RESUMO
The proteins derived from the latex (LP) of Calotropis procera are well known for their anti-inflammatory property. In view of their protective effect reported in the sepsis model, they were evaluated for their efficacy in maintaining coagulation homeostasis in sepsis. Intraperitoneal injection of LP markedly reduced the procoagulation and thrombocytopenia observed in mice infected with Salmonella; while in normal mice, LP produced a procoagulant effect. In order to understand its mechanism of action, the LP was subjected to ion-exchange chromatography, and the three subfractions (LPPI, LPPII, and LPPIII) thus obtained were tested for their proteolytic effect and thrombin- and plasmin-like activities in vitro. Of the three subfractions tested, LPPII and LPPIII exhibited proteolytic effect on azocasein and exhibited procoagulant effect on human plasma in a concentration-dependent manner. Like trypsin and plasmin, these subfractions produced both fibrinogenolytic and fibrinolytic effects that were mediated through the hydrolysis of the Aα, Bß, and γ chains of fibrinogen and α-polymer and γ-dimer of fibrin clot, respectively. This study shows that the cysteine proteases present in the latex of C. procera exhibit thrombin- and plasmin-like activities and suggests that these proteins have therapeutic potential in various conditions associated with coagulation abnormalities.
Assuntos
Calotropis , Cisteína Proteases/farmacologia , Proteínas de Plantas/farmacologia , Infecções por Salmonella/sangue , Sepse/sangue , Animais , Coagulação Sanguínea/efeitos dos fármacos , Cisteína Proteases/isolamento & purificação , Fibrinogênio/metabolismo , Hemostasia/efeitos dos fármacos , Humanos , Látex/química , Masculino , Camundongos , Tempo de Tromboplastina Parcial , Proteínas de Plantas/isolamento & purificação , Contagem de Plaquetas , Tempo de Protrombina , Salmonella typhimuriumRESUMO
AIM OF THE STUDY: The latex of Calotropis procera has been used in the traditional medicinal system for the treatment of leprosy, ulcers, tumors, piles and diseases of liver, spleen, abdomen and toothache. It comprises of a non-dialyzable protein fraction (LP) that exhibits anti-inflammatory properties and a dialyzable fraction (DF) exhibiting pro-inflammatory properties. The present study was carried out to evaluate the effect of LP sub-fractions on neutrophil functions and nociception in rodent models and to elucidate the mediatory role of nitric oxide (NO). MATERIAL AND METHODS: The LP was subjected to ion exchange chromatography and the effect of its three sub-fractions (LP(PI), LP(PII) and LP(PIII)) thus obtained was evaluated on leukocyte functions in the rat peritonitis model and on nociception in the mouse model. RESULTS: LP sub-fractions exhibit distinct protein profile and produce a significant decrease in the carrageenan and DF induced neutrophil influx and exhibit anti-nociceptive property. The LP and its sub-fractions produced a marked reduction in the number of rolling and adherent leukocytes in the mesenteric microvasculature as revealed by intravital microscopy. The anti-inflammatory effect of LP(PI), the most potent anti-inflammatory fraction of LP, was accompanied by an increase in the serum levels of NO. Further, our study shows that NO is also involved in the inhibitory effect of LP(PI) on neutrophil influx. CONCLUSIONS: Our study shows that LP fraction of Calotropis procera comprises of three distinct sets of proteins exhibiting anti-inflammatory and anti-nociceptive properties of which LP(PI) was most potent in inhibiting neutrophil functions and its effects are mediated through NO production.
Assuntos
Calotropis/química , Látex/farmacologia , Migração e Rolagem de Leucócitos/efeitos dos fármacos , Óxido Nítrico/imunologia , Peritonite/imunologia , Proteínas de Plantas/imunologia , Animais , Adesão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Masculino , Mesentério/irrigação sanguínea , Óxido Nítrico/sangue , Peritonite/induzido quimicamente , Ratos , Ratos WistarRESUMO
Cytotoxic properties of plant extracts and drugs being developed for cancer treatment are usually evaluated by a variety of in vivo and in vitro tests carried out in animal or plant based models. In the present study we have evaluated the possibility of using the germinating mung beans (Vigna radiata), for rapid and inexpensive screening of drugs exhibiting cytotoxic properties. Mung beans were allowed to germinate either in tap water or in different drug solutions, and parameters like percent germination, increase in radicle length, change in seedling weight and mitotic index of apical root meristems were determined at two time intervals coinciding with the time at which the radicle length in control group was 1.0 to 1.5 cm (time 0, T0) and 48 h later (T48). Methanol extract of Calotropis procera latex as well as drugs like podophyllotoxin, cyclophosphamide, cyproheptadine and aspirin produced a dose-dependent inhibitory effect on seed germination, seed weight gain, radicle growth and mitotic index in the radicle meristems. The inhibitory effect of some of the drugs tested was associated with reduction in water imbibition. Some of the drugs at higher concentrations allowed seed germination to take place but produced radicle decay and seedling weight loss. Our study shows that germinating V radiata beans could be used as a convenient model for the preliminary screening of drugs exhibiting cytotoxic properties.
Assuntos
Aspirina/farmacologia , Ciclofosfamida/farmacologia , Ciproeptadina/farmacologia , Citotoxinas/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Extratos Vegetais/farmacologia , Fabaceae , Fabaceae/fisiologia , Germinação , Germinação/fisiologia , Podofilotoxina/farmacologia , Sementes , Sementes/fisiologiaRESUMO
Cytotoxic properties of plant extracts and drugs being developed for cancer treatment are usually evaluated by a variety of in vivo and in vitro tests carried out in animal or plant based models. In the present study we have evaluated the possibility of using the germinating mung beans (Vigna radiata), for rapid and inexpensive screening of drugs exhibiting cytotoxic properties. Mung beans were allowed to germinate either in tap water or in different drug solutions, and parameters like percent germination, increase in radicle length, change in seedling weight and mitotic index of apical root meristems were determined at two time intervals coinciding with the time at which the radicle length in control group was 1.0 to 1.5 cm (time 0, T0) and 48 h later (T48). Methanol extract of Calotropis procera latex as well as drugs like podophyllotoxin, cyclophosphamide, cyproheptadine and aspirin produced a dose-dependent inhibitory effect on seed germination, seed weight gain, radicle growth and mitotic index in the radicle meristems. The inhibitory effect of some of the drugs tested was associated with reduction in water imbibition. Some of the drugs at higher concentrations allowed seed germination to take place but produced radicle decay and seedling weight loss. Our study shows that germinating V radiata beans could be used as a convenient model for the preliminary screening of drugs exhibiting cytotoxic properties.(AU)