RESUMEN
Taxodin A (1), a unique C30 terpenoid featuring an unprecedented skeleton composed of an abietane-type diterpene and a menthane-type monoterpene, was obtained from the leaves and branches of Taxodium mucronatum. The structure and absolute configuration of compound 1 was unequivocally established by the combination of extensive spectroscopic analyses and X-ray single-crystal diffraction analysis. Compound 1 exhibited potent cytotoxic activities against A549, SMMC-7721, MDA-MB-231, and SW480â cell lines with IC50 values of 15.35±0.73, 8.49±0.35, 17.53±0.79, 18.93±0.60â µM, respectively.
Asunto(s)
Antineoplásicos Fitogénicos , Ensayos de Selección de Medicamentos Antitumorales , Taxodium , Humanos , Taxodium/química , Línea Celular Tumoral , Antineoplásicos Fitogénicos/farmacología , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/aislamiento & purificación , Terpenos/química , Terpenos/farmacología , Terpenos/aislamiento & purificación , Conformación Molecular , Proliferación Celular/efectos de los fármacos , Cristalografía por Rayos X , Hojas de la Planta/química , Relación Estructura-Actividad , Estructura Molecular , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Modelos MolecularesRESUMEN
Taxodisones A and B, C30-terpenes with an unprecedented tetracyclo[12.4.0.0.2,709,14]octodecane core, were isolated from the seeds of Taxodium distichum. Their structures, including their configurations, were unambiguously determined. Their biomimetic synthesis suggests that they stem from diterpenes and monoterpenes, and not from squalene or oxidosqualene. In addition, their bioactivities were also evaluated.
Asunto(s)
Diterpenos/química , Taxodium/química , Biomimética , Catálisis , Complejos de Coordinación/química , Cristalografía por Rayos X , Reacción de Cicloadición , Diterpenos/metabolismo , Erbio/química , Conformación Molecular , Semillas/química , Semillas/metabolismo , Taxodium/metabolismo , Terpenos/química , Terpenos/metabolismoRESUMEN
The resins bled from stems and in seed cones and leaves of Cryptomeria japonica, Glyptostrobus pensilis, Taxodium distichum, and T. mucronatum were characterized to provide an overview of their major natural product compositions. The total solvent extract solutions were analyzed as the free and derivatized products by gas chromatography-mass spectrometry to identify the compounds, which comprised minor mono- and sesquiterpenoids, and dominant di- and triterpenoids, plus aliphatic lipids (e.g., n-nonacosan-10-ol). Ferruginol, 7α-p-cymenylferruginol, and chamaecydin were the major characteristic markers for the Taxodioideae conifer subfamily. The mass spectrometric data can aid polar compound elucidation in environmental, geological, archeological, forensic and pharmaceutical studies.
Asunto(s)
Cupressaceae/química , Cromatografía de Gases y Espectrometría de Masas/métodos , Taxodium/química , Terpenos/análisisRESUMEN
In order to understand the effect of submergence on nutrient release of the reforested tree leaves and assess the environmental risk of leaf decomposition under submergence, the mass loss and nutrient release rates of three reforestation tree species, Taxodium ascendens Brongn, Taxodium distichum (L.) Rich., and Salix matsudana Koidz., at different elevation in the hydro-fluctuation zone of the Three Gorges Dam Reservoir (TGDR) region were tested in situ. Results showed that the initial macroelement contents of the leaves of the three tree species varied among different elevations due to different submergence stresses. All foliar mass loss rates of the three tree species at 165 m a.s.l. were significantly higher than that at 175 m a.s.l. (except that of S. matsudana at 165 m a.s.l.), after 179 days of incubation commenced September 20. After 138 days of incubation commenced October 5, the foliar mass loss rates of the three tree species at 170 m a.s.l. were significantly higher than that at 175 m a.s.l. Moreover, the leaf mass loss rates of S. matsudana were higher than the other two species when compared at the same elevation of the same incubation period. In addition, foliar release rates of N and Ca in T. ascendens, C, N, and Ca in T. distichum as well as Ca in S. matsudana at 165 m a.s.l. after 179 days of incubation and at 170 m a.s.l. after 138 days of incubation were significantly higher than that at 175 m a.s.l., respectively. Leaf mass loss rates of T. ascendens were significantly correlated with its initial leaf K, Ca, and Mg contents. In contrast, leaf mass loss rates of T. distichum had significant correlations with the initial leaf P and K contents, as well as C/P and N/P ratios. However, the mass loss rates of S. matsudana significantly correlated with initial leaf N, P, and Ca contents and C/N, C/P, and N/P ratios. Foliar nutrient release rates, especially the foliar release of C, N, and P of the three tree species, had significant correlations with initial leaf C/P and N/P ratios. Our results suggested that submergence facilitated the decomposition and nutrient release rates of the leaves of the three woody species, especially the broad leaves of S. matsudana, which may potentially cause secondary pollution to the water body of the TGDR. Thus, we suggested that a sustainable harvest of leaves of the reforested forest stands prior to submergence should be considered in the hydro-fluctuation zone so as to protect the water quality of the TGDR.
Asunto(s)
Hojas de la Planta/metabolismo , Salix/metabolismo , Taxodium/metabolismo , Árboles , China , Inundaciones , Bosques , Nitrógeno/análisis , Nutrientes/análisis , Hojas de la Planta/química , Salix/química , Taxodium/químicaRESUMEN
Extracts and components of Taxodium ascendens Brongn, an excellent afforestation tree, have exhibited several activities, including antibacterial activity and inhibitory activity on carbonic anhydrase II. However, the anti-hepatocellular carcinoma (anti-HCC) activity of extracts from the leaves of T. ascendens (TALE) remains unclear. In the present study, six diterpenoid compounds were isolated from a TALE extract. Here, the pro-apoptotic activities and the molecular mechanisms of TALE and the compounds 1-6 on HepG2 and Hep3B HCC cells were evaluated. Results show that the TALE and compounds 1-6 were able to induce apoptosis in the HepG2 and Hep3B HCC cells, particularly ferruginol (3). Mechanistically, the application of TALE and ferruginol (3) resulted in a significant decrease in mitochondria membrane potential, which was coupled with an increase in the Bax/Bcl-2 ratio and caspase-3/-9 activity. In vivo experiments showed that oral administration of TALE inhibited the proliferation of transplanted H22 cells in Kunming mice. However, TALE toxicity in KM mice was undetectable. The study provides strong evidence for the anti-HCC capacity of TALE.
Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Diterpenos/farmacología , Mitocondrias/efectos de los fármacos , Taxodium/química , Animales , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Femenino , Células Hep G2 , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/metabolismo , Masculino , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Mitocondrias/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto/métodos , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Two dimeric diterpenoids, taxodikaloids A (1) and B (2), have been identified from the seeds of Taxodium ascendens. The diterpenoid structures were established on the basis of comprehensive spectroscopic analysis, and the absolute configuration of taxodikaloid A (1) was further confirmed by single-crystal X-ray diffraction. Both structures feature an unprecedented oxazoline ring linkage connecting two abietane diterpenoid monomers. A plausible biosynthetic pathway for compounds 1 and 2 is proposed. Both compounds show potential neuroprotective activity against Aß25-35-induced damage in SH-SY5Y cells.
Asunto(s)
Taxodium/química , Abietanos , Diterpenos , Estructura MolecularRESUMEN
Influenza virus remains an emerging virus and causes pandemics with high levels of fatality. After screening different plant extracts with potential anti-influenza activity, a water extract of Taxodium distichum stems (TDSWex) showed excellent activity against influenza viruses. The EC50 of TDSWex was 0.051 ± 0.024 mg/mL against influenza virus A/WSN/33. TDSWex had excellent antiviral efficacy against various strains of human influenza A and B viruses, particularly oseltamivir-resistant clinical isolates and a swine-origin influenza strain. We observed that the synthesis of viral RNA and protein were inhibited in the presence of TDSWex. The results of the time-of-addition assay suggested that TDSWex inhibited viral entry and budding. In the hemagglutination inhibition assay, TDSWex inhibited the hemagglutination of red blood cells, implying that the extract targeted hemagglutin-related functions such as viral entry. In the attachment and penetration assay, TDSWex showed antiviral activity with EC50s of 0.045 ± 0.026 and 0.012 ± 0.003 mg/mL, respectively. In addition, TDSWex blocked neuraminidase activity. We conclude that TDSWex has bimodal activities against both hemagglutinin and neuraminidase during viral replication.
Asunto(s)
Hemaglutininas/metabolismo , Neuraminidasa/metabolismo , Orthomyxoviridae/metabolismo , Extractos Vegetales/metabolismo , Taxodium/química , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Perros , Hemaglutininas/química , Humanos , Células de Riñón Canino Madin Darby , Microscopía Fluorescente , Neuraminidasa/antagonistas & inhibidores , Orthomyxoviridae/enzimología , Extractos Vegetales/química , Extractos Vegetales/toxicidad , ARN Viral/química , ARN Viral/metabolismo , Taxodium/metabolismo , Proteínas Virales/metabolismo , Internalización del Virus/efectos de los fármacos , Liberación del Virus/efectos de los fármacosRESUMEN
BACKGROUND: Lymphatic filariasis caused by Wuchereria bancrofti, Brugia malayi and B. timori, is a debilitating disease with an adverse social and economic impact. The infection remains unabated in spite of treatment with existing antifilarial drugs diethylcarbamazine (DEC) and ivermectin which are chiefly microfilaricides. There is therefore, need for macrofilaricides, embryostatic agents and better microfilaricides. In the present study we explored the antifilarial potential of crude extract and its molecular fractions of the plant Taxodium distichum using in vitro assay systems and rodent models of B. malayi infection. METHODS: Ethanolic extract (A001) of aerial parts of T. distichum was solvent fractionated and sub-fractionated. Four molecules, 3-Acetoxylabda-8(20), 13-diene-15-oic acid (K001), Beta-sitosterol (K002), labda-8(20),13-diene-15-oic acid (K003) and Metasequoic acid A (K004) were isolated from the fractions and their structure determined by spectroscopic analysis. The extract, subfractions and molecules were evaluated for antifilarial activity against B. malayi by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) reduction and motility assays in vitro and in two animal models, Meriones unguiculatus and Mastomys coucha, harbouring B. malayi infection. RESULTS: A001 was effective in killing microfilariae (mf) and adult worms in vitro. The diterpenoid K003 produced 100 % reduction in motility of both mf and adult worms and > 80 % inhibition in MTT reduction potential of adult female worms. In B. malayi-M. unguiculatus model, A001 killed all the adult worms in > 80 % of infected animals. K003 was embryostatic (> 95 %) in this model. In the B. malayi-M. coucha model, K003 killed ~54 % of adult worms (macrofilaricidal activity) and rendered > 36 % female worms sterile; it also stopped any further rise in microfilaraemia after day 42 post-initiation of treatment. CONCLUSION: Ethanolic extract of aerial parts of the plant T. distichum possesses potent antifilarial activity and the active principle was localised to K003 which showed significant macrofilaricidal activity and late suppression of peripheral microfilaraemia and some embryostatic activity. These findings indicate that labdane diterpenoid molecule(s) may provide valuable leads for design and development of new macrofilaricidal agent(s). To the best of our knowledge, this is the first report on antifilarial efficacy of products from the plant T. distichum.
Asunto(s)
Brugia Malayi/efectos de los fármacos , Diterpenos/farmacología , Filariasis Linfática/tratamiento farmacológico , Filaricidas/farmacología , Extractos Vegetales/farmacología , Taxodium/química , Animales , Brugia Malayi/citología , Dietilcarbamazina/uso terapéutico , Modelos Animales de Enfermedad , Diterpenos/química , Diterpenos/aislamiento & purificación , Femenino , Filaricidas/química , Filaricidas/aislamiento & purificación , Gerbillinae , Humanos , Ivermectina/uso terapéutico , Masculino , Microfilarias , Murinae , Componentes Aéreos de las Plantas/química , Extractos Vegetales/químicaRESUMEN
The leaf essential oil composition of Taxodium distichum L., collected from the foothills of Uttarakhand, India was analyzed using gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS) equipped with DB-5 (5% diphenyl-95% dimethyl polysiloxane) and ß-cyclodextrin (6-tertiarybutyldimethylsiliyl-2,3-diethyl-ß-cyclodextrin) capillary columns. Seventeen constituents, representing 90.3 to 99.4% of composition were identified in the essential oils from different seasons, viz. spring, summer, rainy, autumn and winter. The essential oil composition was mainly dominated by monoterpene hydrocarbons, represented mainly by α-pinene (81.9-94.3%). Other constituents of the oil were myrcene (0.5-4.7%), ß-pinene (2.2-2.9%), limonene (0.5-1.5%), camphene (≤ 0.03-1.5%), and α-terpineol (upto 1.6%). Chiral analysis of T. distichum essential oil on an ethyl substituted ß-cyclodextrin capillary column revealed the presence of a-pinene in racemic form, with an enantiomeric ratio of 49.3% for (1R)-(+)- and 50.7% for (1S)-(-)-α-pinene.
Asunto(s)
Aceites Volátiles/química , Hojas de la Planta/química , Aceites de Plantas/química , Taxodium/química , IndiaRESUMEN
Two new compounds, namely, a para-benzoquinone ring-containing abietane (1) and a para-benzoquinone ring-containing 7,8-seco-abietane (2), and 14 other known highly oxidized abietane diterpenoids (3-16) were isolated from an extract prepared from the cones of Taxodium distichum, collected in central Ohio. The active subfraction from which all compounds isolated in this study were purified was tested in vivo using Leishmania donovani-infected mice and was found to dose-dependently reduce the parasite burden in the murine livers after iv administration of this crude mixture at 5.6 and 11.1 mg/kg. The structures of 1 and 2 were established by detailed 1D- and 2D-NMR experiments, HRESIMS data, and electronic circular dichroism studies. Compounds 3 and 4 were each fully characterized spectroscopically and also isolated from a natural source for the first time. Compounds 2-16 were tested in vitro against L. donovani promastigotes and L. amazonensis intracellular amastigotes. Compound 2 was the most active against L. amazonensis amastigotes (IC50 = 1.4 µM), and 10 was the most potent against L. donovani promastigotes (IC50 = 1.6 µM). These compounds may be suggested for further studies such as in vivo experimentation either alone or in combination with other Taxodium isolates.
Asunto(s)
Abietanos/aislamiento & purificación , Abietanos/farmacología , Leishmania donovani/efectos de los fármacos , Taxodium/química , Abietanos/química , Animales , Benzoquinonas/química , Concentración 50 Inhibidora , Ratones , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Ohio , Oxidación-ReducciónRESUMEN
The chemical complexity of dissolved organic matter (DOM) obstructs our ability to definitively recover source compounds from within DOM, an objective which has the capacity to alter our understanding of carbon sequestration on a global scale. To advance compositional studies of DOM we have applied a previously published reduction method to an environmental standard, Suwannee River Fulvic Acid (SRFA). The reduction products, comprising 12% of the prereduced carbon, were then separated by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF-MS). Results indicate that the majority of observed reduced compounds corresponded to alicyclic hydrocarbons in the size range C10 to C17. Cyclic terpenoids are the only biomolecule class with contiguous, alicyclic carbon backbones of this size. These terpenoid reduction products contain series offset by CH2 and exhibit great isomeric diversity, features previously inferred from ultrahigh resolution mass spectrometry and NMR studies of unreduced SRFA. Reduction of Taxodium leaf litter as a source material to SRFA confirmed the prevalence of terpenoids in SRFA and provided insight into the parent compounds that must be diagenetically modified on relatively short time scales. These data corroborate several recent studies that suggest alicyclic hydrocarbons to be important components of longer-lived DOM.
Asunto(s)
Benzopiranos/química , Ríos/química , Terpenos/análisis , Cromatografía de Gases y Espectrometría de Masas , Espectroscopía de Resonancia Magnética , Hojas de la Planta/química , Taxodium/químicaRESUMEN
One new and seven known diterpenes were identified from an antibacterial chromatographic fraction of Taxodium ascendens. Of these, demethylcryptojaponol (2), 6-hydroxysalvinolone (3), hydroxyferruginol (4), and hinokiol (5) demonstrated potent activity against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). These compounds represent a class of synthetically accessible compounds that could be further developed for treatment of drug-resistant bacterial infections.
Asunto(s)
Antibacterianos/farmacología , Diterpenos/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Extractos Vegetales/farmacología , Taxodium/química , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Diterpenos/química , Diterpenos/aislamiento & purificación , Humanos , Pruebas de Sensibilidad Microbiana , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificaciónRESUMEN
Long-term monitoring (LTM) of groundwater remedial projects is costly and time-consuming, particularly when using phytoremediation, a long-term remedial approach. The use of trees as sensors of groundwater contamination (i.e., phytoscreening) has been widely described, although the use of trees to provide long-term monitoring of such plumes (phytomonitoring) has been more limited due to unexplained variability of contaminant concentrations in trees. To assess this variability, we developed an in planta sampling method to obtain high-frequency measurements of chlorinated ethenes in oak (Quercus rubra) and baldcypress (Taxodium distichum) trees growing above a contaminated plume during a 4-year trial. The data set revealed that contaminant concentrations increased rapidly with transpiration in the spring and decreased in the fall, resulting in perchloroethene (PCE) and trichloroethene (TCE) sapwood concentrations an order of magnitude higher in late summer as compared to winter. Heartwood PCE and TCE concentrations were more buffered against seasonal effects. Rainfall events caused negligible dilution of contaminant concentrations in trees after precipitation events. Modeling evapotranspiration potential from meteorological data and comparing the modeled uptake and transport with the 4 years of high frequency data provides a foundation to advance the implementation of phytomonitoring and improved understanding of plant contaminant interactions.
Asunto(s)
Monitoreo del Ambiente/métodos , Quercus/crecimiento & desarrollo , Taxodium/crecimiento & desarrollo , Tetracloroetileno/análisis , Tricloroetileno/análisis , Contaminantes Químicos del Agua/análisis , Biodegradación Ambiental , Agua Subterránea/química , Quercus/química , Estaciones del Año , Taxodium/química , Estados UnidosRESUMEN
The chemical composition of Taxodium distichum cones and the antifungal activities of twelve diterpenoids against two wood decay fungi, Trametes versicolor (white-rot) and Fomitopsis palustris (brown-rot) were examined. The chemical composition of the major extractive fraction, the n-C(6)H(14) extract, was evaluated and its antifungal properties were identified. Twelve diterpenoids including ten abietane-type components were isolated from the n-C(6)H(14) extract: 6,7-dehydroferruginol (1), ferruginol (2), 6,7-dehydroroyleanone (3), sandaracopimaric acid (4), taxodione (5), taxodal (6), taxodone (7), sugiol (8), xanthoperol (9), salvinolone (10), 5,6-dehydrosugiol (11), and 14-deoxycoleon U (12). Compounds 5 and 12 were highly active against both wood-decay fungi. In particular, the activities of these compounds against F. palustris were potent. The results suggest that the position and the number of hydroxyl groups on abietane-type structures may be related to antifungal activities against T. versicolor and F. palustris.
Asunto(s)
Abietanos/análisis , Coriolaceae/química , Taxodium/química , Abietanos/farmacología , Diterpenos/química , Fungicidas Industriales/análisis , Fungicidas Industriales/farmacología , Trametes/efectos de los fármacosRESUMEN
Eight known abietane-type diterpenes were isolated from the weak acidic fraction of the n-hexane extract from cones of Taxodium distichum, one of the extant, living fossil conifers. They were identified as 6,7-dehydroroyleanone (1), taxodal (2), taxodione (3), salvinolone (4), 14-deoxycoleon U (5), 5,6-dehydrosugiol (6), sandaracopimaric acid (7), and xanthoperol (8). The structures of these compounds were determined by comparison of NMR spectral data with published data. The antitermitic (termicidal and antifeedant) activities of the compounds 1-8 against the subterranean termite, Reticulitermes speratus Kolbe, were evaluated. Compounds 1 and 3 showed potent termicidal activity, and 5 and 8 showed potent antifeedant activity. Compound 1 was found to be one of the representative bioactive compounds in the n-hexane extract of T. distichum cones. Compounds 1-8, with the exception of 7, were oxides of ferruginol (9). Therefore, the presence of various oxidation forms of the abietane-type structure reflects their various bioactivities.
Asunto(s)
Abietanos , Insecticidas , Isópteros , Taxodium/química , Abietanos/química , Animales , Insecticidas/química , Isópteros/crecimiento & desarrollo , Espectroscopía de Resonancia MagnéticaRESUMEN
A new norlignan, (2R,3R,4S,5S)-2,4-bis(4-hydroxyphenyl)-3,5-dihydroxy-tetrahydropyran (1), together with 9 known compounds were isolated from the branches and leaves of Taxodium ascendens. Their structures were mainly determined on the basis of MS, IR, 1D and 2D NMR spectral evidences. Methanol extract showed inhibitory activity on carbonic anhydrase II with an IC(50) value of 4.27 microg/ml, acetone extract and methanol extract inhibited activity of cathepsin B with IC(50) values of 2.12 and 3.71 microg/ml, respectively.
Asunto(s)
Inhibidores de Anhidrasa Carbónica/aislamiento & purificación , Lignanos/aislamiento & purificación , Extractos Vegetales/aislamiento & purificación , Taxodium/química , Inhibidores de Anhidrasa Carbónica/química , Inhibidores de Anhidrasa Carbónica/farmacología , Catepsinas/antagonistas & inhibidores , Concentración 50 Inhibidora , Lignanos/química , Lignanos/farmacología , Estructura Molecular , Extractos Vegetales/química , Extractos Vegetales/farmacología , Hojas de la Planta , Tallos de la PlantaRESUMEN
8-beta-Hydroxypimar-15-en-19-oic acid (1), taxodione (2), 6,7-dehydro-8-hydrotaxodone (3), quercetin-3-O-beta-D-glucopyranoside (4), and shikimic acid (5) were isolated from the leaves of Taxodium distichum L. (Rich.) for the first time. Previously reported compounds [beta-sitosterol (6), isorhamnetin (7), quercetin (8), isorhamnetin-3-O-alpha-arabinofuranoside (9), quercetin-3-O-a-arabinofuranoside (10)] have also been isolated. The activity of taxodione as an inhibitor for hepatic stellate cells was determined. The antitumour activity of 2, 3, and 5 using a DNA affinity probe was examined.
Asunto(s)
Diterpenos/aislamiento & purificación , Hojas de la Planta/química , Taxodium/química , Animales , Sitios de Unión , ADN/metabolismo , Diterpenos/farmacología , Flavonoles/aislamiento & purificación , Flavonoles/farmacología , Glicósidos/aislamiento & purificación , Glicósidos/farmacología , Hígado/citología , Hígado/efectos de los fármacos , Quercetina , Ratas , SolventesRESUMEN
Two new abietane-type diterpenes, taxodistines A (1) and B (2), have been isolated by the guidance of inhibitory effect of tubulin polymerization from the fruits of Taxodium distichum and the structures were elucidated by using 2D NMR data. Taxodistine B (2) showed inhibition of tubulin polymerization.
Asunto(s)
Diterpenos/aislamiento & purificación , Taxodium/química , Animales , Línea Celular Tumoral , Diterpenos/química , Diterpenos/farmacología , Espectroscopía de Resonancia Magnética , Ratones , Modelos Moleculares , Estructura Molecular , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
Cathepsin B and K, two important members in lysosomal proteases, involve in many serious human diseases, such as tumor and osteoporosis. In order to find their novel inhibitors, we performed the inhibition assays of cathepsin B and cathepsin K in vitro, randomly screened compounds from plants, and found six biflavones, named AMF1-5 and HIF, can potently inhibit cathepsin B and cathepsin K, especially AMF4 and HIF with IC(50) of 0.62 and 0.58 microM against cathepsin B. They are novel inhibitors for cathepsin B and K. Inhibition and flexible docking studies indicated that these biflavones are reversible inhibitors of cathepsin B, and their binding patterns and interaction modes with cathepsin B made them more specific to cathepsin B endopeptidase.