 in three groups, respectively, (P = 0.013; Kruskal-Wallis) with significant difference between group II and group III (P = 0.002; Mann-Whitney). The percentage of LC killed after exposure was 51.32 ± 39.07, 36.65 ± 38.48, and 75.41 ± 22.6 in three groups, respectively (P = 0.091; Kruskal-Wallis). CONCLUSIONS: Diode lasers exerted antibacterial effect of varying levels against all the three cariogenic bacteria. Although they are recommended as a supplementary antibacterial surface pretreatment technique for efficient removal of cariogenic bacteria, further clinical studies are required to confirm the in vitro findings.

Effect of Pereskia aculeata Mill. in vitro and in overweight humans: A randomized controlled trial.

OBJECTIVES: The objective of this study was to investigate the influence of ora-pro-nobis (Pereskia aculeata Mill.) flour on the adhesion of probiotics to intestinal epithelial cells and to evaluate the effect of a product based on this flour on gastrointestinal symptoms, weight, body fat, glycemia, and lipid profile in overweight men. METHODS: Microbiological counts (probiotic count, survival after in vitro gastrointestinal resistance, Caco-2 cell adhesion) were analyzed. A randomized, cross-over intervention was performed. Intestinal microbiota was indirectly assessed on the basis of consistency, color of feces, and gastrointestinal symptoms. RESULTS: P. aculeata did not affect Lactobacillus casei adhesion to Caco-2 cells. Ora-pro-nobis flour improved gastrointestinal symptoms and increased satiety. CONCLUSION: The consumption of ora-pro-nobis flour improved intestinal health. In addition, it maintained the high adherence of L. casei to intestinal cells as well as patient anthropometric and biochemical parameters. PRACTICAL APPLICATIONS: Pereskia aculeata Mill. is well known in folk medicine and has several nutrients; however, there are few studies on this plant. This is the first study to analyze the influence of P. aculeata on bacterial adherence and the first cross-over clinical trial to evaluate the beneficial potential of ora-pro-nobis flour in overweight men. Thus, this study will contribute to the promotion of ora-pro-nobis as a functional ingredient and will arouse the interest of industries to develop related healthy foods. In addition, it is an effective dietary strategy to improve the gastrointestinal health of men.

Sensitivity to the two peptide bacteriocin plantaricin EF is dependent on CorC, a membrane-bound, magnesium/cobalt efflux protein.

Lactic acid bacteria produce a variety of antimicrobial peptides known as bacteriocins. Most bacteriocins are understood to kill sensitive bacteria through receptor-mediated disruptions. Here, we report on the identification of the Lactobacillus plantarum plantaricin EF (PlnEF) receptor. Spontaneous PlnEF-resistant mutants of the PlnEF-indicator strain L. plantarum NCIMB 700965 (LP965) were isolated and confirmed to maintain cellular ATP levels in the presence of PlnEF. Genome comparisons resulted in the identification of a single mutated gene annotated as the membrane-bound, magnesium/cobalt efflux protein CorC. All isolates contained a valine (V) at position 334 instead of a glycine (G) in a cysteine-ß-synthase domain at the C-terminal region of CorC. In silico template-based modeling of this domain indicated that the mutation resides in a loop between two ß-strands. The relationship between PlnEF, CorC, and metal homeostasis was supported by the finding that PlnEF-resistance was lost when PlnEF was applied together with high concentrations of Mg2+ , Co2+ , Zn2+ , or Cu2+ . Lastly, PlnEF sensitivity was increased upon heterologous expression of LP965 corC but not the G334V CorC mutant in the PlnEF-resistant strain Lactobacillus casei BL23. These results show that PlnEF kills sensitive bacteria by targeting CorC.

Tetrahydrocurcumin-loaded vaginal nanomicrobicide for prophylaxis of HIV/AIDS: in silico study, formulation development, and in vitro evaluation.

A vaginal microbicide is a front-line women-dependent approach and an alternative to a condom for prevention of unprotected sexual intercourse-associated HIV. The microbicide research is still in its infancy with several products in the clinical studies being reported to have good efficacy, safe, but with poor adherence. One such molecule reported with an excellent efficacy when tested preclinically is curcumin, a natural polyphenol derived from Curcuma longa. Despite its potential HIV-1 inhibitory activity, it has intense yellow color staining properties, which would result in poor consumer compliance and adherence for vaginal application. To address this issue, tetrahydrocurcumin (THC), a colorless derivative of curcumin, was subjected to in silico screening (molecular docking and dynamics simulation studies) using homology model of gp120-CD4 binding. It was found that THC exhibited equivalent gp120-CD4 binding inhibitory activity as compared with curcumin due to its stable hydrophobic interactions with residues Asp368 and Trp427 deeper in the Phe43 cavity of CD4 receptor. Hence, it can be effectively used as a potential microbicide candidate. THC, a BCS Class II molecule exhibits poor solubility, spreadability, and intracellular uptake when used in the conventional form. Thus, it was decided to develop a lipid-based nanomicrobicide gel for delivery of THC. The developed THC-loaded o/w microemulsion gel was characterized for physicochemical properties (globule size, drug content, drug release, and permeation) and further used for in vitro cell line studies (cell viability, cellular uptake, and anti-HIV activity). The developed formulation was found to be stable with coitus-independent release profile and exhibited a rapid time-independent intracellular uptake. In addition, it exhibited a fourfold increase in efficacy as compared with conventional THC. Thus, the novel THC-loaded o/w microemulsion gel exhibited the potential for prevention of HIV-1 infection associated with unprotected sexual intercourse.

Agrimonia procera exerts antimicrobial effects, modulates the expression of defensins and cytokines in colonocytes and increases the immune response in lipopolysaccharide-challenged piglets.

BACKGROUND: Because antibiotic use in livestock is assumed to contribute to the emerging public health crisis of antibiotic resistance, alternatives are required. Phytogenic additives are extensively studied due to their antibiotic properties. Components of Agrimonia species have been reported as candidate antimicrobials that possess antioxidative and anti-inflammatory properties. We studied the impact of Agrimonia procera (AP) on the growth of selected strains of gut bacteria, the effect of AP on the mRNA abundance of genes involved in inflammation and bacterial defense in a colon carcinoma cell line, the effect of AP in piglets challenged with lipopolysaccharides, and the effect of AP on the growth performance of healthy piglets. RESULTS: The in vitro growth rate of different bacteria strains was negatively affected by AP, especially in Pediococcus pentosaceus and all tested E. coli strains. Stimulation of Caco-2 cells with TNFα resulted in elevated mRNA expression of CXCL1, IL-8 and GPX2. After pretreatment of cells with AP, stimulation of Caco-2 cells with TNFα still resulted in elevated mRNA expression of CXCL1 and IL-8 at all measured points in time. However, mRNA expression in AP-pretreated cells was lower after 6 h and 24 h. In addition, expression of DEFB1 and GPX2 was significantly elevated after TNFα stimulation. In vivo, application of lipopolysaccharides induced significantly increased animal body temperatures. Piglets pretreated with AP prior to lipopolysaccharide application showed a faster and larger increase in body temperature than controls. In addition, piglets pretreated with AP appeared to release more TNFα than controls. In healthy piglets, AP treatment had no impact on growth performance parameters. Fecal dry matter and total plasma antioxidant capacity tended to be higher in piglets treated with AP than in control piglets (P = 0.055 and P = 0.087, respectively). CONCLUSIONS: AP has antimicrobial effects in vitro and stimulated the expression of proinflammatory cytokines in Caco-2 cells. The additive had no effect on growth in healthy piglets but increased the immune response in LPS-treated animals. In addition, AP appeared to have antioxidative effects in vivo. Therefore, AP merits testing as a future alternative to antibiotics in animal husbandry.

Atividade antimicrobiana de Stevia rebaudiana Bertoni e de adoçantes não calóricos sobre bactérias cariogênicas: estudo in vitro / Antimicrobial activity of Stevia rebaudiana Bertoni and non-caloric sweeteners on cariogenic bacteria: in vitro study

Objetivo: avaliar a atividade antimicrobiana in vitro da planta Stevia rebaudiana Bertoni e de adoçantes não calóricos sobre o crescimento de Streptococcus mutanse Lactobacillus casei, micro-organismos cariogênicos presentes na cavidade bucal. Materiais e método: o estudo foi realizado utilizando as cepas padrões de S.mutans (UA159) e L. casei (ATCC7469). Foram avaliados diferentes compostos não calóricos substitutos dasacarose nas concentrações de 1%, 5% e 10%: eritritol(ER), Fit Sucralose® (SU), Stevita® (ST), solução de Steviarebaudiana Bertoni (SSr) e, como controle positivo,digluconato de clorexidina (DC). A análise do efeito inibitório desses compostos no crescimento das bactériasfoi feita por meio da técnica de difusão em ágar. Resultado:observou-se que existe um efeito inibitório decrescimento de ambos os micro-organismos por parte da SSr e do ER, enquanto os demais adoçantes testa dosnão tiveram efeito inibitório sobre esses micro-organismos.Conclusão: os resultados demonstram que SSR eER apresentam efeito inibidor no crescimento das cepastestadas de S. mutans e L. casei. (AU)

Objective: The study evaluated the in vitro antimicrobial activity of the Stevia rebaudiana Bertoni plant and non-caloric sweeteners on the growth of Streptococcus mutans and Lactobacillus casei, which are cariogenic microorganisms present in the oral cavity. Materials and method: The study was conducted using the standard strains of S. mutans (UA159) and L. casei (ATCC7469). Different non-caloric compounds were evaluated at concentrations of 1%, 5%, and 10%: erythritol (ER), Fit Sucralose™ (SU), Stevita™ (ST), Stevia rebaudiana Bertoni solution (SSr), and chlorhexidine digluconate (CD) as positive control. The inhibitory effect of these compounds on the growth of bacteria were analyzed by the agar diffusion technique. Result: There was a growth inhibition effect for both microorganisms by SSr and ER, whereas the other sweeteners tested had no inhibitory effect on the microorganisms. Conclusion: The results showed that SSr and ER present an inhibitory effect on the growth the strains tested of S. mutans and L. casei. (AU)

Construction and characterization of thymidine auxotrophic (ΔthyA) recombinant Lactobacillus casei expressing bovine lactoferricin.

BACKGROUND: Lactobacillus casei (L. casei) is well known for its probiotic property in human and animals. Lactoferricin (Lfcin) polypeptide can effectively modulate host immune responses and have antimicrobial activity in vivo and in vitro. In order to develop a food-grade L. casei system constitutively expressing bovine Lfcin, this study constructed a thymidine auxotrophy (ΔthyA) recombinant L. casei. RESULTS: Based on the thymidylate synthase gene (thyA) insert site, LFEC(Lfcin expression cassette)was inserted into L. casei genome through homologous recombination, successfully expressed and could be stably inherited. The recombinant L. casei, ΔthyA L. casei-LFEC, is sensitive to chloramphenicol and limited when cultured without thymine. Meanwhile, ΔthyA L. casei-LFEC has both good antibacterial activity against Escherichia coli and Staphylococcus aureus and antiviral activity against porcine epidemic diarrhea virus (PEDV). CONCLUSIONS: We successfully constructed a recombinant L. casei strain expressing Lfcin, ΔthyA L. casei-LFEC, which could only survive in the presence of thymine, and had excellent antimicrobial and antiviral activity with good genetic stability and sensitivity. This research provides a cost-effective alternative to the antibiotics with additional biological functions and wider applicability prospect. Using ΔthyA as the selectable mark instead of antibiotic to construct genetic engineering L.casei provides a safe and effective approach of feed additives in livestock raising.

Integrative Genomic and Proteomic Analysis of the Response of Lactobacillus casei Zhang to Glucose Restriction.

Nutrient starvation is an important survival challenge for bacteria during industrial production of functional foods. As next-generation sequencing technology has greatly advanced, we performed proteomic and genomic analysis to investigate the response of Lactobacillus casei Zhang to a glucose-restricted environment. L. casei Zhang strains were permitted to evolve in glucose-restricted or normal medium from a common ancestor over a 3 year period, and they were sampled at 1000, 2000, 3000, 4000, 5000, 6000, 7000, and 8000 generations and subjected to proteomic and genomic analyses. Genomic resequencing data revealed different point mutations and other mutational events in each selected generation of L. casei Zhang under glucose restriction stress. The differentially expressed proteins induced by glucose restriction were mostly related to fructose and mannose metabolism, carbohydrate metabolic processes, lyase activity, and amino-acid-transporting ATPase activity. Integrative proteomic and genomic analysis revealed that the mutations protected L. casei Zhang against glucose starvation by regulating other cellular carbohydrate, fatty acid, and amino acid catabolism; phosphoenolpyruvate system pathway activation; glycogen synthesis; ATP consumption; pyruvate metabolism; and general stress-response protein expression. The results help reveal the mechanisms of adapting to glucose starvation and provide new strategies for enhancing the industrial utility of L. casei Zhang.

Chemical Composition and Antibacterial Activity of the Essential Oil of Vitex agnus-castus L. (Lamiaceae).

Abnormal multiplication of oral bacteria causes dental caries and dental plaque. These diseases continue to be major public health concerns worldwide, mainly in developing countries. In this study, the chemical composition and antimicrobial activity of the essential oil of Vitex agnus-castus leaves (VAC‒EO) collected in the North of Brazil against a representative panel of cariogenic bacteria were investigated. The antimicrobial activity of VAC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by using the broth microdilution method in 96-well microplates. The chemical constituents of VAC-EO were identified by gas chromatography (GC‒FID) and gas chromatography‒mass spectrometry (GC‒MS). VAC‒EO displayed some activity against all the investigated oral pathogens; MIC values ranged from 15.6 to 200 µg/mL. VAC-EO had promising activity against Streptococcus mutans (MIC= 15.6 µg/mL), Lactobacillus casei (MIC= 15.6 µg/mL), and Streptococcus mitis (MIC= 31.2 µg/mL). The compounds 1,8-cineole (23.8%), (E)-ß-farnesene (14.6%), (E)-caryophyllene (12.5%), sabinene (11.4%), and α-terpinyl acetate (7.7%) were the major chemical constituents of VAC‒EO. VAC-EO displays antimicrobial activity against cariogenic bacteria. The efficacy of VAC-EO against S. mutans is noteworthy and should be further investigated.

Chemical Composition and Antibacterial Activity of the Essential Oil of Vitex agnus-castus L. (Lamiaceae)

ABSTRACT Abnormal multiplication of oral bacteria causes dental caries and dental plaque. These diseases continue to be major public health concerns worldwide, mainly in developing countries. In this study, the chemical composition and antimicrobial activity of the essential oil of Vitex agnus-castus leaves (VAC‒EO) collected in the North of Brazil against a representative panel of cariogenic bacteria were investigated. The antimicrobial activity of VAC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by using the broth microdilution method in 96-well microplates. The chemical constituents of VAC-EO were identified by gas chromatography (GC‒FID) and gas chromatography‒mass spectrometry (GC‒MS). VAC‒EO displayed some activity against all the investigated oral pathogens; MIC values ranged from 15.6 to 200 μg/mL. VAC-EO had promising activity against Streptococcus mutans (MIC= 15.6 μg/mL), Lactobacillus casei (MIC= 15.6 μg/mL), and Streptococcus mitis (MIC= 31.2 μg/mL). The compounds 1,8-cineole (23.8%), (E)-β-farnesene (14.6%), (E)-caryophyllene (12.5%), sabinene (11.4%), and α-terpinyl acetate (7.7%) were the major chemical constituents of VAC‒EO. VAC-EO displays antimicrobial activity against cariogenic bacteria. The efficacy of VAC-EO against S. mutans is noteworthy and should be further investigated.

Chemical Composition, Antibacterial, Schistosomicidal, and Cytotoxic Activities of the Essential Oil of Dysphania ambrosioides (L.) Mosyakin & Clemants (Chenopodiaceae).

We have investigated the chemical composition and the antibacterial activity of the essential oil of Dysphania ambrosioides (L.) Mosyakin & Clemants (Chenopodiaceae) (DA-EO) against a representative panel of cariogenic bacteria. We have also assessed the in vitro schistosomicidal effects of DA-EO on Schistosoma mansoni and its cytotoxicity to GM07492-A cells in vitro. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) revealed that the monoterpenes cis-piperitone oxide (35.2%), p-cymene (14.5%), isoascaridole (14.1%), and α-terpinene (11.6%) were identified by as the major constituents of DA-EO. DA-EO displayed weak activity against Streptococcus sobrinus and Enterococcus faecalis (minimum inhibitory concentration (MIC) = 1000 µg/ml). On the other hand, DA-EO at 25 and 12.5 µg/ml presented remarkable schistosomicidal action in vitro and killed 100% of adult worm pairs within 24 and 72 h, respectively. The LC50 values of DA-EO were 6.50 ± 0.38, 3.66 ± 1.06, and 3.65 ± 0.76 µg/ml at 24, 48, and 72 h, respectively. However, DA-EO at concentrations higher than 312.5 µg/ml significantly reduced the viability of GM07492-A cells (IC50  = 207.1 ± 4.4 µg/ml). The selectivity index showed that DA-EO was 31.8 times more toxic to the adult S. mansoni worms than GM07492-A cells. Taken together, these results demonstrate the promising schistosomicidal potential of the essential oil of Dysphania ambrosioides.

Concentração inibitória mínima e concentração bactericida mínima de extratos hidroalcoólicos das folhas de Myracrodruon urundeuva All. e Qualea grandiflora Mart. sobre Streptococcus mutans e Lactobacillus casei / Minimum inhibitory concentration and minimum bactericidal concentration of hydroalcoholic extracts of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves on Streptococcus mutans and Lactobacillus casei

A cárie dentária é uma doença bucal de alta prevalência e impactante em países em desenvolvimento. É causada pela presença de biofilme dentário rico em bactérias acidogênicas e acidúricas, como Streptococcus mutans e Lactobacillus casei. Neste sentido, a fitoterapia tem sido aplicada na odontologia devido ao seu conhecido efeito antimicrobiano, tendo potencial para prevenir doenças como a cárie dentária. Portanto, o presente estudo tem como objetivo testar o potencial antimicrobiano de extratos bruto e etanólico das folhas de Myracrodruon urundeuva (M. urundeuva.) e Qualea grandiflora (Q. grandiflora) sobre S.mutans e L. casei. Para tal, determinaram-se a Concentração Inibitória Mínima (CIM) e a Concentração Bactericida Mínima (CBM). A CIM foi definida como a menor concentração do agente antimicrobiano capaz de inibir 100% o crescimento microbiano (absorbância) em relação aos controles negativos. Para a CBM, alíquotas foram removidas dos poços que não apresentaram nenhuma absorbância (viabilidade, concentrações CIM) e semeadas em placas de ágar BHI, incubadas por 24 h a 37°C em estufa de CO2 5%. A CBM foi determinada considerando a menor concentração dos extratos capaz de impedir o crescimento bacteriano visível. Cepas de S. mutans (ATCC 21175) e L. casei (ATTC 334) foram ativadas em BHI e caldo Rogosa, respectivamente. A CIM foi determinada pela técnica de diluição em microplacas de 96 poços (100 l de extrato + 80 l BHI/Rogosa + 20 l da bactéria diluída em BHI/Rogosa equivalente a 5x105 UFC/mL), as quais foram incubadas por 24 h (S. mutans) e 48 h (L. casei) a 37°C em estufa de CO2 5%. Os extratos de M. urundeuva e Q. grandiflora inicialmente foram diluídos em BHI/Rogosa variando as concentrações entre 2 mg/ml a 0,00012207 mg/ml e os mesmos extratos diluídos em álcool foram avaliados nas concentrações entre 20 mg/ml a 0,00244 mg/ml para S. mutans e L. casei. Não foi possível determinar a CIM e a CBM para os extratos diluídos no BHI/Rogosa. Foram utilizados como controle positivo a clorexidina e como controles negativos BHI/Rogosa com e sem álcool a 5%. As CIMs (CBMs) da M. urundeuva e Q. grandiflora, diluídas em álcool, e clorexidina contra S. mutans foram 2,5 mg/ml (2,5 mg/ml), 5,0 mg/ml (--) e 0,00468 mg/ml (0,00937 mg/ml), respectivamente. Em relação ao L. casei, as CIMs (CBMs) da M. urundeuva e Q. grandiflora, diluídas em álcool, e da clorexidina foram 0,156 mg/ml (0,312 mg/ml), 0,156 0,625 mg/ml (0,312 0,625mg/ml) e 0,00468 mg/ml (0,3 mg/ml), respectivamente. Como conclusão, nosso estudo mostrou que L. casei (ATTC 334) é mais susceptível aos extratos que S. mutans (ATCC 21175) e o extrato M. urundeuva apresenta melhor efeito antimicrobiano que a Q. grandiflora em S. mutans (ATCC 21175), porém os dois extratos apresentam efeito similar sobre L. casei (ATTC 334) e ambos foram inferiores à CHX.(AU)

Dental caries is an oral disease of high prevalence and impact in developing countries. It is caused by the presence of a dental biofilm rich in acidogenic and aciduric bacteria, such as Streptococcus mutans and Lactobacillus casei. Accordingly, phytotherapy has been applied in dentistry due to its known antimicrobial effect, having potential to prevent diseases such as dental caries. Therefore, the present study aims to test the antimicrobial potential of crude and ethanolic extracts of Myracrodruon urundeuva (M. urundeuva) and Qualea grandiflora (Q. grandiflora) leaves on S. mutans and L. casei. For this, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined. MIC was defined as the lowest concentration of the antimicrobial agent capable of inhibiting 100% the microbial growth in comparison to the negative controls. For MBC, aliquots were removed from the wells that did not show any absorbance (viability, concentrations than MIC) and seeded on BHI agar plates, incubated for 24 h at 37°C and 5% CO2. The MBC was determined considering the lowest concentration of extracts capable of preventing visible bacterial growth. Strains of S. mutans (ATCC 21175) and L. casei (ATTC 334) were activated in BHI and Rogosa broth. MIC was determined by the dilution technique in 96-wells microplates (100 l of extract + 80 l BHI/ Rogosa + 20 l of bacterium diluted in BHI/Rogosa equivalent to 5x105 CFU/ml), which were incubated for 24 h (S. mutans) and 48 h (L. casei) at 37°C and 5% CO2. The extracts were firstly diluted in BHI/Rogosa varying the concentrations between 2 mg/mL and 0.00012207 mg/ml; the same extracts were also diluted in alcohol at concentrations ranging from 20 mg/ml to 0.00244 mg/ml and both tested against S. mutans and L. casei. It was not possible to determine the MIC and MBC for the extracts diluted in BHI/Rogosa. Chlorhexidine was used as positive control, while BHI/Rogosa with or without 5% alcohol were used as negative controls. The MICs (MBCs) of M. urundeuva and Q. grandiflora diluted in alcohol, and clorexidine against S. mutans were 2.5 mg/ml (2.5 mg/ml), 5.0 mg/ml (--) and 0.00468 mg/ml (0.00937 mg/ml), respectively. In respect to L. casei, the MICs (MBCs) of M. urundeuva and Q. grandiflora, diluted in alcohol, and chlorhexidine were 0.156 mg/ml (0.312 mg/ml), 0.156 0.625 mg/ml (0.312 0.625 mg/ml) and 0.00468 mg/ml (0.3 mg/ml), respectively. In conclusion, our study showed that L. casei (ATTC 334) is more susceptible than S. mutans (ATCC 21175) to the extracts and the extract of M. urundeuva has a better antimicrobial effect than Q. grandiflora against S. mutans (ATCC 21175), but both extracts have similar effect on L. casei (ATTC 334) and they were inferior to CHX.(AU)

Milk digesta and milk protein fractions influence the adherence of Lactobacillus gasseri R and Lactobacillus casei FMP to human cultured cells.

Adhesion to the intestinal epithelium is considered an important feature of probiotic bacteria, which may increase their persistence in the intestine, allowing them to exert their beneficial health effect or promote the colonisation process. However, this feature might be largely dependent on the host specificity or diet. In the present study, we investigated the effect of selected milks and milk protein fractions on the ability of selected lactobacilli to adhere to the cells of an intestinal model based on co-culture Caco-2/HT29-MTX cell lines. Most milk digesta did not significantly affect bacterial adhesion except for UHT-treated milk and sheep milk. The presence of UHT-treated milk digesta reduced the adhesion of Lactobacillus gasseri R by 61% but not that of Lactobacillus casei FMP. However, sheep milk significantly increased the adherence of L. casei FMP (P < 0.05) but not of L. gasseri R. Among the protein fractions, rennet casein (RCN) and bovine serum albumin (BSA) showed reproducible patterns and strain-specific effects on bacterial adherence. While RCN reduced the adherence of L. gasseri R to <50% compared to the control, it did not have a significant effect on L. casei FMP. In contrast, BSA reduced L. casei FMP adherence to a higher extent than that of L. gasseri R. Whey protein (WH) tended to increase the adherence of both strains by 130%-180%. Recently, interactions between the host diet and its microbiota have attracted considerable interest. Our results may explain one of the aspects of the role of milk in the development of microbiota or support of probiotic supplements. Based on our data, we conclude that the persistence of probiotic strains supplemented as part of dairy food or constitutional microbiota in the gut might be affected negatively or positively by the food matrix through complex strain or concentration dependent effects.

Copaifera reticulata oleoresin: Chemical characterization and antibacterial properties against oral pathogens.

Oral infections such as periodontitis and tooth decay are the most common diseases of humankind. Oleoresins from different copaifera species display antimicrobial and anti-inflammatory activities. Copaifera reticulata is the commonest tree of this genus and grows abundantly in several Brazilian states, such as Pará, Amazonas, and Ceará. The present study has evaluated the chemical composition and antimicrobial potential of the Copaifera reticulata oleoresin (CRO) against the causative agents of tooth decay and periodontitis and has assessed the CRO cytotoxic potential. Cutting edge analytical techniques (GC-MS and LC-MS) aided the chemical characterization of CRO. Antimicrobial assays included determination of the Minimum Inhibitory Concentration (MIC), determination of the Minimum Bactericidal Concentration (MBC), determination of the Minimum Inhibitory Concentration of Biofilm (MICB50), Time Kill Assay, and Checkerboard Dilution. Conduction of XTT assays on human lung fibroblasts (GM07492-A cells) helped to examine the CRO cytotoxic potential. Chromatographic analyses revealed that the major constituents of CRO were ß-bisabolene, trans-α-bergamotene, ß-selinene, α-selinene, and the terpene acids ent-agathic-15-methyl ester, ent-copalic acid, and ent-polyalthic acid. MIC and MBC results ranged from 6.25 to 200 µg/mL against the tested bacteria. The time-kill assay conducted with CRO at concentrations between 50 and 100 µg/mL showed bactericidal activity against Fusobacterium nucleatum (ATCC 25586) and Streptococcus mitis (ATCC 49456) after 4 h, Prevotella nigrescens (ATCC 33563) after 6 h, Porphyromonas gingivalis (ATCC 33277) and Lactobacillus casei (clinical isolate) after 12 h, and Streptococcus salivarius (ATCC 25975) and Streptococcus mutans (ATCC 25175) after 18 h. The fractional inhibitory concentration indexes (FICIs) revealed antagonistic interaction for Lactobacillus casei (clinical isolate), indifferent effect for Porphyromonas gingivalis (ATCC 33277), Fusobacterium nucleatum (ATCC 25586), Prevotella nigrescens (ATCC 33563), and Streptococcus salivarius (ATCC 25975), and additive effect for Streptococcus mutans (ATCC 25175) and Streptococcus mitis (ATCC 49456). Treatment of GM07492-A cells with CRO demonstrated that concentrations up to 39 µg/mL significantly reduced cell viability as compared to the negative control, being IC50 equal to 51.85 ± 5.4 µg/mL. These results indicated that CRO plays an important part in the search for novel sources of agents that can act against oral pathogens.

Characterization of Extracellular Yeast Peptide Factors and Their Stress-Protective Effect on Probiotic Lactic Acid Bacteria.

Protective effect of the extracellular peptide fraction (reactivating factors, RF) produced by yeasts of various taxonomic groups (Saccharomyces cerevisiae, Kluyveromyces lactis, Candida utilis, and Yarrowia li- polytica) on probiotic lactic acid bacteria (LAB) Lactobacillus casei, L. acidophilus,'and L. reuteri under bile salt (BS)-induced stress was shown. RF of all yeasts were shown to be of peptide nature; the active component of the S. cerevisiae RF was identified as a combination of low-molecular polypeptides with molecular masses of 0.6 to 1.5 kDa. The protective and reactivating effects of the yeast factors were not species-specific and were similar to those of the Luteococcusjaponicus subsp. casei R. In BS-treated cells of the tester bacteria, a pro- tective effect was observed after 10-min preincubation of the LAB cell suspension with yeast RE: the number of surviving cells (CFU) was 2 to 4.5 times higher than in the control. The reactivating effect was observed when RF was added to LAB cell suspensions not later than 15 min after stress treatment. It was less pro- nounced than the protector effect, with the CFU number I to 3 times that of the control. Both the protector and the reactivating effects were most pronounced in the S. cerevisiae and decreased in the row: C. utilis > K. lactis > Y lipolytica. The efficiency of protective action of yeast RF was found to depend on the properties of recepient LAB cells, with the L. casei strain being most sensitive to BS treatment. In both variants, the highest protective effect of RF (increase in the CFU number) was observed for L. acidophilus, while the least pronounced one, for L. casei. The reasons for application of the LAB strains combining high stress resistance and high response to stress-protecting metabolites, including RF factors, as probiotics, is discussed.

Antimicrobial activity of the essential oil of Tetradenia riparia (Hochst.) Codd. (Lamiaceae) against cariogenic bacteria.

In Brazilian folk medicine, Tetradenia riparia (Hochst.) Codd. (Lamiaceae) is used to treat toothaches and dental abscesses and diseases induced by worms, bacteria, or fungi. This paper aims to investigate the chemical composition and the antibacterial effects of the essential oil obtained from Tetradenia riparia leaves (TR-EO) grown in Southeastern Brazil against a representative panel of oral pathogens. We evaluated the antibacterial activity of TR-EO in terms of the minimal inhibitory concentration (MIC). We identified aromadendrene oxide (14.0%), (E,E)-farnesol (13.6%), dronabinol (12.5%), and fenchone (6.2%) as the major constituents of TR-EO. TR-EO displayed MIC values between 31.2 and 500 µg/mL, with the lowest MIC value being obtained against Streptococcus mitis (31.2 µg/mL), S. mutans (62.5 µg/mL), S. sobrinus (31.2 µg/mL), and Lactobacillus casei (62.5 µg/mL). In time-kill experiments, TR-EO demonstrated bactericidal activity against S. mutans within the first 12 h, resulting in a curve profile similar to that of chlorhexidine. These results revealed that the essential oil of Tetradenia riparia displays promising activity against most of the selected cariogenic bacteria, including Streptococcus mutans.

Antimicrobial activity of the essential oil of Tetradenia riparia (Hochst.) Codd. (Lamiaceae) against cariogenic bacteria

In Brazilian folk medicine, Tetradenia riparia (Hochst.) Codd. (Lamiaceae) is used to treat toothaches and dental abscesses and diseases induced by worms, bacteria, or fungi. This paper aims to investigate the chemical composition and the antibacterial effects of the essential oil obtained from Tetradenia riparia leaves (TR-EO) grown in Southeastern Brazil against a representative panel of oral pathogens. We evaluated the antibacterial activity of TR-EO in terms of the minimal inhibitory concentration (MIC). We identified aromadendrene oxide (14.0%), (E,E)-farnesol (13.6%), dronabinol (12.5%), and fenchone (6.2%) as the major constituents of TR-EO. TR-EO displayed MIC values between 31.2 and 500 μg/mL, with the lowest MIC value being obtained against Streptococcus mitis (31.2 μg/mL), S. mutans (62.5 μg/mL), S. sobrinus (31.2 μg/mL), and Lactobacillus casei (62.5 μg/mL). In time-kill experiments, TR-EO demonstrated bactericidal activity against S. mutans within the first 12 h, resulting in a curve profile similar to that of chlorhexidine. These results revealed that the essential oil of Tetradenia riparia displays promising activity against most of the selected cariogenic bacteria, including Streptococcus mutans.

Probiotic lactic acid bacteria detoxify N-nitrosodimethylamine.

Humans can be exposed to N-nitroso compounds (NOCs) due to many environmental sources, as well as endogenous formation. The main nitrosamine found in food products and also synthesised in vivo by intestinal microbiota is N-nitrosodimethylamine (NDMA). It can cause cancer of the stomach, kidney and colon. The effect of four probiotic Lactobacillus strains on NDMA was studied under different culture conditions (24 h in MRS, 168 h in modified MRS N, and 168 h in phosphate buffer). HPLC and GC-TEA methods were used for NDMA determination in supernatants. The influence of lactic acid bacteria on NDMA genotoxicity was investigated by means of the comet assay. Additionally, the effect of NDMA (2-100 µg ml⁻¹) on the growth and survival of the probiotic strains was studied. The results indicate that the bacteria decreased NDMA concentration by up to 50%, depending on the culture conditions, time of incubation, NDMA concentration, pH and bacterial strain. Lb. brevis 0945 lowered the concentration and genotoxicity of NDMA most effectively by up to 50%. This could be due to either adsorption or metabolism. The growth and survival of the bacteria was not affected by any of the tested NDMA concentrations.