ANTIOXIDANT AND ANTI-HEMOLITIC ACTIVITIES OF ALGERIAN NIGELLA SATIVA TOTAL OIL AND ITS NEUTRAL LIPID FRACTION

Objective: Nigella sativa (NS) oil is usually considered as oxidatively stable, the aim of this study is to evaluate its antioxidant capacity in vitro through four mechanisms. Methods: NS seed total oil (TO) was extracted with n-hexane and this oil was further fractionated into neutral lipid fraction (NLF) and polar lipid fraction. Total oil and its neutral lipid fraction were investigated for the antioxidant activity using the following spectrophotometric assays; DPPH and ABTS radicals scavenging tests, reducing power test, ß-carotene bleaching test and anti-hemolytic test. All tests were realized by spectrophotometric methods. Results: Quantitative determination of phenols and flavonoids in TO and NLF showed that TO has the highest phenolic and flavonoid concentrations with 26,44±0,21 µg GAE/g extract and 1.34±0.21 µg QAE/g extract respectively. All antioxidant assays showed that TO has the strongest antioxidant capacity with; IC50 83.023±4.58 µg/ml in DPPH scavenging assay, IC50 80.09±10.51 µg/ml in ABTS scavenging assay, EC50 85.93±20.01 µg/ml in reducing power assay and a percentage of inhibition 60.62 % in ß-carotene bleaching assay, equally, TO has the strongest anti-hemolytic activity with HT50 of 76.96±1.22 µg/ml. Conclusion: The results obtained in this investigation showed that Nigella sativa has an important antioxidant capacity, which makes it an attractive source of new therapeutic components

Effect of Thymoquinone as Prophylactic Treatment Against CCl4-Induced Hepatotoxicity on Antioxidants Status

Objective: The present study aims to study the effect of thymoquinone as prophylactic treatment against CCl4-induced hepatotoxicity on antioxidants status. Methodology: Hepatotoxicity was induced in rats by intraperitoneal administration of 3 ml/kg, 1:1 (V/V) mixture of CCl4 and olive oil after treatment for 7 days with TQ, using two doses. The method consists of studying the antioxidant effect of thymoquinone pretreatment by measuring superoxide dismutase (SOD) and catalase (CAT) activities, with reduced glutathione level in both plasma and liver homogenate. Results: The results revealed that hepatotoxicity is accompanied by significant decrease (p ≤ 0.01) of SOD and CAT activities with GSH level, in both plasma and liver homogenate. While prophylactic treatment using TQ at doses of 02.5 and 05 mg/kg increase significantly the status of the antioxidants, as dose dependent manner, in both plasma and liver homogenate.  Conclusion: The results of this study show that thymoquinone has an antioxidant effect when it used as prophylactic treatment against CCl4-induced hepatotoxicity. Keywords: Thymoquinone, hepatotoxicity, CCl4, prophylactic and antioxidant

PEffect of lipid extracts of Nigella sativa L. seeds on the liver ATP reduction and alpha-glucosidase inhibition

Various extracts from the seeds of Nigella sativa have been used in traditional folk medicine to treat inflammation, liver disorders and arthritis. These seeds have been experimentally shown to possess antioxidant and hepatoprotective properties. Beside the hypoglycaemic and hypolipidemic effects, this study was carried out to evaluate, in vitro, toxicological effect of lipid extracts from the Nigella sativa seeds. The tested fractions were: (i) defatted methanolic extract, (ii) total lipid extract obtained by hexane extraction from methanolic extract and (iii) neutral and polar lipid fractions. The fractions were assessed, in vitro, for their inhibitory activity potential on the enzyme alphaglucosidase as suppressing the enzyme activity is one among the therapeutic approaches to attenuate postprandial hyperglycemia. High inhibition of alpha-glucosidase by the two polar lipid fractions (F6 and F7) was reflected by their IC50 (0.51±0.04mg/ml and 0.55±0.09mg/ml, respectively), compared to acarbose (0.53±0.06mg/ml) and thymoquinone (0.65±0.05mg/ml). The hypoglycaemic effect of the polar lipid fraction of Nigella sativa could be explained by the inhibition of alpha-glucosidase, which is one of early steps of carbohydrate metabolism. Toxicological evaluation was investigated on precision-cut rat liver slices (PCLS). On PCLS, lipid extracts reduced ATP levels by 27 to 35%. Results indicate suggest that Nigella sativa extracts don't show a hepatoprotective effect against acetaminophen, but don't exhibit a major hepatotoxicity when tested alone.SCOPUS: ar.jinfo:eu-repo/semantics/publishe