J. LI

Sichuan University, Hua-yang, Sichuan, China

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Publications (4)2.5 Total impact

  • X. ZHOU, L. CHENG, J. LI
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    ABSTRACT: Aim: The effect of Galla chinensis on enamel surface during a long-term de-/re-mineralization experiment were investigated by using scanning electron microscopy in vitro. Methods: Baseline mineral contents of sound enamels were first analyzed. Then lesions were produced in acidic buffer solution(2.2 mM Ca(NO3)2, 2.2 mM KH2PO4, and pH=4.5 for 3 weeks, with three daily 3 min treatments with one of four treatments: Group A: 1000 ppm F aq. (as NaF, positive control); Group B: deionized water (DDW, negative control); Group C: 4000 ppm crude aqueous extract of Galla chinensis (GCE); Group D: 4000 ppm gallic acid. Next, the blocks were immersed in a remineralization solution (1.5 mM CaCl2, 0.9 mM KH2PO4, 0.1 ppm F and pH = 7.0) for 200 days. The enamel specimens in each treatment groups were analyzed by Scanning electron microscopic (SEM) at different time points Results:Enamel samples in each group showed different SEM images at different time points. In GCE treatment group, enamel crystals fused together and showed bundle arrangement with obvious intercrystalline space after 3 weeks demineralization. After 50 days remineralization, some intercrystalline space could also be observed while some deposit could be seen on the surface layer. During 50-200days remineralization, enamel surface was covered by the new formed deposit . Conclusion: GCE could slow down the remineralization of enamel in the surface layer and thereby facilitates ions transport into the lesion body. The mechanism of Galla chinesis in enhancing the remineralization of dental caries is different from fluoride.
    IADR General Session 2011; 03/2011
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    ABSTRACT: Galla chinensis extract (GCE) interferes with de- and remineralization of dental enamel and the growth and metabolism in planktonic bacteria. However, no information is available on GCE effects on biofilms formed with saliva as inoculum. The aim of the current experiments was to investigate the effects of GCE at different stages of salivary microcosm biofilm formation. Biofilms formed on glass or enamel surfaces were treated with GCE solutions at different concentrations and at different time points. Effects were assessed by lactic acid formation and colony-forming unit (CFU) counts of the biofilms. The results showed that GCE treatments inhibited growth and acid metabolism of both nascent and mature microcosm biofilms. Pretreatment of the substratum with GCE solutions inhibited growth and lactic acid production of biofilms grown on enamel, but had little effects on biofilms formed on glass surfaces. A maximum GCE effect was found when biofilms, on either surface type, were treated after 8 h of formation with 40 h of subsequent growth. In medium with sucrose-fermenting biofilms, low concentrations of GCE (0.2 and 0.1 mg/ml) inhibited acid production without killing bacteria of the biofilm. Differences were found in GCE effects on biofilms formed with saliva from different donors, with reductions in acid formation and CFU values ranging between 0 and 78%. In conclusion, bioactive components in GCE reduce or inhibit both growth and lactic acid formation in biofilms.
    Caries Research 02/2011; 45(2):87-92. · 2.50 Impact Factor
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    ABSTRACT: Objective: Galla Chinensis Extract (GCE) has been proven to interfere with de-/re-mineralization balance of dental enamel and the growth and metabolism in planktonic bacteria. However, little information is available on GCE effects on biofilms formed with saliva as inoculum. The present study was to investigate the effect of GCE on the microcosm biofilm growing on different substratum with or without dental pellicle. Methods: Glass or enamel surfaces with or without preformed dental pellicle were pre-treated with GCE solutions, followed by microcosm biofilm formation using saliva as inoculum. GCE effects were assessed by lactic acid formation and CFU counts of the biofilms. Results: Pre-treatment with GCE solutions inhibited growth and metabolism of biofilms grown on enamel without dental pellicle, but not on glass surfaces. In contrast, GCE did not inhibit biofilms on surfaces pretreated with pellicle prior to a single GCE treatment. Multiple GCE treatments during biofilm formation, however, were effective in inhibiting growth and metabolism. Conclusion: Bioactive components in GCE could inhibit both growth and lactic acid formation in microcosm biofilms. Therefore, GCE is promising to be further developed into an effective caries preventive agent.
    IADR General Session 2010; 07/2010
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    ABSTRACT: Objectives: Magnolia officinalis, a kind of traditional Chinese medicine, are used as an anti-allergic and anti-asthmatic compound with a wide spectrum of pharmacological activities. The purpose of this study was to investigate magnolol and honokiol found in Magnolia offinalis on the growth and cell membrane and cell morphology of streptococcus mutans. Methods: The microorganisms used in this study were Streptococcus mutans ATCC 25175. Magnolol and honokiol were extracted from Magnolia officinalis and their antimicrobial activity was assessed by determination of MIC and MBC, and the effect of on the kinetic of time-killing was also examined. The leakage of K2+ from streptococcus mutans cells has been evaluated by atomic absorption spectrometer. To further confirm whether the bacterial surfaces were the target of Magnolol and Honokiol, scanning electronic microscope (SEM) was used to get the image of bacteria after treatment with Magnolol and Honokiol. Results: Both Magnolol and Honokiol exhibited remarkable antimicrobial activity against streptococcus mutans (MIC of 7.8 g /mL and 31.3 g /mL; MBC of 62.5g /mL and 125g /mL) and fast killing rate. Magnolol and Honokiol can lead to K2+ leakage of streptococcus mutans cells, the leakage increased as the drug concentration increased. No obvious alterations in the surface morphology of streptococcus mutans cells were observed under SEM in Magnolol and Honokiol groups of either concentration. Cells were smooth, plump and located in chains, suggested that the Magnolol and Honokiol has not destroyed cell wall obviously. Conclusion: Magnolol and honokiol present remarkable antimicrobial activity against streptococcus mutans, which may target on ion channels of cell membrane. Further studies on this aspect should be carried out. Support for this study is provided from Chinese Natural Science Grant (Grant No.30572409)
    IADR General Session 2010; 07/2010