Nigella sativa thymoquinone-rich fraction greatly improves plasma antioxidant capacity and expression of antioxidant genes in hypercholesterolemic rats

Abstract

The antioxidant activities of the thymoquinone-rich fraction (TQRF) extracted from Nigella sativa and its bioactive compound, thymoquinone (TQ), in rats with induced hypercholesterolemia were investigated. Rats were fed a semipurified diet supplemented with 1% (w/w) cholesterol and were treated with TQRF and TQ at dosages ranging from 0.5 to 1.5 g/kg and 20 to 100 mg/kg body wt, respectively, for 8 weeks. The hydroxyl radical (OH(.))-scavenging activity of plasma samples collected from experimental rats was measured by electron spin resonance. The GenomeLab Genetic Analysis System was used to study the molecular mechanism that mediates the antioxidative properties of TQRF and TQ. Plasma total cholesterol and low-density-lipoprotein cholesterol levels were significantly decreased in the TQRF- and TQ-treated rats compared to untreated rats. Feeding rats a 1% cholesterol diet for 8 weeks resulted in a significant decrease in plasma antioxidant capacity, as measured by the capacity to scavenge hydroxyl radicals. However, rats treated with TQRF and TQ at various doses showed significant inhibitory activity toward the formation of OH(.) compared to untreated rats. Upon examination of liver RNA expression levels, treatment with TQRF and TQ caused the up-regulation of the superoxide dismutase 1 (SOD1), catalase, and glutathione peroxidase 2 (GPX) genes compared to untreated rats (P<0.05). In support of this, liver antioxidant enzyme levels, including SOD1 and GPX, were also apparently increased in the TQRF- and TQ-treated rats compared to untreated rats (P<0.05). In conclusion, TQRF and TQ effectively improved the plasma and liver antioxidant capacity and enhanced the expression of liver antioxidant genes of hypercholesterolemic rats.

Nigella sativa protects against formaldehyde-induced neurotoxicity in the rat frontal cortex

“…Moreover, the level of NO increased significantly in the frontal lobe of the NS and FA-treated group compared to FA-treated rats. This is in agreement with the study of Ismail et al [57] who reported that thymoquinone had an inhibitory effect on lipid peroxidation and markedly improved plasma antioxidant status by inhibiting formation of hydroxyl radicals.…”

Potentials of enhancing the physicochemical and functional characteristics of <em>Nigella sativa</em> oil by using the screw pressing technique for extraction

“…The importance of the volatile oil fraction in the suppression of oxidation of its parent crude oil is attributed to its content of thymoquinone (TQ). This volatile compound is known to possess a potent antioxidant activity (Ismail et al, 2009). The results in Table 2 indicate that the thymoquinone (TQ) percentage of the volatile oil isolated from the SPO was higher (68.13%) than that isolated from the HPO (56.29%).…”

Light, Salinity and Temperature Effects on the Seed Germination of Nigella Sativa L.

“…Other medical effects like: Antiasthmatic (M.H. Boskabady, et al 2010), protective toxicity (Ahmed M. Mohamadin et al 2010), plasma antioxidant capacity (Maznah Ismail et al 2010, Mahmoud et al, 2015, antifungal (Eugene A. Rogozhin et al 2010), anti-nephrotoxicity (İhsan and Engin 2010), antiallergic (Soheila et al 2010, retards the progression of atherosclerosis (Mohammad and Hedi, 2010) and many other diseases (G. Lupidi, et al 2010, Osama andSoliman, 2010) were cited.…”