[Composition and immunomodulatory activity of neutral and acidic polysaccharides isolated from Epimedii Folium].

Epimedii Folium possesses many pharmacological activities including immunomodulation, anti-oxidation, and anti-tumor. Polysaccharides are the main components of Epimedii Folium, and their activities are closely related to the structure. The present study isolated a neutral polysaccharide(EPS-1-1) and an acidic polysaccharide(EPS-2-1) from the aqueous extract of Epimedii Folium through DEAE-52 cellulose anion-exchange chromatography and Sephadex G-100. The structures were characterized by chemical composition analysis, high-performance gel permeation chromatography(HPGPC), Fourier-transform infrared spectrometry(FT-IR), 1-phenyl-3-methyl-5-pyrazolone(PMP) derivatization, scanning electron microscopy(SEM), Congo red test, etc. The immunomodulatory activity of polysaccharides in vitro was determined by investigating the effects on the maturation of bone marrow-derived dendritic cells(BMDCs) and the release of inflammatory cytokines. According to the structural characterization analysis, EPS-1-1 was composed of fructose(Fuc), mannose(Man), ribose(Rib), rhamnose(Rha), glucose(Glc), galactose(Gal), xylose(Xyl), and arabinose(Ara) at 1.90∶0.67∶0.05∶0.08∶3.29∶1.51∶0.05∶0.37(molar ratio), while EPS-2-1 was mainly composed of Fuc, Man, Rha, glucuronic acid(GlcA), galacturonic acid(GalA), Glc, Gal, Xyl, and Ara at 5.25∶0.18∶0.32∶0.13∶1.14∶0.16∶0.55∶0.08∶0.2. EPS-1-1 and EPS-2-1 could promote the maturation and function of BMDCs through up-regulating the expression of MHC-Ⅱ, CD86, CD80, and CD40, and increasing the levels of inflammatory cytokines(IL-6, IL-12, and TNF-α) in vitro experiments, which suggested that EPS-1-1 and EPS-2-1 possessed good immunomodulatory activity.

[Effects and mechanism of epimedium polysaccharide on solubility of icariin and baohuoside â ].

This study evaluated the effects of epimedium polysaccharide(EPS) on the solubility of icariin and baohuoside Ⅰ so as to preliminary explore its solubilization function and the underlying mechanism. The solubility of these two insoluble flavonoids in water and polysaccharide solutions was compared by high performance liquid chromatography, and the mechanism was investigated by diffe-rential scanning calorimetry(DSC) and critical micelle concentration determination. The results indicated that their solubilization in crude EPS solutions was concentration-dependent. The solubility of icariin and baohuoside Ⅰ in 20 mg·mL~(-1) EPS-1-1 was 9.05 times and 5.76 times that in water, respectively; while their solubility in 20 mg·mL~(-1) EPS-2-1 was 10.55 and 8.39 times that in water, respectively. The change of the DSC thermograms suggested the formation of new complexes from icariin and baohuoside Ⅰ with polysaccharides. The critical micelle concentrations proved the micellar properties of both EPS-1-1 and EPS-2-1. In short, EPS can significantly increase the solubility of icariin and baohuoside Ⅰ, the mechanism of which may be related to the formation of micellar complexes between EPS and insoluble flavonoids.

[Response surface analysis for the optimization of extraction condition for polysaccharides from Epimedium polysaccharides and studies on its tumor immune activities].

To enhance the efficiency of the extraction for Epimedium koreanum Nakai polysaccharides, we conducted the Box-Benhnken experiment and examined the response surface. C57 BL6 mice were used as Lewis-bearing mice model in the study of the polysaccharides in the regulation of tumor immunity. In the first place, different factors including extraction time, temperature, and ratio were evaluated in the yield of polysaccharides. The second order polynomial equation was formed to fit the experimental data. The optimal condition was temperature 87 ℃, extraction time 3.84 h, and ratio of solution and material 1:16.33 to get polysaccharides from Epimedium koreanum Nakai. Under this condition, model-predicted and experimentally measured values of polysaccharide yield were 1.045% and 1.023%, respectively, with a relative error between them at 2.15%. The extraction method is reliable, simple and applicable to the extraction of Epimedium polysaccharides. In addition, this data suggests that Epimedium polysaccharides have obvious immune-regulatory activities in the tumor-bearing mice through increasing the immune-enhancing cytokines to override the immune- suppressing factors.

[Research thoughts on tumor immune responses by polysaccharide of Chinese medicine via oral administration].

Tumor immunotherapy is one of the most significant scientific progresses. The idea of applying the traditional Chinese theory of "the balance of Yin and Yang" to treat cancer is in accordance with that of modern tumor immune strategy. Researches indicated that polysaccharide of Chinese medicine through regulation in immune responses could offer better paradigm for tumor immune treatment under the traditional Chinese theory. However, current studies related to tumor immunotherapy largely focus on the immunity enhancement while lack of the exploration of suppressive factors. Meanwhile, the complex analysis and detection on composition as well as structure definitely increase the difficulty in mechanism of oral absorption and function in vivo. To better exploit novel Chinese medicine of polysaccharide for tumor immune treatment, this article will provide some constructive thoughts on regulation of tumor immune responses based on up to date researches of structure-function relationship, absorbent process and molecular mechanisms responsible for tumor immune as well.

[Research thoughts on structural components of Chinese medicine combined with bioinformatics].

Traditional Chinese medicine(TCM) is a complex system, featured with integrity and characteristics. Structural component TCM is a well-organized integrity of traditional Chinese medicine, reflecting multi-component integration effect of TCM. It gives us a new view on the material basis of TCM. Currently, conventional researching strategies are not enough to deal with the relationship between material basis and efficacy, multi-composition, multi-targets, and multi-section mechanism. Post-genome area gives a birth to bioinformatics, which involves systematic biology, different levels of omics, corresponding mathematics and computer techniques. It increasingly becomes a powerful tool to understand complicated system and life essential laws. Research ideas, methods. and knowledge of data mining technology of bioinformatics combined with the theory of structural components of Chinese medicine bring a new opportunity for developing structural components of Chinese medicine, systematically exploring the essence of TCM and promoting the modernization of TCM.

[Study on oral absorption enhancers of astragalus polysaccharides].

Astragalus polysaccharides was lounded to 4-(2-aminoethylphenol), followed by labeling the APS-Tyr with fluorescein-5-isothiocyanate (FITC) at the secondary amino group. The absorption enhancement effects of low molecular weight chitosan and protamine on astragalus polysaccharides were evaluated via Caco-2 cell culture model. The results show that the fluorecent labeling compound has good stability and high sensitivity. On the other hand low molecular weight chitosan and protamine also can promoted absorption of the astragalus polysaccharides without any cytotoxity, and the absorption increase was more significant with increasing the amount of low molecular weight chitosan and protamine. At the same time, the low molecular weight chitosan has slightly better effect. The transepithelial electric resistance (TEER) of Caco-2 cells show that absorption enhancers could improve its membrane transport permeability by opening tight junctions between cells and increasing the cell membrane fluidity.

[Comparison of protective effects of eight ethyl acetate extracts from Eclipta prostrate on NHBE cells based on component structure theory].

To analyze and compare the protective effects of active components in different ethyl acetate extracts (EAEEPs) from Eclipta prostrate, in order to study the comparison of materials bases protecting normal human bronchial epithelial (NHBE) cells. The MTT assay was taken to compare the protective effect of different EAEEPs on cigarette smoke extracts (CSE) -induced NHBE cells. The ultra-performance liquid chromatography (UPLC) was applied to analyze the content of phenolic acid, coumaric grass ether and flavonoid in EAEEPs. According to the results, all of the eight EAEEPs (0-200 mg x L(-1)) showed certain protective effect on NHBE cells, with statistical difference. Specifically, the total mass of EAEEP VII (89.15 mg x L(-1)) and EAEEP VIII (57.44 mg x L(-1)), which showed the strongest activity, was not the highest, while EAEEP III (132.25 mg x L(-1)) displayed the highest total mass. In the combination with the "component structure" theory, the analysis showed a significant difference in the mass structure among phenolic acid, coumaric grass ether and flavonoid in EAEEP VIII and EAEEP VIII, which were 1.0: 1. 0: 0.5 and 1.0: 1.9: 0.8, respectively. The results suggested a specific optimal "component structure" relationship may exist in EAEEP, which could provide reference for the material base study and quality control.

[Construction of research system for processing mechanism of traditional Chinese medicine based on chemical composition transformation combined with intestinal absorption barrier].

Based on practice of Epimedium processing mechanism for many years and integrated multidisciplinary theory and technology, this paper initially constructs the research system for processing mechanism of traditional Chinese medicine based on chemical composition transformation combined with intestinal absorption barrier, which to form an innovative research mode of the " chemical composition changes-biological transformation-metabolism in vitro and in vivo-intestinal absorption-pharmacokinetic combined pharmacodynamic-pharmacodynamic mechanism". Combined with specific examples of Epimedium and other Chinese herbal medicine processing mechanism, this paper also discusses the academic thoughts, research methods and key technologies of this research system, which will be conducive to systematically reveal the modem scientific connotation of traditional Chinese medicine processing, and enrich the theory of Chinese herbal medicine processing.

A novel drug-phospholipid complex loaded micelle for baohuoside I enhanced oral absorption: in vivo and in vivo evaluations.

Baohuoside I is an effective anti-cancer drug currently used for a variety of cancers in vitro. Unfortunately, baohuoside I has a very poor solubility in both water and in organic solvents. Besides that, it is subject to significant efflux. This work therefore aimed at evaluating the ability of mixed micelles to solubilize baohuoside I, increase permeability and inhibit efflux of baohuoside I to promote oral absorption. A novel (TPGS-baohuoside I-phospholipid complex) mixed micelles was formed by phospholipid complex and TPGS to increase the solubility, enhance permeability, and inhibit efflux of baohuoside I. Micelle formation was confirmed by differential scanning calorimetry and transmission electron microscopy. The average diameters and efflux ratio of mixed micelles decreased as the ratio of TPGS increased with a respective increase in solubility of baohuoside I. Nevertheless, a slow release of baohuoside I from loaded micelles was noted. The results showed that at a 1:9 ratio for baohuoside I-phospholipid complex: TPGS in mixed micelles, solubility of baohuoside I increased up to 88 fold while the efflux ratio decreased by 85%. Their smaller size and higher zeta potential values indicated that mixed micelles would be easily absorbed and more stable. The relative bioavailability of the micelles (AUC(0-∞)) compared with baohuoside I (AUC(0-∞)) was 533%, demonstrating great potential for clinical application. Hence, the novel micelles formed with phospholipid complex and TPGS considerably increased drug concentration in the media and enhanced absorption.

[Polybasic research on the biopharmaceutical characteristics of 20 (S)-protopanaxadiol].

In this study, the biopharmaceutical properties of 20 (S)-protopanaxadiol (PPD) were studied. Firstly, the equilibrium solubility and apparent oil/water partition coefficient of PPD were used to predict the absorption in vivo. Meanwhile the membrane permeability and absorption window were studied by Caco-2 cell model and single-pass intestinal perfusion model. Furthermore, the bioavailability and metabolism were combined to study the absorption properties and metabolic properties in vivo. All of them were used to provide theoretical and practical foundation for designing PPD preparation. The results showed that PPD is poorly water-soluble, and the equilibrium solubility in water is only 35.24 mg x L(-1). The oil-water partition coefficient is 46.21 (logP = 1.66). By Caco-2 cell model, the results showed PPD uptake in general, and it also has efflux. By in situ intestinal perfusion model, the results showed that the absorption of PPD in the intestine is good, and the effective permeability coefficient were duodenum > jejunum > ileum > colon. The oral bioavailability of PPD was 29.39%. It was not well. Metabolic studies showed PPD in vivo presented a wide spread metabolism. So the main factors that restricted oral bioavailability of PPD were the poor solubility and first-pass effect.

[Study on effective substances of tea for chemoprevention of lung cancer based on principal component analysis].

OBJECTIVE: To study the effective substances of tea for chemoprevention of lung cancer based on Principal Component Analysis (PCA). METHODS: UPLC was used to determine the content of each component in tea, MTT was used to analyze the survival of CSE-induced NHBE cells. DTNB and the colorimetric assay were used to detect the rate of GSH/GSSG, PCA was used to calculate the correlation coefficient matrix, eigen values and variance of contribution ratio to chemoprevention of lung cancer. RESULTS: Longjing (L) was the most effective one to protect NHBE cells from damaging, and the IC50 of L for prevention of NHBE cells was 0.2559 mg/mL and could make the GSH/GSSG ratio recovery ranging from 0.142 to 0.858 in a dose-dependent manner. The contribution of GCG prevention of lung cancer was 79.602% and that of GA was 11.037% by PCA. CONCLUSION: Different kinds of tea have different protective effect on NHBE cells. GCGC and GA are the main active ingredients in tea for chemoprevention of lung cancer by PCA.

Enhancement of epimedium fried with suet oil based on in vivo formation of self-assembled flavonoid compound nanomicelles.

The purpose of this work was to research the enhancement of Epimedium fried with suet oil based on the in vivo formation self-assembled flavonoid nanomicelles. Taking icariin as the representative, under the action of suet oil, self-assembled nanomicelles were prepared under simulated gastrointestinal tract conditions and were characterized by dynamic light scattering and transmission electron microscopy (TEM). The experiments with icariin self-assembled nanomicelles without suet oil were done according to the above. The influence of suet oil on the transportation of icariin across Caco-2 cell monolayers and the absorption in rat intestine of self-assembled nanomicelles were evaluated. The particle size of icariin self-assembled nanomicelles with suet oil was smaller than without suet oil. The nanomicelles seemed to be monodisperse spherical particle with smooth surfaces. The icariin entrapment efficiency of self-assembled nanomicelles with suet oil was increased from 43.1% to 89.7%. In Caco-2 cell monolayers, the absorptive permeability, secretory permeability and efflux ratio of icariin self-assembled nanomicelles with suet oil was 1.26 × 10−6 cm/s, 5.91 × 10−6 cm/s and 4.69, respectively, while that of icariin self-assembled nanomicelles without suet oil was 0.62 × 10−6 cm/s, 3.00 × 10−6 cm/s, and 4.84, respectively. In rat intestinal perfusion experiments, the permeability coefficient of icariin self-assembled nanomicelles with suet oil in duodenum was higher than the value of icariin self-assembled nanomicelles without suet oil (p < 0.05). With the action of suet oil, icariin self-assembled nanomicelles were more stable and the entrapment efficiency was higher than that without suet oil, which could increase the solubility of icariin and improve its intestinal absorption. Therefore, suet oil plays a role in its enhancement.

Preparation of icariside II-phospholipid complex and its absorption across Caco-2 cell monolayers.

In the present study, an icariside II-phospholipid complex was prepared, and its physicochemical properties including UV spectrum, IR spectrum, differential scanning calorimetry (DSC) were tested. Furthermore, the absorption of icariside II and icariside II-phospholipid complex was compared in a Caco-2 cell culture model. The results show that icariside II-phospholipid complex could significantly increase the A-B transport of icariside II (P < 0.01), with A-B Papp of (3.92 +/- 0.50) x 10(-6) cm/s compared to control (2.05 +/- 0.18) x 10(-6) cm/s (increased by 91%). Likewise, the B-A transport of icariside II was significantly enhanced (P < 0.01), with Papp of (15.3 +/- 0.72) x 10(-6) cm/s (control) to (22.4 +/- 1.4) x 10(-6) cm/s (46% increase). Efflux ratio of icariside II decreased by 23.5% after forming icariside II-phospholipid complex. The therefore, it could be concluded that phospholipid complexation can increase the intestinal absorption of icariside II.

[Regulation mechanism of triterpenoid components from Prunella asiatica on phase II detoxifying enzymes in vitro and in vivo].

To study the effects of triterpenoid components from Prunella asiatica on phase II detoxifying enzymes and protein expression in vitro and in vivo. Normal human bronchial epithelial (NHBE) cell model was used in vitro, and the mouse model of Kunming (KM) mice was used in vivo. CDNB assay was used to measure the activity of GST. NADPH and DCIP was used to detect the activity of NQO1. DTNB colorimetric assay was used to detect GSH. Western blot was use to detect the protein expression of NQO1. We found that triterpenoid components from P. asiatica could increase the activity of GST, NQO1 and GSH in NHBE cells and KM mice. NQO1 protein expression can also be increased in vitro. The study suggests that triterpenoid components from P. asiatica can prevent the lung cancer by regulating the body phase II detoxification enzyme activity and protein expression.

Combination of active components enhances the efficacy of Prunella in prevention and treatment of lung cancer.

The efficacy of Prunella extracts in the prevention and treatment of lung cancer has been attributed to different components. In this study, an "active components combination model" hypothesis was proposed to explain the anti-tumor activity of Prunella. The efficacy of Prunella extracts from different regions was compared in vitro and in vivo, and the TNF-α activity in serum of tumor-bearing mice was also evaluated. High performance liquid chromatography (HPLC) was used to analyze the extracts and identify 26 common peaks. Prunella samples from different regions were classified by the cluster analysis method; both P. vulgaris L. from Bozhou and P. asiatica Nakai from Nanjing, which had the highest activities, were further divided into different classes. Six peaks from the HPLC analysis were very similar, and were identified as caffeic acid, rosmarinic acid, rutin, quercetin, oleanolic acid and ursolic acid. The total ratio of these compounds in Prunella from Bozhou and Nanjing were 1.0:14.7:3.9:1.0:4.4:1.4 and 1.0:14.8:4.0:0.8:5.6:1.8, respectively. Total triterpenes and total phenols in Prunella were separated by macroporous resin purification for activity studies. The results showed that total triterpenes and total phenols had anti-lung cancer activity and their combination significantly enhanced the activity. In addition, the combination also significantly increased the TNF-α content compared to total triterpenes or total phenols. The results indicated that the efficacy of Prunella against lung cancer was attributable to multiple components acting at an optimal ratio.

Improved oral absorption and anti-lung cancer activity of paclitaxel-loaded mixed micelles.

The aim of this study was to establish a paclitaxel (PTX)-loaded mixed micelle delivery system (PTX-TP-M) with vitamin E-TPGS (TPGS) and Plasdone®S-630 Copovidone (PVPS630) as carriers to improve the solubility, oral absorption, and anti-tumor activity of PTX against lung cancer. In this study, PTX-TP-M was prepared using the ethanol thin-film dispersion method followed by characterization of the binary mixed micelles system. The average size of the PTX-TP-M was 83.5 ± 1.8 nm with a polydispersity index of 0.265 ± 0.007 and the drug loading (DL%) and entrapment efficiency (EE%) were 3.09 ± 0.09% and 95.67 ± 2.84%, respectively, which contributed to a high solubility of PTX about 24947-fold increase in water (4.78 ± 0.14 mg/mL). In addition, TEM analysis showed that the PTX-TP-M appeared spherical in structure and was well dispersed without aggregation and adhesion. In vitro release studies showed that the PTX-TP-M displayed a sustained release compared to free PTX in the dialysis bag. The efflux ratio of PTX reduced from 44.83 to 3.52 when formulated as PTX-TP-M; a 92.15% reduction, studied using the Caco-2 monolayer model. The oral bioavailability of PTX also improved by 4.35-fold, suggesting that PTX-TP-M can markedly promote the absorption in the gastrointestinal tract. Using in vitro MTT assays, it was observed that cytotoxicity was markedly increased, and IC50 values of PTX-TP-M (3.14 ± 0.85 and 8.28 ± 1.02 µg/mL) were lower than those of PTX solution (5.21 ± 0.93 and 14.53 ± 1.96 µg/mL) in A549 and Lewis cell, respectively. In vivo anti-tumor studies showed that PTX-TP-M achieved higher anti-tumor efficacy compared with PTX in Lewis bared C57BL/6 mice. Furthermore, a gastrointestinal safety assay also proved the safety of PTX-TP-M. All results demonstrated that the PTX-TP-M exhibited great potential for delivering PTX with increased solubility, oral bioavailability, and anti-cancer activity and this binary mixed micelles drug delivery system has potential to be used clinically.

Anti-inflammatory Effects of Phyllanthus emblica L on Benzopyrene-Induced Precancerous Lung Lesion by Regulating the IL-1ß/miR-101/Lin28B Signaling Pathway.

BACKGROUND: Phyllanthus emblica L (PEL), a well-known medical plant, has been used in Asian countries for a long time. Increasing evidence suggests that it can prevent the tumorigenesis of cancer associated with nonresolving inflammation. However, the possible anti-inflammatory mechanism responsible for preventing tumorigenesis of precancerous lung lesions is not well elucidated. MATERIALS AND METHODS: Male A/J mice were randomly divided into 5 groups with 10 mice in each group: (1) blank group (saline), (2) benzo(a)pyrene [B(a)P] group, (3) and (4) B(a)P + PEL (5 g/kg/d, 10 g/kg/d, administered by gavage), (5) B(a)P + celecoxib (30 mg/kg/d, administered by gavage). Nodes on the lung surface were observed and calculated. The levels of macrophage inflammatory protein (MIP-2), tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1ß were detected by enzyme-linked immunosorbent assay (ELISA) kits. Cyclo-oxygenase-2 (COX-2), hypoxia-inducible factor-1 (HIF-α), IL-1ß, miR-101, and Lin28B protein levels were evaluated by immunohistochemistry and Western blotting. RESULTS: PEL extract treatment significantly reduced the number of nodes on the lung surface and attenuated B(a)P-induced levels of proinflammatory cytokines MIP-2, TNF-α, IL-6, and IL-1ß in lung tissue. The protein expressions of COX-2 and HIF-α were significantly decreased by the treatment of PEL. In addition, both PEL extract and celecoxib markedly upregulate the expression of miR-101 while downregulating IL-1ß and Lin28B levels. CONCLUSION: Our study indicated that treatment with PEL extract can not only protect the lung from inflammatory injury but effectively prevent precancerous lung lesions through regulating the IL-1ß/miR-i101/Lin28B signaling pathway.

Components of Goutengsan in Rat Plasma by Microdialysis Sampling and Its Protection on Aß1-42-Induced PC12 Cells Injury.

Goutengsan, a Chinese herbal formula, potential protection on Alzheimer's disease (AD) has been less reported. In current study, we investigated the protection of Goutengsan on Aß1-42-induced pheochromocytoma-derived cells (PC12). Furthermore, the components from Goutengsan in rat plasma were identified by microdialysis (MD) for in vivo sampling. Meanwhile, the protection of components identified was also verified. At last, we found that Goutengsan has a potential protective effect on Aß1-42-induced PC12 cells via reducing cells damage and increasing cells vitality as well as six components (pachymic acid, liquiritin, rhynchophylline, isorhynchophylline, corynoxeine, and isocorynoxeine) which may be effective components. This study helps to understand the treatment of Goutengsan for AD and would facilitate the clinical and further studies for this formula.

Curcumin inhibits advanced glycation end product-induced oxidative stress and inflammatory responses in endothelial cell damage via trapping methylglyoxal.

Methylglyoxal (MGO)-induced carbonyl stress and pro-inflammatory responses have been suggested to contribute to endothelial dysfunction. Curcumin (Cur), a polyphenolic compound from Curcuma longa L., may protect endothelial cells against carbonyl stress-induced damage by trapping dicarbonyl compounds such as MGO. However, Cur-MGO adducts have not been studied in depth to date and it remains to be known whether Cur-MGO adducts are able to attenuate endothelial damage by trapping MGO. In the present study, 1,2-diaminobenzene was reacted with MGO to ensure the reliability of the reaction system. Cur was demonstrated to trap MGO at a 1:1 ratio to form adducts 1, 2 and 3 within 720 min. The structures of these adducts were identified by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. The kinetic curves of Cur (10(-7), 10(-6) and 10(-5) M) were measured from 0-168 h by fluorescent intensity. Cur significantly inhibited the formation of advanced glycation end products (AGEs). The differences in oxidative damage and the levels of pro-inflammatory cytokines following MGO + HSA or Cur-MGO treatment were investigated in human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to the Cur-MGO reaction adducts significantly reduced the intracellular ROS levels and improved cell viability compared with MGO alone. Furthermore, there was a significant reduction in the expression levels of transforming growth factor-ß1 and intercellular adhesion molecule(-1) following treatment with Cur-MGO adducts compared with MGO alone. These results provide further evidence that the trapping of MGO by Cur inhibits the formation of AGEs. The current study indicates that the protective effect of Cur on carbonyl stress and pro-inflammatory responses in endothelial damage occurs via the trapping of MGO.

Effect of emodin on the cariogenic properties of Streptococcus mutans and the development of caries in rats.

Emodin is an active herbal component traditionally used in East Asian countries for treating a variety of diseases. The present study investigated the effects of emodin on specific virulence factors of Streptococcus mutans (S. mutans) in vitro and on caries development in vivo. The growth and acid production of S. mutans were significantly inhibited by emodin (0.5-2 mg/ml). Emodin also significantly suppressed the synthesis of insoluble glucans by S. mutans. Furthermore, the topical application of emodin reduced the incidence and severity of carious lesions in rats. These results suggest that the natural compound emodin may be a novel pharmacological agent for the prevention and treatment of dental caries.