Abdelfattah Elfeki

Hypoglycemic and antioxidant effects of phenolic extracts and purified hydroxytyrosol from olive mill waste in vitro and in rats.

This study aimed to evaluate the effect of phenolic extract and purified hydroxytyrosol (HT) from olive mill waste (OMW) on oxidative stress and hyperglycemia in alloxan-induced diabetic rats. The OMW biophenols were extracted using ethyl acetate. The obtained extract was fractionated by solid phase extraction (SPE) experimentation to generate two fractions: (F1) and (F2). HPLC-UV and HPLC-MS analysis showed that (F1) was made of known OMW monomeric phenolics mainly hydroxytyrosol (HT) while (F2) contained oligomeric and polymeric phenols such as verbascosid and ligstrosid. (HT) was purified from (F1) using silica gel-column chromatography and silica gel-TLC techniques. In incubated pancreas, supplementation of OMW fractions enhanced insulin secretion. The administration of OMW extract fractions (F1) and (F2) as well as purified (HT) in diabetic rats caused a decrease in glucose level in plasma and an increase in renal superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities in liver and kidney. Furthermore, a protective action against hepatic and renal toxicity in diabetic rats was clearly observed. Furthermore, a significant decrease in hepatic and renal indices toxicity was observed, i.e. alkalines phosphatases (ALP), aspartate and lactate transaminases (AST and ALT) activities and the thiobarbituric acid-reactive substances (TBARs), total and direct bilirubin, creatinine and urea levels. In addition, (F1), (F2) and especially (HT) decreased triglycerides (TG), total-cholesterol (T-Ch) and higher HDL-cholesterol (HDL-Ch) in serum. These beneficial effects of OMW biophenols were confirmed by histological findings in hepatic, renal and pancreatic tissues of diabetic rats. This study demonstrates for the first time that OMW polyphenols and especially (HT) are efficient in inhibiting hyperglycemia and oxidative stress induced by diabetes and suggests that administration of HT may be helpful in the prevention of diabetic complications associated with oxidative stress.

Protective effect of date palm fruit extract (Phoenix dactylifera L.) on dimethoate induced-oxidative stress in rat liver

Nowadays, peoples exposure to chemical compounds such as organophosphorus insecticides is continuously on the rise more and more. Theses compounds have induced an excessive production of free radicals which are responsible for several cell alterations in the organism. Recent investigations have proved the crucial role of nutritional antioxidants to prevent the damage caused by toxic compounds. In this study, we investigate the role of date palm fruit extract (Phoenix dactylifera L.) in protection against oxidative damage and hepatotoxicity induced by subchronic exposure to dimethoate (20mg/kg/day). Oral administration of dimethoate caused hepatotoxicity as monitored by the increase in the levels of hepatic markers enzymes (transaminases, alkaline phosphatase, gamma-glutamyl transferase and lactate dehydrogenase), as well as in hepatic malondialdehyde thus causing drastic alteration in antioxidant defence system. Particularly, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were found increased by dimethoate while catalase (CAT) activity was reduced significantly. These biochemical alterations were accompanied by histological changes marked by appearance of vacuolization, necrosis, congestion, inflammation, and enlargement of sinusoids in liver section. Pretreatment with date palm fruit extract restored the liver damage induced by dimethoate, as revealed by inhibition of hepatic lipid peroxidation, amelioration of SOD, GPx and CAT activities and improvement of histopathology changes. The present findings indicate that in vivo date palm fruit may be useful for the prevention of oxidative stress induced hepatotoxicity.

Combined vitamins (C and E) and insulin improve oxidative stress and pancreatic and hepatic injury in alloxan diabetic rats

The aim of the present study is to determine if a combination of vitamins (C and E) has any advantage over insulin therapy on lipid peroxidation, antioxidant activity, liver dysfunction parameters, and histological changes in the alloxan-induced diabetic rats. The enzymatic activities of glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT) and the lipid peroxidation product, thiobarbituric acid-reacting substances (TBARS) were measured in liver and pancreas as indicators of antioxidation in these tissues. The liver dysfunction parameters: the activity of lactate dehydrogenase (LDH), gamma glutamyl transferase (GGT), phosphatase alkalines (PAL), aspartate and lactate transaminase (AST and ALT) were measured in serum. In diabetic rats, the TBARS contents of the liver and pancreatic tissues were found to have significantly increased as compared to non-diabetic rats (P < 0.001). The SOD, CAT, and GPX activities in the liver and pancreas in diabetic rats significantly decreased as compared to normal rats (P < 0.001). AST, ALT, LDH, GGT, and PAL activities increased in the diabetic rats (p > 0.05). In diabetic rats treated with insulin or with combined vitamins (C and E), an ameliorative effect was observed. This amelioration was more pronounced in the group of rats treated with combined vitamins (C and E).

Hyperglycaemia, stress oxidant, liver dysfunction and histological changes in diabetic male rat pancreas and liver : Protective effect of 17β-estradiol

Oxidative stress is thought to play a crucial role in the pathogenesis of chronic diabetic complications. We investigated the protective effects of 17 beta-estradiol (E2) on alloxan-induced stress oxidant, hepatic dysfunction and histological changes in male rats liver and pancreas. Our results showed that 17 beta-estradiol could attenuate the increase of blood glucose in plasma and normalise the hepatic glycogen level. In addition, E2 enhanced superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) (by 207, 52 and 72%, respectively, as compared to diabetic rats), reduced lipid peroxidation in the hepatic tissue (by 54%) and improved the liver dysfunction parameters by the significant decrease of gamma-glytamyl transferase (GGT), phosphatases alkalines (PAL), lactate deshydrogenase (LDH) and aspartate and lactate transaminases (AST and ALT) activities which increased in diabetic rats. Moreover, 17 beta-estradiol treatment in diabetic rats protects against alloxan-induced pancreatic beta-cells and hepatic cells damages.

Hypoglycemic and antilipidemic properties of kombucha tea in alloxan-induced diabetic rats.

BackgroundDiabetes has become a serious health problem and a major risk factor associated with troublesome health complications, such as metabolism disorders and liver-kidney dysfunctions. The inadequacies associated with conventional medicines have led to a determined search for alternative natural therapeutic agents. The present study aimed to investigate and compare the hypoglycemic and antilipidemic effects of kombucha and black tea, two natural drinks commonly consumed around the world, in surviving diabetic rats.MethodsAlloxan diabetic rats were orally supplied with kombucha and black tea at a dose of 5 mL/kg body weight per day for 30 days, fasted overnight, and sacrificed on the 31st day of the experiment. Their bloods were collected and submitted to various biochemical measurements, including blood glucose, cholesterol, triglcerides, urea, creatinine, transaminases, transpeptidase, lipase, and amylase activities. Their pancreases were isolated and processed to measure lipase and α-amylase activities and to perform histological analysis.ResultsThe findings revealed that, compared to black tea, kombucha tea was a better inhibitor of α-amylase and lipase activities in the plasma and pancreas and a better suppressor of increased blood glucose levels. Interestingly, kombucha was noted to induce a marked delay in the absorption of LDL-cholesterol and triglycerides and a significant increase in HDL-cholesterol. Histological analyses also showed that it exerted an ameliorative action on the pancreases and efficiently protected the liver-kidney functions of diabetic rats, evidenced by significant decreases in aspartate transaminase, alanine transaminase, and gamma-glytamyl transpeptidase activities in the plasma, as well as in the creatinine and urea contents.ConclusionsThe findings revealed that kombucha tea administration induced attractive curative effects on diabetic rats, particularly in terms of liver-kidney functions. Kombucha tea can, therefore, be considered as a potential strong candidate for future application as a functional supplement for the treatment and prevention of diabetes.

Protective effects of estrogens and caloric restriction during aging on various rat testis parameters.

AIM To investigate the effects of 17beta-estradiol (E2), Peganum harmala extract (PHE) and caloric restriction (CR) on various testis parameters during aging. METHODS Twelve month-old male rats were treated for 6 months with either E2 or PHE, or submitted to CR (40%). RESULTS Our results show that estrogens and CR are able to protect the male gonad by preventing the decrease of testosterone and E2 levels as well as the decrease of aromatase and estrogen receptor gene expressions. Indeed, E2, PHE and CR treatments induced an increase in the superoxide dismutase activities and decreased the activity of testicular enzymes: gamma-glutamyl transferase, alkaline phosphatase, lactate deshydrogenase as well as the aspartate and lactate transaminases in aged animals. In addition, the testicular catalase and gluthatione peroxidase activities were enhanced in E2, PHE and CR-treated rats compared to untreated animals at 18 months of age. Moreover, the positive effects of estradiol, PHE and CR were further supported by a lower level of lipid peroxidation. Recovery of spermatogenesis was recorded in treated rats. CONCLUSION Besides a low caloric diet which is beneficial for spermatogenesis, a protective antioxydant role of estrogens is suggested. Estrogens delay testicular cell damage, which leads to functional senescence and, therefore, estrogens are helpful in protecting the reproductive functions from the adverse effects exerted by reactive oxygen species (ROS) produced in large quantities in the aged testis.

Therapeutic effects of soy isoflavones on α-amylase activity, insulin deficiency, liver–kidney function and metabolic disorders in diabetic rats

Natural estrogens have demonstrated a wide variety of biological activities, which makes them a good candidate for the treatment of diabetes. In vitro, this study evidenced that isoflavones enhanced insulin secretion and inhibited α-amylase activity. In vivo, the findings indicated that soy isoflavones stimulated insulin secretion, increased the hepatic glycogen content and suppressed blood glucose level. The soy isoflavones were also protected hepatic-kidney functions showed by the significant increase in superoxide dismutase, catalase and glutathione peroxidase activities and the decrease in thiobarbituric acid reactive substances, total bilirubin, creatinine and transaminases content. Moreover, soy isoflavones induced a decrease in LDL-cholesterol and triglycerides and an increase in HDL-cholesterol in plasma and liver. Overall, the findings of the current study indicate that soy isoflavones exhibit attractive properties and can, therefore, be considered a promising candidate for future application as alternative therapeutic agents, particularly in the development of anti-diabetic and hypolipidaemic drugs.

Inhibition of Key Digestive Enzymes Related to Diabetes and Hyperlipidemia and Protection of Liver-Kidney Functions by Trigonelline in Diabetic Rats

Diabetes is a serious health problem and a source of risk for numerous severe complications such as obesity and hypertension. Treatment of diabetes and its related diseases can be achieved by inhibiting key digestive enzymes related to starch and lipid digestion. The findings revealed that the administration of trigonelline to surviving diabetic rats helped to protect the pancreas β-cells from death and damage. Additionally, the supplement of trigonelline to surviving diabetic rats significantly decreased intestinal α-amylase and maltase by 36 and 52%, respectively, which led to a significant decrease in the blood glucose rate by 46%. Moreover, the administration of trigonelline to surviving diabetic rats potentially inhibited key enzymes of lipid metabolism and absorption such as lipase activity in the small intestine by 56%, which led to a notable decrease in serum triglyceride (TG) and total cholesterol (TC) rates and an increase in the HDL cholesterol level. This treatment also improved glucose, maltase, starch, and lipid oral tolerance. Trigonelline was also observed to protect the liver-kidney functions efficiently, which was evidenced by the significant decrease in the serum aspartate transaminase (AST), alanine transaminase (ALT), gamma-glutamyl transpeptidase (GGT), and lactate dehydrogenase (LDH) activities and creatinine, albumin, and urea rates. The histological analysis of the pancreas, liver, and kidney tissues further established the positive effect of trigonelline. Overall, the findings presented in this study demonstrate that the administration of trigonelline to diabetic rats can make it a potentially strong candidate for industrial application as a pharmacological agent for the treatment of hyperglycemia, hyperlipidemia, and liver-kidney dysfunctions.

Potential protective effect on key steroidogenesis and metabolic enzymes and sperm abnormalities by fenugreek steroids in testis and epididymis of surviving diabetic rats

The current study showed that the daily oral treatment of fenugreek steroids, designated F(steroids), to diabetic rats during 30 days demonstrated a significant (p < 0.05) decrease of blood glucose level and a considerable increase of the area of insulin-immunoreactive β-cells in diabetic rats. Interestingly, this study showed that F(steroids) potentially unregulated the key steroidogenesis enzymes such as 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase), malic enzyme, 3β-hydroxysteroid dehydrogenase (3β-HSD) and glucose-6-phosphate dehydrogenase (G6P-DH) activities as cholesterol rate in testis, which considerably enhanced testosterone and estradiol levels in the plasma of surviving diabetic rats. More interestingly, F(steroids) obviously prevented the alteration of the key carbohydrate enzymes such as hexokinase and pyruvate kinase activities as well as testicular glycogen and seminal fructose contents in surviving diabetic rats. Furthermore, F(steroids) administration to surviving diabetic rats significantly decreased the sperm shape abnormality and improved the sperm count. Above all, the potential protective action of reproductive systems was approved by the histological study of testis and epididymis.

Experimental diabetes treated with trigonelline: effect on key enzymes related to diabetes and hypertension, β-cell and liver function

Type 2 diabetes is quite diverse, including the improvement of insulin sensitivity by dipeptidylpeptidase-4 (DPP-4) inhibitor, α-glucosidase inhibitors, and the protection of β-cells islet. The aim of this study was to search the effect of trigonelline (Trig) on DPP-4, α-glucosidase and angiotensin converting enzyme (ACE) activities as well as β-cells architecture, and starch and glucose tolerance test. In surviving diabetic rats, the supplement of Trig potentially inhibited DPP-4 and α-glucosidase activities in both plasma and small intestine. The pancreas islet and less β-cells damage were observed after the administration of trig to diabetic rats. The increase of GLP-1 in surviving diabetic rats suppressed the increase of blood glucose level and improved results in the oral glucose and starch tolerance test. Trig also normalized key enzyme related to hypertension as ACE and improved the hemoglobin A1c and lipid profiles (plasma triglyceride, HDL-cholesterol, LDL-cholesterol, and total cholesterol), and liver indices toxicity. Therefore, these results revealed that Trig was successful in improving glycemic control, metabolic parameters, and liver function in diabetic rats. It is therefore suggested that Trig may be a potential agent for the treatment of type 2 diabetes.