nigellone and thymoquinone

NIGELLA SATIVA L. has many effects including those on the gastrointestinal tract and trachea and is, therefore, used in the Mediteranean area and in India/Pakistan. Our aim was to investigate the effect of two main constituents, nigellone and thymoquinone, on trachea (antispasmodic effect) and their influence on respiratory clearance. The effects on Ba (2+)-, carbachol- and leukotriene-induced trachea contractions and the transport of the fluorescence dye rhodamin B concerning ciliary action in the tracheal area were investigated using a microdialysis technique. Nigellone and high concentrations of thymoquinone had a concentration-dependent inhibitory effect on the trachea when being contracted by the depolarizing effect of Ba (2+). The trachea contractions induced by leukotriene-d (4) were inhibited by nigellone and by thymoquinone. The cholinergic system (stimulation by carbachol) was hardly involved. The rate of ciliary clearance (mucociliary transport) was slightly modified by a high thymoquinone concentration (153.0 vs. 505.0 sec/12 mm distance, respectively), and was highly increased by nigellone (217.5 vs. 505.0 sec/12 mm distance). In conclusion, this study provides evidence for an antispasmodic effect and an increase in mucociliary clearance for nigellone but not for thymoquinone. Altogether the data indicate that nigellone but not thymoquinone may be useful in treatment of different respiratory diseases.

Topics: Animals; Barium Compounds; Benzoquinones; Chlorides; Leukotriene D4; Mice; Mice, Inbred C57BL; Mucociliary Clearance; Muscle Contraction; Nigella sativa; Rats; Trachea

In the present study, Nigella sativa oil (NSO), nigellone (polythymoquinone) and derived thymoquinone were studied to evaluate their effect on the formation of 5-lipoxygenase (5-LO) products from polymorphonuclear leukocytes (PMNL).NSO produced a concentration dependent inhibition of 5-LO products and 5-hydroxy-eicosa-tetra-enoic acid (5-HETE) production with half maximal effects (IC(50)) at 25+/-1 micro g/ml, respectively 24+/-1 micro g/ml. Nigellone caused a concentration-related inhibition of 5-HETE production (IC(50): 11.9+/-0.3 micro g/ml). Moreover thymoquinone, the active principle of NSO inhibited the production of 5-LO products (IC(50): 0.26+/-0.02 micro g/ml) and 5-HETE production (IC(50): 0.36+/-0.02 micro g/ml) in a similar way. The effects are probably due to an antioxidative action. The data may in part explain the effect of the oil, its derived thymoquinone and nigellone in ameliorating inflammatory diseases.

Topics: Animals; Arachidonate 5-Lipoxygenase; Benzoquinones; Dose-Response Relationship, Drug; Lipoxygenase Inhibitors; Neutrophils; Plant Oils; Rats; Rats, Wistar; Seeds

A plant mixture containing extracts of Nigella sativa possesses blood glucose lowering effects, but the direct antidiabetic effect of Nigella sativa is not yet established. Therefore, the effect of Nigella sativa oil (NSO) on blood glucose concentrations was studied in streptozotocin diabetic rats. In addition, the effect of NSO, nigellone and thymoquinone were studied on insulin secretion of isolated rat pancreatic islets in the presence of 3, 5.6 or 11.1 mM glucose. NSO significantly lowered blood glucose concentrations in diabetic rats after 2, 4 and 6 weeks. The blood lowering effect of NSO was, however, not paralleled by a stimulation of insulin release in the presence of NSO, nigellone or thymoquinone. The data indicate that the hypoglycemic effect of NSO may be mediated by extrapancreatic actions rather than by stimulated insulin release.

Topics: Animals; Benzoquinones; Blood Glucose; Diabetes Mellitus, Experimental; Dose-Response Relationship, Drug; Female; Glucose; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Pancreas; Plant Oils; Rats; Rats, Wistar

The effects of thymol (TOH), thymoquinone (TQ) and dithymoquinone (TQ2) on the reactions generating reactive oxygen species (ROS) such as superoxide anion radical (O2*-), hydroxyl radical (HO*) and singlet oxygen (1O2) were tested using the chemiluminescence (CL) and spectrophotometry methods. All tested compounds acted as scavengers of various ROS. The rate constant of 1O2-dimols quenching by thymol was calculated.

Topics: Anti-Infective Agents; Antineoplastic Agents; Benzoquinones; Free Radicals; Luminescent Measurements; Reactive Oxygen Species; Spectrophotometry; Thymol