Hyeon-Hee Yu

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-β-elemenone (5.65%), curlone (5.45%), and β-sesquiphellandrene (4.73%). These results suggest that C. longa may inhibit the cariogenic properties of S. mutans.

Caesalpinia sappan Induces Cell Death by Increasing the Expression of p53 and p21WAF1/CIP1 in Head and Neck Cancer Cells

Caesalpinia sappan L. (C. sappan) has been used in Oriental medicine as an antitumor agent. The present study shows the effects of the chloroform extract of C. sappan on cell death in head and neck cancer cell lines. The viability of HNSCC4 and HNSCC31 cells (head and neck cancer cell lines) was noticeably decreased compared to that of HaCaT cells (control group) in the presence of chloroform extract. No significant difference was observed in the viability of HNSCC4 and HNSCC31 cells when compared with HaCaT cells in the presence of n-butanol, methanol, and water extracts. Exposure to the chloroform extract of C. sappan resulted in an increase in the Sub-G1 phase of the cell cycle and condensation and shrinkage of nuclei in the HNSCC4 and HNSCC31 cells. The levels of p53 and p21WAF1/CIP1 were also increased in the HNSCC4 and HNSCC31 cells. The results suggest that the chloroform extract of C. sappan may increase cell death in the HNSCC4 and HNSCC31 cells, which is linked to increased cellular levels of p53 and p21WAF1/CIP1.

Anticariogenic Properties of the Extract of Cyperus rotundus

Streptococcus mutans (S. mutans) is known as the causative bacteria in the formation of dental plaque and dental caries. The aim of this experiment was to investigate the effects of Cyperus rotundus (C. rotundus) tuber extract on the growth, acid production, adhesion, and water-insoluble glucan synthesis of S. mutans. The growth and acid production were reduced by the extract of C. rotundus in a dose dependent manner. The extract of C. rotundus markedly inhibited the adherence of S. mutans to saliva-coated hydroxyapatite beads (HAs). The adherence was repressed by more than 50% at the concentration of 0.5 mg/ml of the extract and complete inhibition was observed at the concentration of 4 mg/ml of the extract. On the activity of glucosyltransferase (GTFase) which synthesizes water-insoluble glucan from sucrose, the extract of C. rotundus showed more than 10% inhibition at a concentration of 2 mg/ml. These results suggest that C. rotundus may inhibit cariogenic properties of S. mutans. Further studies are necessary to clarify the active constituents of C. rotundus responsible for such biomolecular activities.

Protective effect of ursolic acid from Cornus officinalis on the hydrogen peroxide-induced damage of HEI-OC1 auditory cells.

The fruits of Cornus officinalis have been used in traditional oriental medicine for treatment of inner ear diseases, such as tinnitus and hearing loss. In the present study, we investigated the protective effect of C. officinalis on hydrogen peroxide-induced cytotoxicity in HEI-OC1 auditory cells. The results from bioassay-guided fractionation of methanol extract of C. officinalis fruits showed that ursolic acid is a major active component. Ursolic acid (0.05-2 microg/ml) had protective effect against the HEI-OC1 cell damage and reduced lipid peroxidation in a dose-dependent manner. In addition, pre-treatment with ursolic acid significantly attenuated the decrease of activities of catalase (CAT) and glutathione peroxidase (GPX), but superoxide dismutase (SOD) activity was not significantly affected by ursolic acid. These results indicate that ursolic acid protects hydrogen peroxide-induced HEI-OC1 cell damage through inhibition of lipid peroxidation and induction of antioxidant enzymes, CAT and GPX, and may be one of the active components responsible for these effects of C. officinalis fruits.

Rehmannia glutinosa activates intracellular antioxidant enzyme systems in mouse auditory cells.

Steamed roots of Rehmannia glutinosa (R. glutinosa) have been traditionally used in Oriental medicine for the treatment of auditory diseases such as tinnitus and hearing loss. To investigate whether the ethanol extract of steamed roots of R. glutinosa (SRG) increases activity of antioxidant enzymes and the level of glutathione (GSH), we measured activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GR) and GSH level in HEI-OC1 cells after treatment with 5-50 microg/ml of SRG. The SOD and CAT activities were significantly increased in the presence of SRG compared to the control group. Maximal activities of SOD and CAT were observed in these cells exposed to 10 microg/ml of SRG. The GPX activity also increased dramatically in response to the treatment with SRG in a dose-dependent manner. The GR activity was only increased in the presence of 50 microg/ml of SRG compared to the control group. The level of GSH gradually increased in the presence of 5-50 microg/ml of SRG. In the cytotoxicity test, 5-50 microg/ml of SRG did not show any significant cytotoxicity. These results suggest that the traditional use of R. glutinosa for the treatment of auditory diseases may be explained, in part, by activation of intracellular antioxidant enzyme systems. Further studies are necessary to clarify the active constituents of SRG responsible for such biomolecular activities.

Effects of Aqueous Extract of Sophora flavescens on the Expression of Cell Cycle Regulatory Proteins in Human Oral Mucosal Fibroblasts

Sophorae Radix, the dried roots of Sophora flavescens AITON (Leguminosae), has been used in Oriental traditional medicine for treatment of skin and mucosal ulcers, sores, gastrointestinal hemorrhage, diarrhea, inflammation and arrhythmia. In the present study, we examine the effect of the aqueous extract of Sophorae Radix (AESR) on cell proliferation and cell cycle regulation in human oral mucosal fibroblasts (HOMFs). To study the molecular mechanisms of cell cycle regulation by AESR, we also measured the intracellular levels of cell cycle regulatory proteins such as cyclin D, cyclin-dependent kinases (CDK)-4, CDK-6, cyclin E, CDK-2, p53, p21WAF1/CIP1 and p16INK4A. Cell proliferation was increased in the presence of 10 approximately 500 microg/ml of AESR. Maximal growth stimulation was observed in those cells exposed to 100 microg/ml of AESR. Exposure of HOMFs to 100 microg/ml of AESR resulted in an increase of cell cycle progression. The levels of cyclin E and CDK-2 were increased in HOMFs after 100 microg/ml of AESR treatment, but the levels of cyclin D, CDK-4, and CDK-6 were unchanged. After exposure to 100 microg/ml of AESR, the protein levels of p16INK4A and p53 were decreased as compared to that of the control group, but the level of p21WAF1/CIP1 was similar in the cells treated with 100 microg/ml of AESR and untreated cells. The results suggest that AESR may increase cell proliferation and cell cycle progression in HOMFs, which is linked to increased cellular levels of cyclin E and CDK-2 and decreased cellular levels of p53 and p16INK4A. Further studies are necessary to clarify the active constituents of AESR responsible for such biomolecular activities.