The Effect of Food Polymers (Pectin, Alginate, and Gum Arabic) on Carbonated Drink-Induced Enamel Demineralization: An In Vitro Study.

INTRODUCTION: The increased use of soft drinks leads to a high prevalence of dental erosion (DE), and the use of polymers can decrease tooth demineralization by a carbonated drink. Assessment of the effect of food-approved polymers such as highly esterified pectin (HP), propylene glycol alginate (PGA), and gum arabic (GA) on their efficiency to reduce enamel demineralization on addition with a commercially available carbonated drink was the main objective of this study. MATERIALS AND METHODS: For this study, 300 premolar teeth were studied for enamel erosion and were divided into five groups consisting of 60 samples in each group. The teeth treated with distilled water had negative control, a commercially available carbonated drink with pH 2.7 had positive control, and food polymers were added individually to the carbonated drink in a specified quantity with minimal pH change and were taken as groups A, B, and C, respectively. The enamel erosion that occurred in study groups was measured using a laser fluorescence spectroscopic system with laser excitation at 404 nm at different treatment times (30, 60, and 120 seconds).  Results: Demineralization was less in samples treated with polymer added to carbonated drink solutions compared to samples exposed to plain carbonated drink. As the time of exposure increased up to 120 seconds, a significant decrease in demineralization occurred in polymer-treated groups of samples as against plain carbonated drink with HP showing more decreased demineralization with extended exposure periods compared to other polymers. The surface morphology of tooth samples exhibited the anti-erosive effect of polymers, and the scanning electron microscopic pictures revealed a smoother surface for the polymer-added group. CONCLUSION: This study shows the efficacy of HP, PGA, and GA on reducing the effect of carbonated drink-induced enamel demineralization, and these polymers' addition to drinks can be an innovative way to reduce the demineralization potential of carbonated acidic drinks.

Breaking Free from Your Fetal Chains: A Case-Based Review of the Literature on Gamma Chain Variant Hemoglobinopathies

Methemoglobinemia is a dyshemoglobinemia characterized by cyanosis and reduced oxygen saturation with increased methemoglobin values. The etiology may be congenital or acquired, with the latter being more common. We report a case of a full-term neonate who presented with transient cyanosis and methemoglobinemia caused by a mutation in the gamma chain of fetal hemoglobin.

Probing the interaction of the phytochemical 6-gingerol from the spice ginger with DNA.

6-Gingerol [5-hydroxy-1-(4-hydroxy-3-methoxyphenyl) decan-3-one], the bio-active ingredient of the popular Indian spice ginger (Zingiber officinale Roscoe), is well-known for its pharmacological and physiological actions. The potent antioxidant, antiemetic, antiulcer, antimicrobial, analgesic, hypoglycemic, antihypertensive, antihyperlipidemic, immunostimulant, anti-inflammatory, cardiotonic, and cancer prevention activities of 6-Gingerol has been investigated and explored. 6-Gingerol is a good candidate for the treatment of various cancers including prostrate, pancreatic, breast, skin, gastrointestinal, pulmonary, and renal cancer. In this study we report for the first time the molecular recognition of 6-Gingerol with calf thymus DNA (ctDNA) through experimental and molecular modeling techniques confirming a minor groove binding mode of 6-Gingerol with ctDNA. Fluorescence and UV-vis spectroscopic studies confirm the complex formation of 6-gingerol with ctDNA. The energetics and thermodynamics of the interaction of 6-Gingerol with ctDNA was explored by Isothermal Titration Calorimetry (ITC) and Differential Scanning Calorimetry (DSC). The ctDNA helix melting upon 6-Gingerol binding was examined by melting temperature Tm analysis. Further the electrophoretic mobility shift assay confirms a possible groove binding of 6-Gingerol with ctDNA. Molecular docking and Molecular dynamics (MD) studies provide a detailed understanding on the interaction of 6-Gingerol binding in the minor groove of DNA which supports experimental results.

Experimental Probing and Molecular Dynamics Simulation of the Molecular Recognition of DNA Duplexes by the Flavonoid Luteolin.

Luteolin (C15H10O6) is an important flavonoid found in many fruits, plants, medicinal herbs, and vegetables exhibiting many pharmacological properties. The anticancer, antitumor, antioxidant, and anti-inflammatory activities of luteolin have been reported. The pharmacological action of small molecules is dependent upon its interaction with biomacromolecules. The interactions of small molecules with DNA play a major role in the transcription and translation process. In this work, we explored the energetic profile of DNA-luteolin interaction by isothermal titration calorimetry (ITC). The effect of temperature and salt concentration on DNA binding was examined by UV-Vis method. The mode of interaction was further probed by UV melting temperature analysis and differential scanning calorimetry. An atomic level insight on the recognition of luteolin with DNA was achieved by employing molecular dynamics (MD) simulation on luteolin in complex with AT- and GC-rich DNA sequences. AMBER force field proves to be appropriate in providing an understanding on the binding mode and specificity of luteolin with duplex DNA. MD results suggest a minor groove binding of luteolin with DNA and the binding free energy obtained is in agreement with the experimental results.

A comprehensive approach to ascertain the binding mode of curcumin with DNA.

Curcumin is a natural phytochemical from the rhizoma of Curcuma longa, the popular Indian spice that exhibits a wide range of pharmacological properties like antioxidant, anticancer, anti-inflammatory, antitumor, and antiviral activities. In the published literatures we can see different studies and arguments on the interaction of curcumin with DNA. The intercalative binding, groove binding and no binding of curcumin with DNA were reported. In this context, we conducted a detailed study to understand the mechanism of recognition of dimethylsulfoxide-solubilized curcumin by DNA. The interaction of curcumin with calf thymus DNA (ctDNA) was confirmed by agarose gel electrophoresis. The nature of binding and energetics of interaction were studied by Isothermal Titration Calorimetry (ITC), Differential Scanning Calorimetry (DSC), UV-visible, fluorescence and melting temperature (Tm) analysis. The experimental data were compared with molecular modeling studies. Our investigation confirmed that dimethylsulfoxide-solubilized curcumin binds in the minor groove of the ctDNA without causing significant structural alteration to the DNA.

Energetics, Thermodynamics, and Molecular Recognition of Piperine with DNA.

Piperine, the bioactive phytochemical from black pepper (Piper nigrum L.), is a nontoxic natural compound exhibiting many physiological and pharmacological properties. They include antioxidant, anti-inflammatory, antimutagenic, antitumor, antiapoptotic, antigenotoxic, antiarthritic, antifungal, antimicrobial, antidepressant, anti-HBV, and gastro-protective activities. It also enhances the bioavailability of phytochemicals and drugs. The molecular mechanism of action of piperine with DNA has not yet been addressed, while its pharmacological activities have been reported. In this work we report for the first time the interaction of piperine molecule with DNA duplex. We have carried out UV-vis absorption and fluorescence spectroscopy to confirm the binding of piperine with calf thymus DNA (ctDNA). The energetics of interaction of piperine with ctDNA was monitored by isothermal titration calorimetry (ITC). Differential scanning calorimetry (DSC) and melting temperature (Tm) analysis were also performed, confirming a minor groove mode of binding of piperine with ctDNA. The binding free energy ΔG values obtained from molecular dynamics simulation studies agree well with ITC values and reveal a sequence dependent minor groove binding exhibiting a specificity toward AT rich sequences.