Therapeutic effects of Teucrium polium extract on oxidative stress in pancreas of streptozotocin-induced diabetic rats.

Increased oxidative stress is a widely accepted factor in the development and progression of diabetes and its complications. In this study, we evaluated the antioxidative potential of Teucrium polium (Family Lamiaceae) aqueous extract for protecting rat pancreatic tissue against streptozotocin (STZ)-induced oxidative stress. Diabetes was induced in rats by intraperitoneal injections of at a single dose of STZ at 40 mg/kg. The crude extract (equivalent to 0.5 g of plant powder/kg of body weight) was administered orally (intragastrically) to a group of STZ diabetic rats for 30 consecutive days. Changes in antioxidant status were evaluated by determining catalase (CAT) and superoxide dismutase (SOD) activities and the level of reduced glutathione (GSH) in pancreatic tissue. In addition, serum nitric oxide (NO) concentration, pancreatic tissue malondialdehyde (MDA) (an index of lipid peroxidation) level, and reliable markers of protein oxidation such as protein carbonyl content (PCO) and advanced oxidation protein products (AOPP) were also determined. Under diabetic conditions, blood glucose level, serum NO concentration, and pancreatic MDA, PCO, and AOPP levels were all increased. The diabetic rats also exhibited pancreatic GSH depletion along with significant reductions in activities of CAT and SOD. Rats treated with T. polium extract had significantly higher GSH levels along with enhanced CAT and SOD activities in pancreatic tissue. In addition to suppressed blood glucose levels, serum NO, pancreatic MDA, PCO, and AOPP levels were all lower than in the diabetic group. Our results strongly support the proposal that antioxidative activity of T. polium occurs by quenching the extent of lipid and protein oxidation. Based on these observations, it is concluded that T. polium may have protective effect(s) on pancreatic tissue in STZ-induced oxidative stress due to its high antioxidative potential.

In vitro antioxidant and free radical scavenging activity of Cyperus rotundus.

Cyperus rotundus (Family Cyperaceae) is used both as a functional food and as a drug. In this study, the antioxidative potential of a hydroalcoholic extract of C. rotundus (CRE) was evaluated by various antioxidant assays, including antioxidant capacity by the phosphomolybdenum method, total antioxidant activity in linoleic acid emulsion systems, 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, hydroxyl radicals, and nitric oxide (NO) scavenging. We further evaluated the reducing potential of the extract as well as Fe(2+)/ascorbate-induced lipid peroxidation in rat liver homogenate. These various antioxidant activities were compared to standard antioxidants such as butylated hydroxytoluene, tocopherol, L-ascorbic acid, and catechin. Total phenolic and flavonoid content of CRE was also determined by a colorimetric method. The extract exhibited high reduction capability and powerful free radical scavenging, especially against DPPH and superoxide anions as well as a moderate effect on NO. CRE also showed inhibited lipid peroxidation in rat liver homogenate induced by Fe(2+)/ascorbate and prevented deoxyribose degradation in both non-site-specific and site-specific assays showing the hydroxyl radical scavenging and metal chelating activity of the hydroalcoholic extract. Moreover, the peroxidation inhibiting activity of CRE was demonstrated in the linoleic acid emulsion system. These results clearly established the antioxidative potency of C. rotundus, which may account for some of the medical claims attributed to this plant.