Chronic Treatment with Nigella sativa Oil Exerts Antimanic Properties and Reduces Brain Inflammation in Rats.

Nigella sativa (NS) is a native herb consumed habitually in several countries worldwide, possessing manifold therapeutic properties. Among them, anti-inflammatory features have been reported, presumably relating to mechanisms involved in the nuclear factor kappa-B pathway, among others. Given the observed association between neuroimmune factors and mental illness, the primary aim of the present study was to examine the effects of chronic NS use on manic-like behavior in rats, as well as analyze levels of brain inflammatory mediators following NS intake. Using male and female rats, baseline tests were performed; thereafter, rats were fed either regular food (control) or NS-containing food (treatment) for four weeks. Following intervention, behavioral tests were induced (an open field test, sucrose consumption test, three-chamber sociality test, and amphetamine-induced hyperactivity test). Subsequently, brain samples were extracted, and inflammatory mediators were evaluated, including interleukin-6, leukotriene B4, prostaglandin E2, tumor necrosis factor-α, and nuclear phosphorylated-p65. Our findings show NS to result in a marked antimanic-like effect, in tandem with a positive modulation of select inflammatory mediators among male and female rats. The findings reinforce the proposed therapeutic advantages relating to NS ingestion.

Anti-Inflammatory Activity of Natural Products.

This article presents highlights of the published literature regarding the anti-inflammatory activities of natural products. Many review articles were published in this regard, however, most of them have presented this important issue from a regional, limited perspective. This paper summarizes the vast range of review and research articles that have reported on the anti-inflammatory effects of extracts and/or pure compounds derived from natural products. Moreover, this review pinpoints some interesting traditionally used medicinal plants that were not investigated yet.

Psychotropic drugs attenuate lipopolysaccharide-induced hypothermia by altering hypothalamic levels of inflammatory mediators in rats.

Recent evidence suggests that inflammation may contribute to the pathophysiology of mental disorders and that psychotropic drugs exert various effects on brain inflammation. The administration of bacterial endotoxin (lipopolysaccharide, LPS) to mammals is associated with robust production of inflammatory mediators and pathological changes in body temperature. The objective of the present study was to examine the effects of four different psychotropic drugs on LPS-induced hypothermia and production of prostaglandin (PG) E2, tumor necrosis factor (TNF)-α and phosphorylated-p65 (P-p65) levels in hypothalamus of LPS-treated rats. Rats were treated once daily with lithium (100mg/kg), carbamazepine (40mg/kg), haloperidol (2mg/kg), imipramine (20mg/kg) or vehicle (NaCl 0.9%) for 29 days. On day 29, rats were injected with LPS (1mg/kg) or saline. At 1.5h post LPS injection body temperature was measured, rats were sacrificed, blood was collected and their hypothalami were excised, homogenized and centrifuged. PGE2, TNF-α and nuclear P-p65 levels were determined by specific ELISA kits. We found that lithium, carbamazepine, haloperidol and imipramine significantly attenuated LPS-induced hypothermia, resembling the effect of classic anti-inflammatory drugs. Moreover, lithium, carbamazepine, haloperidol and imipramine differently but significantly affected the levels of PGE2, TNF-α and P-p65 in plasma and hypothalamus of LPS-treated rats. The results suggest that psychotropic drugs attenuate LPS-induced hypothermia by reducing hypothalamic production of inflammatory constituents, particularly PGE2. The effects of psychotropic drugs on brain inflammation may contribute to their therapeutic mechanism but also to their toxicological profile.

Glycogen synthase kinase-3 is required for optimal de novo synthesis of inositol.

Studies have shown that the inositol biosynthetic pathway and the enzyme glycogen synthase kinase-3 (GSK-3) are targets of the mood-stabilizing drugs lithium and valproate. However, a relationship between these targets has not been previously described. We hypothesized that GSK-3 may play a role in inositol synthesis, and that loss of GSK-3 may lead to inositol depletion, thus providing a mechanistic link between the two drug targets. Utilizing a yeast Saccharomyces cerevisiae gsk-3Delta quadruple-null mutant, in which all four genes encoding homologues of mammalian GSK-3 are disrupted, we tested the hypothesis that GSK-3 is required for de novo inositol biosynthesis. The gsk-3Delta mutant exhibited multiple features of inositol depletion, including defective growth in inositol-lacking medium, decreased intracellular inositol, increased INO1 and ITR1 expression, and decreased levels of phosphatidylinositol. Treatment of wild-type cells with a highly specific GSK-3 inhibitor led to a significant increase in INO1 expression. Supplementation with inositol alleviated the temperature sensitivity of gsk-3Delta. Activity of myo-inositol-3 phosphate synthase, the rate-limiting enzyme in inositol de novo biosynthesis, was decreased in gsk-3Delta. These results demonstrate for the first time that GSK-3 is required for optimal myo-inositol-3 phosphate synthase activity and de novo inositol biosynthesis, and that loss of GSK-3 activity causes inositol depletion.