Antibacterial and Cytotoxic Activities of Pinus tropicalis and Pinus elliottii Resins and of the Diterpene Dehydroabietic Acid Against Bacteria That Cause Dental Caries

Strawberry tree fruits (Arbutus unedo L.): Bioactive composition, cellular antioxidant activity, and 3D printing of functional foods

The aim of this study was to investigate the use of Arbutus unedo L. fruits for the production of functional foods by three-dimensional printing (3DP). First, the biological activity of the fruits was investigated in vitro, followed by 3DP with different starch types and proportions using two 3DP programs. All 3DP samples were characterized for their bioactive, antioxidant, physicochemical and rheological properties. In terms of biological activity, the recommended daily dose of polyphenols from the aqueous extract of A. unedo can protect the integrity of DNA. Moreover, it could be useful as an antimicrobial agent. All 3DP parameters significantly affected bioactive compounds and antioxidant capacity. The 3DP products were found to be a good source of polyphenols (632.60 mg/100 g), among which condensed tannins were predominant (42 %). In conclusion, the fruits of A. unedo should be considered as a sustainable resource for the production of innovative functional foods with 3DP.

Reduction of oral pathogens and oxidative damage in the CAL 27 cell line by Rosmarinus officinalis L. and Taraxacum officinale Web. Extracts

ETHNOPHARMACOLOGICAL RELEVANCE

Dandelion (Taraxacum officinale Web.) and rosemary (Rosmarinus officinalis L.) are treasured botanicals with a long usage history in traditional herbal practices worldwide. Dandelion was used to treat kidney, spleen, and liver disease, as well as cardiovascular disease, diabetes, and bacterial infections, whereas rosemary was used to treat pain, spasms, and to improve blood circulation.

AIM OF THE STUDY

The aim of this study was to determine the influence of rosemary and dandelion leaves aqueous extracts on the human tongue epithelial carcinoma cell line (CAL 27) at the level of interaction between oral microbiota and tongue epithelial cells, genomic damage, and H₂O₂ - induced oxidative damage protection.

MATERIALS AND METHODS

The polyphenolic composition of the extracts was determined by spectrophotometric and HPLC analyses. After extract treatment, cytotoxic impact and ROS generation in CAL 27 cells were measured using the MTT assay and the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay, respectively. Microdilutions were applied to investigate the antimicrobial and adhesive properties against representatives of the oral microbiota. The single-cell gel electrophoresis (comet assay) and cytokinesis-blocked micronucleus cytome assay (CBMN cyt) were used to detect induced genomic damages.

RESULTS

Both extracts increased the adhesion of the lactic acid bacteria L. plantarum but decreased the adhesion of the bacterial pathogens S. enterica serovar Typhimurium LT21 and E. coli K-12 MG1655 adhesion onto CAL 27 cells. 1 h treatment with 5x concentrated dandelion extract and 1x, 2.5x, and 5x of rosemary extract caused an increase in comet tail intensity. CBMN cyt results demonstrated a significant increase in micronucleus formation even at concentrations several times lower than the usual bioactive compound concentrations found in a cup of beverage, with higher concentrations also inducing cell apoptosis and necrosis. Rosemary extract showed a protective effect against H₂O₂ - induced oxidative damage by decreasing the apoptotic cell number, probably preventing mutations leading to tumor aggressiveness, invasion, and metastasis.

CONCLUSIONS

Both tested extracts demonstrated their usefulness in maintaining good oral bacteria balance and their protective capability as powerful antitumor agents by causing a protective apoptotic effect in tumor cell line already at the dosage of an average daily cup.

Ferroptosis in non-alcoholic liver disease: Molecular mechanisms and therapeutic implications

Ferroptosis refers to a novel modality of regulated cell death characterized by excessive iron accumulation and overwhelming lipid peroxidation, which takes an important part in multiple pathological processes associated with cell death. Considering the crucial roles of the liver in iron and lipid metabolism and its predisposition to oxidative insults, more and more studies have been conducted to explore the relationship between ferroptosis and various liver disorders, including non-alcoholic fatty liver disease (NAFLD). With increased morbidity and high mortality rates, NAFLD has currently emerged as a global public health issue. However, the etiology of NAFLD is not fully understood. In recent years, an accumulating body of evidence have suggested that ferroptosis plays a pivotal role in the pathogenesis of NAFLD, but the precise mechanisms underlying how ferroptosis affects NAFLD still remain obscure. Here, we summarize the molecular mechanisms of ferroptosis and its complicated regulation systems, delineate the different effects that ferroptosis exerts in different stages of NAFLD, and discuss some potential effective therapies targeting ferroptosis for NAFLD treatment, which putatively points out a novel direction for NAFLD treatment.

Bacterial sensitivity to chlorhexidine and povidone-iodine antiseptics over time: a systematic review and meta-analysis of human-derived data

Surgical site infection (SSI) is the most common complication of surgery, increasing healthcare costs and hospital stay. Chlorhexidine (CHX) and povidone-iodine (PVI) are used for skin antisepsis, minimising SSIs. There is concern that  resistance to topical biocides may be emergeing, although the potential clinical implications remain unclear. The objective of this systematic review was to determine whether the minimum bactericidal concentration (MBC) of topical preparations of CHX or PVI have changed over time, in microbes relevant to SSI. We included studies reporting the MBC of laboratory and clinical isolates of common microbes to CHX and PVI. We excluded studies using non-human samples and antimicrobial solvents or mixtures with other active substances. MBC was pooled in random effects meta-analyses and the change in MBC over time was explored using meta-regression. Seventy-nine studies were included, analysing 6218 microbes over 45 years. Most studies investigated CHX (93%), with insufficient data for meta-analysis of PVI. There was no change in the MBC of CHX to Staphylococci or Streptococci over time. Overall, we find no evidence of reduced susceptibility of common SSI-causing microbes to CHX over time. This provides reassurance and confidence in the worldwide guidance that CHX should remain the first-choice agent for surgical skin antisepsis.

Physicochemical Profile, Antioxidant and Antimicrobial Activities of Honeys Produced in Minas Gerais (Brazil)

Honeys can be classified as polyfloral or monofloral and have been extensively studied due to an increased interest in their consumption. There is concern with the correct identification of their flowering, the use of analyses that guarantee their physicochemical quality and the quantification of some compounds such as phenolics, to determine their antioxidant and antimicrobial action. This study aims at botanical identification, physicochemical analyses, and the determination of total polyphenols, chromatographic profile and antiradical and antimicrobial activity of honey from different regions of Minas Gerais. Seven different samples were analyzed for the presence of pollen, and color determination. The physicochemical analyses performed were total acidity, moisture, HMF, reducing sugar, and apparent sucrose. The compound profile was determined by UHPLC/MS, the determination of total phenolics and antiradical activity (DPPH method) were performed by spectrophotometry, and minimum inhibitory and bacterial concentrations were determined for cariogenic bacteria. All honey samples met the quality standards required by international legislation, twenty compounds were detected as the main ones, the polyfloral honey was the only honey that inhibited all of the bacteria tested. Sample M6 (Coffee) was the one with the highest amount of total polyphenols, while the lowest was M4 (Cipó-uva). Regarding the antioxidant activity, M5 (Velame) had the best result and M4 (Cipó-uva) was the one that least inhibited oxidation. Of the polyfloral honeys, there was not as high a concentration of phenolic compounds as in the others. Coffee, Aroeira, Velame and Polyfloral have the best anti-radical actions. Betônica, Aroeira, Cipó-uva and Pequi inhibited only some bacteria. The best bacterial inhibition results are from Polyfloral.

In vitro evaluation of the antibacterial and cytotoxic activities of the Euclea natalensis crude extract and fractions against oral infection agents

OBJECTIVE

This study aimed (i) to evaluate the antibacterial and cytotoxic activities of the crude extract and fractions obtained from Euclea natalensis A.D.C. roots against bacteria that cause periodontal disease and caries and (ii) to identify the isolated compounds.

DESIGN

The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the extract and fractions were determined by the microplate dilution assay. The cytotoxicity of the extract and fractions was evaluated by using the XTT colorimetric assay and normal human fibroblast cells (GM07492A, lung fibroblasts). The compounds present in the most promising fraction were determined by qualitative analysis through liquid chromatography coupled to mass spectrometry (HPLC-MS-ESI).

RESULTS

The MIC results ranged from 25 to > 400 μg/mL for the extract and from 1.56 to > 400 μg/mL for the fractions. To evaluate cytotoxicity, the tested concentrations of the extract and fractions ranged from 19.5 to 2500 μg/mL; IC₅₀ values between 625 and 1250 μg/mL were obtained. Analysis of the main bioactive fraction by HPLC-MS-ESI identified phenolic acids, coumarins, naphthoquinones, lignans, and fatty acids.

CONCLUSIONS

The E. natalensis root extract and fractions displayed good antibacterial activity against periodontal pathogenic and cariogenic bacteria. The antibacterial activity may be due to compounds present in the extract and fractions, which also showed low cytotoxicity to normal human cells. These data are relevant and encourage further research into this plant species, which may contribute to the discovery of new herbal medicines that will help to mitigate the problems caused by oral pathogenic bacteria.

The Antimicrobial Efficacy Against Selective Oral Microbes, Antioxidant Activity and Preliminary Phytochemical Screening of Zingiber officinale

Introduction

Ginger (Zingiber officinale) has been one of the most commonly consumed herbal medicines for a long time to treat several common diseases. Antibacterial activity, antioxidant properties and many bioactive compounds in ginger have been identified previously, which could be used as an alternative method to treat many infectious diseases.

Methods

The current study evaluates ginger’s biochemical profile using qualitative and quantitative analysis and its bioactive potentials using antioxidant and antimicrobial assays against Streptococcus mutans and selective oral microbes. HPLC analysis was performed for the quantitative analysis. DPPH and disc diffusion assays were used for antioxidant and antimicrobial activities. The antimicrobial activity was checked against Streptococcus mutans, Enterococcus faecalis, Staphylococcus spp., and Lactobacillus spp. All solvents were removed by rotary evaporation before testing the dried extracts.

Results

The observed IC₅₀ value showed that distilled water extract exhibited the highest antioxidant activity (43.9), followed by ethanol extract (52.4), and the lowest activity was observed in n-butanol extract (91.2) and n-hexane (90.6). Different plant extracts have shown significant antibacterial activity (p = 0.001) against each bacterium. The highest antibacterial activity against tested bacteria was observed in n-hexane, chloroform and ethanol extracts. In comparison, the ethyl acetate, n-butanol and water extracts showed low antibacterial activity.

Conclusion

This study emphasizes that Zingiber officinale (Z. officinale) against Gram-positive bacteria is an effective antimicrobial herb. Furthermore, it can be used as a potential natural source of antioxidants. Further studies on the toxicity analysis of ginger are recommended.

Evaluation of Antibacterial Activity of Pine Tar on Periodontal Pathogenic Bacteria: An In Vitro Study

Background

Periodontal pathogens play an important role in etiology and pathogenesis of periodontitis. Microbiological examination of sub gingival plaque is used at the present time in etiological research as well as in clinical treatment of periodontitis to select the appropriate antibiotic agent if indicated. Pine tar has been used for the treatment of various skin diseases. So the study was done to evaluate the effect of Pine Tar oil on bacteria isolated from periodontitis patients.

Methods

Plaque samples from volunteer patients were collected using sterile paper points. Robertson's Cooked Meat (RCM) medium was used for the transportation and cultivation of aerobic, microaerophilic, and anaerobic microorganisms.

Results

The result suggests the use of Pine tar oil for topical application in periodontal diseases. Disc diffusion analysis was sufficient enough to illustrate that 75 µl tar oil solution produced growth inhibition of microbial strains.

Conclusion

Pine tar oil has become one of the important areas of research both in pharmaceutical and periodontal research, hence in vivo studies has to be carried out with various form of pine tar.

Green and Red Brazilian Propolis: Antimicrobial Potential and Anti-Virulence against ATCC and Clinically Isolated Multidrug-Resistant Bacteria

Brazilian green and red propolis stand out as commercial products for different medical applications. In this article, we report the antimicrobial activities of the hydroalcoholic extracts of green (EGP) and red (ERP) propolis, as well as guttiferone E plus xanthochymol (8) and oblongifolin B (9) from red propolis, against multidrug-resistant bacteria (MDRB). We undertook the minimal inhibitory (MIC) and bactericidal (MBC) concentrations, inhibition of biofilm formation (MICB₅₀ ), catalase, coagulase, DNase, lipase, and hemolysin assays, along with molecular docking simulations. ERP was more effective by displaying MIC and MBC values <100 μg mL^-1 . Compounds 8 and 9 displayed the lowest MIC values (0.98 to 31.25 μg mL^-1 ) against all tested Gram-positive MDRB. They also inhibited the biofilm formation of S. aureus (ATCC 43300 and clinical isolate) and S. epidermidis (ATCC 14990 and clinical isolate), with MICB₅₀ values between 1.56 and 6.25 μg mL^-1 . The molecular docking results indicated that 8 and 9 might interact with the catalase's amino acids. Compounds 8 and 9 have great antimicrobial potential.

Ethnobotany and the Role of Plant Natural Products in Antibiotic Drug Discovery

The crisis of antibiotic resistance necessitates creative and innovative approaches, from chemical identification and analysis to the assessment of bioactivity. Plant natural products (NPs) represent a promising source of antibacterial lead compounds that could help fill the drug discovery pipeline in response to the growing antibiotic resistance crisis. The major strength of plant NPs lies in their rich and unique chemodiversity, their worldwide distribution and ease of access, their various antibacterial modes of action, and the proven clinical effectiveness of plant extracts from which they are isolated. While many studies have tried to summarize NPs with antibacterial activities, a comprehensive review with rigorous selection criteria has never been performed. In this work, the literature from 2012 to 2019 was systematically reviewed to highlight plant-derived compounds with antibacterial activity by focusing on their growth inhibitory activity. A total of 459 compounds are included in this Review, of which 50.8% are phenolic derivatives, 26.6% are terpenoids, 5.7% are alkaloids, and 17% are classified as other metabolites. A selection of 183 compounds is further discussed regarding their antibacterial activity, biosynthesis, structure-activity relationship, mechanism of action, and potential as antibiotics. Emerging trends in the field of antibacterial drug discovery from plants are also discussed. This Review brings to the forefront key findings on the antibacterial potential of plant NPs for consideration in future antibiotic discovery and development efforts.

Dehydroabietic acid improves nonalcoholic fatty liver disease through activating the Keap1/Nrf2-ARE signaling pathway to reduce ferroptosis

The accumulation of iron-dependent lipid peroxides is one of the important causes of NAFLD. The purpose of this study is to explore the effect of dehydroabietic acid (DA) on ferroptosis in nonalcoholic fatty liver disease (NAFLD) mice and its possible mechanisms. DA improved NAFLD and reduced triglycerides (TG), total cholesterol (TC), and lipid peroxidation level and inhibited ferroptosis in the liver of HFD-induced mice. DA binds with Keap1 to form 3 stable hydrogen bonds at VAL512 and LEU557 and increased nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response elemen (ARE) luciferase activity. DA promoted the expression downstream of Nrf2 such as heme oxygenase-1 (HO-1), glutathione (GSH) and its peroxidase 4 (GPX4), so as to eliminate the accumulation of reactive oxygen species (ROS) and reduce lipid peroxides malondialdehyde (MDA) in the liver. DA inhibited ferroptosis and increased the expression of key genes such as ferroptosis suppressor protein 1 (FSP1) in vitro and vivo. In all, DA may bind with Keap1, activate Nrf2-ARE, induce its target gene expression, inhibit ROS accumulation and lipid peroxidation, and reduce HFD-induced NAFLD.

Mass spectrometry imaging as a potential technique for diagnostic of Huanglongbing disease using fast and simple sample preparation

Huanglongbing (HLB) is a disease of worldwide incidence that affects orange trees, among other commercial varieties, implicating in great losses to the citrus industry. The disease is transmitted through Diaphorina citri vector, which inoculates Candidatus Liberibacter spp. in the plant sap. HLB disease lead to blotchy mottle and fruit deformation, among other characteristic symptoms, which induce fruit drop and affect negatively the juice quality. Nowadays, the disease is controlled by eradication of sick, symptomatic plants, coupled with psyllid control. Polymerase chain reaction (PCR) is the technique most used to diagnose the disease; however, this methodology involves high cost and extensive sample preparation. Mass spectrometry imaging (MSI) technique is a fast and easily handled sample analysis that, in the case of Huanglongbing allows the detection of increased concentration of metabolites associated to the disease, including quinic acid, phenylalanine, nobiletin and sucrose. The metabolites abieta-8,11,13-trien-18-oic acid, suggested by global natural product social molecular networking (GNPS) analysis, and 4-acetyl-1-methylcyclohexene showed a higher distribution in symptomatic leaves and have been directly associated to HLB disease. Desorption electrospray ionization coupled to mass spectrometry imaging (DESI-MSI) allows the rapid and efficient detection of biomarkers in sweet oranges infected with Candidatus Liberibacter asiaticus and can be developed into a real-time, fast-diagnostic technique.