Antidiabetic effect of flavonoids from Malus toringoides (Rehd.) Hughes leaves in diabetic mice and rats

Malus toringoides (Rehd.) Hughes decoction alleviates isoproterenol-induced cardiac fibrosis by inhibiting cardiomyocyte inflammation and pyroptosis via the HK1/NLRP3 signaling pathway

Malus toringoides (Rehd.) Hughes, called "Eseye (Ese)," is a traditional medicinal plant from the Tibet province of China that has proven effective in treating cardiac conditions due to its anti-inflammatory, antioxidative, and antiapoptotic properties. In this study, we explored the underlying protective mechanisms of Ese decoction in isoproterenol (ISO)-induced cardiac fibrosis (CF) and established the fact that treatment with an Ese decoction attenuated tissue injury, decreased the release of IL-1β, IL-18, TNF-α, and caspase-3, and elevated the Bax/Bcl-2 ratio in CF mice. We also found that with Ese treatment damage to the mitochondrial ultrastructure of myocardium was alleviated, and the level of reactive oxygen species was markedly diminished. Ese inhibited the expression of proteins associated with pyroptosis by the HK1/NLRP3 signaling pathway and also improved CF. Due to the anti-inflammatory, antioxidative, and antiapoptotic characteristics of Ese decoction, we found that Ese protected against ISO-induced CF, by inhibiting inflammation and pyroptosis as mediated by the HK1/NLRP3 signaling pathway.

Sodium alginate/polyvinyl alcohol nanofibers loaded with Shikonin for diabetic wound healing: In vivo and in vitro evaluation

Diabetic wounds are typically chronic wounds and the healing process is limited by problems such as high blood glucose levels, bacterial infections, and other issues that make wound healing difficult. Designing drug-loaded wound dressings is an effective way to promote diabetic wound healing. In this study, we developed an SA/PVA nanofiber (SPS) containing Shikonin (SK) for the treatment of diabetic wounds. The prepared nanofibers were uniform in diameter, had good hydrophilicity and high water vapor permeability, and effectively promoted gas exchange between the wound site and the outside world. The results of in vitro experiments showed that SPS was effective in antimicrobial, antioxidant, and biocompatible. In vivo tests showed that the wound healing rate of mice treated with SPS reached 85.5 %. Immunohistochemical staining results showed that SPS was involved in the diabetic wound healing process through the up-regulation of growth factors (CD31, HIF-1α) and the down-regulation of inflammatory factors (CD68). Western blotting experiments showed that SPS attenuated the inflammation through the inhibition of the IκBα/NF-κB signaling pathway. These results suggest that SPS is a promising candidate for future clinical application of chronic wound dressings.

E Se tea extract ameliorates CCl4 induced liver fibrosis via regulating Nrf2/NF-κB/TGF-β1/Smad pathway

BACKGROUND

Liver fibrosis is a crucial progress to deteriorate liver disease. E Se tea (ES) is an ethnic herbal tea in China that has various biological activities for human beings. However, the traditional application on the treatment of liver disease is not studied.

PURPOSE

This study is firstly performed to explore the chemical constituents of ES extract together with its anti-hepatic fibrosis effect and potential mechanism on CCl₄ treated mice.

STUDY DESIGN AND METHODS

The chemical constituents of ethanol-aqueous extract from ES (ESE) were analyzed by UPLC-ESI-MS/MS. The anti-hepatic fibrosis effect of ESE was determined by measuring ALT and AST activities, antioxidative indexes, inflammatory cytokines and collagen protein levels on CCl₄ treated mice. Moreover, H&E, Masson staining and immunohistochemical analysis were performed for evaluating the protective effect of ESE on histopathological changes of liver tissues.

RESULTS

UHPLCHRESI-MS/MS analysis showed that the ESE was rich in flavonoids such as phlorizin, phloretin, quercetin and hyperoside. ESE could significantly reduce the plasma AST and ALT activities. The cytokines (IL-6, TNF-α, IL-1β) expressions were inhibited after ESE administration via suppressing NF-κB pathway. In addition, ESE could decrease MDA accumulation for alleviating CCl₄ induced liver oxidative stress via regulating Nrf2 pathway to promote the expressions of antioxidant enzymes (SOD, HO-1, CAT and NQO1). Moreover, ESE could inhibit the expressions of TGF-β1, Smad2, α-SMA, and collagens Ⅰ and III proteins, thereby effectively alleviate the liver fibrosis.

CONCLUSION

This study demonstrated that ESE could alleviate liver fibrosis through enhancing antioxidant and anti-inflammatory abilities by Nrf2/NF-κB pathway and reducing deposition of liver fibrosis via suppressing TGF-β/Smad pathway.

Malus toringoides (Rehd.) Hughes Ameliorates Nonalcoholic Fatty Liver Disease with Diabetes via Downregulation of SREBP-1c and the NF-κB Pathway In Vivo and In Vitro

Diabetic patients are more prone to developing nonalcoholic fatty liver disease (NAFLD) compared with healthy people. As a plant homologous to both medicine and food, Malus toringoides (Rehd.) Hughes has been used as an intervention for both NAFLD and diabetes. However, the effect and mechanism of M. toringoides on NAFLD on type 2 diabetes mellitus (T2DM) is unclear. The current investigation was designed to evaluate the ameliorative effects and mechanism of M. toringoides ethanol extract (CBTM-E375) on T2DM, and to identify the compounds in these extracts. The effects of CBTM-E375 on T2DM were verified using a high-fat diet-/streptozotocin-induced diabetic rat and free fatty acid (0.5 mM)-induced human hepatocellular carcinoma cell (HepG2) models. The components of CBTM-E375 were identified by high performance liquid chromatography-mass spectrometry/mass spectrometry. Our results demonstrate that CBTM-E375 ameliorated lipid accumulation (total cholesterol, triglyceride), oxidative stress (superoxide dismutase, catalase, malondialdehyde, glutathione peroxidase), and inflammation (tumor necrosis factor-α [TNF-α], interleukin [IL]-1β, IL-6, C-reactive protein [CRP]) in vivo and in vitro, these effects were associated with a CBTM-E375-mediated downregulation of SREBP-1c (sterol regulatory element binding protein 1c) and the NF-κB (nuclear factor κB) signaling pathway. A total of 20 chemical compounds were identified in CBTM-E375, including phlorizin, isoquercitrin, chlorogenic acid, quercetin, naringenin, and trigonelline, which have been reported to have positive effects on diabetes or on NAFLD.

A novel family of small molecule HIF-1 alpha stabilizers for the treatment of diabetic wounds; an integrated in silico, in vitro, and in vivo strategy

Hypoxia-inducible factor-1 alpha (HIF-1α) is a crucial regulator of wound healing, which includes epithelialization, angiogenesis, granulation, tissue development, and wound contraction. Even though diabetic wounds are hypoxic, HIF-1α levels are decreased during healing. Diabetic wound healing necessitates the modulation of hypoxia-induced responses by VHL-HIF-1α protein-protein inhibition. Our proposed hypothesis is to increase HIF-1α levels by inhibiting VHL and HIF-1α interactions by novel small bioactive molecules, accelerating diabetic wound healing. A three features (two aromatic rings and one hydrogen bond acceptor) pharmacophore hypothesis was generated from the existing HIF-1α modulators. Virtual screening was done based on the generated pharmacophore, and a library consisting of the top 20 out of 3728 compounds was selected using ZINCPharmer. Of the top 20 molecules, the pyrazole moiety was identified as the top "HIT". Five analogues of pyrazole were designed, and Scifinder ascertained the novelty. The designed compounds were synthesized and characterized by IR, Mass, and NMR. Preliminarily, we have carried out a scratch wound assay using 3T3L1 cell lines. All the synthesized compounds showed significant wound healing activity. Further, to validate the in vitro assay, the compound CI, which showed effective in vitro results was used for in vivo study. Using the diabetes mouse model, comprising streptozotocin-induced (STZ) diabetic mice and scratch wound assay, we demonstrated that inhibiting the VHL and HIF-1α connection is a promising strategy for treating diabetic ulcers. Molecules CI and CP were found to have substantial in silico, in vitro, and in vivo outcomes.

Vascular Protective Effects of Malus toringoides (Rehd.) Hughes Extracts and their Mechanism in Diabetic Rats and HUVECs

Malus toringoides (Rehd.) Hughes (Rosaceae) is used as a traditional folk medicine in the Tibet autonomous region of China to treat hypertension, hyperglycemia, and hyperlipidemia. However, few modern pharmacological data on the use of this plant against diabetic syndrome are available. In this study, we examined the vascular protection provided by a 70% ethanol extract of M. toringoides (EMT) in human umbilical vein endothelial cells (HUVECs) grown in high-glucose medium and in a high-fat diet/streptozotocin-induced rat diabetes model. EMT significantly suppressed the expression of cell adhesion molecules in both HUVECs and diabetic rats. EMT also inhibited activation of the CX3CL1/CX3CR1 axis and the nuclear factor kappa B (NF-κB) signaling pathway in vivo and in vitro. The results provide a significant information on the vasoprotective properties of M. toringoides that may contribute to the development and application of related herbal medicines.

Chemical characterization of the antioxidant and α-glucosidase inhibitory active fraction of Malus transitoria leaves

Chinese Tibetan tea made from the tender leaves of Malus transitoria is a widely consumed health drink, but there are few reports on its chemical composition and biological activity. In this study, we found that a 50% ethanol extract of M. transitoria had good antioxidant and α-glucosidase inhibitory activities in vitro. Guided by in vitro bioassays, chromatographic separation and purification were conducted, and the most active fraction in M. transitoria was determined. UPLC-Orbitrap-MS/MS was used to further quickly and comprehensively characterize the chemical composition. Library searches, MS/MS fragmentation patterns of two isolated reference compounds, and bibliography were used to annotate 81 compounds, of which 2 were new compounds, and 79 were identified from M. transitoria for the first time. This study provides a scientific basis for the development of antioxidant and anti-diabetic functional foods from M. transitoria.

E Se tea alleviates acetaminophen-induced liver injury by activating the Nrf2 signaling pathway

E Se tea is a traditional herbal tea used in the prevention of liver diseases. However, the hepatoprotective effect of E Se tea has not been investigated. This study aimed to determine the protective effect of E Se tea on acetaminophen (APAP)-induced acute liver injury and its potential mechanism. Hot water extracts and aqueous-ethanol extracts of E Se tea were obtained, which were analyzed to determine the chemical constituents of the tea. Phlorizin and phloretin were found to be the dominant chemical compounds. Histopathological analysis showed that E Se tea extract inhibited APAP-induced inflammatory infiltration, necrosis, and cellular vacuolization of hepatocytes in the liver tissue. The E Se tea extract could significantly ameliorate liver injury, inhibit an inflammatory response, and reduce oxidative stress. Western blot analysis revealed that E Se tea extract upregulated the expressions of nuclear Nrf2, HO-1 and NQO1 proteins and downregulated the expressions of cytoplasmic Nrf2 and Keap1 proteins in the hepatocyte. qPCR results showed that E Se tea extract also increased the expression of antioxidant genes (SOD2, Gpx1, GCLC and GCLM). These findings exhibited that E Se tea, enriched in dihydrochalcones, can be used to effectively prevent and manage liver dysfunction.

Malus toringoides (Rehd.) Hughes improves glucose and lipid metabolism and liver injury in high fructose-induced mice

Malus toringoides (Rehd.) Hughes, as a traditional medicinal and edible plant used in Tibet, China, is used to treat hypertension, hyperlipidemia, and liver diseases. In recent decades, excessive fructose intake with diet has greatly increased the occurrence of a series of metabolic diseases including obesity, insulin resistance, hypertension, and hyperlipidemia. The present study was designed to investigate the effects of an ethanol extract of M. toringoides (EMT) on glucose and lipid metabolism and liver injury in high fructose-induced mice. The C57BL/6J male mice were orally administrated with 30% fructose solution for 8 weeks, and EMT was given orally for another 8 weeks. The level of liver lipids related parameters, hepatic oxidative stress, and inflammatory mediators was detected by the kits. The improving effects of EMT on liver injury and lipid accumulation of mice were observed by hematoxylin and eosin staining and Oil Red O staining. In vitro, the hypolipidemic effect of EMT on palmitic acid-induced HepG2 cells was detected by the kits and Oil Red O staining. Our results showed that EMT has the hypolipidemic effect in vivo and in vitro, and can improve liver injury caused by fructose intake though ameliorating oxidative stress and inflammatory responses. Thus, we suggested that EMT may be a candidate therapeutic agent to improve a series of metabolic diseases including obesity, insulin resistance, and hyperlipidemia. PRACTICAL APPLICATIONS: Our study was aimed to find a novel candidate drug for liver diseases using natural products. We assessed the protective effects of Malus toringoides (Rehd.) Hughes in the pathogenesis of glucose and lipid metabolism. In vivo, the plant significantly improved the disorder of blood lipid and blood glucose, and liver injury in mice induced by fructose, and in vitro, this plant significantly improved the lipid accumulation of HepG2 cells induced by palmitic acid. To sum up, our studies suggested that the plant may be beneficial in the prevention and management of diet-induced abnormal glucose and lipid metabolism and liver diseases. Therefore, it will be a candidate therapeutic agent to improve liver diseases.

Flavonoids, alkaloids and terpenoids: a new hope for the treatment of diabetes mellitus

Diabetes mellitus is a metabolic syndrome characterized by a hyperglycemic state and multi-organ failure. Millions of people worldwide are suffering from this deadly disease taking a hit on their pocket and mental health in the name of its treatment. Modern medical practices with new technological advancements and discoveries have made revolutionary changes in the treatment. But, unfortunately, Glucose-lowering drugs used have many accompanying effects such as chronic vascular disease, renal malfunction, liver disease and, many skin problems. These complications have made us think about alternative treatments for diabetes with minimum or no side effects. Nowadays, in addition to modern medicine, herbal treatment has been suggested to treat diabetes mellitus. These herbal medicines contain biological macromolecules such as flavonoids, Terpenoids, glycosides, and alkaloids, which show versatile anti-diabetic effects. These phytochemicals are generally considered safe, and naturally occurring compounds have a potential role in preventing or controlling diabetes mellitus. The underlying mechanism of their anti-diabetic effects includes improvement in insulin secretion, decrease in insulin resistance, enhanced liver glycogen synthesis, antioxidant and anti-inflammatory activities. In this review, we have focused on the mechanism of various phytochemicals targeting hyperglycemia and its underlying pathogenesis.

Safety evaluation and hypolipidemic effect of aqueous-ethanol and hot-water extracts from E Se tea in rats

E Se tea, processed by the fresh leaves of Malus toringoides (Rehd.) Hughes, is a traditional herbal tea with various human benefits. The present study was aimed to evaluate the toxicity and hypolipidemic effect of aqueous-ethanol extract (EE) and hot-water extract (WE) from E Se tea. Eight main chemical constituents in EE and WE were respectively identified and quantified by UHPLC-HRMS/MS. EE is rich in TPC and TFC, while WE had higher TPS content. Both EE and WE exhibited strong antioxidant activity with no significant difference. The acute toxicity study revealed that the LD₅₀ values were higher than 5000 mg/kg, while both WE and EE had no significant adverse effect in rats by subacute toxicity assay. However, the triglyceride (TG) content in experiment groups (male) and highest doses groups (female) significantly decreased. Furthermore, the hypolipidemic effect of WE and EE were performed on high fat diet induced hyperlipidemic rats. The result exhibited that either WE or EE could effectively regulate lipid droplet accumulation in liver, and reduce the adipocyte size. These results demonstrated that these two extracts from E Se tea could be regarded as a potential functional dietary supplement in preventing and treating diet induced metabolic diseases.

The optimization of ultrasonic-microwave assisted synergistic extraction of Lotus plumule extract rich in flavonoids and its hypoglycemic activity

Lotus (Nelumbo nucifera Gaertn), a kind of perennial aquatic plant, is widely cultivated and consumed by people in Asian countries. Lotus plumule flavonoids (LPF) have been recognized as a hypoglycemic agent. LPF was optimally obtained using novel ultrasonic-microwave assisted synergistic extraction (UMSE) method by response surface methodology (RSM) on the basis of the results of single-factor experiments. Furthermore, the hypoglycemic activity of LPF was investigated by measuring the body weight, fasting blood glucose (FBG) level, and oral glucose tolerance test (OGTT) and analyzing the physiological indexes in streptozotocin-diabetic mice model. The optimum extraction conditions consisted of microwave power 355 W, ultrasonic power 423 W, extraction time 15 min, solid-liquid ratio 1:40, ultrasound/interval time 1/0, and ethanol concentration 70% with the maximum LPF yield of 2.62%. LPF supplementation significantly decreased the body weight, FBG, OGTT, serum total cholesterol (TC), serum total triglycerides (TG), and insulin levels, indicating the antidiabetic activity of LPF. This research verified that the UMSE technique was highly efficient to extract LPF to the maximum extent and the flavonoids from L. plumule exhibited hypoglycemic activity, which showed broad development and application prospects.

A small molecule HIF-1α stabilizer that accelerates diabetic wound healing

Impaired wound healing and ulcer complications are a leading cause of death in diabetic patients. In this study, we report the design and synthesis of a cyclometalated iridium(III) metal complex 1a as a stabilizer of hypoxia-inducible factor-1α (HIF-1α). In vitro biophysical and cellular analyses demonstrate that this compound binds to Von Hippel-Lindau (VHL) and inhibits the VHL-HIF-1α interaction. Furthermore, the compound accumulates HIF-1α levels in cellulo and activates HIF-1α mediated gene expression, including VEGF, GLUT1, and EPO. In in vivo mouse models, the compound significantly accelerates wound closure in both normal and diabetic mice, with a greater effect being observed in the diabetic group. We also demonstrate that HIF-1α driven genes related to wound healing (i.e. HSP-90, VEGFR-1, SDF-1, SCF, and Tie-2) are increased in the wound tissue of 1a-treated diabetic mice (including, db/db, HFD/STZ and STZ models). Our study demonstrates a small molecule stabilizer of HIF-1α as a promising therapeutic agent for wound healing, and, more importantly, validates the feasibility of treating diabetic wounds by blocking the VHL and HIF-1α interaction.

Mangosteen Concentrate Drink Supplementation Promotes Antioxidant Status and Lactate Clearance in Rats after Exercise

High-strength or long-duration exercise can lead to significant fatigue, oxidative stress, and muscle damage. The purpose of this study was to examine the effect of mangosteen concentrate drink (MCD) supplementation on antioxidant capacity and lactate clearance in rats after running exercise. Forty rats were divided into five groups: N, non-treatment; C, control; or supplemented with MCD, including M1, M5, and M10 (0.9, 4.5, and 9 mL/day) for 6 weeks. The rats were subjected to 30 min running and exhaustive-running tests using a treadmill. The blood lactate; triglyceride; cholesterol and glucose levels; hepatic and muscular malonaldehyde (MDA) levels; and antioxidant enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT), were analyzed. The results of this study demonstrated that MCD supplementation can increase GPx and CAT activities, alleviate oxidative stress in muscle, and increase lactate clearance, and is thereby beneficial to reduced muscle fatigue after exercise.

UHPLC-ESI-HRMS/MS analysis on phenolic compositions of different E Se tea extracts and their antioxidant and cytoprotective activities

E Se tea, prepared from the leaves of Malus toringoides (Rehd.) Hughes, is a traditional beverage, but there is little known about its chemical substances. This paper is aimed to investigate the chemical composition, antioxidant, and cytoprotective activities of the extract and fractions from E Se tea. Sixteen compounds were characterized by UHPLC-ESI-HRMS/MS. Phloridzin was the main compound, especially in ethyl acetate fraction (EAF). Moreover, EAF had the highest total phenolic and flavonoid contents with 197.54 ± 7.52 mg gallic acid equivalents/g extract and 85.94 ± 5.39 mg rutin equivalents/g extract, respectively, and exhibited the strongest antioxidant capacity (DPPH: IC₅₀ = 54.91 ± 3.38 μg/mL; ABTS: IC₅₀ = 98.08 ± 6.92 μg/mL). Different fractions of E Se tea, especially EAF, significantly inhibited intracellular ROS generation, reduced cell apoptosis, and decreased oxidative stress damage in H₂O₂-induced HepG-2 cells. Therefore, the obtained results highlight that E Se tea is a promising source for functional beverage or nutritional foods.

Protective Effect of Benzoquinone Isolated from the Roots of Averrhoa carambola L. on Streptozotocin-Induced Diabetic Mice by Inhibiting the TLR4/NF-κB Signaling Pathway

BACKGROUND

Studies have demonstrated that the roots of Averrhoa carambola L. (Oxalidaceae), a traditional Chinese medicine, can be used to treat diabetes and diabetes-related diseases. Nevertheless, the potential beneficial effects and mechanism of benzoquinone isolated from the roots of Averrhoa carambola L. (BACR) on diabetes remain unclear.

METHODS

Diabetic Kunming mice were injected with STZ (120 mgkg^-1) in the tail vein. Fasting blood glucose (FBG) and the change of body weight were measured after oral administration of BACR (120, 60, 30 mg/kg/d) every week. The levels of the total cholesterol (TC), triglyceride (TG), free fatty acids (FFA), glucosylated hemoglobin (GHb), fasting insulin (FINS), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured. The histological examination of pancreatic tissues and the TLR4/NF-κB pathway was analyzed by RT-PCR, immunohistochemistry and Western blot.

RESULTS

The study found that clearly the BACR obviously reduced the blood glucose, serum lipids, GHb and FINS. In addition, BACR treatment markedly reduced the release of inflammatory factors, including IL-6 and TNF-α, and down-regulated the expression of the TLR4/NF-κB pathway.

CONCLUSION

BACR has potential benefits for the treatment of diabetes by ameliorating metabolic functions and attenuating the inflammatory response via inhibition of the activation of theTLR4/NF-κB pathway.

Optimization of Ultrasound-Assisted Extraction on Antioxidative Activity of Malus toringoides Using Response Surface Methodology

Ultrasonic-assisted extraction (UAE) was optimized using response surface methodology (RSM) to maintain the cyto-protective activity of M.toringoides against oxidative stress. The optimal conditions for UAE were a 58 mL/g liquid-solid ratio, a 38 °C extraction temperature, an 85% solvent concentration, and a 19-min extraction time, which resulted in a protection rate of 54.57% against hydrogen peroxide-induced oxidative stress in human umbilical vein endothelial cells (HUVECs). These results were comparable to the predicted value of 53.75%. The extracts showed excellent antioxidant activity, and phlorizin was detected in the dried leaves of Malus.toringoides. The highest yield of phlorizin (101.239 mg/g) was also obtained using these conditions. Taken together, these results showed that the method successfully integrated RSM and partial least squares regression methods to optimize M.toringoides extraction to yield the highest cyto-protective activity and effectively increase the yield of phlorizin from M.toringoides.

Systematic Chemical Analysis Approach Reveals Superior Antioxidant Capacity via the Synergistic Effect of Flavonoid Compounds in Red Vegetative Tissues

The flavonoid system comprises an abundance of compounds with multiple functions; however, their potential synergism in antioxidant function remains unclear. We established an approach using ever-red (RL) and ever-green leaves (GL) of crabapple cultivars during their development to determine interrelationships among flavonoid compounds. RL scored significantly better than GL in terms of the type, composition, and diversity of flavonoids than GL. Principal component analysis predicted flavonoids in RL to have positive interaction effects, and the total antioxidant capacity was significantly higher than the sum of antioxidant capacities of the individual compounds. This synergy was verified by the high antioxidant capacity in rat serum after feeding on red leaves. Our findings suggest that the synergistic effect is a result of the high transcription levels regulated by McMYBs in RL. In summary, individual flavonoids cooperate in a flavonoid system, thus producing a synergistic antioxidant effect, and the approach used herein can provide insights into the roles of flavonoids and other compounds in future studies.

Influence of Flavonoids on Mechanism of Modulation of Insulin Secretion

BACKGROUND

The development of alternatives for insulin secretion control in vivo or in vitro represents an important aspect to be investigated. In this direction, natural products have been progressively explored with this aim. In particular, flavonoids are potential candidates to act as insulin secretagogue.

OBJECTIVE

To study the influence of flavonoid on overall modulation mechanisms of insulin secretion.

METHODS

The research was conducted in the following databases and platforms: PubMed, Scopus, ISI Web of Knowledge, SciELO, LILACS, and ScienceDirect, and the MeSH terms used for the search were flavonoids, flavones, islets of Langerhans, and insulin-secreting cells.

RESULTS

Twelve articles were included and represent the basis of discussion on mechanisms of insulin secretion of flavonoids. Papers in ISI Web of Knowledge were in number of 1, Scopus 44, PubMed 264, ScienceDirect 511, and no papers from LILACS and SciELO databases.

CONCLUSION

According to the literature, the majority of flavonoid subclasses can modulate insulin secretion through several pathways, in an indication that corresponding molecule is a potential candidate for active materials to be applied in the treatment of diabetes.

SUMMARY

The action of natural products on insulin secretion represents an important investigation topic due to their importance in the diabetes controlIn addition to their typical antioxidant properties, flavonoids contribute to the insulin secretionThe modulation of insulin secretion is induced by flavonoids according to different mechanisms. Abbreviations used: KATP channels: ATP-sensitive K+ channels, GLUT4: Glucose transporter 4, ERK1/2: Extracellular signal-regulated protein kinases 1 and 2, L-VDCCs: L-type voltage-dependent Ca+2 channels, GLUT1: Glucose transporter 1, AMPK: Adenosine monophosphate-activated protein kinase, PTP1B: Protein tyrosine phosphatase 1B, GLUT2: Glucose transporter 2, cAMP: Cyclic adenosine monophosphate, PKA: Protein kinase A, PTK: Protein tyrosine kinase, CaMK II: Ca2+/calmodulin-dependent protein kinase II, GSIS: Glucose-stimulated insulin secretion, Insig-1: Insulin-induced gene 1, IRS-2: Insulin receptor substrate 2, PDX-1: Pancreatic and duodenal homeobox 1, SREBP-1c: Sterol regulatory element binding protein-1c, DMC: Dihydroxy-6'-methoxy-3',5'-dimethylchalcone, GLP-1: Glucagon-like peptide-1, GLP-1R: Glucagon-like peptide 1 receptor.

Euterpe oleracea Mart. seed extract protects against renal injury in diabetic and spontaneously hypertensive rats: role of inflammation and oxidative stress

PURPOSE

Euterpe oleracea Mart. (açaí) seed extract (ASE), through its anti-hypertensive, antioxidant and anti-inflammatory properties, may be useful to treat or prevent human diseases. Several evidences suggest that oxidative stress and inflammation contribute to the pathogenesis of diabetic nephropathy; therefore, we tested the hypothesis that ASE (200 mg/kg^-1day^-1) prevents diabetes and hypertension-related oxidative stress and inflammation, attenuating renal injury.

METHODS

Male rats with streptozotocin (STZ)-induced diabetes (D), and spontaneously hypertensive rats with STZ-induced diabetes (DH) were treated daily with tap water or ASE (D + ASE and DH + ASE, respectively) for 45 days. The control (C) and hypertensive (H) animals received water.

RESULTS

The elevated serum levels of urea and creatinine in D and DH, and increased albumin excretion in HD were reduced by ASE. Total glomeruli number in D and DH, were increased by ASE that also reduced renal fibrosis in both groups by decreasing collagen IV and TGF-β1 expression. ASE improved biomarkers of renal filtration barrier (podocin and nephrin) in D and DH groups and prevented the increased expression of caspase-3, IL-6, TNF-α and MCP-1 in both groups. ASE reduced oxidative damage markers (TBARS, carbonyl levels and 8-isoprostane) in D and DH associated with a decrease in Nox 4 and p47 subunit expression and increase in antioxidant enzyme activity in both groups (SOD, catalase and GPx).

CONCLUSION

ASE substantially reduced renal injury and prevented renal dysfunction by reducing inflammation, oxidative stress and improving the renal filtration barrier, providing a nutritional resource for prevention of diabetic and hypertensive-related nephropathy.