Ameliorating efficacy of eugenol against metanil yellow induced toxicity in albino Wistar rats.

Metanil yellow, an azo dye, is a non-permitted synthetic food colour used extensively in India and other developing countries as food additive. Present communication reports the toxic effects of metanil yellow on hepatic and kidney tissues and its amelioration by eugenol, vitamin E and vitamin C. Oral administration of metanil yellow in albino Wistar rats for 28 days caused elevation in serum enzymes (glutamate oxaloacetate transaminase, gluatamate pyruvate transaminase, alkaline phosphatase), and total bilirubin along with decline in albumin and total protein levels. At tissue level, activities of oxidative stress markers viz., superoxide dismutase, catalase and reduced glutathione in liver and kidney were reduced to about half while malondialdehyde level increased significantly under the influence of metanil yellow. Co-administration of eugenol/vitamin E/vitamin C in metanil yellow intoxicated rats exhibited considerable restoration of oxidative stress as well as hepatic and renal function markers in serum and tissues. The study revealed that eugenol has antioxidant, hepatoprotective and renoprotective activities.

Renoprotective effect of cinnamaldehyde in food color induced toxicity.

Present study reports the effects of metanil yellow, a non-permitted food colouring dye, on the biomarkers of oxidative stress and kidney function in blood and renal tissue of albino Wistar rats and its mitigation by cinnamaldehyde, a major phytoconstituents of cinnamon. Oral administration of metanil yellow in rats caused about 70% reduction in ferric reducing ability (FRAP 5.1 µM/L) and 50% decline in reduced glutathione (GSH 59.27 nM/mg protein) content in plasma with simultaneous increase in serum creatinine level. In kidney tissues, activities of superoxide dismutase (SOD), catalase and GSH dropped while malondialdehyde (MDA) content increased. Co-administration of cinnamaldehyde with metanil yellow showed considerable restorative effect on the biomarkers of plasma antioxidant status and kidney function i.e., FRAP (11.5 µM/L), GSH (83-88.5 nM/mg protein), urea, creatinine, SOD, catalase and MDA. Administration of cinnamaldehyde restored the kidney enzyme activities up to 75% of the base level. The study revealed that reno-protective action of cinnamaldehyde was mediated by lowering oxidative stress level.

Medicinal attributes of major phenylpropanoids present in cinnamon.

BACKGROUND: Excessive production of free radicals has been implicated in many diseases including cancer. They are highly reactive and bring about oxidation of biomolecules i.e., proteins, lipids and nucleic acids which are associated with many degenerative diseases. Natural products acting as antioxidants have ability to neutralize free radicals and their actions and hence they mitigate their harmful effects. The present study was designed to investigate pharmacological properties viz., antioxidant, antibacterial and antiproliferative activities of cinnamaldehyde and eugenol, the two naturally occurring phenylpropanoids present in Cinnamomum spp. and other plants. METHODS: The antioxidant potential of test compounds was evaluated by measuring DPPH free radical scavenging, reducing power and metal ion chelating activities. Protection against membrane damage was assayed by inhibition of lipid peroxidation in rat liver homogenate. Antibacterial activity was measured by Kirby-Bauer disc diffusion method while antiproliferative activity of test compounds was measured by sulforhodamine-B (SRB) assay. RESULTS: Eugenol exhibited noticeable antioxidant potential in DPPH radical scavenging (81 %) and reducing power (1.12) assays at 1.0 µM/ml and 0.1 µM/ml concentrations, respectively. IC50 value of eugenol for radical scavenging activity was found to be 0.495 µM/ml. Cinnamaldehyde demonstrated considerable metal ion chelating ability (75 %) at 50 µM/ml and moderate lipo-protective activity in lipid peroxidation assay at 3 µM/ml. In addition cinnamaldehyde also showed appreciable antibacterial activity (zone of inhibition 32-42 mm) against Bacillus cereus (MTCC 6840), Streptococcus mutans (MTCC 497), Proteus vulgaris (MTCC 7299), Salmonella typhi (MTCC 3917) and Bordetella bronchiseptica (MTCC 6838) while eugenol produced moderate activity at 80 µM/disc. Cinnamaldehyde exhibited comparatively better antiproliferative potential against breast (T47D) and lung (NCI-H322) cancer cell lines than eugenol in SRB assay at 50 µM concentration. CONCLUSION: Cinnamaldehyde possessed metal ion chelating, lipo-protective, antibacterial and antiproliferative activities while eugenol showed potent H-atom donating potential indicating radical quenching and reducing power abilities. Medicinal attributes shown by both the compounds indicated their usefulness in food and pharmaceutical sector.