Drynaria quercifolia suppresses paracetamol­induced hepatotoxicity in mice by inducing Nrf-2.

Paracetamol is a popular and safe drug preferred by victims of pain or pyrexia; however, its overdose or abuse is a growing concern worldwide. Here the hepatoprotective effect of an ethnomedicinal plant Drynaria quercifolia against paracetamol­induced toxicity in murine model is demonstrated. This fern, native to tropical countries including the Northeast India, is used by local tribes to treat inflammatory conditions. Paracetamol 500 mg/kg body weight was orally administered on alternate days for a period of 21days to mimic a chronic overdose. Drynaria quercifolia acetone extract (DQA) treatment interspaced with paracetamol significantly decreased serum biomarkers of hepatotoxicity (ALT, AST and ALP) renal toxicity (urea, creatinine), lipid peroxidation level, histological damage in liver and kidney. The protein and mRNA expressions of the transcription factor, Nrf2, and its target antioxidant genes (SOD1, CAT and GST) as well as activities of these antioxidant enzymes were downregulated by paracetamol administration but significantly recovered following the DQA treatment (Tab. 3, Fig. 5, Ref. 31). Keywords: acetaminophen/paracetamol, Drynaria quercifolia, renal toxicity, hepatotoxicity, Nrf-2.

Ascorbic acid metabolism in diabetes mellitus.

In contrast to normal subjects diabetic patients and very low plasma ascorbic acid and significantly high (p less than 0.001) dehydroascorbic acid irrespective of age, sex, duration of the disease, type of treatment, and glycemic control. However, there was no significant difference between the mean leukocyte ascorbate concentrations of the two populations. The in vitro rates of dehydroascorbate reduction in the hemolysate and the erythrocyte reduced glutathione levels and the glucose-6-phosphate dehydrogenase activities, which regulate the dehydroascorbate reduction, were similar in normal and diabetic subjects. The turnover of ascorbic acid was higher in the diabetics than that in the normal volunteers. Experiments with diabetic rats indicated that the increased turnover of ascorbic acid was probably due to increased oxidation of ascorbate to dehydroascorbate in tissue mitochondria. Ascorbic acid supplementation at a dose of 500 mg per day for a brief period of 15 days resulted in an increase in the plasma ascorbate level temporarily, but it did not lower the blood glucose level of the diabetic patients.