Journal
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY
Volume 19, Issue 5, Pages 431-436Publisher
TAYLOR & FRANCIS LTD
DOI: 10.1080/14756360400002072
Keywords
Nigella sativa; thymoquinone; 5-lipoxygenase; LTC4 synthase; LTA(4) hydrolase; anti-inflammatory
Ask authors/readers for more resources
Black cumin seed, Nigella sativa L., and its oils have traditionally been used for the treatment of asthma and other inflammatory diseases. Thymoquinone (TQ) has been proposed to be one of the major active components of the drug. Since leukotrienes (LTs) are important mediators in asthma and inflammatory processes, the effects of TQ on leukotriene formation were studied in human blood cells. TQ provoked a significant concentration-dependent inhibition of both LTC4 and LTB4 formation from endogenous substrate in human granulocyte suspensions with IC50 values of 1.8 and 2.3 muM, respectively, at 15 min. Major inhibitory effect was on the 5-lipoxygenase activity (IC50 3 muM) as evidenced by suppressed conversion of exogenous arachidonic acid into 5-hydroxy eicosatetraenoic acid (5HETE) in sonicated polymorphonuclear cell suspensions. In addition, TQ induced a significant inhibition of LTC4 synthase activity, with an IC50 of 10 muM, as judged by suppressed transformation of exogenous LTA(4) into LTC4. In contrast, the drug was without any inhibitory effect on LTA(4) hydrolase activity. When exogenous LTA(4) was added to intact or sonicated platelet suspensions preincubated with TQ, a similar inhibition of LTC4 synthase activity was observed as in human granulocyte suspensions. The unselective protein kinase inhibitor, staurosporine failed to prevent inhibition of LTC4 synthase activity induced by TQ. The findings demonstrate that TQ potently inhibits the formation of leukotrienes in human blood cells. The inhibitory effect was dose- and time-dependent and was exerted on both 5-lipoxygenase and LTC4 synthase activity.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available