Effects of a combined thymol and carvacrol application on rat kidney damage parameters after L-arginine application

Thymol and carvacrol are two frequently abundant volatile monoterpene phenols found as constituents of different, widely used medicinal plants mainly belonging to the Lamiaceae family. The two compounds were previously proven to possess a large number of pharmacological/toxicological activities, including the nephroprotective activity. The present study aims to evaluate the nephroprotective potential of the two mentioned monoterpenes in L-arginine-induced rat kidney damage model. The potentials of thymol and carvacrol to alleviate kidney impairment were investigated using a different serum (urea, creatinine, sodium, potassium) and homogenate (neutrophil gelatinase-associated lipocalin-NGAL) parameters that reflect kidney tissue damage. Significant rat kidney damage, increased serum urea, creatinine, sodium and potassium levels, as well as NGAL tissue activity, followed the application of L-arginine (3.5 g/kg). Thymol (10 mg/kg), carvacrol (10 mg/kg) or their combination (1:1, w/w, 10 mg/kg) application prior to L-arginine reduced the kidney tissue damage based on the determined values of the previously mentioned parameters. The activity of the combination of the two monoterpenes was found to be more pronounced than the activity of the individual ones at the same total dose. These differences were clearly visible in the urea and potassium serum levels and in the NGAL tissue activity obtained from the corresponding experimental groups. Such greater nephroprotective potential of the combination of the two compounds could be attributed to a possible synergistic effect of the two volatile phenols, since they were proven alone to both possess antioxidant, anti-inflammatory, immunomodulatory, anti-apoptotic, etc. activities

Effects of pH on the stability of cyanidin and cyanidin 3-O-β-glucopyranoside in aqueous solution

The colour variation, colour intensity and stability at various pH values (2.0, 4.0, 7.0 and 9.0) of cyanidin 3-O-β-glucopyranoside (Cy3Glc) and its aglycone cyanidin was investigated during a period of 8 hours storage at 25ºC. Our data showed that pH of aqueous solution had impact on spectroscopic profile of cyanidin and Cy3Glc. Beginning with the most acidic solutions, increasing the pH induce bathochromic shifts of absorbance maximum in the visible range for all examined pH values (with the exception pH 4.0 for cyanidin), while the presence of the 3-glucosidic substitution induce hypsochromic shift. Compared to cyanidin, Cy3Glc has higher colour intensity and higher stability in the whole pH range, except at pH 7.0. The 3-glucosidic substitution influences on the colour intensity of Cy3Glc in the alkaline region. After 8-hour incubation of Cy3Glc and cyanidin at pH 2.0 and 25 ºC, 99% of Cy3Glc and only 27% of cyanidin remained unchanged