Anti-diabetic effects of Cichorium intybus in streptozotocin-induced diabetic rats.

The present study was designed to investigate the hypoglycemic and hypolipidemic properties of an ethanolic extract of Cichorium intybus (CIE) which is widely used in India as a traditional treatment for diabetes mellitus. Male Sprague-Dawley rats aged 9 weeks (160-200 g) were administered with streptozotocin (STZ, 50mg/kg) intraperitoneally to induce experimental diabetes. The Cichorium intybus whole plant was exhaustively extracted with 80% ethanol, concentrated at 40 degrees C using a rotavapor and freeze dried to get powder. Hypoglycemic effects of CIE were observed in an oral glucose tolerance test (OGTT) in which, a dose of 125 mg of plant extract/kg body weight exhibited the most potent hypoglycemic effect. Moreover, daily administration of CIE (125 mg/kg) for 14 days to diabetic rats attenuated serum glucose by 20%, triglycerides by 91% and total cholesterol by 16%. However, there was no change in serum insulin levels, which ruled out the possibility that CIE induces insulin secretion from pancreatic beta-cells. In addition, hepatic glucose-6-phosphatase activity (Glc-6-Pase) was markedly reduced by CIE when compared to the control group. The reduction in the hepatic Glc-6-Pase activity could decrease hepatic glucose production, which in turn results in lower concentration of blood glucose in CIE-treated diabetic rats. In conclusion, our results support the traditional belief that Cichorium intybus could ameliorate diabetic state.

Antioxidants in Chinese herbal medicines: a biochemical perspective.

Recently, intense interest has focused on the antioxidant properties of natural products. In particular, Chinese herbal medicines (CHM) have become hot topics for life science researchers since many are reported to possess cardioprotective compounds, many of which remain to be identified. Indeed, the exact mechanisms by which CHM work remain unknown. Although many of these herbal remedies are undoubtedly efficacious, few have been scientifically investigated for their active chemical constituents and biological activities. We have previously reported higher activities of antioxidant defence enzymes such as superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferases in the liver of rats treated with the herb Salvia miltiorrhiza in a model of acute myocardial infarction. Using well established in vitro antioxidant assays employing 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and diphenyl-l-picrylhydrazyl (DPPH) we have shown that in addition to elevating endogenous antioxidant enzyme activity, Salvia miltiorrhiza and other CHM traditionally used for cardiovascular disorders (such as Rhizoma ligustici, Herba leonuri, Radix achyranthis bidentatae, and Camellia sinensis) contain potent antioxidant moieties in addition to their phenolic constituents. Furthermore, these novel non-phenolic components are effective inhibitors of oxidative reactions mediated by the inflammatory oxidants, peroxynitrite,hypochlorous acid and hydroxyl radical as well as iron-dependent lipid peroxidation. In this review, we discuss the various antioxidant properties of CHM in the context of their biochemical mechanisms.

Photoactivation of hypericin down-regulates glutathione S-transferase activity in nasopharyngeal cancer cells.

Photodynamic therapy (PDT) is a new modality of treatment for cancer. Hypericin is a photosensitizer, which is known to generate reactive oxygen species upon activation with light. We observed that photoactivated hypericin induces the generation of reactive oxygen intermediates in nasopharyngeal cancer (NPC) cells in vitro. There was also significant reduction of Glutathione S-transferase (GST) activity in HK1 and CNE-2 NPC cells and in tumor tissues from the NPC/HK1 murine tumor model by hypericin-mediated PDT. As antioxidants protect cells against phototoxicity, down-regulation of GST activity would potentiate the efficacy of hypericin-PDT treatment.

Evaluation of the hypoglycemic and anti-oxidant activities of Morinda officinalis in streptozotocin-induced diabetic rats.

AIM OF STUDY: The aim was to investigate the hypoglycemic and anti-oxidant activities of the dried roots of Morinda officinalis in streptozotocin-induced diabetic rats. METHODOLOGY: An ethanolic extract of the dried roots of Morinda officinalis and its three fractions (ethyl acetate, n-butanol and water) were obtained. We evaluated the hypoglycemic effects of three different single doses of the crude extract and its fractions in normal and diabetic rats for three hours after administration. Administration of the extract at 150 mg/kg twice daily for 10 days to the diabetic rats was also carried out. The effects of the 10-day treatment on the fasting serum glucose, insulin, total cholesterol, triglycerides, body weight, food intake, fluid intake, hepatic superoxide dismutase (SOD), catalase (CAT) activities, reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS) and renal TBARS levels were monitored. RESULTS: In the three-hour dose response study, the crude ethanolic extract reduced the fasting serum glucose levels of the diabetic rats significantly at 150 mg/kg but increased those of the normal rats significantly at 600 mg/kg only. The water fraction demonstrated a dose dependent hypoglycemic effect in the diabetic rats whereas the n-butanol fraction increased the fasting serum glucose levels of the diabetic rats significantly at 50 mg/kg only within three hours after administration. The 10-day oral administration of the extract reduced the fasting serum glucose, hepatic and renal TBARS level and significantly increased the hepatic SOD and CAT activities as well as GSH levels. CONCLUSION: The results indicate that the dried roots of Morinda officinalis possess hypoglycemic, hyperglycemic and anti-oxidant properties.