The Potential Role of Curcumin in Modulating the Master Antioxidant Pathway in Diabetic Hypoxia-Induced Complications.

Oxidative stress is the leading player in the onset and development of various diseases. The Keap1-Nrf2 pathway is a pivotal antioxidant system that preserves the cells' redox balance. It decreases inflammation in which the nuclear trans-localization of Nrf2 as a transcription factor promotes various antioxidant responses in cells. Through some other directions and regulatory proteins, this pathway plays a fundamental role in preventing several diseases and reducing their complications. Regulation of the Nrf2 pathway occurs on transcriptional and post-transcriptional levels, and these regulations play a significant role in its activity. There is a subtle correlation between the Nrf2 pathway and the pivotal signaling pathways, including PI3 kinase/AKT/mTOR, NF-κB and HIF-1 factors. This demonstrates its role in the development of various diseases. Curcumin is a yellow polyphenolic compound from Curcuma longa with multiple bioactivities, including antioxidant, anti-inflammatory, anti-tumor, and anti-viral activities. Since hyperglycemia and increased reactive oxygen species (ROS) are the leading causes of common diabetic complications, reducing the generation of ROS can be a fundamental approach to dealing with these complications. Curcumin can be considered a potential treatment option by creating an efficient therapeutic to counteract ROS and reduce its detrimental effects. This review discusses Nrf2 pathway regulation at different levels and its correlation with other important pathways and proteins in the cell involved in the progression of diabetic complications and targeting these pathways by curcumin.

Crocin improved locomotor function and mechanical behavior in the rat model of contused spinal cord injury through decreasing calcitonin gene related peptide (CGRP).

Various approaches have been offered to alleviate chronic pain resulting from spinal cord injuries (SCIs). Application of herbs and natural products, with potentially lower adverse effects, to cure diseases has been recommended in both traditional and modern medicines. Here, the effect of crocin on chronic pain induced by spinal cord contusion was investigated in an animal model. Female Wistar rats were randomly divided into five groups (5 rats in each); three groups were contused at the L1 level. One group was treated with crocin (150mg/kg) two weeks after spinal cord injury; the second group, control, was treated with vehicle only; and the third group was treated with ketoprofen. Two normal groups were also considered with or without crocin treatment. The mechanical behavioral test, the locomotor recovery test and the thermal behavioral test were applied weekly to evaluate the injury and recovery of rats. Significant improvements (p<0.05) in mechanical behavioral and locomotor recovery tests were seen in the rats treated with crocin. Thermal behavioral test did not show any significant changes due to crocin treatment. Plasma concentration of calcitonin-gene related peptide (CGRP) changed from 780.2±2.3 to 1140.3±4.5pg/ml due to SCI and reached 789.1±2.7pg/ml after crocin treatment. These changes were significant at the level of p<0.05. The present study shows the beneficial effects of crocin treatment on chronic pain induced by SCI, through decreasing CGRP as an important mediator of inflammation and pain.

Methanolic extract of African mistletoe (Viscum album) improves carbohydrate metabolism and hyperlipidemia in streptozotocin-induced diabetic rats.

OBJECTIVE: To justify the use of African mistletoe (AM) Viscum album (V. album) in folkoric medicine to treat diabetes. METHODS: In one experiment, the fasting blood glucose (FBG) levels of diabetic rats were monitored for 4 h. Diabetic rats were treated with AM at doses of 50 mg/kg (AM1) and 100 mg/kg (AM2), glibenclamide (GB) (positive control) and saline solution (SS). In another experiment, diabetic rats were treated with AM2, GB and SS daily for 3 weeks. RESULTS: AM1 and AM2 elicited significant (P<0.05) hypoglycaemic effects within 4 h of extract administration. AM1 and AM2 decreased the FBG by 41% and 49%, respectively, at 2 h. AM2 was found to lower FBG by 51%, relative to baseline, which was comparable to GB at 3 h. In the second experiment, AM2 and GB significantly (P<0.05) decreased the FBG by 34% and 51%, respectively. This was followed by marked decrease in levels of HbA1C in AM2- and GB- treated diabetic rats. AM2 significantly (P<0.05) decreased the STZ-induced increase in levels of serum triglyceride, urea, lactate dehydrogenase, α-amylase and low-density lipoprotein-cholesterol. Furthermore, diabetic rats treated with AM2 had significantly (P<0.05) elevated high-density lipoprotein-cholesterol. In contrast, STZ administration produced insignificant (P<0.05) effect on the levels of serum creatinine and total bilirubin. CONCLUSIONS: Extract of African mistletoe has anti-diabetic and anti-hyperlipidemic effects in STZ-diabetic rats. AM may find clinical application in the amelioration of diabetes-induced lipid disorders.

Large scale screening of commonly used Iranian traditional medicinal plants against urease activity.

BACKGROUND AND PURPOSE OF THE STUDY: H. pylori infection is an important etiologic impetus usually leading to gastric disease and urease enzyme is the most crucial role is to protect the bacteria in the acidic environment of the stomach. Then urease inhibitors would increase sensitivity of the bacteria in acidic medium. METHODS: 137 Iranian traditional medicinal plants were examined against Jack bean urease activity by Berthelot reaction. Each herb was extracted using 50% aqueous methanol. The more effective extracts were further tested and their IC50 values were determined. RESULTS: 37 plants out of the 137 crude extracts revealed strong urease inhibitory activity (more than 70% inhibition against urease activity at 10 mg/ml concentration). Nine of the whole studied plants crude extracts were found as the most effective with IC50 values less than 500 µg/ml including; Rheum ribes, Sambucus ebulus, Pistachia lentiscus, Myrtus communis, Areca catechu, Citrus aurantifolia, Myristica fragrans, Cinnamomum zeylanicum and Nicotiana tabacum. CONCLUSIONS: The most potent urease inhibitory was observed for Sambucus ebulus and Rheum ribes extracts with IC50 values of 57 and 92 µg/ml, respectively.