Effects and mechanisms of total flavones of Abelmoschus manihot in attenuating diabetic tubulopathy by targeting endoplasmic reticulum stress-induced cell apoptosis / 中国中药杂志

Renal tubular injury in patients with diabetic kidney disease(DKD) may be accompanied by glomerular and microvascular diseases. It plays a critical role in the progression of renal damage in DKD, and is now known as diabetic tubulopathy(DT). To explore the multi-targeted therapeutic effects and pharmacological mechanisms in vivo of total flavones of Abelmoschus manihot(TFA), an extract from traditional Chinese medicine for treating kidney disease, in attenuating DT, the authors randomly divided all rats into four groups: a normal control group(normal group), a DT model group(model group), a DT model+TFA-treated group(TFA group) and a DT model+rosiglitazone(ROS)-treated group(ROS group). The DT rat model was established based on the DKD rat model by means of integrated measures. After successful modeling, the rats in the four groups were continuously given double-distilled water, TFA suspension, and ROS suspension, respectively by gavage every day. After 6 weeks of treatment, all rats were sacrificed, and the samples of their urine, blood, and kidneys were collected. The effects of TFA and ROS on various indicators related to urine and blood biochemistry, renal tubular injury, renal tubular epithelial cell apoptosis and endoplasmic reticulum stress(ERS), as well as the activation of the protein kinase R-like endoplasmic reticulum kinase(PERK)-eukaryotic translation initiation factor 2α(eIF2α)-activating transcription factor 4(ATF4)-C/EBP homologous protein(CHOP) signaling pathway in the kidney of the DT model rats were investigated. The results indicated that hypertrophy of renal tubular epithelial cells, renal tubular hyperplasia and occlusion, as well as interstitial extracellular matrix and collagen deposition occurred in the DT model rats. Moreover, significant changes were found in the expression degree and the protein expression level of renal tubular injury markers. In addition, there was an abnormal increase in tubular urine proteins. After TFA or ROS treatment, urine protein, the characteristics of renal tubular injury, renal tubular epithelial cell apoptosis and ERS, as well as the activation of the PERK-eIF2α-ATF4-CHOP signaling pathway in the kidney of the DT model rats were improved to varying degrees. Therein, TFA was superior to ROS in affecting the pathological changes in renal tubule/interstitium. In short, with the DT model rats, this study demonstrated that TFA could attenuate DT by multiple targets through inhibiting renal tubular ERS-induced cell apoptosis in vivo, and its effect and mechanism were related to suppressing the activation of the PERK-eIF2α-ATF4-CHOP signaling pathway in the kidney. These findings provided preliminary pharmacological evidence for the application of TFA in the clinical treatment of DT.

Effects and mechanisms of total flavones of Abelmoschus manihot in improving insulin resistance and podocyte epithelial-mesenchymal transition in diabetic kidney disease based on IRS1/PI3K/Akt pathway / 中国中药杂志

This study aimed to explore the effects and mechanisms of total flavones of Abelmoschus manihot(TFA), the extracts from traditional Chinese medicine indicated for kidney diseases, on insulin resistance(IR) and podocyte epithelial-mesenchymal transition(EMT) in diabetic kidney disease(DKD), and further to reveal the scientific connotation. Thirty-two rats were randomly divided into a normal group, a model group, a TFA group, and a rosiglitazone(ROS) group. The modified DKD model was induced in rats by methods including high-fat diet feeding, unilateral nephrectomy, and streptozotocin(STZ) intraperitoneal injection. After modeling, the rats in the four groups were given double-distilled water, TFA suspension, and ROS suspension correspondingly by gavage every day. At the end of the 8th week of drug administration, all rats were sacrificed, and the samples of urine, blood, and kidney tissues were collected. The parameters and indicators related to IR and podocyte EMT in the DKD model rats were examined and observed, including the general condition, body weight(BW) and kidney weight(KW), the biochemical parameters and IR indicators, the protein expression levels of the key signaling molecules and structural molecules of slit diaphragm in the renal insulin receptor substrate(IRS) 1/phosphatidylinositol 3-kinase(PI3K)/serine-threonine kinase(Akt) pathway, foot process form and glomerular basement membrane(GBM) thickness, the expression of the marked molecules and structural molecules of slit diaphragm in podocyte EMT, and glomerular histomorphological characteristics. The results showed that for the DKD model rats, both TFA and ROS could improve the general condition, some biochemical parameters, renal appearance, and KW. The ameliorative effects of TFA and ROS were equivalent on BW, urinary albumin(UAlb)/urinary creatinine(UCr), serum creatinine(Scr), triglyceride(TG), and KW. Secondly, they could both improve IR indicators, and ROS was superior to TFA in improving fast insulin(FIN) and homeostasis model assessment of insulin resistance(HOMA-IR). Thirdly, they could both improve the protein expression levels of the key signaling molecules in the IRS1/PI3K/Akt pathway and glomerulosclerosis in varying degrees, and their ameliorative effects were similar. Finally, both could improve podocyte injury and EMT, and TFA was superior to ROS. In conclusion, this study suggested that podocyte EMT and glomerulosclerosis could be induced by IR and the decreased activation of the IRS1/PI3K/Akt pathway in the kidney in DKD. Similar to ROS, the effects of TFA in inhibiting podocyte EMT in DKD were related to inducing the activation of the IRS1/PI3K/Akt pathway and improving IR, which could be one of the scientific connotations of TFA against DKD. This study provides preliminary pharmacological evidence for the development and application of TFA in the field of diabetic complications.

Pedalitin from isodon japonica, an inactivation of soybean lipoxygenase-1 / Pedalitina de isodon japonica, un inactivador de la lipo oxigenasa-1 de poroto de soya

Pedalitin, isolated from the aerial part of Rabdosia japonica (Labiatae), inhibited soybean lipoxygenase-1 (EC 1.13.11.12, Type I) with an IC50 of 152.5 uM. The progress curves for an enzyme reaction, pedalitin inactivate the lipoxygenase-1 in a time dependent, irreversible manner, exhibiting kinetics with a kinact/KI of 59.6 +/- 10 mM-1min-1. In the pseudoperoxidase activity, pedalitin is very slowly oxidized by the soybean lipoxygenase-1 catalyzed decomposition of lipid hydroperoxides.

Pedalitina, aislada de las partes aereas de Rabdosia japonica inhibió a la lipooxigenasa-1 (EC 1.13.11.12 tipo I) con un IC50 de 152.5 uM. La curva de progreso para una acción enzimática, pedalitina inactivó a la lipooxigenasa-1 de una manera dependiente del tiempo, de una manera irreversible, exhibiendo una cinética con una kinact/KI de 59.6 +/- mM-1min-1. En la actividad pseudoperoxidasa, pedalitina es oxidada lentamente por la descomposición de la lípido hidroperóxido de la lipooxigenasa-1 de poroto de soya.

Evaluation of platelet aggregation in platelet concentrates: storage implications / Efeito das catequinas (catequina e epicatequina) na agregação plaquetária

Os flavonóides representam um dos grupos fenólicos mais importantes e diversificados entre os produtos de origem natural. Dentre os compostos fenólicos temos os derivados flavânicos (flavan-3-óis e flavan-3,4-dióis) que podem se polimerizar originando taninos. O representante mais importante do grupo dos flavan-3-óis é a catequina. Estes compostos exibem inúmeros efeitos biológicos incluindo ação antiviral, antioxidante e antitrombótica. No presente trabalho foi avaliado o efeito das catequinas (catequina e epicatequina) sobre a função plaquetária. Foram estudados vinte indivíduos adultos, clinicamente saudáveis. A agregação plaquetária foi avaliada em plasma rico em plaquetas (PRP) e plaquetas lavadas utilizando-se agonistas colágeno (2,0 µg/ml) e trombina (0,25U/ml), respectivamente. Como controle utilizou-se o veículo da droga (DMSO 0.2 por cento). O pré-tratamento das plaquetas com epicatequina (200 µg/ml) causou inibição significativa da agregação para o colágeno (9.0 ± 7.8 por cento) e para a trombina (10.0 ± 2.2) em relação aos respectivos controles (70.0 ± 7.8) e (68.0 ± 5.0), (p<0.001; Student t-test). Por outro lado, a catequina não promoveu inibição da resposta de agregação. Conclui-se que a epicatequina apresenta potencial antiagregante.

Os flavonóides representam um dos grupos fenólicosmais importantes e diversificados entre os produtosde origem natural. Dentre os compostos fenólicos temosos derivados flavânicos (flavan-3-óis e flavan-3,4-dióis) que podem se polimerizar originando taninos.O representante mais importante do grupodos flavan-3-óis é a catequina. Estes compostos exibeminúmeros efeitos biológicos incluindo açãoantiviral, antioxidante e antitrombótica. No presentetrabalho foi avalia(catequina e epicatequina) sobre a função plaquetária.Foram estudados vinte indivíduos adultos,clinicamente saudáveis. A agregação plaquetária foiavaliada em plasma rico em plaquetas (PRP) e plaquetaslavadas utilizando-se agonistas colágeno (2,0μg/ml) e trombina (0,25U/ml), respectivamente.Como controle utilizou-se o veículo da droga (DMSO0.2%). O pré-tratamento das plaquetas com epicatequina(200 μg/ml) causou inibição significativa daagregação para o colágeno (9.0 ± 7.8%) e para atrombina (10.0 ± 2.2) em relação aos respectivoscontroles (70.0 ± 7.8) e (68.0 ± 5.0), ( p<0.001;Student t-test). Por outro lado, a catequina não promoveuinibição da resposta de agregação. Concluise que a epicatequina apresenta potencial antiagregantedo o efeito das catequinas.

Diuretie activity of gossypetin isolated from hibiscus sabdariffa in rats

Gossypetin [3, 5, 7, 8, 3', 4'-hexahydroxy flavone] isolated from the flowers of Hibiscus sabdariffa has been tested for diuretic activity in rats. The parameters observed for each individual rat included body weight before and after test period, total urine volume [corrected for water intake during the test period], urine concentration of Na[+], K[+] and Cl[-]. The values of urine volume and cation excretion were increased with reference to saline control by Gossypetin [100 mg/kg of body weight]. Furosemide was used as a reference diuretic

Molecular mechanisms involved in human platelet aggregation by synergistic interaction of platelet-activating factor and 5-hydroxytryptamine

Our recent studies have shown that co-activation of Gq and Gi proteins by 5-hydroxytryptamine (5-HT) and adrenaline show synergism in human platelet aggregation. This study was conducted to examine the mechanism(s) of synergistic interaction of 5-HT and platelet activating factor (PAF) in human platelets. We show that PAF, but not 5-HT, increased platelet aggregation in a concentration-dependent manner. However, low concentrations of 5-HT (2 microM) potentiated platelet aggregation induced by subthreshold concentration of PAF (40 nM) indicating a synergistic interaction between the two agonists and this synergism was blocked by receptor antagonists to either 5-HT or PAF. 5-HT also potentiated the effect of PAF on thromboxane A2 (TXA2) formation and phosphorylation of extracellularly regulated mitogen-activated protein kinases (ERK1/2). The synergism of 5-HT and PAF in platelet aggregation was inhibited by calcium (Ca2+) channel blockers, verapamil and diltiazem, phospholipase C (PLC) inhibitor, U73122, cyclooxygenase (COX) inhibitor, indomethacin, and MEK inhibitor, PD98059. These data suggest that synergistic effect of 5-HT and PAF on human platelet aggregation involves activation of PLC/Ca2+, COX and MAP kinase pathways.

Molecular mechanisms involved in human platelet aggregation by synergistic interaction of platelet-activating factor and 5-hydroxytryptamine

Our recent studies have shown that co-activation of Gq and Gi proteins by 5-hydroxytryptamine (5-HT) and adrenaline show synergism in human platelet aggregation. This study was conducted to examine the mechanism(s) of synergistic interaction of 5-HT and platelet activating factor (PAF) in human platelets. We show that PAF, but not 5-HT, increased platelet aggregation in a concentration-dependent manner. However, low concentrations of 5-HT (2 microM) potentiated platelet aggregation induced by subthreshold concentration of PAF (40 nM) indicating a synergistic interaction between the two agonists and this synergism was blocked by receptor antagonists to either 5-HT or PAF. 5-HT also potentiated the effect of PAF on thromboxane A2 (TXA2) formation and phosphorylation of extracellularly regulated mitogen-activated protein kinases (ERK1/2). The synergism of 5-HT and PAF in platelet aggregation was inhibited by calcium (Ca2+) channel blockers, verapamil and diltiazem, phospholipase C (PLC) inhibitor, U73122, cyclooxygenase (COX) inhibitor, indomethacin, and MEK inhibitor, PD98059. These data suggest that synergistic effect of 5-HT and PAF on human platelet aggregation involves activation of PLC/Ca2+, COX and MAP kinase pathways.

Antimicrobial flavonoids from solanum dobium fres

Two flavonoids compounds were isolated from Solanum dobium Fers [Solanaceae]. One major compound was identified as astragalin [kampferol-3-O-glucoside], and a minor compound that was tentatively identified as quercetin-3-glycoside. The antimicrobial activities of the 2 compounds were tested against 12 microorganisms [7 bacteria, 2 fungi and 3 C and ida of different strains]. The major compound was found to possess a pronounced antibacterial activity as presented by the minimum inhibitory concentration showing activity 4 times as that of streptomycin and double that of tobramycin against Pseudomonas aeruginosa UM 60690. It displayed double activity of streptomycin against both Salmonella typhi UM 26049 and Flavobacterium meningosepticum UM 260494. In addition, the isolated astragalin showed a significant 2-4 times antic and idal activity as compared with nystatin against C and ida intermedia ATCC 5159, C and ida albicans Um 050494, and C and ida lipolytica ATCC 8661. However, this compound did not show any significant antifungal activity. The isolated minor flavonoid showed significant antic and idal, antifungal as well as moderate antibacterial activity

Role of Ras/ERK-dependent pathway in the erythroid differentiation of K562 cells

The chronic myelogenous leukemic K562 cell line carrying Bcr-Abl tyrosine kinase is considered as pluripotent hematopoietic progenitor cells expressing markers for erythroid, granulocytic, monocytic, and megakaryocytic lineages. Here we investigated the signaling modulations required for induction of erythroid differentiation of K562 cells. When the K562 cells were treated with herbimycin A (an inhibitor of protein tyrosine kinase), ras antisense oligonucleotide, and PD98059 (a specific inhibitor of MEK), inhibition of ERK/MAPK activity and cell growth, and induction of erythroid differentiation were observed. The ras mutant, pZIPRas61leu-transfected cells, K562-Ras61leu, have shown a markedly decreased cell proliferation rate with approximately 2-fold doubling time, compared with the parental K562 cells, and about 60% of these cells have shown the phenotype of erythroid differentiation. In addition, herbimycin A inhibited the growth rate and increased the erythroid differentiation, but did not affect the elevated activity of ERK/MAPK in the K562-Ras61leu cells. On the other hand, effects of PD98059 on the growth and differentiation of K562-Ras61leu cells were biphasic. At low concentration of PD98059, which inhibited the elevated activity of ERK/MAPK to the level of parental cells, the growth rate increased and the erythroid differentiation decreased slightly, and at high concentration of PD98059, which inhibited the elevated activity of ERK/MAPK below that of the parental cells, the growth rate turned down and the erythroid differentiation was restored to the untreated control level. Taken together, these results suggest that an appropriate activity of ERK/MAPK is required to maintain the rapid growth and transformed phenotype of K562 cells.

Effect of flavonoids on aspergillus flavus growth and aflatoxin production

Os flavanóides tem demonstrado efeito impediente contra microrganismos e uma alternativa no controle de fungos contaminantes de gräos armazenados. Neste trabalho, pesquisou-se a atividade de quatro flavonóides (kampferol, kampferitrina, naringinina e quercetina), no crescimento de Aspergillus flavus (NRRL 6513) e na produçäo da Aflatoxina B1. As suspensöes de esporos forma inoculadas em Erlenmeyer de 250 ml, contendo 50 ml de meio de Yes com diferentes concentraçöes dos flavonóides, preparados a partir de uma soluçäo de 2000 ppm. Para cada diluiçäo dos flavonóides pesquisados foram feitas 4 repetiçöes e para determinaçäo do peso seco miceliar. A toxina foi extraida do meio de cultura, adicionando-se clorofórmio e os extratos cromatografados, em placas de camada delgada de sílica gel 60 (Merck) e quantificado pela fotodensotometria. A naringinina causou inibiçäo de 60,5 por cento no crescimento de Aspergillus flavus na concentraçäo de 125 ppm, enquanto a kampferitrina e o kampferol resultaram na inibiçäo de 49,4 p/cento e 40 p/cento, nas concentraçöes de 300 e 100 ppm, rrespectivamente. A quercetina demonstrou menor taxa de inibiçäo (36 p/cento). Em relaçäo a produçäo de aflatoxina B1, a máxima inibiçäo ocorreu na presença de kampferitrina (99 p/cento) na concentraçäo de 100 ppm

Flavonoids of nymphea hybrida tach.V.and biological evaluation

The chemistry of the flavonoids of Nymphaea hybrida Tach. V. is described for the first time. The flavonol aglycones quercetin and myricetin were isolated from the ether extract while, the flavonol glycosides quercetin 3-glucoside, quercetrin and myricetrin were isolated from the ethyl acetate extract. Physicochemical methods were applied to determine their structure. Isolated flavonol aglycones were tested for antimicrobial, anti-inflammatory, analgesic and ulcerogenic activities

Flavonoids of nelumbo nucifera gaertn and biological evaluation

The aerial parts of the Nelumbo nucifera Gaertn were found to contain quercetin, myricetin, kaempferol 3-0 glucoside, quercetin 3-0 glucoside and luteolin 7-0 glucoside reported for the first time. They were identified by physicochemical methods and direct comparison. The glycosidal flavonoids kaempferol 3-0 glucoside and luteolin 7-0 glucoside showed significant antimicrobial, anti-inflammatory and analgesic activities with no ulcerations

Actividad antioxidante de los flavonoides / Antioxidizer activity of the flavonoids

Los flavonoides son substancias de origen vegetal, ampliamente distribuidas en la naturaleza. Se sintetizan principalmente en las plantas superiores especialmente en las familias de las Poligonáceas, Rutáceas, Leguminosas, Umbelíferas y compuestas. En la actualidad se conocen más de 2000 de estos compuestos, que, generalmente, se encuentran glicosilados con uno o más azúcares unidos a los grupos hidroxilos de su estructura, o no, llamados en este caso agliconas. Los flavonoides contribuyen a dar color a numerosos vegetales y poseen, como característica estructural básica, un esqueleto carbonado C6-C3-C6, formando tres anillos de los cuales los de C6 son de tipo aromático. El núcleo central, por lo general, posee una estructura de tipo gama-pirona. Otra de las características es que la estructura básica del flavonoide puede tener modificaciones en pasos subsiguientes a su síntesis, tales como hidroxilaciones o reducciones adicionales, metilaciones, isoprenilaciones, metilenaciones, sulfonaciones y glicosilaciones (por unión de diversos azúcares) y dimerizaciones (para producir biflavonoides), dando múltiples variaciones. Por esta razón, se los califica como el grupo más numeroso de los heterósidos fenólicos naturales. Los flavonoides constituyen, en la actualidad, un campo de continuas investigaciones. Es muy probable que diversas plantas medicicnales cuyos principios activos son, hasta ahora, desconocidos, deban su acciónfarmacológica a los flavonoides. Desde los primeros informes acerca de la capacidad de los flavonoides para reducir la fragilidad capilar, hasta la fecha, se han descripto múltiples trabajos sobre diversas propiedades farmacológicas, principalmente acciones antiinflamatorias, antihepatotóxicas, sobre el sistema vascular central, antitumoral, antibacteriana y antiviral

Anti-anaphylactic and anti-inflammatory effects of ternatin, a flavonoid isolated from Egletes viscosa Less

Ternatin, a tetramethoxy flavone isolated from Egletes viscosa Less (Compositae), was tested for its efficacy in modulating mouse passive cutaneous anaphylaxis (PCA) and rat carrageenan-induced pleurisy. Ternatin (12.5, 25 and 50 mg/kg, ip) caused a dose-dependent inhibition of IgG antibody-mediated 1.5-h homologous PCA as well as IgE antibody-mediated 48-h homologous PCA in 2-month old mice (N = 5 per group). The inhibitory activity of ternatin was more potent on IgE-mediated PCA (47-79%) than on IgG (45-59%). In the rat carrageenan pleurisy test, ternatin (25 and 50 mg/kg, ip) reduced the response to carrageenan at 5 h both by decreasing exudate volume (33-40%) and leukocyte number (60%) in 5-6-month old rats (N = 6 per group). In contrast, indomethacin (2 mg/kg, po), a known cyclooxygenase inhibitor, showed greater potency in the inhibition of exudate volume (57%) and leukocyte number (77%). These results show that ternatin has both anti-inflammatory and anti-anaphylactic properties and suggest that it may be a useful alternative to anti-allergic drugs of the disodium cromoglycate (DSCG) type for use in bronchial asthma