Curcumin protects against tartrazine-mediated oxidative stress and hepatotoxicity in male rats.

OBJECTIVE: Synthetic dyes have been reported to exert detrimental effects on the health of humans. This study evaluated the effects of a diet containing tartrazine (Tz) on rats which included: i) biochemical parameters including hepatic enzymes, kidney functions and profiles of lipids; ii) markers of oxidative stress in cells by measuring concentrations of malondialdehyde (MDA) and glutathione (GSH); iii) activities of selected, key hepatic antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx); iv) pathologies of liver. Also, protective effects of three doses of curcumin (CUR), a natural food coloring agent, on these parameters in rats that had been co-exposed to Tz. MATERIALS AND METHODS: Fifty Wistar male albino rats were randomly divided into five groups: Group I, control, where rats were fed a normal diet; Group II, rats were fed normal diets containing 7.5 mg Tz/kg diet, dry mass (dm); In Groups III, IV and V, rats were fed diets containing Tz plus 1.0, 2.0 or 4.0 g CUR/kg diet, dm, respectively. Whole blood was collected after 90 d of exposure, homogenates of liver were prepared and the above analyses were conducted. RESULTS: Exposure to Tz in the diet caused statistically significant (p<0.05) greater concentrations of lipids, hepatic enzymes, and kidney function parameters as well as the indicator of oxidative stress MDA. Alternatively, activities of several antioxidant enzymes (i.e. CAT, SOD and GPx) and concentration of the substrate GSH, an indicator of non-enzymatic antioxidant capability, were significantly (p<0.05) less than those in control rats not exposed to Tz. Tz caused various histopathological changes in livers of rats, which were characterized by hemorrhage and dilatation of the central vein and sinusoids, hepatocyte necrosis, intracellular vacuolization. Co-administration of 2.0 (Group IV) or 4.0 g CUR/kg diet (Group V) with Tz significantly mitigated effects on functions of liver and kidney and the profile of relative concentrations of lipids. CUR significantly (p<0.05), and almost completely, reversed effects on enzymatic and non-enzymatic antioxidant and indicators of oxidative stress about rats fed Tz (Group II) to values in control rats. However, co-administration of 1.0 g CUR with Tz (Group III) exhibited a negligible effect on those parameters. The results of this study suggest benefits of the use of CUR, as a promising natural food additive to counteract oxidative stress caused by dietary exposure to the synthetic dye Tz due to potent protective antioxidant activity. CONCLUSIONS: Blending some natural food additives, such as CUR with diets containing synthetic dyes, could moderate potential effects of these artificial dyes. Decreasing or removing toxins in food is an essential step for the amelioration of human health status and decreasing risk of onset or progression of degenerative diseases.

Isolation and distribution of mosquito-larvicidal cry genes in Bacillus thuringiensis strains native to Saudi Arabia.

A total of 157 environmental samples were collected from 11 ecological regions across Saudi Arabia to isolate native Bacillus thuringiensis (Bt) strains. Bt isolates (n=103) were recovered by the 50% (v/v) ethanol treatment method with Bt index range of 0.01 to 0.4. Most of Bt isolates showed spherical crystals (54%), while, irregular, bi-pyramidal, and spore-attached crystal constituted 27, 16 and 3% respectively. PCR analysis with eight general and specific dipteran primers of Cry and Cyt genes, revealed positive amplification for cry4 & cyt1, and cry4A, cry4B and cyt2, and cry 10 and cry 11 genes in 28%, 26%, 22%, and 25% of tested strains respectively; whereas cry2 gene was not detected except with the reference Bt kurstaki HD-1 strain. Bioassays against Aedes caspuis and Culex pipiens larvae indicated that 11 strains displayed better larvicidal activity compared with Bacillus thuringiensis H14 (Bti) reference (LC50 0.6 µg/ml) strain against Ae. caspuis, but only two strains (620A & 633R1, LC50 of 0.09 µg/ml & 0.064 µg/ml) that gave significant enhancement. Additionally, one strain (633R1) showed LC50 similar to that of Bti H14 (LC50 0.064 µg/ml) against Cx. pipiens. With the exception of cyt primers, sequenced DNA of all positive primers amplicons revealed 95 to 99% identity in GenBank with Bacillus thuringiensis subsp. israelensis plasmid pBtoxis and also correlated with its SDS-PAGE expressed protein profiles analysis. It is hoped that our wild bio-insecticide Bt strains can be explored in future in the control of mosquito-vector borne diseases in Saudi Arabia.