Efficacy of 20-OH-ecdysone on hepatic key enzymes of carbohydrate metabolism in streptozotocin induced diabetic rats

Recent advances in identifying protein targets of bioactive natural products

Background

Natural products exhibit structural complexity, diversity, and historical therapeutic significance, boasting attractive functions and biological activities that have significantly influenced drug discovery endeavors. The identification of target proteins of active natural compounds is crucial for advancing novel drug innovation. Currently, methods for identifying targets of natural products can be categorized into labeling and label-free approaches based on whether the natural bioactive constituents are modified into active probes. In addition, there is a new avenue for rapidly exploring the targets of natural products based on their innate functions.

Aim

This review aimed to summarize recent advancements in both labeling and label-free approaches to the identification of targets for natural products, as well as the novel target identification method based on the natural functions of natural products.

Methods

We systematically collected relevant articles published in recent years from PubMed, Web of Science, and ScienceDirect, focusing on methods employed for identifying protein targets of bioactive natural products. Furthermore, we systematically summarized the principles, procedures, and successful cases, as well as the advantages and limitations of each method.

Results

Labeling methods allow for the direct labeling of target proteins and the exclusion of indirectly targeted proteins. However, these methods are not suitable for studying post-modified compounds with abolished activity, chemically challenging synthesis, or trace amounts of natural active compounds. Label-free methods can be employed to identify targets of any natural active compounds, including trace amounts and multicomponent mixtures, but their reliability is not as high as labeling methods. The structural complementarity between natural products and their innate receptors significantly increase the opportunities for finding more promising structural analogues of the natural products, and natural products may interact with several structural analogues of receptors in humans.

Conclusion

Each approach presents benefits and drawbacks. In practice, a combination of methods is employed to identify targets of natural products. And natural products' innate functions-based approach is a rapid and selective strategy for target identification. This review provides valuable references for future research in this field, offering insights into techniques and methodologies.

Innate functions of natural products: A promising path for the identification of novel therapeutics

In the course of evolution, living organisms have become well equipped with diverse natural products that serve important functions, including defence from biotic and abiotic stress, growth regulation, reproduction, metabolism, and epigenetic regulation. It seems to be the organism's ecological niche that influences the natural product's structural and functional diversity. Indeed, natural products constitute the nuts and bolts of molecular co-evolution and ecological relationships among different life forms. Since natural products in the form of specialized secondary metabolites exhibit biological functions via interactions with specific target proteins, they can provide a simultaneous glimpse of both new therapeutics and therapeutic targets in humans as well. In this review, we have discussed the innate role of natural products in the ecosystem and how this intrinsic role provides a futuristic opportunity to identify new drugs and therapeutic targets rapidly.

20-Hydroxyecdysone, from Plant Extracts to Clinical Use: Therapeutic Potential for the Treatment of Neuromuscular, Cardio-Metabolic and Respiratory Diseases

There is growing interest in the pharmaceutical and medical applications of 20-hydroxyecdysone (20E), a polyhydroxylated steroid which naturally occurs in low but very significant amounts in invertebrates, where it has hormonal roles, and in certain plant species, where it is believed to contribute to the deterrence of invertebrate predators. Studies in vivo and in vitro have revealed beneficial effects in mammals: anabolic, hypolipidemic, anti-diabetic, anti-inflammatory, hepatoprotective, etc. The possible mode of action in mammals has been determined recently, with the main mechanism involving the activation of the Mas1 receptor, a key component of the renin-angiotensin system, which would explain many of the pleiotropic effects observed in the different animal models. Processes have been developed to produce large amounts of pharmaceutical grade 20E, and regulatory preclinical studies have assessed its lack of toxicity. The effects of 20E have been evaluated in early stage clinical trials in healthy volunteers and in patients for the treatment of neuromuscular, cardio-metabolic or respiratory diseases. The prospects and limitations of developing 20E as a drug are discussed, including the requirement for a better evaluation of its safety and pharmacological profile and for developing a production process compliant with pharmaceutical standards.

High-carbohydrate diet-induced metabolic disorders in Gerbillus tarabuli (a new model of non-alcoholic fatty-liver disease). Protective effects of 20-hydroxyecdysone

The aim of our study was to reveal the effects of long-term consumption of a high-carbohydrate diet (HCD) on metabolic dysfunctions and histopathological liver alterations in Gerbillus tarabuli, as well as to assess the preventive effects of 20-hydroxyecdysone (20E) in the same animals. Contrary to control diet, HCD induces several metabolic disorders including increased adiposity, dyslipidemia, ectopic fat deposition in the liver, associated with higher levels of plasma AST and ALT. These gerbils showed enhanced oxidative stress with liver damages characteristic of steatohepatitis development. By contrast, adding 20E to HCD resulted in a dose-dependent reduction of all changes induced by HCD. In addition, the hepatoprotective effect of 20E was demonstrated by decreased plasma concentrations of AST, ALT and of hepatic malondialdehyde. Our results suggest that G. tarabuli represents a good model to study diet-induced metabolic disorders and hepatic dysfunctions. Moreover, they demonstrate the efficacy of 20E treatment to counteract the damaging effects of HCD.

20-Hydroxyecdysone ameliorates metabolic and cardiovascular dysfunction in high-fat-high-fructose-fed ovariectomized rats

Background

Ecdysteroids are polyhydroxylated steroids present in invertebrates and plants. 20-Hydroxyecdysone (20E) is the most common and the main biologically active compound of ecdysteroids. Previous studies have demonstrated anabolic and metabolic effects of 20E in mammals. However, it is unknown whether 20E has a positive effect on all aspects of cardiometabolic syndrome. The aims of this study were to investigate the favorable effect and possible underlying mechanisms of 20E in a rat model of cardiometabolic syndrome (CMS) induced by a high-calorie diet combined with female sex hormone deprivation.

Methods

20E (5 mg/kg, 10 mg/kg, or 20 mg/kg) or pioglitazone (PIO) (10 mg/kg) was intragastrically administered to sham-operated Sprague-Dawley female rats and ovariectomized rats fed a high-fat-high-fructose diet (OHFFD) for 8 weeks. The phenotypic characteristics of CMS, including central adiposity, blood pressure, serum lipid profile, glucose tolerance, insulin action on skeletal muscle glucose transport activity and hepatic protein expression, were determined.

Results

Some CMS characteristics were improved by 20E treatment. Rats treated with 20E had lower body weight, abdominal fat accumulation than rats treated with vehicle control without changes in total caloric intake and fat-free mass. OHFFD rats exhibited high blood pressure, but 20E-treated rats maintained normal blood pressure with a lower level of low-density lipoprotein (LDL)-cholesterol. Although 20E showed no positive effect on inducing insulin-mediated glucose transport in the skeletal muscle of OHFFD rats, 20E improved whole body glucose homeostasis. Analysis of protein expression in livers from 20E-treated rats revealed significantly increased expression of pAkt Ser⁴⁷³, pFOXO1 Ser²⁵⁶, pAMPKα Thr¹⁷², and FGF21.

Conclusion

20E treatment can alleviate cardiometabolic disorder caused by a high-fat-high-fructose diet and female sex hormone deprivation. In particular, 20E helps improve whole body insulin sensitivity in OHFFD rats, and the mechanisms that underlie this favorable effect are potentially mediated by the activation of AMPK and FGF21. The present study indicates that 20E could be an alternative therapeutic option for the prevention and alleviation of cardiometabolic syndrome.

Protective effects of Zygophyllum album extract against deltamethrin-induced hyperglycemia and hepato-pancreatic disorders in rats

The current study was designed to investigate the possible mechanism involved in hyperglycemia induced by chronic exposure to deltamethrin (DLM) in rat and to assess whether this damage is amenable to modulation by Zygophyllum album. DLM, a synthetic pyrethroid pesticide, was administrated at a dose of 4 mg/kg body mass, during 60 days. Compared with control, DLM showed a significant increase of blood glucose (p ≤ 0.01) and glycosylated hemoglobin levels (p ≤ 0.01) and a clear decrease (p ≤ 0.01) of insulin and total hemoglobin levels. In addition, hepatic glycogen content and the activity of hexokinase decreased (p ≤ 0.01), whereas the activities of glucose-6-phosphatase and glycogen phosphorylase were significantly increased (p ≤ 0.01). Moreover, pancreatic lipid peroxidation (TBARS level) was higher (p ≤ 0.01) and oxidative stress biomarkers (SOD, CAT, GPx, and GSH) were altered owing to DLM toxicity. However, Z. album, when combined with DLM, significantly ameliorated almost all the hepato-pancreatic disorders induced by DLM alone. Furthermore, Z. album supplement was found to be effective in preserving the normal histological appearance of hepatic and pancreatic tissue. In conclusion, this study suggested that, owing to its antioxidant effects, methanolic extract of Z. album (MEZAL) can potentially prevent the hyperglycemia observed in DLM-treated group.

Antidiabetic, antihyperlipidaemic, and antioxidant activity of Syzygium densiflorum fruits in streptozotocin and nicotinamide-induced diabetic rats

Context Syzygium densiflorum Wall. ex Wight & Arn (Myrtaceae) has been traditionally used by local tribes of the Nilgiris, Tamil Nadu, India, for the treatment of diabetes, however, no definitive experimental studies are available. Objective This study investigates the antidiabetic, antihyperlipidaemic and antioxidant activities of ethanol extract of S. densiflorum (EFSD) fruits in streptozotocin (STZ) and nicotinamide (NA)-induced diabetic rats. Materials and methods Acute oral toxicity and oral glucose tolerance were assessed in normal rats. The antidiabetic, antihyperlipidaemic and antioxidant activities were investigated in STZ - NA-induced diabetic rats. Diabetic rats were orally administered with glibenclamide (10 mg/kg b.wt), EFSD (200, 400 and 800 mg/kg b.wt) for 28 d. Further, changes in the blood glucose level (BGL), biochemical parameters, antioxidants were observed and histology of pancreas was performed. Results No toxicity and lethality were observed. Results of the following parameters are represented by treated versus disease control (STZ + NA) groups. BGL (161.33 ± 22.8 versus 476.17 ± 56.58 mg/dl), glycosylated haemoglobin (5.285 ± 0.19 versus 8.05 ± 0.55%), urea (40.32 ± 1.96 versus 75.37 ± 2.91 mg/dl), uric acid (1.2 ± 0.07 versus 2.16 ± 0.05 mg/dl), total cholesterol (89.3 ± 5.14 versus 139.7 ± 5.95 mg/dl) and triglycerides (79.65 ± 2.52 versus 108.9 ± 3.61 mg/dl) were significantly decreased, whereas haemoglobin (11.75 ± 0.73 versus 7.95 ± 0.42 g/dl), high-density lipoprotein cholesterol (14.2 ± 1.11 versus 6.97 ± 0.84 mg/dl), total protein (45%) and liver glycogen (87%) were significantly increased in EFSD-treated diabetic group. Significant changes were observed in the enzymatic and non-enzymatic antioxidants in EFSD-treated groups (p < 0.001). Histopathological examination showed the regeneration of β-cells in Islets of Langerhans. Conclusion This study confirms the antidiabetic, antihyperlipidaemic and antioxidant activities of S. densiflorum fruits.

Tyrosol, a phenolic compound, ameliorates hyperglycemia by regulating key enzymes of carbohydrate metabolism in streptozotocin induced diabetic rats

The present study was designed to evaluate the effects of tyrosol, a phenolic compound, on the activities of key enzymes of carbohydrate metabolism in the control and streptozotocin-induced diabetic rats. Diabetes mellitus was induced in rats by a single intraperitoneal injection of streptozotocin (40 mg/kg body weight). Experimental rats were administered tyrosol 1 ml intra gastrically at the doses of 5, 10 and 20mg/kg body weight and glibenclamide 1 ml at a dose of 600 μg/kg body weight once a day for 45 days. At the end of the experimental period, diabetic control rats exhibited significant (p<0.05) increase in plasma glucose, glycosylated hemoglobin with significant (p<0.05) decrease in plasma insulin, total hemoglobin and body weight. The activities of key enzymes of carbohydrate metabolism such as phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase and glucose-6-phosphatase were significantly (p<0.05) increased and the activities of hexokinase and glucose-6-phosphate dehydrogenase were significantly (p<0.05) decreased in the liver and kidney of diabetic control rats. Further, antioxidants were lowered in diabetic control rats. A significant (p<0.05) decline in glycogen level in the liver and muscle and glycogen synthase activity in the liver and a significant (p<0.05) increase in the activity of liver glycogen phosphorylase were observed in diabetic control rats compared to normal control rats. Oral administration of tyrosol to diabetic rats reversed all the above mentioned biochemical parameters to near normal in a dose dependent manner. Tyrosol at a dose of 20mg/kg body weight showed the highest significant effect than the other two doses. Immunohistochemical staining of pancreas revealed that tyrosol treated diabetic rats showed increased insulin immunoreactive β-cells, which confirmed the biochemical findings. The observed results were compared with glibenclamide, a standard oral hypoglycemic drug. The results of the present study suggest that tyrosol decreases hyperglycemia, by its antioxidant effect.

Effects of N-adamantyl-4-methylthiazol-2-amine on hyperglycemia, hyperlipidemia and oxidative stress in streptozotocin-induced diabetic rats

Thiazole derivatives are attractive candidates for drug development because they can be efficiently synthesized and are active against a number of diseases and conditions, including diabetes. In our present study, we investigated the anti-inflammatory and antioxidant properties of N-adamantyl-4-methylthiazol-2-amine (KHG26693), a new thiazole derivative, in a streptozotocin (STZ)-induced model of diabetes mellitus. STZ-induced diabetic rats were intraperitoneally administered KHG26693 (3mg/kg-body weight/day) for 4 weeks. KHG26693 administration significantly decreased blood glucose, triglycerides, and cholesterol and increased insulin. KHG26693 also suppressed several inflammatory responses in STZ-induced diabetic rats, as evidenced by decreased levels of serum tumor necrosis factor-α, interleukin-1β, and nitric oxide. Additionally, KHG26693 significantly modulated hepatic lipid peroxidation, catalase and superoxide dismutase activity, and the nonenzymatic antioxidant status (e.g., vitamins C and E), and reduced the glutathione content. These anti-inflammatory/antioxidative actions occurred as a result of the downregulation of inducible nitric oxide synthase and nuclear factor-kappa B. Taken together, our results suggest that KHG26693 successfully reduces the production of oxidative stress in STZ-induced diabetic rats by regulating the oxidation-reduction system, specifically increasing antioxidant capacity. Furthermore, KHG26693 treatment significantly reverted the key enzymes of glucose metabolism, such as glucokinase, glucose-6-phosphatase, glycogen synthase, glycogen phosphorylase, and fructose-1,6-bisphosphatase, to near-normal levels in liver tissues. These results indicate that KHG26693 normalizes disturbed glucose metabolism by enhancing glucose utilization and decreasing liver glucose production via insulin release, suggesting the possibility of future diabetes treatments.

Protective role of 20-OH ecdysone on lipid profile and tissue fatty acid changes in streptozotocin induced diabetic rats

Hyperlipidemia is an associated complication of diabetes mellitus. The association of hyperglycemia with an alteration of lipid parameters presents a major risk for cardiovascular complications in diabetes. The present study was designed to examine the antihyperlipidemic effect of 20-OH ecdysone on lipid profile and tissue fatty acid changes in streptozotocin induced diabetic rats. The levels of blood glucose, cholesterol, triglycerides, free fatty acids, phospholipids, low density lipoprotein, very low density lipoprotein, high density lipoprotein, lipoprotein lipase, lecithin cholesterol acyl transferase, 3-hydroxy 3-methylglutaryl coenzyme A reductase and fatty acid composition were estimated in plasma, liver and kidneys of control and experimental groups of rats. Oral administration of 20-OH ecdysone at a dose of 5mg/kg bodyweight per day to STZ-induced diabetic rats for a period of 30 days resulted in a significant reduction in fasting blood glucose, cholesterol, triglycerides, free fatty acids, phospholipids, low density lipoprotein, very low density lipoprotein, 3-hydroxy 3-methylglutaryl coenzyme A reductase and elevation of high density lipoprotein, lipoprotein lipase and lecithin cholesterol acyl transferasein comparison with diabetic untreated rats. Moreover, administration of 20-OH ecdysone to diabetic rats also decreased the concentrations of fatty acids, viz., palmitic, stearic (16:1) and oleic acid (18:1), whereas linolenic (18:3) and arachidonic acid (20:4) were elevated. The antihyperlipidemic effect of 20-OH ecdysone was compared with glibenclamide a well-known antihyperglycemic drug. The result of the present study indicates that 20-OH ecdysone showed an antihyperlipidemic effect in addition to its antidiabetic effect in experimental diabetes.