Sweroside Prevents Non-Alcoholic Steatohepatitis by Suppressing Activation of the NLRP3 Inflammasome.

Non-alcoholic steatohepatitis (NASH), a type of non-alcoholic fatty liver disease, is characterized as steatosis and inflammation in the liver. NLRP3 inflammasome activation is associated with NASH pathology. We hypothesized that suppressing the NLRP3 inflammasome could be effective in preventing NASH. We searched substances that could inhibit the activation of the NLRP3 inflammasome and identified sweroside as an NLRP3 inhibitor. We investigated whether sweroside can be applied to prevent the pathological symptoms associated with NASH in a methionine-choline-deficient (MCD) diet-induced NASH mouse model. The activation of the NLRP3 inflammasome was determined by detecting the production of caspase-1 and IL-1ß from pro-caspase-1 and pro-IL-1ß in primary mouse macrophages and mouse liver. In a NASH model, mice were fed an MCD diet for two weeks with daily intraperitoneal injections of sweroside. Sweroside effectively inhibited NLRP3 inflammasome activation in primary macrophages as shown by a decrease in IL-1ß and caspase-1 production. In a MCD diet-induced NASH mouse model, intraperitoneal injection of sweroside significantly reduced serum aspartate transaminase and alanine transaminase levels, hepatic immune cell infiltration, hepatic triglyceride accumulation, and liver fibrosis. The improvement of NASH symptoms by sweroside was accompanied with its inhibitory effects on the hepatic NLRP3 inflammasome as hepatic IL-1ß and caspase-1 were decreased. Furthermore, sweroside blocked de novo synthesis of mitochondrial DNA in the liver, contributing to suppression of the NLRP3 inflammasome. These results suggest that targeting the NLRP3 inflammasome with sweroside could be beneficially employed to improve NASH symptoms.

Schisandra chinensis extract ameliorates age-related muscle wasting and bone loss in ovariectomized rats.

Exercise and healthy diet consumption support healthy aging. Schisandra chinensis (Turcz.) also known as "Baill." has anti-inflammatory and antioxidant properties. However, the role of S. chinensis as an antiaging compound has yet to be demonstrated. This study elucidated the antiaging effect of S. chinensis ethanol-hexane extract (C1) and the effect of C1 treatment on muscle and bone following physical exercise in ovariectomized (OVX) rats. RAW 264.7, human diploid fibroblasts (HDFs), C2C12 myoblasts, bone marrow macrophages, and MC3T3-E1 cells were used for in vitro, and muscle and bone of OVX rats were used for in vivo study to demonstrate the effect of C1. The C1 significantly inhibited the expression of inflammatory molecules, ß-galactosidase activity, and improved antioxidant activity via down-regulation of reactive oxygen species in RAW 264.7 and aged HDF cells. The C1 with exercise improved muscle regeneration in skeletal muscle of OVX rats by promoting mitochondrial biogenesis and autophagy. C1 induced osteoblast differentiation, and C1 + exercise modulated the bone formation and bone resorption in OVX rats. C1 exhibited anti-inflammatory, antioxidant, myogenic, and osteogenic effects. C1 with exercise improved age-related muscle wasting and bone loss. Therefore, S. chinensis may be a potential prevent agent for age-related diseases such as sarcopenia and osteoporosis.

Anti-obesity potential of Glycyrrhiza uralensis and licochalcone A through induction of adipocyte browning.

The main function of brown adipose tissue is to dissipate surplus caloric intake into heat energy by thermogenesis, increasing energy expenditure. Inducible brown adipocytes can develop within white adipose tissue (WAT) through a process referred to as browning. Browning of white fat represents a promising strategy for treatment of obesity and the related complications. We investigated whether Glycyrrhiza uralensis and its ingredients modulated adipogenesis through adipocyte browning using 3T3-L1 adipocytes and a high-fat diet (HFD)-induced obesity mice model. Amongst extracts and fractions of G. uralensis, methyl dichloride (MeCl2) fraction was the most effective to induce expression of uncoupling protein 1 (UCP1), a fat browning marker, in 3T3-L1 adipocytes. Ingredients of G. uralensis such as licochalcone A (LicoA), isoliquiritigenin, and liquiritigenin induced UCP1 expression in 3T3-L1 adipocytes. After inducing obesity in mice by 6-week HFD, MeCl2 fraction of G. uralensis or LicoA was intraperitoneally administered for additional 19 days. MeCl2 fraction or LicoA significantly reduced body weight gain and inguinal fat pad weights. Furthermore, MeCl2 fraction or LicoA improved metabolic disorders induced by HFD as the treatments decreased serum levels of glucose and cholesterol, and blocked insulin resistance. MeCl2 fraction or LicoA enhanced expression of brown fat markers such as UCP1, PRDM16, and PGC-1α and increased brown fat phenotype population in inguinal WAT of HFD-fed mice. Our results demonstrate that G. uralensis and LicoA are effective to reduce obesity and to recover metabolic homeostasis by inducing the brown fat phenotype.

Gomisin A modulates aging progress via mitochondrial biogenesis in human diploid fibroblast cells.

Gomisin A from the fruit of Schisandra chinensis has many pharmacological properties, including hepato-protective, anti-diabetic, and anti-oxidative stress. However, the potential benefit of gomisin A is still not well understood, especially in aging progression. Therefore, the aim of this study was to clarify whether the promotion of mitochondrial biogenesis and autophagy of gomisin A affects anti-aging progression, and its mechanism. Intermediate (PD32) human diploid fibroblast (HDF) cells were brought to stress-induced premature senescence (SIPS) using hydrogen peroxide. Gomisin A inhibited reactive oxygen species production even in the SIPS-HDF cells. Gomisin A was also able to attenuate the activity of senescence-associated ß-galactosidase and the production of pro-inflammatory molecules in the SIPS as well as aged HDF cells. The antioxidant activity of gomisin A was determined by recovering the Cu/Zn, Mn-SOD, and HO-1 expression in the SIPS-HDF cells. In mechanistic aspect, gomisin A inhibited the mitogen-activated protein kinase pathway and the translocation of nuclear factor kappa B to the nucleus. In addition, gomisin A promoted the autophagy and mitochondrial biogenesis factors through the translocation of nuclear factor erythroid 2-related factor-2, and inhibited aging progression in the SIPS-HDF cells. In summary, the enhanced properties of mitochondrial biogenesis and autophagy of gomisin A has a benefit to control age-related molecules against SIPS-induced chronic oxidative stress, and gomisin A may be a potential therapeutic compound for the enhancement of intracellular homeostasis to aging progression.

Licochalcone A attenuates acne symptoms mediated by suppression of NLRP3 inflammasome.

Activation of the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome by Propionibacterium acnes (P. acnes) is critical for inducing inflammation and aggravating the development of acne lesions. We searched for available small-molecule inhibitors of the NLRP3 inflammasome that could be topically administered for the treatment of acne. We found that licochalcone A, a chalconoid isolated from the root of Glycyrrhiza inflate, was an effective inhibitor for P. acnes-induced NLRP3 inflammasome activation. Licochalcone A blocked P. acnes-induced production of caspase-1(p10) and IL-1ß in primary mouse macrophages and human SZ95 sebocytes, indicating the suppression of NLRP3 inflammasome. Licochalcone A suppressed P. acnes-induced ASC speck formation and mitochondrial reactive oxygen species. Topical application of licochalcone A to mouse ear skin attenuated P. acnes-induced skin inflammation as shown by histological assessment, ear thickness measurement, and inflammatory gene expression. Licochalcone A reduced caspase-1 activity and IL-1ß production in mouse ear injected with P. acnes. This study demonstrated that licochalcone A is effective in the control of P. acnes-induced skin inflammation as an efficient inhibitor for NLRP3 inflammasome. Our study provides a new paradigm for the development of anti-acne therapy via targeting NLRP3 inflammasome.

In vitro Potential Effect of Morin in the Combination with ß-Lactam Antibiotics Against Methicillin-Resistant Staphylococcus aureus.

Morin, a plant-derived flavonol, is known to be an effective inhibitor of Gram-positive bacteria. In this study, we explored the combined effect of morin with ß-lactam antibiotics against methicillin-resistant Staphylococcus aureus (MRSA), a multidrug-resistant pathogen. The anti-MRSA activity of morin was investigated by the broth microdilution method, checkerboard dilution test, and time-kill curve assay. The expression of the resistant protein, penicillin-binding protein (PBP2a) encoded by mecA, was analyzed by the Western blotting method in the presence of morin and oxacillin. An increased susceptibility of MRSA toward oxacillin was observed in the presence of morin. The protein level of PBP2a was reduced when MRSA (ATCC 33591) was treated with the combination of morin and oxacillin, indicating that the combination of morin and oxacillin potentiates the killing effect against MRSA. The present study indicates that the killing effect by the combinative treatment of morin and ß-lactam antibiotic is dependent on the PBP2a-mediated resistance mechanism.

The mechanism of antibacterial activity of tetrandrine against Staphylococcus aureus.

Tetrandrine (TET) is a bis-benzylisoquinoline alkaloid derived from the radix of Stephania tetrandra S. Moore. TET performs a wide spectrum of biological activities. The radix of S. tetrandrae has been used traditionally in Asia, including Korea, to treat congestive circulatory disorders and inflammatory diseases. The aim of this study was to examine the mechanism of antibacterial activity of tetrandrine against Staphylococcus aureus. The mechanism was investigated by studying the effects of TET in combination with detergent or membrane potential un-couplers. In addition, the direct involvement of peptidoglycan (PGN) was assessed in titration assays. TET activity against S. aureus was 125-250 µg/mL, and the minimum inhibitory concentration (MIC) of the two reference strains was 250 µg/mL. The OD(600) of each suspension treated with a combination of ethylenediaminetetraacetic acid (EDTA), tris(hydroxymethyl) aminomethane (TRIS), and Triton X-100 (TX) with TET (0.25×MIC) had been reduced from 43% to 96%. Additional structure-function studies on the antibacterial activity of TET in combination with other agents may lead to the discovery of more effective antibacterial agents.

Gomisin N has anti-allergic effect and inhibits inflammatory cytokine expression in mouse bone marrow-derived mast cells.

Gomisin N is a bioactive compound and a prominent anti-allergic agent found in the fruits of tree Schizandra chinensis. However, its effects on the bone marrow-derived mast cell (BMMC)-mediated allergy and inflammation mechanism remain unknown. In this study, the biological effects of gomisin were evaluated while focusing on its effects on the allergic mediator in PMA + A23187-stimulated BMMCs. The anti-allergic effect of gomisin has shown that inhibited PMA + A23187-induced interleukin-6 (IL-6) production. An investigation was also conducted to determine its effects on the production of several allergic mediators including prostaglandin D(2) (PGD(2)), leukotriene C(4) (LTC(4)), ß-hexosaminidase (ß-Hex), and cyclooxygenase-2 (COX-2) protein. The results revealed that gomisin inhibited the PMA + A23187-induced production of IL-6, PGD(2), LTC(4), ß-Hex, and COX-2 protein. Taken together, these findings indicate that gomisin N has the potential for use in the treatment of allergy.

In vitro potentiation of ampicillin, oxacillin, norfloxacin, ciprofloxacin, and vancomycin by sanguinarine against methicillin-resistant Staphylococcus aureus.

Few new drugs are available against methicillin-resistant Staphylococcus aureus (MRSA), because MRSA has the ability to acquire resistance to most antibiotics, which consequently increases the cost of medication. The objective of this study is to evaluate the potentiation of sanguinarine (SN) with selected antibiotics (ampicillin [AC], oxacillin [OX], norfloxacin [NR], ciprofloxacin [CP], and vancomycin [VC]) against MRSA. Minimum inhibitory concentration was determined by using the broth microdilution method and the synergistic effect of AC, OX, NR, CP, and VC in combination with SN was examined by the checkerboard dilution test. The results of the checkerboard test suggested that all combinations exhibited some synergy, partial synergy, or additivity. None of the combinations showed an antagonism effect. The combination of SN plus CP exhibited maximum synergistic effect in 11/13 strains, followed by SN plus NR in 9/13 strains, and AC and OX in 7/13 strains each. The combination of SN with VC, however, mostly showed partial synergy in 11/13 strains. The time-kill assay showed that SN in combination with other antibiotics reduced the bacterial count by 10(2)-10(3) colony forming units after 4 h and to less than the lowest detectable limit after 24 h. Although in vivo synergy and clinical efficacy of SN cannot be predicted, it can be concluded that SN has the potential to restore the effectiveness of the selected antibiotics, and it can be considered in an alternative MRSA treatment.

Effect of gomisin A on osteoblast differentiation in high glucose-mediated oxidative stress.

BACKGROUND: Gomisin A is a lignan isolated from the hexane of Schisandra chinensis fruit extract with antioxidant properties. Oxidative stress mediated by high glucose is one of the major complications of diabetes mellitus. PURPOSE: This study investigates the role of gomisin A in osteoblast differentiation under high glucose-induced oxidative stress in MC3T3 E1 cells and determines its relationship with heme oxygenase-1 (HO-1) and mitochondrial biogenesis. METHODS: MC3T3 E1 cells were treated by gomisin A following induced by high glucose levels and glucose oxidase to investigate the inhibitory effect of gomisin A against high glucose oxidative stress. Western blot analysis, alizarin red staining, alkaline phosphatase (ALP) activity, analysis of reactive oxygen species (ROS) and confocal microscopy were used to determine mitochondrial biogenesis, oxidative stress, osteoblast differentiation and mineralization. To analyze the role of HO-1, the MC3T3 E1 cells were treated with the HO-1 inhibitor zinc protoporphyrin IX (ZnPP). RESULTS: Gomisin A enhanced the expression of HO-1, increased mitochondrial biogenesis factors (peroxisome proliferator-activated receptor gamma coactivator 1-alpha, nuclear respiratory factor-1, and mitochondrial transcription factor A), antioxidant enzymes (copper-zinc superoxide dismutases and manganese superoxide dismutase), osteoblast differentiation molecules (bone morphogenic protein-2/7, osteoprotegerin and Runt-related transcription factor-2) and mineralization by upregulation of ALP and alizarin red staining, which were decreased by ZnPP and high glucose oxidative stress. Similarly, gomisin A inhibited ROS which was increased by ZnPP and the high glucose-mediated oxidative stress. CONCLUSIONS: The findings demonstrated the antioxidative effects of gomisin A, and its role in mitochondrial biogenesis and osteoblast differentiation. It potentially regulated osteoblast differentiation under high glucose-induced oxidative stress via upregulation of HO-1 and maintenance of mitochondrial homeostasis. Thus, gomisin A may represent a potential therapeutic agent for prevention of bone fragility fractures and implant failure triggered by diabetes.

Repurposing Auranofin, an Anti-Rheumatic Gold Compound, to Treat Acne Vulgaris by Targeting the NLRP3 Inflammasome.

Activation of the NLRP3 inflammasome is critical for host defense as well as the progression of inflammatory diseases through the production of the proinflammatory cytokine IL-1ß, which is cleaved by active caspase-1. It has been reported that overactivation of the NLRP3 inflammasome contributes to the development and pathology of acne vulgaris. Therefore, inhibiting activation of the NLRP3 inflammasome may provide a new therapeutic strategy for acne vulgaris. In this study, we investigated whether auranofin, an anti-rheumatoid arthritis agent, inhibited NLRP3 inflammasome activation, thereby effectively treating acne vulgaris. Auranofin suppressed NLRP3 inflammasome activation induced by Propionibacterium acnes, reducing the production of IL-1ß in primary mouse macrophages and human sebocytes. In a P. acnes-induced acne mouse model, injection of P. acnes into the ears of mice induced acne symptoms such as redness, swelling, and neutrophil infiltration. Topical application of auranofin (0.5 or 1%) to mouse ears significantly reduced the inflammatory symptoms of acne vulgaris induced by P. acnes injection. Topical application of auranofin led to the downregulation of the NLRP3 inflammasome activated by P. acnes in mouse ear skin. These results show that auranofin inhibits the NLRP3 inflammasome, the activation of which is associated with acne symptoms. The results further suggest that topical application of auranofin could be a new therapeutic strategy for treating acne vulgaris by targeting the NLRP3 inflammasome.

Hepatoprotective Effect and Synergism of Bisdemethoycurcumin against MCD Diet-Induced Nonalcoholic Fatty Liver Disease in Mice.

Nonalcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome, has become one of the most common causes of chronic liver disease over the last decade in developed countries. NAFLD includes a spectrum of pathological hepatic changes, such as steatosis, steatohepatitis, advanced fibrosis, and cirrhosis. Bisdemethoxycurcumin (BDMC) is polyphenolic compounds with a diarylheptanoid skeleton, curcumin close analogues, which is derived from the Curcumae Longae Rhizoma. While the rich bioavailability research of curcumin, BDMC is the poor studies. We investigated whether BDMC has the hepatoprotective effect and combinatory preventive effect with silymarin on methionine choline deficient (MCD)-diet-induced NAFLD in C57BL/6J mice. C57BL/6J mice were divided into five groups of normal (normal diet without any treatment), MCD diet (MCD diet only), MCD + silymarin (SIL) 100 mg/kg group, MCD + BDMC 100 mg/kg group, MCD + SIL 50 mg/kg + BDMC 50 mg/kg group. Body weight, liver weight, liver function tests, histological changes were assessed and quantitative real-time polymerase chain reaction and Western blot analyses were conducted after 4 weeks. Mice lost body weight on the MCD-diet, but BDMC did not lose less than the MCD-diet group. Liver weights decreased from BDMC, but they increased significantly in the MCD-diet groups. All liver function test values decreased from the MCD-diet, whereas those from the BDMC increased significantly. The MCD- diet induced severe hepatic fatty accumulation, but the fatty change was reduced in the BDMC. The BDMC showed an inhibitory effect on liver lipogenesis by reducing associated gene expression caused by the MCD-diet. In all experiments, the combinations of BDMC with SIL had a synergistic effect against MCD-diet models. In conclusion, our findings indicate that BDMC has a potential suppressive effect on NAFLD. Therefore, our data suggest that BDMC may act as a novel and potent therapeutic agent against NAFLD.

Luteolin potentiates the effects of aminoglycoside and ß-lactam antibiotics against methicillin-resistant Staphylococcus aureus in vitro.

Methicillin-resistant Staphylococcus aureus (MRSA) infection has become a serious clinical problem worldwide, and alternative natural or combination drug therapies are required for its treatment. The aim of the present study was to examined the antimicrobial activity of luteolin (LUT) against MRSA. Luteolin is a polyphenolic flavonoid compound with a wide spectrum of biological activities. The antimicrobial activities of LUT and the antibiotics ampicillin (AM), oxacillin (OX) and gentamicin (GT), used alone or in combination, were evaluated against five clinical MRSA isolates and two reference strains using a minimum inhibitory concentration (MIC) assay, MTT colorimetric assay, checkerboard dilution test and time-kill assay. The MIC of LUT against all strains was found to be 62.5 µg/ml. The combinations of LUT and antibiotics exhibited a synergistic effect against MRSA in the majority of cases, as determined by the checkerboard method. Time-kill curves revealed that a combination of LUT with AM, OX or GT significantly reduced bacterial counts, which dropped below the lowest detectable limit after 24 h. These results indicate that LUT potentiates the effects of ß-lactam and aminoglycoside antibiotics against MRSA.

Anti-inflammatory effect of salidroside on phorbol-12-myristate-13-acetate plus A23187-mediated inflammation in HMC-1 cells.

Salidroside [2-(4-hydroxyphenyl)ethyl ß-D-gluco-pyranoside (SAS)] has been identified as the most potent ingredient of the plant Rhodiola rosea L. Previous studies have demonstrated that it possesses a number of pharmacological properties, including anti-aging, anti-fatigue, antioxidant, anticancer and anti-inflammatory properties. In this study, to ascertain the molecular mechanisms responsible for the anti-inflammatory activity of SAS, we used phorbol-12-myristate-13-acetate (PMA) plus A23187 to induce inflammation in human mast cell line-1 (HMC-1). The HMC-1 cells were treated with SAS prior to being stimulated with PMA plus A23187. Pro-inflammatory cytokine production was measured by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR). Western blot analysis was used to examine the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB). SAS inhibited the mRNA expression and production of interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF). In cells stimulated with PMA plus A23187, SAS suppressed the phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and c-jun N-terminal kinase 1/2 (JNK1/2), but not that of p38 MAPK. SAS suppressed the expression of NF-κB in the nucleus. On the whole, our results suggest that SAS exerts an anti-inflammatory effect by inhibiting the production of pro-inflammatory cytokines through the blocking of the NF-κB and MAPK signaling pathways.

Potentiating activity of luteolin on membrane permeabilizing agent and ATPase inhibitor against methicillin-resistant Staphylococcus aureus.

OBJECTIVE: To investigate the mechanism of antibacterial activity of luteolin (LUT) against methicillin-resistant Staphylococcus aureus (MRSA). METHODS: The mechanism of anti-MRSA activity of LUT was analyzed by the viability assay in membrane permeabilizing agent, ATPase inhibitors, and peptidoglycan (PGN) derived from Staphylococcus aureus (S. aureus). Also, transmission electron microscopy was used to monitor survival characteristics and changes in S. aureus morphology. RESULTS: Compared to the LUT alone, the optical density of suspensions treated with the combination of 125 µg/mL Tris and 250 µg/mL N,N'-dicyclohexylcarbodiimide were reduced to 60% and 46% of the control, respectively. PGN (15.6 µg/mL) gradually impeded the activity of LUT, and PGN (62.5 µg/mL) completely blocked the activity of LUT on S. aureus. CONCLUSIONS: Increased susceptibility to LUT with the Tris-dicyclohexylcarbodiimide combinations is evident in all tested MRSA isolates. The results indicate LUT synergy in increasing cytoplasmic membrane permeability and inhibiting ATPase. S. aureus PGN directly blocks the antibacterial activity of LUT, suggesting the direct binding of LUT with PGN. These findings may be validated for the development of antibacterial agent for low MRSA resistance.

The Mechanism Underlying the Antibacterial Activity of Shikonin against Methicillin-Resistant Staphylococcus aureus.

Shikonin (SKN), a highly liposoluble naphthoquinone pigment isolated from the roots of Lithospermum erythrorhizon, is known to exert antibacterial, wound-healing, anti-inflammatory, antithrombotic, and antitumor effects. The aim of this study was to examine SKN antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). The SKN was analyzed in combination with membrane-permeabilizing agents Tris and Triton X-100, ATPase inhibitors sodium azide and N,N'-dicyclohexylcarbodiimide, and S. aureus-derived peptidoglycan; the effects on MRSA viability were evaluated by the broth microdilution method, time-kill test, and transmission electron microscopy. Addition of membrane-permeabilizing agents or ATPase inhibitors together with a low dose of SKN potentiated SKN anti-MRSA activity, as evidenced by the reduction of MRSA cell density by 75% compared to that observed when SKN was used alone; in contrast, addition of peptidoglycan blocked the antibacterial activity of SKN. The results indicate that the anti-MRSA effect of SKN is associated with its affinity to peptidoglycan, the permeability of the cytoplasmic membrane, and the activity of ATP-binding cassette (ABC) transporters. This study revealed the potential of SKN as an effective natural antibiotic and of its possible use to substantially reduce the use of existing antibiotic may also be important for understanding the mechanism underlying the antibacterial activity of natural compounds.

The anti-inflammatory effect of Cheongseoikki-tang ethanol extract on allergic reactions mediated by bone marrow-derived mast cells.

OBJECTIVE: Cheongseoikki-tang (CIT, Korean), also called Qingshu Yiqi decoction () and Seisho-ekki-to (Japanese), is well known as an effective traditional combination of herbs for treating cardiovascular diseases. This study was to research its effects on bone marrow-derived mast cell (BMMC)-mediated allergy and inflammation mechanisms. METHODS: In this study, the biological effect of Cheongseoikki-tang ethanol extract (CITE) was evaluated, focusing on its effects on the production of allergic mediators by phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187 (A23187)-stimulated BMMCs. These allergic mediators included interleukin-6 (IL-6), prostaglandin D2 (PGD2), leukotriene C4 (LTC4), and ß-hexosaminidase (ß-hex). RESULTS: Our data revealed that CITE inhibited the production of IL-6, PGD2, LTC4, and ß-hex induced by PMA plus A23187 (P<0.05). CONCLUSION: These findings indicate that CITE has the potential for use in the treatment of allergy.

Combination Therapy of Sophoraflavanone B against MRSA: In Vitro Synergy Testing.

Sophoraflavanone B (SPF-B), a known prenylated flavonoid, was isolated from the roots of Desmodium caudatum. The aim of this study was to determine the antimicrobial synergism of SPF-B combined with antibiotics against methicillin-resistant Staphylococcus aureus (MRSA). MRSA, a multidrug-resistant pathogen, causes both hospital- and community-acquired infections worldwide. The antimicrobial activity of SPF-B was assessed by the broth microdilution method, checkerboard dilution test, and time-kill curve assay. The MIC of SPF-B for 7 strains of S. aureus ranges from 15.6 to 31.25 µ g/mL determined. In the checkerboard method, the combinations of SPF-B with antibiotics had a synergistic effect; SPF-B markedly reduced the MICs of the ß -lactam antibiotics: ampicillin (AMP) and oxacillin (OXI); aminoglycosides gentamicin (GET); quinolones ciprofloxacin (CIP) and norfloxacin (NOR) against MRSA. The time-kill curves assay showed that a combined SPF-B and selected antibiotics treatment reduced the bacterial counts below the lowest detectable limit after 24 h. These data suggest that the antibacterial activity of SPF-B against MRSA can be effectively increased through its combination with three groups of antibiotics ( ß -lactams, aminoglycosides, and quinolones). Our research can be a valuable and significant source for the development of a new antibacterial drug with low MRSA resistance.

The mechanism of action of sanguinarine against methicillin-resistant Staphylococcus aureus.

Sanguinarine is a benzophenanthridine alkaloid derived from the root of Sanguinaria canadensis. It is known to perform a wide spectrum of biological activities. The aim of this study is to examine the antimicrobial actions of sanguinarine against methicillin-resistant Staphylococcus aureus (MRSA). Sanguinarine antimicrobial activity was assessed by broth dilution method; its mechanism of action was investigated by bacteriolysis, detergent or ATPase inhibitors and transmission electron microscopy were used to monitor the survival characteristics and the changes in bacteria morphology. The activity of sanguinarine against MRSA strains ranged from 3.12 to 6.25 µg/ml, while the minimum inhibitory concentrations of the two reference strains are 3.12 µg/ml and 1.56 µg/ml. The treatment of the cells with sanguinarine induced the release of membrane-bound cell wall autolytic enzymes, which eventually resulted in lysis of the cell. The OD(600s) of the suspensions treated with the combination of Tris-(hydroxymethyl) aminomethane and Triton X-100 with sanguinarine were reduced to 40% and 8%, respectively. Transmission electron microsco-py of MRSA treated with sanguinarine showed alterations in septa formation. The predisposition of lysis and the altered morphology seen by transmission electron microscopy suggest that sanguinarine compromises the cytoplasmic membrane.

Synergistic effect of tetrandrine and ethidium bromide against methicillin-resistant Staphylococcus aureus (MRSA).

Methicillin-resistant Staphylococcus aureus (MRSA) along with other resistant bacteria have become a significant social and clinical problem. Therefore, there is an urgent need to develop bioactive compounds from natural products as alternatives to the very few antibiotics that remain effective. Recently, the efflux mechanism has been identified as the main contributor to antibiotic resistance in bacteria. This study therefore aimed to evaluate tetrandrine (TET), an efflux pump inhibitor (EPI), as a potential antibiotic against MRSA. We investigated the antimicrobial activity of TET against 17 MRSA strains, of which 3 selected strains were studied in further detail using a time-kill assay. When these bacterial strains (1 × 10(6) colony-forming units (cfu)/ml) were incubated with TET in a time-kill assay, log-scale bactericidal activity was observed, which lasted for 24 hr. In addition, TET exhibits a synergistic effect when combined with the multi-drug resistance (MDR)-efflux pump substrate ethidium bromide (EtBr). Structure-function studies of the antibiotic activity of TET in combination with EtBr may lead to the discovery of more effective efflux pump inhibitors.