RESUMEN
Liver fibrosis is a common pathological feature of most chronic liver diseases with no effective drugs available. Phosphodiesterase 1 (PDE1), a subfamily of the PDE super enzyme, might work as a potent target for liver fibrosis by regulating the concentration of cAMP and cGMP. However, there are few PDE1 selective inhibitors, and none has been investigated for liver fibrosis treatment yet. Herein, compound AG-205/1186117 with the dihydropyrimidine scaffold was selected as the hit by virtual screening. A hit-to-lead structural modification led to a series of dihydropyrimidine derivatives. Lead 13h exhibited the IC50 of 10 nM against PDE1, high selectivity over other PDEs, as well as good safety properties. Administration of 13h exerted significant anti-liver fibrotic effects in bile duct ligation-induced fibrosis rats, which also prevented TGF-ß-induced myofibroblast differentiation in vitro, confirming that PDE1 could work as a potential target for liver fibrosis.
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Fosfodiesterasas de Nucleótidos Cíclicos Tipo 1 , Diseño de Fármacos , Cirrosis Hepática , Inhibidores de Fosfodiesterasa , Pirimidinas , Animales , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 1/antagonistas & inhibidores , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 1/metabolismo , Cirrosis Hepática/tratamiento farmacológico , Cirrosis Hepática/patología , Pirimidinas/síntesis química , Pirimidinas/farmacología , Pirimidinas/química , Pirimidinas/uso terapéutico , Humanos , Ratas , Inhibidores de Fosfodiesterasa/farmacología , Inhibidores de Fosfodiesterasa/síntesis química , Inhibidores de Fosfodiesterasa/uso terapéutico , Inhibidores de Fosfodiesterasa/química , Masculino , Relación Estructura-Actividad , Ratas Sprague-Dawley , Simulación del Acoplamiento Molecular , Estructura MolecularRESUMEN
Phosphodiesterase 1 (PDE1) is a subfamily of PDE super enzyme families that can hydrolyze cyclic adenosine monophosphate and cyclic guanosine monophosphate simultaneously. Currently, the number of PDE1 inhibitors is relatively few, significantly limiting their application. Herein, a novel series of quinolin-2(1H)-ones were designed rationally, leading to compound 10c with an IC50 of 15 nM against PDE1C, high selectivity across other PDEs, and remarkable safety properties. Furthermore, we used the lead compound 10c as a chemical tool to explore whether PDE1 could work as a novel potential target for the treatment of inflammatory bowel disease (IBD), a disease which is a chronic, relapsing disorder of the gastrointestinal tract inflammation lacking effective treatment. Our results showed that administration of 10c exerted significant anti-IBD effects in the dextran sodium sulfate-induced mice model and alleviated the inflammatory response, indicating that PDE1 could work as a potent target for IBD.
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Enfermedades Inflamatorias del Intestino , Inhibidores de Fosfodiesterasa , Ratones , Animales , Inhibidores de Fosfodiesterasa/farmacología , Inhibidores de Fosfodiesterasa/uso terapéutico , Hidrolasas Diéster Fosfóricas , GMP Cíclico , AMP Cíclico , Enfermedades Inflamatorias del Intestino/tratamiento farmacológicoRESUMEN
Harmful Microcystis blooms (HMBs) and microcystins (MCs) that are produced by Microcystis seriously threaten water ecosystems and human health. This study demonstrates an eco-friendly strategy for simultaneous removal of MCs and HMBs by adopting unique hyperoxic graphene oxides (HGOs) as carrier and pure microcystinase A (PMlrA) as connecting bridge to form stable HGOs@MlrA composite. After oxidation, HGOs yield inherent structural strain effects for boosting the immobilization of MlrA by material characterization and density functional theory calculations. HGO5 exhibits higher loading capacities for crude MlrA (1,559 mg·g-1) and pure MlrA (1,659 mg·g-1). Moreover, the performances of HGO5@MlrA composite, including the capability of removing MCs and HMBs, the ecological and human safety compared to MlrA or HGO5 treatment alone, have been studied. These results indicate that HGO5 can be used as a promising candidate material to effectively improve the application potential of MlrA in the simultaneous removal of MCs and HMBs.
RESUMEN
Strepyrazinone (1), a tricyclic diketopiperazine derivative with a carbon skeleton unprecedented in natural products, was isolated from the marine-derived Streptomyces sp. B223. Its structure was elucidated by spectroscopic analyses and electronic circular dichroism calculation. Compound 1 showed cytotoxic activity against HCT-116 cancer cell lines with an IC50 value of 0.34 µM.
Asunto(s)
Antineoplásicos , Streptomyces , Antineoplásicos/farmacología , Línea Celular Tumoral , Dicetopiperazinas/farmacología , Células HCT116 , Humanos , Estructura MolecularRESUMEN
We report an I2/FeCl3-co-promoted formal [2 + 2+1] annulation of aryl methyl ketones, 2-aminobenzyl alcohols, and p-toluenesulfonylmethyl isocyanide (TosMIC) by neighboring group (-CH2OH) assistance. This is a novel example of using the Van Leusen reagent as a unique C1N1 "two-atom synthon" in the synthesis of imidazoles. Preliminary mechanism studies showed that TsCH2NH2 might be the key intermediate in this reaction. Furthermore, this reaction not only unlocks a novel strategy for imidazole synthesis, but also exploits a new reactivity of TosMIC.
RESUMEN
BACKGROUND This study aimed to evaluate superb microvascular imaging (SMI) as an adjunctive imaging method to evaluate mesenteric lymph nodes in children with mesenteric lymphadenitis compared with healthy children. MATERIAL AND METHODS A retrospective study compared children with mesenteric lymphadenitis (n=27) and healthy children (n=30). Lymph node size was determined using grayscale ultrasonography and parameters of lymph node vascularity were compared using color Doppler flow imaging (CDFI) and SMI. The diagnostic performance of ultrasound (US), US combined with SMI, and US combined with CDFI were compared. RESULTS Lymph nodes from children with mesenteric lymphadenitis (n=77) and normal lymph nodes (n=84) were evaluated by SMI, which showed that the least diameter of lymph nodes in cases of mesenteric lymphadenitis was 0.58±0.15 mm and of normal mesenteric lymph nodes was 0.47±0.08 mm (p<0.001). SMI identified 92.6% of abnormal mesenteric lymph nodes while CDFI detected 85.2%. US combined with SMI had the highest sensitivity (81.5%), and specificity (78.9%) compared with US alone (sensitivity, 63.0%; specificity, 64.9%), and compared with US combined with CDFI (sensitivity, 74.1%; specificity, 75.4%). US combined with SMI and US combined with CDFI achieved the same specificity (76.7%), which was higher than that of US alone (66.7%). CONCLUSIONS SMI was superior to color Doppler flow imaging in evaluating the microvasculature in lymphadenopathy in mesenteric lymphadenitis. SMI may be used as an adjunct to grayscale ultrasonography to assist in identifying mesenteric lymphadenopathy in pediatric patients.
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Linfadenitis Mesentérica/diagnóstico por imagen , Linfadenitis Mesentérica/fisiopatología , Microvasos/diagnóstico por imagen , Niño , Preescolar , China , Diagnóstico Diferencial , Femenino , Humanos , Ganglios Linfáticos/efectos de los fármacos , Ganglios Linfáticos/fisiopatología , Masculino , Linfadenitis Mesentérica/metabolismo , Mesenterio/metabolismo , Estudios Retrospectivos , Sensibilidad y Especificidad , Ultrasonografía/métodos , Ultrasonografía Doppler en Color/métodosRESUMEN
BACKGROUND: Plasma cell mastitis (PCM), a common type of mastitis often mimics malignancy clinically and radiologically. OBJECTIVE: The study was designed to explore the diagnostic value of superb microvascular imaging (SMI) in differentiating PCM from malignant breast lesions. METHODS: A total of 95 breast lesions underwent conventional ultrasound (US) and SMI examination between May 2016 and April 2018. Vessels were detected in SMI in a quantitative manner. Blood flow parameters including systolic peak velocity (SPV), resistance index (RI), and pulsatility index (PI) were evaluated. We further assessed the diagnostic performances of US and US+SMI. RESULTS: The majority of PCM were in regular shape and displayed no calcification compared with malignant breast lesions. Regarding blood flow parameters, PCM obtained significantly lower mean value of RI and PI compared with malignant lesions (Pâ<â0.05). The sensitivity, specificity and accuracy rate of US+SMI (84.62%, 76.47%, 83.16%) was significantly higher than those of US (78.21%, 64.71%, 75.59%). CONCLUSIONS: The present study supports that SMI is a novel ultrasound technology in revealing micro-vessels in breast lesions. The combined modality of US+SMI presented a better diagnostic performance in making a distinction between PCM and malignant breast carcinomas.
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Neoplasias de la Mama/patología , Microvasos/diagnóstico por imagen , Células Plasmáticas/metabolismo , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
Juglonols A-C (1-3), three new juglone derivatives possessing a hydroxyethyl side chain, were isolated from an organic extract of the immature exocarps of Juglans mandshurica together with five known tetralones (4-8). Their structures were elucidated by extensive spectroscopic analyses and comparison with literature data. The new juglone derivatives exhibited inhibitory activities towards a panel of bacteria and fungi, as well as cancer cell lines. In contrast, the known tetralone homologues (4-8) appeared to be much less efficacy.
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Antiinfecciosos/aislamiento & purificación , Juglans/química , Naftoquinonas/farmacología , Extractos Vegetales/química , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , Antiinfecciosos/farmacología , Antifúngicos/química , Antifúngicos/aislamiento & purificación , Antifúngicos/farmacología , Antineoplásicos/química , Antineoplásicos/aislamiento & purificación , Antineoplásicos/farmacología , Línea Celular , Humanos , Estructura Molecular , Naftoquinonas/aislamiento & purificación , Naftoquinonas/toxicidad , Extractos Vegetales/farmacología , Análisis Espectral/métodos , Tetralonas/aislamiento & purificación , Tetralonas/farmacologíaRESUMEN
Avian bone metabolism diseases affect the development and production of chickens, and many of these diseases can be prevented and controlled by balanced nutrition and hormone medicine. The steroid hormone 1α,25-dihydroxyvitamin D3 plays a key role in maintaining the balance of avian bone metabolism. Clinically, 1α,25-(OH)2D3 has been used to treat several bone diseases. Although several previous studies have investigated the effects of 1α,25-(OH)2D3 on osteoclastogenesis, the mechanisms underpinning osteoclast (OC) activity remain largely unknown. Herein, we used molecular and cell biology approaches to demonstrate that 1α,25-(OH)2D3 increases avian OC formation and activity, and upregulates bone resorption-related genes. Moreover, 1α,25-(OH)2D3 regulates the OC cytoskeleton by increasing the formation of zipper-like structure in OC precursor cells to potentiate OC activity via the Src/Rac1 signaling pathway. These findings provide new insight into the role of 1α,25-(OH)2D3 in OC activity.
Asunto(s)
Osteoclastos/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Vitamina D/análogos & derivados , Vitaminas/farmacología , Proteína de Unión al GTP rac1/metabolismo , Familia-src Quinasas/metabolismo , Animales , Células Cultivadas , Pollos , Citoesqueleto/efectos de los fármacos , Citoesqueleto/metabolismo , Citoesqueleto/ultraestructura , Osteoclastos/citología , Osteoclastos/metabolismo , Vitamina D/metabolismo , Vitamina D/farmacología , Vitaminas/metabolismoRESUMEN
We compared the treatment outcomes, toxicities and prognoses of patients with stage IE-IIE extranodal natural killer/T-cell lymphoma (ENKTL) treated with intensity-modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3DCRT). Newly diagnosed early-stage ENKTL patients (N = 173) were enrolled and received extended involved-field radiotherapy following induction chemotherapy. Patients were treated with 3DCRT (n = 98) or IMRT (n = 75). One-to-one matching of the IMRT and 3DCRT groups was performed through propensity score matching, which yielded 23 pairs of patients. The two groups achieved similar complete remission rates before and after radiotherapy (P > 0.05). All patients were followed up for a median of 41 months. The rates of local recurrence-free survival (LRFS, P < 0.001), progression-free survival (PFS, P = 0.003) and overall survival (OS, P = 0.003) were longer in the IMRT than 3DCRT group. In the matched patients, IMRT was still associated with superior LRFS (P = 0.024), but not with improved PFS (P = 0.113) or OS (P = 0.115). Multivariate analysis also suggested IMRT was a favorable independent factor for LRFS (HR = 2.230, P = 0.043), but not for PFS (P = 0.195) or OS (P = 0.116). Equivalent acute toxicities were observed for 3DCRT and IMRT; however, among stage II patients who had received cervical irradiation, the rate of late xerostomia was lower in the IMRT than 3DCRT group (38.5% vs. 66.7%, P = 0.046). Overall, IMRT yielded a better treatment response and local control than 3DCRT, and tended to reduce late xerostomia in patients with cervical irradiation, but failed to enhance OS. Thus, IMRT is recommended for the treatment of stage IE-IIE ENKTL patients.
RESUMEN
Objective: Great heterogeneity exists in clinical behavior and survival outcome in patients with stage IE/IIE extranodal natural killer/T-cell lymphoma, nasal type (ENKTL). In this study, we proposed lymphocyte/monocyte ratio (LMR) as a new prognostic factor for these early stage ENKTL. Methods: We retrospectively examined the LMR as a prognostic variable in a cohort of 379 patients with newly diagnosed stage IE/IIE ENKTL. The relationship between the LMR and clinicopathologic variables were analyzed in Kaplan-Meier log-rank survival analysis, and the Cox proportional hazards model was used to determine the survival significance of the LMR for both progression-free survival (PFS) and overall survival (OS). Results: Patients were categorized into two different groups based on the LMR using cut-off value of 2.0. The 5-year PFS rates in the low and high LMR group were 43.9% and 62.7%, respectively, and the 5-year OS rates in the two groups were 59.1% and 77.7%, respectively. In multivariate analysis, low LMR at diagnosis was associated with worse PFS (hazard ratio 1.611, 95% confidence interval: 1.027-2.525, P =0.038) independent of age (P=0.033) and treatment stratagem (P<0.001), and indicated worse OS (hazard ratio 2.003, 95% confidence interval: 1.124-3.569, P =0.018) independent of age (P=0.007), LDH level (P=0.042), local tumor invasiveness (P=0.008), and treatment stratagem (P<0.001). Conclusion: The LMR is an independent prognostic factor for both DFS and OS in patients with stage IE/IIE ENKTL, and provides additional prognostic value beyond standard clinicopathological parameters.
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This study retrospectively investigated asparaginase-based chemotherapy treatment outcomes with or without radiotherapy in 143 patients with stage IE-IIE extranodal natural killer/T cell lymphoma (ENKTCL). All patients received a median of three cycles of asparaginase-based chemotherapy, while 121 patients received radiotherapy following the chemotherapy. The complete remission (CR) rate for all patients post-chemotherapy was 58.7%, and rose to 73.4% by the end of treatment. Patients who received radiotherapy achieved better survival outcomes than those who did not (89.7% vs. 49.0% for 2-year overall survival (OS), P<0.001; 86.8% vs. 37.4% for 2-year progression-free survival (PFS), P<0.001). Additionally, even patients who achieved CR post-chemotherapy exhibited differential survival rates with or without radiotherapy (90.8% vs. 60% for 2-year OS, P=0.006; 86.1% vs. 60% for 2-year PFS, P=0.044). Multivariate analysis revealed that radiotherapy was an independent factor favoring OS (HR=0.098, 95%CI=0.031-0.314, P=0.001) and PFS (HR=0.156, 95%CI=0.062-0.396, P=0.001). Thus, radiotherapy is recommended for stage IE-IIE ENKTCL patients treated with asparaginase-based chemotherapy, even in cases of CR following chemotherapy.
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Quimioradioterapia/métodos , Linfoma Extranodal de Células NK-T/mortalidad , Linfoma Extranodal de Células NK-T/terapia , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Asparaginasa/uso terapéutico , Supervivencia sin Enfermedad , Femenino , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
To identify new antifungal lead compound based on inhibitors of pyruvate dehydrogenase complex E1, a series of 5-iodo-1,4-disubstituted-1,2,3-triazole derivatives 3 were prepared and evaluated for their Escherichia coli PDHc-E1 inhibitory activity and antifungal activity. The in vitro bioassay for the PDHc-E1 inhibition indicated all the compounds exhibited significant inhibition against E. coli PDHc-E1 (IC50<21µM), special compound 3g showed the most potent inhibitory activity (IC50=4.21±0.11µM) and was demonstrated to act as a competitive inhibitor of PDHc-E1. Meanwhile, inhibitor 3g exhibited very good enzyme-selective inhibition of PDHc-E1 between pig heart and E. coli. The assay of antifungal activity showed compounds 3e, 3g, and 3n exhibited fair to good activity against Rhizoctonia solani and Botrytis cinerea even at 12.5µg/mL. Especially compound 3n (EC50=5.4µg/mL; EC90=21.1µg/mL) exhibited almost 5.50 times inhibitory potency against B. cinerea than that of pyrimethanil (EC50=29.6µg/mL; EC90=113.4µg/mL). Therefore, in this study, compound 3n was found to be a novel lead compound for further optimization to find more potent antifungal compounds as microbial PDHc-E1 inhibitors.
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Antifúngicos/síntesis química , Antifúngicos/farmacología , Piruvato Deshidrogenasa (Lipoamida)/antagonistas & inhibidores , Triazoles/síntesis química , Triazoles/farmacología , Animales , Piruvato Deshidrogenasa (Lipoamida)/metabolismo , Complejo Piruvato Deshidrogenasa/antagonistas & inhibidores , Complejo Piruvato Deshidrogenasa/metabolismo , Rhizoctonia/efectos de los fármacos , PorcinosRESUMEN
By targeting the ThDP binding site of Escherichia coli PDHc-E1, two new 'open-chain' classes of E. coli PDHc-E1 inhibitors, amide and urea derivatives, were designed, synthesized, and evaluated. The amide derivatives of compound 6d, with 4-NO2 in the benzene ring, showed the most potent inhibition of E. coli PDHc-E1. The urea derivatives displayed more potent inhibitory activity than the corresponding amide derivatives with the same substituent. Molecular docking studies confirmed that the urea derivatives have more potency due to the two hydrogen bonds formed by two NH of urea with Glu522. The docking results also indicate it might help us to design more efficient PDHc-E1 inhibitors that could interact with Glu522.
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Amidas/química , Diseño de Fármacos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Escherichia coli/efectos de los fármacos , Simulación del Acoplamiento Molecular , Piruvato Deshidrogenasa (Lipoamida)/antagonistas & inhibidores , Urea/química , Sitios de Unión , Dominio Catalítico , Escherichia coli/enzimología , Enlace de Hidrógeno , Modelos Moleculares , Estructura MolecularRESUMEN
OBJECTIVE: To study the clinical efficacy of adjuvant therapy with glucocorticoids in children with lobar pneumonia caused by Mycoplasma pneumoniae. METHODS: One hundred and eight children with lobar pneumonia caused by Mycoplasma pneumoniae were randomly divided into routine treatment and hormone treatment groups. Both groups were treated with azithromycin and other symptomatic therapies. In addition to the basic treatment, the hormone treatment group was given dexamethasone 0.25-0.3 mg/(kg·d) by intravenous drip until the body temperature was normal. Then given oral prednisone tablets 0.5-1 mg/(kg·d) (gradually reduced) for a total treatment course of 7-10 days. Before and after treatment pulmonary functions were examined, and serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), interleukin-2 (IL-2) and interleukin-6 (IL-6) were measured. RESULTS: The duration of fever, cough relief time and pulmonary shadow absorption time on chest X-ray were significantly shorter in the hormone treatment group than in the routine treatment group (P<0.05). After treatment, the two groups showed improvements in serum CRP, ESR, IL-2, and IL-6 (P<0.05), but the hormone treatment group showed significantly more improvement (P<0.05). Varying degrees of mixed ventilation dysfunction were seen in the two groups before treatment, and hormone therapy significantly improved pulmonary function, especially promoting the recovery of small airway function. CONCLUSIONS: Adjuvant therapy with glucocorticoids can effectively alleviate clinical symptoms, promote the absorption of pulmonary inflammation, and improve pulmonary function in children with lobar pneumonia caused by Mycoplasma pneumoniae.
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Glucocorticoides/uso terapéutico , Neumonía por Mycoplasma/tratamiento farmacológico , Neumonía/tratamiento farmacológico , Adolescente , Niño , Preescolar , Femenino , Humanos , Interleucina-6/sangre , Pulmón/fisiopatología , Masculino , Neumonía/inmunología , Neumonía/fisiopatología , Neumonía por Mycoplasma/inmunología , Neumonía por Mycoplasma/fisiopatologíaRESUMEN
As potential inhibitors of pyruvate dehydrogenase complex E1 (PDHc-E1), a series of 19 1-((4-amino-2-methylpyrimidin-5-yl)methyl)-5-methyl-N'-(substituent)benzylidene-1H-1,2,3-triazole-4-carbohydrazide 4 has been synthesized and tested for their PDHc-E1 inhibitory activity in vitro. Some of these compounds such as 4a, 4g, 4l, 4o, 4p, and 4q were demonstrated to be effective inhibitors by the bioassay of Escherichia coli PDHc-E1. SAR analysis indicated that the PDHc-E1 inhibitory activity could be further enhanced by optimizing the substituted groups in the parent compound. Molecular modeling study with compound 4o as a model was performed to evaluate docking. The results of modeling study suggested a probable inhibition mechanism.
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Hidrazonas/síntesis química , Piruvato Deshidrogenasa (Lipoamida)/antagonistas & inhibidores , Complejo Piruvato Deshidrogenasa/antagonistas & inhibidores , Hidrazonas/química , Hidrazonas/farmacología , Modelos Moleculares , Complejo Piruvato Deshidrogenasa/farmacologíaRESUMEN
Cyanobacterial fructose-1,6-/sedoheptulose-1,7-bisphoshatase (Cy-FBP/SBPase) is an important target enzyme for finding inhibitors to solve harmful algal bloom (HAB). In this study, as potential inhibitors of Cy-FBP/SBPase, a series of novel chromone-connecting benzohydrazone compounds (Novel N'-((4-oxo-4H-chromen-3-yl)methylene)benzohydrazide) were designed and synthesized. Their inhibitory activities against Cy-FBP/SBPase were further examined in vitro. Some of these compounds, such as f6-f8, f11, f12 and f16, exhibit higher inhibitory activities (IC50=11.2-16.1 µM), especially, the compound f7 was identified as the most potent inhibitor with IC50 value of 11.2 µM. The probable binding-mode of compound f7 was further analyzed carefully by molecular docking methods. These results indicate that compound f7 could be used as a lead compound for further optimization and might have potential to be developed as a new algicide.
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Antibacterianos/síntesis química , Proteínas Bacterianas/antagonistas & inhibidores , Cromonas/síntesis química , Cianobacterias/química , Fructosa-Bifosfatasa/antagonistas & inhibidores , Hidrazonas/síntesis química , Monoéster Fosfórico Hidrolasas/antagonistas & inhibidores , Antibacterianos/química , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Cromonas/química , Cianobacterias/enzimología , Diseño de Fármacos , Escherichia coli/genética , Fructosa-Bifosfatasa/química , Fructosa-Bifosfatasa/genética , Hidrazonas/química , Simulación del Acoplamiento Molecular , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genéticaRESUMEN
Kava (Piper methysticum Foster, Piperaceae) organic solvent-extract has been used to treat mild to moderate anxiety, insomnia, and muscle fatigue in Western countries, leading to its emergence as one of the 10 best-selling herbal preparations. However, several reports of severe hepatotoxicity in kava consumers led the U.S. Food and Drug Administration and authorities in Europe to restrict sales of kava-containing products. Herein we demonstrate that flavokawain B (FKB), a chalcone from kava root, is a potent hepatocellular toxin, inducing cell death in HepG2 (LD(50)=15.3 ± 0.2 µM) and L-02 (LD(50)=32 µM) cells. Hepatocellular toxicity of FKB is mediated by induction of oxidative stress, depletion of reduced glutathione (GSH), inhibition of IKK activity leading to NF-κB transcriptional blockade, and constitutive TNF-α-independent activation of mitogen-activated protein kinase (MAPK) signaling pathways, namely, ERK, p38, and JNK. We further demonstrate by noninvasive bioluminescence imaging that oral consumption of FKB leads to inhibition of hepatic NF-κB transcriptional activity in vivo and severe liver damage. Surprisingly, replenishment with exogenous GSH normalizes both TNF-α-dependent NF-κB as well as MAPK signaling and rescues hepatocytes from FKB-induced death. Our data identify FKB as a potent GSH-sensitive hepatotoxin, levels of which should be specifically monitored and controlled in kava-containing herb products.