Pinus koraiensis Essential Oil Attenuates the Pathogenicity of Superbacteria by Suppressing Virulence Gene Expression.

In the quest to combat infections attributable to antibiotic-resistant superbacteria, an essential oil derived from the needles of Pinus koraiensis Sieb. et Zucc. (PKEO) has emerged as a promising solution. In this study, we demonstrate that PKEO can be used to inhibit the growth, glucose metabolite acidogenicity, and biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA). Quantitative PCR analysis provided direct evidence that PKEO reduces the mRNA expression of the accessory gene regulator A (agrA) and staphylococcal accessory regulator A (sarA), thereby indicating its inhibitory effect on pathogenic regulatory genes. Chromatographic analyses of PKEO identified terpene hydrocarbons as prominent essential oil constituents. These compounds, notably α-pinene, limonene, and ß-caryophyllene, have been established to have antimicrobial properties. Our findings indicate that an oil derived from P. koraiensis can effectively combat antibiotic-resistant strains by disrupting the pathogenicity regulatory system, thereby establishing PKEO as a promising candidate for the treatment of MRSA infections.

The Identification and Quantitative Analysis of Unusual Keto-Carotenoids in Ripe Fruits of Maclura tricuspidate and Its Potential as a Valuable Source of Cryptocapsin.

Ripe fruits of Maclura tricuspidata (MT) are used as food material and a natural colorant in Korea. Although MT fruits have a deep red color due to carotenoid-like pigments, their chemical nature has not been explored in detail so far. The present study aimed at elucidating the chemical structures and composition of carotenoids in MT fruits and changes at different maturity stages. Two carotenoids from saponified MT fruit extract were isolated using repeated silica gel column chromatography. Based on interpretations of spectroscopic data, these compounds were determined as keto-carotenoids, i.e., capsanthin (3,3'-dihydroxy-ß,κ-caroten-6'-one) and cryptocapsin (3'-hydroxy-ß,κ-caroten-6'-one), and the contents of individual carotenoids were quantified with HPLC based on calibration curves obtained from authentic standards. The contents of capsanthin and cryptocapsin in the sample of saponified MT fruits were 57.65 ± 1.97 µg/g and 171.66 ± 4.85 µg/g as dry weight base (dw). The majority of these keto-carotenoids in the MT fruits were present in esterified forms with lauric, myristic or palmitic acid rather than in their free forms. The results also showed that esterification of these compounds occurred starting from early stage (yellow-brownish stage) of maturation. Considering the high cryptocapsin content, MT fruits can be applied as a potentially valuable source of cryptocapsin for food and medicinal application as well as a source of provitamin A.

Identification of Novel Parishin Compounds from the Twig of Maclura tricuspidata and Comparative Analysis of Parishin Derivatives in Different Parts.

Parishin compounds are rare polyphenolic glucosides mainly found in the rhizome of the traditional Chinese medicinal plant, Gastrodia elata. These constituents are reported to have several biological and pharmacological activities. In the present study, two novel parishin derivatives not previously reported as plant-based phytochemicals were identified from a twig of Maclura tricuspidata (MT) and two new compounds were elucidated as 1-(4-(ß-d-glucopyranosyloxy)benzyl)-3-hydroxy-3-methylpentane-1,5-dioate (named macluraparishin E) and 1,3-bis(4-(ß-d-glucopyranosyloxy)benzyl)-3-hydroxy-3-methylpentane- 1,5-dioate (macluraparishin C), based on the experimental data obtained by UV-Visible (UV-Vis) spectroscopy, high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS) and nuclear magnetic resonance (NMR) spectroscopy. Additionally, gastrodin, parishin A and parishin B were positively identified by spectroscopic evidence and the comparison of HPLC retention time with the corresponding authentic standards. Gastrodin, parishin A and parishin B, macluraparishin E and macluraparishin C were found to be the most abundant constituents in the MT twig. The compositions and contents of these constituents were found to vary depending on the different parts of the MT plant. In particular, the contents of parishin A, parishin B, macluraparishin C and macluraparishin E were higher in the twig, bark and root than in the leaves, xylem and fruit.

Production of Minor Ginsenosides C-K and C-Y from Naturally Occurring Major Ginsenosides Using Crude ß-Glucosidase Preparation from Submerged Culture of Fomitella fraxinea.

Minor ginsenosides, such as compounds (C)-K and C-Y, possess relatively better bioactivity than those of naturally occurring major ginsenosides. Therefore, this study focused on the biotransformation of major ginsenosides into minor ginsenosides using crude ß-glucosidase preparation isolated from submerged liquid culture of Fomitella fraxinea (FFEP). FFEP was prepared by ammonium sulfate (30-80%) precipitation from submerged culture of F. fraxinea. FFEP was used to prepare minor ginsenosides from protopanaxadiol (PPD)-type ginsenoside (PPDG-F) or total ginsenoside fraction (TG-F). In addition, biotransformation of major ginsenosides into minor ginsenosides as affected by reaction time and pH were investigated by TLC and HPLC analyses, and the metabolites were also identified by UPLC/negative-ESI-Q-TOF-MS analysis. FFEP biotransformed ginsenosides Rb1 and Rc into C-K via the following pathways: Rd → F2 → C-K for Rb1 and both Rd → F2→ C-K and C-Mc1 → C-Mc → C-K for Rc, respectively, while C-Y is formed from Rb2 via C-O. FFEP can be applied to produce minor ginsenosides C-K and C-Y from PPDG-F or TG-F. To the best of our knowledge, this study is the first to report the production of C-K and C-Y from major ginsenosides by basidiomycete F. fraxinea.

Changes of Phytochemical Components (Urushiols, Polyphenols, Gallotannins) and Antioxidant Capacity during Fomitella fraxinea⁻Mediated Fermentation of Toxicodendron vernicifluum Bark.

The stem bark of Toxicodendron vernicifluum (TVSB) has been widely used as a traditional herbal medicine and food ingredients in Korea. However, its application has been restricted due to its potential to cause allergies. Moreover, there is limited data available on the qualitative and quantitative changes in the composition of its phytochemicals during fermentation. Although the Formitella fraxinea-mediated fermentation method has been reported as an effective detoxification tool, changes to its bioactive components and the antioxidant activity that takes place during its fermentation process have not yet been fully elucidated. This study aimed to investigate the dynamic changes of urushiols, bioactive compounds, and antioxidant properties during the fermentation of TVSB by mushroom F. fraxinea. The contents of urushiols, total polyphenols, and individual flavonoids (fisetin, fustin, sulfuretin, and butein) and 1,2,3,4,6-penta-O-galloyl-ß-D-glucose (PGG) significantly decreased during the first 10 days of fermentation, with only a slight decrease thereafter until 22 days. Free radical scavenging activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6- sulfonic acid) (ABTS), and ferric reducing/antioxidant power (FRAP) as an antioxidant function also decreased significantly during the first six to nine days of fermentation followed by a gentle decrease up until 22 days. These findings can be helpful in optimizing the F. fraxinea⁻mediated fermentation process of TVSB and developing functional foods with reduced allergy using fermented TVSB.

Comparison of Bioactive Compounds and Antioxidant Activities of Maclura tricuspidata Fruit Extracts at Different Maturity Stages.

Abstract: Maclura tricuspidata fruit contains various bioactive compounds and has traditionally been used in folk medicine and as valuable food material in Korea. The composition and contents of bioactive compounds in the fruit can be influenced by its maturity stages. In this study, total phenol, total flavonoid, individual polyphenolic compounds, total carotenoids and antioxidant activities at four maturity stages of the fruit were determined. Polyphenolic compounds were analyzed using high-pressure liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS) and HPLC. Among 18 polyphenolic compounds identified in this study, five parishin derivatives (gastrodin, parishin A, B, C, E) were positively identified for the first time in this plant. These compounds were also validated and quantified using authentic standards. Parishin A was the most abundant component, followed by chlorogenic acid, gastrodin, eriodictyol glucoside, parishin C, parishin E and parishin B. The contents of all the polyphenolic compounds were higher at the immature and premature stages than at fully mature and overmature stages, while total carotenoid was found to be higher in the mature and overmature stages. Overall antioxidant activities by three different assays (DPPH, ABTS, FRAP) decreased as maturation progressed. Antioxidant properties of the fruit extract are suggested to be attributed to the polyphenols.

Enzymatic transglycosylation of ginsenoside Rg1 by rice seed α-glucosidase.

Six α-monoglucosyl derivatives of ginsenoside Rg1 (G-Rg1) were synthesized by transglycosylation reaction of rice seed α-glucosidase in the reaction mixture containing maltose as a glucosyl donor and G-Rg1 as an acceptor. Their chemical structures were identified by spectroscopic analysis, and the effects of reaction time, pH, and glycosyl donors on transglycosylation reaction were investigated. The results showed that rice seed α-glucosidase transfers α-glucosyl group from maltose to G-Rg1 by forming either α-1,3 (α-nigerosyl)-, α-1,4 (α-maltosyl)-, or α-1,6 (α-isomaltosyl)-glucosidic linkages in ß-glucose moieties linked at the C6- and C20-position of protopanaxatriol (PPT)-type aglycone. The optimum pH range for the transglycosylation reaction was between 5.0 and 6.0. Rice seed α-glucosidase acted on maltose, soluble starch, and PNP α-D-glucopyranoside as glycosyl donors, but not on glucose, sucrose, or trehalose. These α-monoglucosyl derivatives of G-Rg1 were easily hydrolyzed to G-Rg1 by rat small intestinal and liver α-glucosidase in vitro.

Rutin from Dendropanax morbifera Leveille protects human dopaminergic cells against rotenone induced cell injury through inhibiting JNK and p38 MAPK signaling.

Dendropanax morbifera Leveille (Araliaceae) is well known in Korean traditional medicine for a variety of diseases. Rotenone is a commonly used neurotoxin to produce in vivo and in vitro Parkinson's disease models. This study was designed to elucidate the processes underlying neuroprotection of rutin, a bioflavonoid isolated from D. morbifera Leveille in cellular models of rotenone-induced toxicity. We found that rutin significantly decreased rotenone-induced generation of reactive oxygen species levels in SH-SY5Y cells. Rutin protected the increased level of intracellular Ca(2+) and depleted level of mitochondrial membrane potential (ΔΨm) induced by rotenone. Furthermore, it prevented the decreased ratio of Bax/Bcl-2 caused by rotenone treatment. Additionally, rutin protected SH-SY5Y cells from rotenone-induced caspase-9 and caspase-3 activation and apoptotic cell death. We also observed that rutin repressed rotenone-induced c-Jun N-terminal kinase and p38 mitogen-activated protein kinase phosphorylation. These results suggest that rutin may have therapeutic potential for the treatment of neurodegenerative diseases associated with oxidative stress.

Effect of AlOx protection layer on AgNWs for flexible transparent heater.

We indicated high performance and stability transparent heaters based on AlOx covered Ag nanowires. We obtained an AlOx covered Ag nanowire thin film which has a 47 ohm/sq of sheet resistance and 88.1% (substrate included) of transmittance at 600 nm on a flexible substrate. We demonstrate that the thin AlOx layer leads to increased contact area at the junction of Ag nanowires, which contributes to lower sheet resistance and improved adhesion of Ag nanowires. Furthermore, high stability and flexibility of Ag nanowire have been achieved by the AlOx layer. Finally, we fabricated a flexible transparent heater with AlOx covered Ag nanowire, and obtained a temperature of 81 °C within 40 sec at the driven voltage of 7 V with fast response and uniform temperature distribution. Therefore, the AlOx covered Ag nanowire film is a promising candidate for the application of the flexible transparent heaters.

Effect of Inductively Coupled Plasma on Multilayer Electrodes for Flexible Single-Layer Touch Screen Panels.

We investigated the effect of inductively coupled plasma (ICP) on multilayer electrodes for flexible capacitive touch sensors. We found that using ICP during Ag deposition generally increased the conductivity and transmittance of multilayer electrodes. As a result, in the case of the multilayer electrode with an ICP power of 150 W during Ag deposition, 5.7 Ω/sq of sheet resistance and 89.6% of transmittance (550 nm) have been achieved. We demonstrate that the crystallization of the ICP supplied Ag layer in multilayer electrodes leads to the smooth surface roughness of the multilayer film; the smooth surface roughness provided low light scattering. As a result, the crystallized Ag thin film by ICP improved the sheet resistance and transmittance of multilayer electrodes. Finally, we fabricated a 221 × 130 mm (active layer)-sized single-layer touch screen panel (TSP) using multilayer electrodes with ICP on a corning glass and polyethylene terephthalate flexible substrate. The single-layer TSPs show high linearity and sensitivity with multitouches.

Chemical Composition and Antioxidant Activity of Steam-Distilled Essential Oil and Glycosidically Bound Volatiles from Maclura Tricuspidata Fruit.

Essential oil obtained from Maclura triscuspidata fruit has been reported to have functional properties. This study aimed at determining chemical compositions and antioxidant activities of steam-distilled essential oil (SDEO) and glycosidically bound aglycone fraction (GBAF) isolated from fully ripe M. triscuspidata fruit. SDEO was isolated by simultaneous steam distillation and extraction (SDE). GBAF was prepared by Amberlite XAD-2 adsorption of methanol extract, followed by methanol elution and enzymatic hydrolysis. Both fractions were analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 76 constituents were identified from both oils. Apart from fatty acids and their esters, the SDEO contained p-cresol in the highest concentration (383.5 ± 17.7), followed by δ-cadinene (147.7 ± 7.7), ß-caryophyllene (145.7 ± 10.5), ß-ionone (141.0 ± 4.5), n-nonanal (140.3 ± 20.5), theaspirane A (121.3 ± 4.5) and theaspirane B (99.67 ± 9.05 µg/g). Thirteen carotenoid-derived compounds identified in the SDEO are being isolated from M. triscuspidata fruit for the first time. Out of the 22 components identified in GBAF, 14 were present only in the glycosidically bound volatiles. Antioxidant activity of the GBAF was higher than that of SDEO. These results suggest that glycosidically bound volatiles of M. triscuspidata fruit have a good potential as natural antioxidants.

Highly regioselective biotransformation of ginsenoside Rb2 into compound Y and compound K by ß-glycosidase purified from Armillaria mellea mycelia.

BACKGROUND: The biological activities of ginseng saponins (ginsenosides) are associated with type, number, and position of sugar moieties linked to aglycone skeletons. Deglycosylated minor ginsenosides are known to be more biologically active than major ginsenosides. Accordingly, the deglycosylation of major ginsenosides can provide the multibioactive effects of ginsenosides. The purpose of this study was to transform ginsenoside Rb2, one of the protopanaxadiol-type major ginsenosides, into minor ginsenosides using ß-glycosidase (BG-1) purified from Armillaria mellea mycelium. METHODS: Ginsenoside Rb2 was hydrolyzed by using BG-1; the hydrolytic properties of Rb2 by BG-1 were also characterized. In addition, the influence of reaction conditions such as reaction time, pH, and temperature, and transformation pathways of Rb2, Rd, F2, compound O (C-O), and C-Y by treatment with BG-1 were investigated. RESULTS: BG-1 first hydrolyzes 3-O-outer ß-d-glucoside of Rb2, then 3-O-ß-d-glucoside of C-O into C-Y. C-Y was gradually converted into C-K with a prolonged reaction time, but the pathway of Rb2 → Rd → F2 → C-K was not observed. The optimum reaction conditions for C-Y and C-K formation from Rb2 by BG-1 were pH 4.0-4.5, temperature 45-60°C, and reaction time 72-96 h. CONCLUSION: ß-Glycosidase purified from A. mellea mycelium can be efficiently used to transform Rb2 into C-Y and C-K. To our best knowledge, this is the first result of transformation from Rb2 into C-Y and C-K by basidiomycete mushroom enzyme.

Enzymatic formation of compound-K from ginsenoside Rb1 by enzyme preparation from cultured mycelia of Armillaria mellea.

BACKGROUND: Minor saponins or human intestinal bacterial metabolites, such as ginsenosides Rg3, F2, Rh2, and compound K, are more pharmacologically active than major saponins, such as ginsenosides Rb1, Rb2, and Rc. In this work, enzymatic hydrolysis of ginsenoside Rb1 was studied using enzyme preparations from cultured mycelia of mushrooms. METHODS: Mycelia of Armillaria mellea, Ganoderma lucidum, Phellinus linteus, Elfvingia applanata, and Pleurotus ostreatus were cultivated in liquid media at 25°C for 2 wk. Enzyme preparations from cultured mycelia of five mushrooms were obtained by mycelia separation from cultured broth, enzyme extraction, ammonium sulfate (30-80%) precipitation, dialysis, and freeze drying, respectively. The enzyme preparations were used for enzymatic hydrolysis of ginsenoside Rb1. RESULTS: Among the mushrooms used in this study, the enzyme preparation from cultured mycelia of A. mellea (AMMEP) was found to convert ginsenoside Rb1 into compound K with a high yield, while those from G. lucidum, P. linteus, E. applanata, and P. ostreatus produced remarkable amounts of ginsenoside Rd from ginsenoside Rb1. The enzymatic hydrolysis pathway of ginsenoside Rb1 by AMMEP was Rb1 → Rd → F2 → compound K. The optimum reaction conditions for compound K formation from ginsenoside Rb1 were as follows: reaction time 72-96 h, pH 4.0-4.5, and temperature 45-55°C. CONCLUSION: AMMEP can be used to produce the human intestinal bacterial metabolite, compound K, from ginsenoside Rb1 with a high yield and without food safety issues.

Purification and characterization of a novel ginsenoside Rc-hydrolyzing ß-glucosidase from Armillaria mellea mycelia.

Ginsenosides are the principal compounds responsible for the pharmacological effects and health benefits of Panax ginseng root. Among protopanaxadiol (PPD)-type ginsenosides, minor ginsenosides such as ginsenoside (G)-F2, G-Rh2, compound (C)-Mc1, C-Mc, C-O, C-Y, and C-K are known to be more pharmacologically active constituents than major ginsenosides such as G-Rb1, G-Rb2, G-Rc, and G-Rd. A novel ginsenoside Rc-hydrolyzing ß-glucosidase (BG-1) from Armillaria mellea mycelia was purified as a single protein band with molecular weight of 121.5 kDa on SDS-PAGE and a specific activity of 17.9 U mg-1 protein. BG-1 concurrently hydrolyzed α-(1 â†’ 6)-arabinofuranosidic linkage at the C-20 site or outer ß-(1 â†’ 2)-glucosidic linkage at the C-3 site of G-Rc to produce G-Rd and C-Mc1, respectively. The enzyme also hydrolyzed outer and inner glucosidic linkages at the C-3 site of G-Rd to produce C-K via G-F2, and inner glucosidic linkage at the C-3 site of C-Mc1 to produce C-Mc. C-Mc was also slowly hydrolyzed α-(1 â†’ 6)-arabinofuranosidic linkage at the C-20 site to produce C-K with reaction time prolongation. Finally, the pathways for formation of C-Mc and C-K from G-Rc by BG-1 were G-Rc â†’ C-Mc1 â†’ C-Mc and G-Rc â†’ G-Rd â†’ G-F2 â†’ C-K, respectively. The optimum reaction conditions for C-Mc and C-K formation from G-Rc by BG-1 were pH 4.0-4.5, temperature 45-60 °C, and reaction time 72-96 h. This is the first report of efficient production of minor ginsenosides, C-Mc and C-K from G-Rc by ß-glucosidase purified from A. mellea mycelia.

Chamaecyparis obtusa Suppresses Virulence Genes in Streptococcus mutans.

Chamaecyparis obtusa (C. obtusa) is known to have antimicrobial effects and has been used as a medicinal plant and in forest bathing. This study aimed to evaluate the anticariogenic activity of essential oil of C. obtusa on Streptococcus mutans, which is one of the most important bacterial causes of dental caries and dental biofilm formation. Essential oil from C. obtusa was extracted, and its effect on bacterial growth, acid production, and biofilm formation was evaluated. C. obtusa essential oil exhibited concentration-dependent inhibition of bacterial growth over 0.025 mg/mL, with 99% inhibition at a concentration of 0.2 mg/mL. The bacterial biofilm formation and acid production were also significantly inhibited at the concentration greater than 0.025 mg/mL. The result of LIVE/DEAD® BacLight™ Bacterial Viability Kit showed a concentration-dependent bactericidal effect on S. mutans and almost all bacteria were dead over 0.8 mg/mL. Real-time PCR analysis showed that gene expression of some virulence factors such as brpA, gbpB, gtfC, and gtfD was also inhibited. In GC and GC-MS analysis, the major components were found to be α-terpinene (40.60%), bornyl acetate (12.45%), α-pinene (11.38%), ß-pinene (7.22%), ß-phellandrene (3.45%), and α-terpinolene (3.40%). These results show that C. obtusa essential oil has anticariogenic effect on S. mutans.

Enzymatic Formation of Novel Ginsenoside Rg1-α-Glucosides by Rat Intestinal Homogenates.

The variation of linkage positions in ginsenosides leads to diverse pharmacological efficiencies. The hydrolysis and transglycosylation properties of glycosyl hydrolase family enzymes have a great impact on the synthesis of novel and structurally diversified compounds. In this study, six ginsenoside Rg1-α-glucosides were found to be synthesized from the reaction mixture of maltose as a donor and ginsenoside Rg1 as a sugar acceptor in the presence of rat small intestinal homogenates, which exhibit high α-glucosidase activities. The individual compounds were purified and were identified by spectroscopy (HPLC-MS, (1)H-NMR, and (13)C-NMR) as 6-O-[α-D-glcp-(1→4)-ß-D-glcp]-20-O-(ß-D-glcp)-20(S)-protopanaxatriol, 6-O-ß-D-glcp-20-O-[α-D-glcp-(1→6)-(ß-D-glcp)]-20(S)-protopanaxatriol, 6-O-ß-D-glcp-20-O-[α-D-glcp-(1→4)-(ß-D-glcp)]-20(S)-protopanaxatriol, 6-O-[α-D-glcp-(1→6)-ß-D-glcp]-20-O-(ß-glcp)-20(S)-protopanaxatriol, 6-O-[α-D-glcp-(1→3)-ß-D-glcp]-20-O-(ß-D-glcp)-20(S)-protopanaxatriol, and 6-O-ß-D-glcp-20-O-[α-D-glcp-(1→3)-(ß-D-glcp)]-20(S)-protopanaxatriol. Among these six, 6-O-ß-D-glcp-20-O-α-D-glcp-(1→6)-(ß-D-glcp)-20(S)-protopanaxatriol and 6-O-α-D-glcp-(1→6)-ß-D-glcp-20-O-(ß-D-glcp)-20(S)-protopanaxatriol are considered to be novel compounds of alpha-ginsenosidal saponins which pharmacological activities should be further characterized. This is the first report on the enzymatic elaboration of ginsenoside Rg1 derivatives using rat intestinal homogenates. To the best of our knowledge, it is also the first to reveal the sixth and 20th positions of an unusual α-D-glucopyranosyl-(1→6)-ß-D-glucopyranosyl sugar chain with 20(S)-protopanaxatriol saponins in Panax ginseng Mayer.

Chamaecyparis obtusa Essential Oil Inhibits Methicillin-Resistant Staphylococcus aureus Biofilm Formation and Expression of Virulence Factors.

The emergence of antibiotic-resistant bacteria has caused difficulty in treating infectious diseases. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most commonly recognized antibiotic-resistant bacteria. Novel antibiotics are urgently required to treat these bacteria. Raw materials derived from natural sources can be used for the development of novel antibiotics, such as Chamaecyparis obtusa (C. obtusa), which has been traditionally used in treating asthmatic disease. In this study, the antibacterial activity of the essential oil (EO) extracted from C. obtusa leaves against MRSA was investigated. MRSA growth and acid production from glucose metabolism were inhibited at concentrations greater than 0.1 mg/mL C. obtusa EO. MRSA biofilm formation was observed using scanning electron microscopy and safranin staining. C. obtusa EO inhibited MRSA biofilm formation at concentrations greater than 0.1 mg/mL. Using real-time polymerase chain reaction, mRNA expression of virulence factor genes, sea, agrA, and sarA, was observed. agrA expression was inhibited with C. obtusa EO concentrations greater than 0.2 mg/mL, whereas inhibition of sea and sarA expression was also observed at a concentration of 0.3 mg/mL. C. obtusa EO was analyzed by gas chromatography (GC) and GC coupled for mass spectrometry, which identified 59 constituents, accounting to 98.99% of the total EO. These findings suggest that C. obtusa EO has antibacterial effects against MRSA, which might be associated with the major components of C. obtusa EO, such as sabinene (19.06%), α-terpinyl acetate (16.99%), bornyl acetate (10.48%), limonene (8.54%), elemol (7.47%), myrcene (5.86%), γ-terpinene (4.04%), and hibaene (3.01%).

Inhibitory Effects of Chrysanthemum boreale Essential Oil on Biofilm Formation and Virulence Factor Expression of Streptococcus mutans.

The aim of the study was to evaluate the antibacterial activity of essential oil extracted from Chrysanthemum boreale (C. boreale) on Streptococcus mutans (S. mutans). To investigate anticariogenic properties, and bacterial growth, acid production, biofilm formation, bacterial adherence of S. mutans were evaluated. Then gene expression of several virulence factors was also evaluated. C. boreale essential oil exhibited significant inhibition of bacterial growth, adherence capacity, and acid production of S. mutans at concentrations 0.1-0.5 mg/mL and 0.25-0.5 mg/mL, respectively. The safranin staining and scanning electron microscopy results showed that the biofilm formation was also inhibited. The result of live/dead staining showed the bactericidal effect. Furthermore, real-time PCR analysis showed that the gene expression of some virulence factors such as gtfB, gtfC, gtfD, gbpB, spaP, brpA, relA, and vicR of S. mutans was significantly decreased in a dose dependent manner. In GC and GC-MS analysis, seventy-two compounds were identified in the oil, representing 85.42% of the total oil. The major components were camphor (20.89%), ß-caryophyllene (5.71%), α-thujone (5.46%), piperitone (5.27%), epi-sesquiphellandrene (5.16%), α-pinene (4.97%), 1,8-cineole (4.52%), ß-pinene (4.45%), and camphene (4.19%). These results suggest that C. boreale essential oil may inhibit growth, adhesion, acid tolerance, and biofilm formation of S. mutans through the partial inhibition of several of these virulence factors.

Influence of modification in core building procedure on fracture strength and failure patterns of premolars restored with fiber post and composite core.

PURPOSE: The influence of the modified process in the fiber-reinforced post and resin core foundation treatment on the fracture resistance and failure pattern of premolar was tested in this study. MATERIALS AND METHODS: Thirty-six human mandibular premolars were divided into 4 groups (n = 9). In group DCT, the quartz fibre post (D.T. Light-post) was cemented with resin cement (DUO-LINK) and a core foundation was formed with composite resin (LIGHT-CORE). In group DMO and DMT, resin cement (DUO-LINK) was used for post (D.T. Light-post) cementation and core foundation; in group DMO, these procedures were performed simultaneously in one step, while DMT group was accomplished in separated two steps. In group LCT, the glass fiber post (LuxaPost) cementation and core foundation was accomplished with composite resin (LuxaCore-Dual) in separated procedures. Tooth were prepared with 2 mm ferrule and restored with nickel-chromium crowns. A static loading test was carried out and loads were applied to the buccal surface of the buccal cusp at a 45 degree inclination to the long axis of the tooth until failure occurred. The data were analyzed with MANOVA (α = .05). The failure pattern was observed and classified as either favorable (allowing repair) or unfavorable (not allowing repair). RESULTS: The mean fracture strength was highest in group DCT followed in descending order by groups DMO, DMT, and LCT. However, there were no significant differences in fracture strength between the groups. A higher prevalence of favorable fractures was detected in group DMT but there were no significant differences between the groups. CONCLUSION: The change of post or core foundation method does not appear to influence the fracture strength and failure patterns.

Essential oil of Curcuma longa inhibits Streptococcus mutans biofilm formation.

Curcuma longa (C. longa) has been used as a spice in foods and as an antimicrobial in Oriental medicine. In this study, we evaluated the inhibitory effects of an essential oil isolated from C. longa on the cariogenic properties of Streptococcus mutans (S. mutans), which is an important bacterium in dental plaque and dental caries formation. First, the inhibitory effects of C. longa essential oil on the growth and acid production of S. mutans were tested. Next, the effect of C. longa essential oil on adhesion to saliva-coated hydroxyapatite beads (S-HAs) was investigated. C. longa essential oil inhibited the growth and acid production of S. mutans at concentrations from 0.5 to 4 mg/mL. The essential oil also exhibited significant inhibition of S. mutans adherence to S-HAs at concentrations higher than 0.5 mg/mL. S. mutans biofilm formation was determined by scanning electron microscopy (SEM) and safranin staining. The essential oil of C. longa inhibited the formation of S. mutans biofilms at concentrations higher than 0.5 mg/mL. The components of C. longa essential oil were then analyzed by GC and GC-MS, and the major components were α-turmerone (35.59%), germacrone (19.02%), α-zingiberene (8.74%), αr-turmerone (6.31%), trans-ß-elemenone (5.65%), curlone (5.45%), and ß-sesquiphellandrene (4.73%). These results suggest that C. longa may inhibit the cariogenic properties of S. mutans.