Antioxidant potential of theaflavin ameliorates the activities of key enzymes of glucose metabolism in high fat diet and streptozotocin - induced diabetic rats

Improvement of Theaflavins on Glucose and Lipid Metabolism in Diabetes Mellitus

In diabetes mellitus, disordered glucose and lipid metabolisms precipitate diverse complications, including nonalcoholic fatty liver disease, contributing to a rising global mortality rate. Theaflavins (TFs) can improve disorders of glycolipid metabolism in diabetic patients and reduce various types of damage, including glucotoxicity, lipotoxicity, and other associated secondary adverse effects. TFs exert effects to lower blood glucose and lipids levels, partly by regulating digestive enzyme activities, activation of OATP-MCT pathway and increasing secretion of incretins such as GIP. By the Ca2+-CaMKK ꞵ-AMPK and PI3K-AKT pathway, TFs promote glucose utilization and inhibit endogenous glucose production. Along with the regulation of energy metabolism by AMPK-SIRT1 pathway, TFs enhance fatty acids oxidation and reduce de novo lipogenesis. As such, the administration of TFs holds significant promise for both the prevention and amelioration of diabetes mellitus.

Antidiabetic Potential of Tea and Its Active Compounds: From Molecular Mechanism to Clinical Evidence

Diabetes mellitus (DM) is a chronic endocrine disorder that poses a long-term risk to human health accompanied by serious complications. Common antidiabetic drugs are usually accompanied by side effects such as hepatotoxicity and nephrotoxicity. There is an urgent need for natural dietary alternatives for diabetic treatment. Tea (Camellia sinensis) consumption has been widely investigated to lower the risk of diabetes and its complications through restoring glucose metabolism homeostasis, safeguarding pancreatic β-cells, ameliorating insulin resistance, ameliorating oxidative stresses, inhibiting inflammatory response, and regulating intestinal microbiota. It is indispensable to develop effective strategies to improve the absorption of tea active compounds and exert combinational effects with other natural compounds to broaden its hypoglycemic potential. The advances in clinical trials and population-based investigations are also discussed. This review primarily delves into the antidiabetic potential and underlying mechanisms of tea active compounds, providing a theoretical basis for the practical application of tea and its active compounds against diabetes.

Theaflavin-3,3'-Digallate Protects Liver and Kidney Functions in Diabetic Rats by Up-Regulating Circ-ITCH and Nrf2 Signaling Pathway

Theaflavin-3,3'-digallate (TFDG) in black tea has a strong antioxidant capacity. However, its effect on diabetic liver and kidney injury and the underlying mechanisms remain unclear. In the present study, our findings indicated that TFDG administration effectively lowers the fasting blood glucose and serum lipid concentrations and enhances the functionality and cellular architecture of the liver and kidney in rats with diabetes. The data also showed that TFDG mitigates oxidative harm in the liver and kidney of rats afflicted with diabetes. Additionally, metformin combined with TFDG was significantly more effective in reducing blood glucose and oxidative stress. Further studies suggested that TFDG upregulates the Nrf2 signal pathway and circ-ITCH (hsa_circ_0001141) expression. Silencing of circ-ITCH by transfection of the interfering plasmid apparently reduces the effects of TFDG on the Nrf2 signal pathway and oxidative stress in high-glucose-treated hepatic and renal cells. In conclusion, the present study highlights the great potential of TFDG in ameliorating diabetic liver and kidney injury by up-regulating circ-ITCH to promote the Nrf2 signal pathway and provides a potential option for the prevention and treatment of diabetic complications.

Comparative effects of pravastatin and rosuvastatin on carbohydrate metabolism in an experimental diabetic rat model

Statin treatment may increase the risk of diabetes; there is insufficient data on how statins affect glucose regulation and glycemic control and the effects of statins on liver enzymes related to carbohydrate metabolism have not been fully studied. Therefore, we aimed to compare the effects of the statin derivatives, pravastatin, and rosuvastatin, on carbohydrate metabolism in an experimental diabetic rat model. Female Wistar albino rats were used and diabetes was induced by intraperitoneal injection of streptozotocin. Thereafter, 10 and 20 mg kg-1 day-1 doses of both pravastatin and rosuvastatin were administered by oral gavage to the diabetic rats for 8 weeks. At the end of the experiment, body masses, the levels of fasting blood glucose, serum insulin, insulin resistance (HOMA-IR), liver glycogen, and liver enzymes related to carbohydrate metabolism were measured. Both doses of pravastatin significantly in creased the body mass in diabetic rats, however, rosuvastatin, especially at the dose of 20 mg kg-1 day-1 reduced the body mass signi ficantly. Pravastatin, especially at a dose of 20 mg kg-1 day-1, caused significant increases in liver glycogen synthase and glucose 6-phosphate dehydrogenase levels but significant decreases in the levels of glycogen phosphorylase, lactate dehydrogenase, and glucose-6-phosphatase. Hence, pravastatin partially ameliorated the adverse changes in liver enzymes caused by diabetes and, especially at the dose of 20 mg kg-1 day-1, reduced the fasting blood glucose level and increased the liver glycogen content. However, rosuvastatin, especially at the dose of 20 mg kg-1 day-1, significantly reduced the liver glycogen synthase and pyruvate kinase levels, but increased the glycogen phosphorylase level in diabetic rats. Rosuvastatin, 20 mg kg-1 day-1 dose, caused significant decreases in the body mass and the liver glycogen content of diabetic rats. It can be concluded that pravastatin, especially at the dose of 20 mg kg-1 day-1 is more effective in ameliorating the negative effects of diabetes by modulating carbohydrate metabolism.

Theaflavin pretreatment ameliorates renal ischemia/reperfusion injury by attenuating apoptosis and oxidative stress in vivo and in vitro

Oxidative stress-induced apoptosis is an important pathological process in renal ischemia/reperfusion injury (RIRI). Theaflavin (TF) is the main active pigment and polyphenol in black tea. It has been widely reported because of its biological activity that can reduce oxidative stress and protect against many diseases. Here, we explored the role of theaflavin in the pathological process of RIRI. In the present study, the RIRI model of 45 min ischemia and 24 h reperfusion was established in C57BL/6 J male mice, and theaflavin was used as an intervention. Compared with the RIRI group, the renal filtration function, renal tissue damage and antioxidant capacity of the theaflavin intervention group were significantly improved, while the level of apoptosis was reduced. TCMK-1 cells were incubated under hypoxia for 48 h and then reoxygenated for 6 h to simulate RIRI in vitro. The application of theaflavin significantly promoted the translocation of p53 from cytoplasm to nucleus, upregulated the expression of glutathione peroxidase 1 (GPx-1) in cells, and inhibited oxidative stress damage and apoptosis. Transfection with p53 siRNA can partially inhibit the effect of theaflavin. Thus, theaflavin exerted a protective effect against RIRI by inhibiting apoptosis and oxidative stress via regulating the p53/GPx-1 pathway. We conclude that theaflavin has the potential to become a candidate drug for the prevention and treatment of RIRI.

The Antiobesity Effects and Potential Mechanisms of Theaflavins

Theaflavins are the characteristic polyphenols in black tea which can be enzymatically synthesized. In this review, the effects and molecular mechanisms of theaflavins on obesity and its comorbidities, including dyslipidemia, insulin resistance, hepatic steatosis, and atherosclerosis, were summarized. Theaflavins ameliorate obesity potentially via reducing food intake, inhibiting pancreatic lipase to reduce lipid absorption, activating the adenosine monophosphate-activated protein kinase (AMPK), and regulating the gut microbiota. As to the comorbidities, theaflavins ameliorate hypercholesterolemia by inhibiting micelle formation to reduce cholesterol absorption. Theaflavins improve insulin sensitivity by increasing the signaling of protein kinase B, eliminating glucose toxicity, and inhibiting inflammation. Theaflavins ameliorate hepatic steatosis via activating AMPK. Theaflavins reduce atherosclerosis by upregulating nuclear factor erythropoietin-2-related factor 2 signaling and inhibiting plasminogen activator inhibitor 1. In randomized controlled trails, black tea extracts containing theaflavins reduced body weight in overweight people and improved glucose tolerance in healthy adults. The amelioration on the hyperlipidemia and the prevention of coronary artery disease by black tea extracts were supported by meta-analysis.

The Effect of Theaflavins on the Gut Microbiome and Metabolites in Diabetic Mice

With the development of diabetes, the gut microbiome falls into a state of dysbiosis, further affecting its progression. Theaflavins (TFs), a type of tea polyphenol derivative, show anti-diabetic properties, but their effect on the gut microbiome in diabetic mice is unclear. It is unknown whether the improvement of TFs on hyperglycemia and hyperlipidemia in diabetic mice is related to gut microbiota. Therefore, in this study, different concentrations of TFs were intragastrically administered to mice with diabetes induced by a high-fat-diet to investigate their effects on blood glucose, blood lipid, and the gut microbiome in diabetic mice, and the plausible mechanism underlying improvement in diabetes was explored from the perspective of the gut microbiome. The results showed that the TFs intervention significantly improved the hyperglycemia and hyperlipidemia of diabetic mice and affected the structure of the gut microbiome by promoting the growth of bacteria positively related to diabetes and inhibiting those negatively related to diabetes. The changes in short-chain fatty acids in mice with diabetes and functional prediction analysis suggested that TFs may affect carbohydrate metabolism and lipid metabolism by regulating the gut microbiome. These findings emphasize the ability of TFs to shape the diversity and structure of the gut microbiome in mice with diabetes induced by a high-fat diet combined with streptozotocin and have practical implications for the development of functional foods with TFs.

Prevalence of Type 2 Diabetes, Impaired Fasting Glucose, and Diabetes Risk in an Adult and Older North-Eastern Portuguese Population

The aims of this study were (1) to evaluate the prevalence of type 2 diabetes (T2D) in a middle-aged north-eastern Portuguese population, (2) to analyze the prevalence of impaired fasting glucose (IFG), and (3) to assess the risk of T2D in this community-based sample. An exploratory, retrospective, and cross-sectional study was conducted from a total of 6570 individuals aged 18-102 years, among which 3865 were women (57.4 ± 18.1 years) and 2705 were men (60.0 ± 16.8 years). T2D diagnosis, IFG, and the diabetes risk score (low to very high risk) were assessed. The prevalence of T2D in this adult and an older north-eastern Portuguese population was 17.4%. A higher prevalence of T2D was reported in men (22.2%) than in women (14.0%); however, this was without significant differences (p = 0.086). Otherwise, the prevalence of T2D was significantly different among the age groups and increased with age (p < 0.001). Regarding IFG, a higher percentage of cases was observed in men (14.1%) than in women (8.4%) (p < 0.001). The risk of developing T2D in the next 10 years showed an association with sex and age group (p < 0.001) with a small-to-moderate effect (V = 0.1-0.3). Men and the elderly had the highest percentage of cases in the moderate-to-very high-risk bands. The current research confirmed a higher prevalence of T2D, IFG, and diabetes risk than previous Portuguese epidemiological reports. The results also suggest potential prediabetes cases, which should be carefully monitored. The current research adds evidence to the worldwide trend of the increasing prevalence of T2D and intermediate hyperglycemia (i.e., prediabetes).

Effectiveness of analog of Humanin in ameliorating streptozotocin-induced diabetic nephropathy in Sprague Dawley rats

Diabetes mellitus(DM) is associated with numerous complications, including nephropathy, which principally occur due to hyperglycemia-induced oxidative stress and inflammation. Humanin(HN), a novel peptide generated from mitochondria, has anti-oxidant and anti-inflammatory potential as observed in different disease models. However, role of HN in diabetic nephropathy (DN) has not yet been explored. This study aimed to evaluate biochemical and molecular aspects of the effects of HN analog, Humanin-glycine([S14G]-humanin) on streptozotocin (STZ)-induced rat model of DN. Ninety Sprague Dawley (SD) rats were randomly segregated into three groups - A (control), B (disease control) and C (treatment). DM type-I was induced in group B and C via single intra-peritoneal dose of STZ (45mg/Kg). Seven days following STZ injection, rats were deemed diabetic if their blood glucose level was >250mg/dL. Subsequently, diabetic rats in group C were injected with [S14G]-humanin intra-peritoneally (0.4mg/Kg/day) for sixteen weeks. Biochemical analysis revealed that diabetic rats had markedly elevated levels of serum glucose, creatinine, BUN, TNF-α, and kidney tissue SOD. Whereas, significant decline was detected in serum insulin and albumin levels. All these parameters were significantly reversed in group C after administering [S14G]-humanin. Moreover, qRT-PCR analysis displayed up-regulation of pro-inflammatory (IL-18, IL-6, IL-1α, IL-1β, TNF-α) and down-regulation of anti-inflammatory cytokines (IL-10, IL-1RN, IL-4) in diabetic rats (group B). [S14G]-humanin treatment significantly reversed the expression IL-18 and IL-1α, however, change in relative expression of IL-6, IL-1β, TNF-α and anti-inflammatory cytokines was insignificant(group C). Conclusively, the findings of this study depicted potential therapeutic role of [S14G]-humanin in pre-clinical rodent model of DN.

Therapeutic role of kaempferol and myricetin in streptozotocin-induced diabetes synergistically via modulation in pancreatic amylase, glycogen storage and insulin secretion

Kaempferol and Myricetin alone have promising benefits on diabetes and related complications, yet the effectiveness of cotreating the two compounds on diabetes have not been studied. The existing investigation was to study the combined anti-diabetic effect of kaempferol and myricetin in Streptozotocin (STZ)-activated diabetes in rats. To evaluate the anti-diabetic activity, 36 Wistar rats were segregated into six groups; Normal, 50 mg/kg STZ-induced diabetes, and four (50 mg/kg kaempferol, 50 mg/kg myricetin, 25 mg/kg kaempferol + myricetin, and 5 mg/kg glibenclamide) compound-treated diabetic groups. The effects of co-treatment on parameters, glucose, insulin, lipid profile, liver enzymes, antioxidant biomarkers, and inflammatory cytokines were measured. The study revealed that combined treatment restored the assessed parameters including glucose levels, inflammatory cytokines, oxidative markers, and lipid and liver enzymes in diabetic rats. The results indicate that cotreatment of kaempferol and myricetin has a beneficial role against diabetes suggesting that cotreatment of these compounds can be used therapeutically in treating diabetes.

Association of crossbite with vertical skeletal growth patterns: A retrospective study

Crossbite is a type of malocclusion in which teeth are positioned more buccally or lingually than their corresponding opposing tooth in the upper or lower dental arch, resulting in a lateral mismatch of the teeth in the dental arches. Crossbite can be unilateral or bilateral, and it can be anterior or posterior. The link between crossbite and skeletal growth pattern remains uncertain. The current study aimed to find the prevalence of crossbite in subjects visiting a private dental hospital and evaluate if there is any association between crossbite and skeletal growth pattern. Data required for the study were procured from the dental information archiving software. The data were sorted and entered into an Excel spreadsheet. IBM SPSS software version 23 was used to conduct the statistical analysis. Graphs and tables were used to interpret the findings. the prevalence of crossbite was found to be 6.4%. Subjects with horizontal growth pattern commonly had crossbite, but no statistical significance (P = 0.07), standard deviation (1.011), was noted. There was no statistically significant association between different skeletal growth patterns however subjects with horizontal growth pattern reported more commonly with crossbite.

Prevalence of pain following single-visit pulpectomy with stainless steel crown done by postgraduate students in a university sitting

Pain is usually a very unpleasant experience, it can be felt by any age group whose sensory and cognitive components have been developed. Children tend to experience pain in around 65% of dental procedures. It can affect daily activities, and in many situations, it can lead to crisis. Since it is a developing child, the concept of pain can influence adversely in the mind of the child. The clinical records of all pulpectomy cases during the period between January 1, 2020, and January 1, 2021, were analyzed. Gender and age of the patients were also included in the study. The majority of children in our study group were males; children who had a proper abscess of any kind of symptoms tend to have a higher incidence of postoperative pain compared to children with the least symptoms. The study identified that children experienced less pain following multi-visit pulpectomy when compared with single visits during the 1^st 3 days. In children who were treated with both single-visit pulpectomy and stainless steel crown experienced no difference in pain perception in the first 3 days of appointment.

Association of vertical growth pattern with canine impactions in Dravidian subjects

Canine impaction, ectopic canines, canine transposition, canine transmigration, and agenesis are all caused by disturbances during development and eruption of the teeth. The position of the canines is of utmost importance, and they should be carefully inspected as they follow the longest path during eruption in the oral cavity and their shape and position play a major role in occlusal guidance. The prevalence of canine impaction may also be connected to the pattern of facial growth. The objective of this study was to analyze the association of vertical growth pattern and canine impaction in Dravidian population. The dental records were consulted for information. The patient information was gathered from the outpatient data records of patients who were treated with fixed orthodontic treatment at the private dental setup. Patients with canine impactions were shortlisted. Malocclusion, growth pattern, and type of impaction were recorded. The data obtained were tabulated and analyzed using statistical software. Out of 1385 subjects, 35 patients had impacted canines. Among 35 patients with impacted canines, 23 (65.71%) have a vertical growth pattern, 6 (17.14%) have an average growth pattern, and 6 (17.14%) have a horizontal growth pattern. According to the findings of this investigation, there was no gender-related difference in canine impaction. The canine impaction prevalence in Dravidian subjects was found to be 2.53%. Most of them with impacted canines had a vertical growth pattern.

Association of Ellis class 1 fracture in children of age 6-12 years

Trauma is a well-known issue in children, and its prevalence is on the rise more than that of dental caries in children. The objective of the study is to evaluate the association of Ellis class 1 fracture in children between 6 and 12 years. This study includes 45 males and 55 female patients of age 6-12 years. All the data regarding the study population was extracted from Dental Information Archiving Software-all patient records from management. The data collected were tabulated and imported to SPSS software. Statistical analysis was done using Chi-square tests. Ellis class 1 fracture ordinarily is observed to affect the central incisors. Majority of school children of 6-12 years of age were more vulnerable to dental trauma. There is a strong association between Ellis class 1 fracture in children of 6-12 years of age.

Assessment of anterior open bite prevalence in children visiting a dental hospital - A retrospective evaluation

Anterior open bite (AOB) is the insufficient vertical overlapping between the maxillary and mandibular anteriors when the teeth are in centric occlusion. The purpose of this study was to determine the prevalence of AOB in children and adolescents who visited a private dental hospital. In this study, subjects aged between 16 and 18 years with AOB were included. Data about orthodontic examination of patients were taken from preentered dental records of the hospital. Data of patients with AOB regarding age, gender, and intraoral and extraoral features were collected from the case records of the subjects, and statistical analysis was performed (Chi-square test and nonparametric correlations). The prevalence percentage of open bite in the anteriors was 2.7%, with more prevalence in Class 1 subjects (81.5%). Subjects with AOB had competent lips (81.8%), straight nasolabial angle (86.8%), and shallow palatal vault (49.5%). AOB had no significant relationship with the type of malocclusion, palatal vault, and lip competency, according to the Chi-square test. AOB and the nasolabial angle had a significant association. Both acute and right-angled nasolabial angles were commonly seen in adolescent patients with AOB. In children and adolescents visiting a private dental hospital in Chennai, the prevalence of AOB was found to be 2.7%. A significant association was observed between AOB and nasolabial angle.

Association of severity of malocclusion with socioeconomic status in the South Indian population

Malocclusion has been linked to various factors out of which certain dietary patterns and unhealthy habits are the most overlooked. The dietary patterns and unhealthy habits vary according to socioeconomic status. The present research was aimed to perform an association of malocclusion severity with socioeconomic status. This study was done in a retrospective manner and was conducted at Saveetha Dental College. A total of 241 clinical case records of the participants with malocclusion reporting for orthodontic therapy were selected and enrolled for the study. Data on the socioeconomic status and the severity of malocclusion as assessed with the Index of Orthodontic Treatment Needs (IOTNs) index were noted. All these records were collected and entered into Excel and then analyzed through statistics. Descriptive statistics and nonparametric Chi-square tests were performed. From the analysis, the proportion of IOTN Grade 1 malocclusion (30%) was found to be the highest. The highest number of patients with Grade 1 malocclusion belonged to the lower socioeconomic class. Socioeconomic status and the severity of malocclusion were significantly associated with each other. Malocclusion prevalence and severity were more among participants belonging to lower socioeconomic groups.

Association of Ellis Class 2 fracture in 13-17 years old children

The objective of the study is to evaluate the association of Ellis Class 2 fracture in children aged between 13 and 17 years. This is a descriptive study that was carried out in a university context, using data from patients with Ellis Class 2 fractures between 13 and 17 years from June 2019 to February 2021, which were obtained by analyzing patient records. The records were transferred to the SPSS software for statistical analysis. The association of Ellis Class 2 fracture is common in relation to 11 which is about 29.41% and more common among the age group of 14 years and had a more male prediction. The knowledge of Ellis Class 2 fracture and its association with several parameters are essential in dentistry for various clinical performances. This can be accomplished by increasing awareness through Continuing Dental Education (CDE) programs, demonstrations, and seminars on the clinical regime of Ellis Class 2 fracture.

Severity of mandibular arch crowding in different sagittal malocclusions

Mandibular anterior crowding is caused by a variety of factors. Mandibular incisor crowding can be caused by a number of causes including incisor and molar inclination, early loss of deciduous molars, mandibular growth, and oral musculature. The study was aimed to perform an association of the lower anterior crowding severity with gender and type of malocclusion. The current study was performed in a hospital setup and data about mandibular arch crowding patients were collected from the Records management system of a Private Dental Hospital in Chennai city. All the patient data on Mandibular arch crowding were sourced and tabulated after which statistical analysis with SPSS-IBM was done. Data collection was done over a period from June 2019 to February 2021. The entire study sample size was 634 case records. The result obtained from the statistical analysis was found that nearly 46% of the patients were found to have Mandibular arch crowding with female predilection (50%). The most commonly associated age groups were children than adults (63.2%) associated with mild type of crowding (65.1%). The most commonly involved malocclusion was found to be Class 1 (88.4%) Mild imbrications of the lower arch were common and were seen mainly in subjects with Class I malocclusion. Female subjects presented with more prevalence of mandibular arch crowding when compared to male subjects. Children were more affected by crowding than adults.

Effect of Carica papaya on IRS-1/Akt Signaling Mechanisms in High-Fat-Diet-Streptozotocin-Induced Type 2 Diabetic Experimental Rats: A Mechanistic Approach

Despite rigorous endeavors, existing attempts to handle type 2 diabetes (T2DM) are still a long way off, as a substantial number of patients do not meet therapeutic targets. Insulin resistance in skeletal muscle is discerned as a forerunner in the pathogenesis of T2DM and can be detected years before its progress. Studies have revealed the antidiabetic properties of Carica papaya (C. papaya), but its molecular mechanism on insulin receptor substrate-1 (IRS-1)/Akt signaling mechanisms is not yet known. The present study aimed to evaluate the role of C. papaya on IRS1 and Akt in high-fat-diet-streptozotocin-induced type 2 diabetic rats and also to analyze the bioactive compounds of C. papaya against IRS-1 and Akt via in silico analysis. Ethanolic extract of the leaves of C. papaya (600 mg/kg of body weight) was given daily for 45 days postinduction of T2DM up to the end of the study. Gluconeogenic enzymes, glycolytic enzymes, gene expression, and immunohistochemical analysis of IRS-1 and Akt in skeletal muscle were evaluated. C. papaya treatment regulated the levels of gluconeogenic and glycolytic enzymes and the levels of IRS-1 and Akt in skeletal muscle of type 2 diabetic animals. In silico studies showed that trans-ferulic acid had the greatest hit rate against the protein targets IRS-1 and Akt. C. papaya restored the normoglycemic effect in diabetic skeletal muscle by accelerating the expression of IRS-1 and Akt.

Transcriptome analysis provides insights into the anti-diabetic mechanism of theaflavins in high-fat diet and streptozotocin-induced mice

Black tea exhibits potential to improve hyperglycemia and insulin resistance, and theaflavins (TFs) are one of its characteristic components. The aim of this study was to explore the anti-diabetic mechanism...

Simultaneous Tests of Theaflavin-3,3'-digallate as an Anti-Diabetic Drug in Human Hepatoma G2 Cells and Zebrafish (Danio rerio)

Theaflavin-3,3′-digallate (TF3) is the most important theaflavin monomer in black tea. TF3 was proved to reduce blood glucose level in mice and rats. However, the elaborate anti-diabetic mechanism was not well elucidated. In this work, human hepatoma G2 (HepG2) cells and zebrafish (Danio rerio) were used simultaneously to reveal anti-diabetic effect of TF3. The results showed that TF3 could effectively rise glucose absorption capacity in insulin-resistant HepG2 cells and regulate glucose level in diabetic zebrafish. The hypoglycemic effect was mediated through down-regulating phosphoenolpyruvate carboxykinase and up-regulating glucokinase. More importantly, TF3 could significantly improve β cells regeneration in diabetic zebrafish at low concentrations (5 μg/mL and 10 μg/mL), which meant TF3 had a strong anti-diabetic effect. Obviously, this work provided the potential benefit of TF3 on hypoglycemic effect, regulating glucose metabolism enzymes, and protecting β cells. TF3 might be a promising agent for combating diabetes.

Study of hepatoprotective effect of bearberry leaves extract under insulin resistance in rats

The aim of our study was to evaluate the antidiabetic and hepatoprotective efficacy of dry extract from bearberry leaves enriched with arginine in dexamethasone induced IR. Materials and methods. IR was induced in rats by low dose intraperitoneally injections of dexamethasone. Dexamethasone-induced IR in rats was treated by bearberry leaves extract enriched with arginine. Thus, animals were randomized into several groups including intact animals and animals, which administered reference compounds and medications. The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamine transferase (GGT) were determined in blood serum and liver homogenate, in addition, in blood serum we measured lactate dehydrogenase (LDH) activity and lactate level and glycogen content liver tissue. Also, for the purpose of our experiment, in liver tissue were determined: thiobarbituric acid reactive substances (TBARS), diene conjugates (DC), and reduced glutathione (GSH) content; and superoxide dismutase (SOD), glutathione peroxidase (Gpx), and catalase (CAT) activities. All indices were determined using generally accepted unified methods or commercially available kits. Results. Long-term dexamethasone administration led to an increase in AST, ALT and GGT overall activity in the liver homogenate and serum; this could be the result of increased permeability of hepatocyte plasma membranes, as well as their enhanced synthesis in the liver. Studied extract ameliorate these indices of liver injury. Evaluation of indices that reflected oxidative stress and the antioxidant system status in liver confirmed oxidative stress development in IR rats` liver. Administration of arginine enriched bearberry leaves extract decrease TBARS and DC content in liver tissue, at the same time, improve SOD, Gpx, and CAT activities and increase GSH content. Conclusions. Bearberry leaves dry extract enriched with arginine inhibit oxidative stress development, improve membrane integrity, and normalize some indices of carbohydrate metabolism, particularly glycogen content in liver and lactate level in blood.

Antioxidant, Anti-Inflammatory, and Immunomodulatory Properties of Tea-The Positive Impact of Tea Consumption on Patients with Autoimmune Diabetes

The physiological markers of autoimmune diabetes include functional disorders of the antioxidative system as well as progressing inflammation and the presence of autoantibodies. Even though people with type 1 diabetes show genetic predispositions facilitating the onset of the disease, it is believed that dietary factors can stimulate the initiation and progression of the disease. This paper analyses the possibility of using tea as an element of diet therapy in the treatment of type 1 diabetes. Based on information available in literature covering the last 10 years, the impact of regular tea consumption or diet supplements containing tea polyphenols on the oxidative status as well as inflammatory and autoimmune response of the organism was analyzed. Studies conducted on laboratory animals, human patients, and in vitro revealed positive effects of the consumption of tea or polyphenols isolated therefrom on the diabetic body. Few reports available in the literature pertain to the impact of tea on organisms affected by type 1 diabetes as most (over 85%) have focused on cases of type 2 diabetes. It has been concluded that by introducing tea into the diet, it is possible to alleviate some of the consequences of oxidative stress and inflammation, thus limiting their destructive impact on the patients' organisms, consequently improving their quality of life, regardless of the type of diabetes. Furthermore, elimination of inflammation should reduce the incidence of immune response. One should consider more widespread promotion of tea consumption by individuals genetically predisposed to diabetes, especially considering the drink's low price, easy availability, overall benefits to human health, and above all, the fact that it can be safely used over extended periods of time, regardless of the patient's age.

Aging and diabetes drive the COVID-19 forwards; unveiling nature and existing therapies for the treatment

Human SARS Coronavirus-2 (SARS-CoV-2) has infected more than 170 million people worldwide and resulted in more than 3.5 million deaths so far. The infection causes Coronavirus disease (COVID-19) in people of all age groups, notably diabetic and old age people, at a higher risk of infectivity and fatality. Around 35% of the patients who have died of the disease were diabetic. The infection is associated with weakening immune response, chronic inflammation, and potential direct pancreatic impairment. There seems to be a three-way association of the SARS-CoV-2 infection with diabetes and aging. The COVID-19 infection causes metabolism complications, which may induce diabetes and accelerate aging in healthy individuals. How does diabetes elevate the likelihood of the infection is not clearly understood. we summarize mechanisms of accelerated aging in COVID-19 and diabetes, and the possible correlation of these three diseases. Various drug candidates under different stages of pre-clinical or clinical developments give us hope for the development of COVID-19 therapeutics, but there is no approved drug so far to treat this disease. Here, we explored the potential of anti-diabetic and anti-aging natural compounds for the COVID-19 treatment. We have also reviewed different therapeutic strategies with plant-based natural products that may be used to cure patients infected with SARS-CoV-2 and post-infection syndrome.

Hypoglycemic and lipid lowering effects of theaflavins in high-fat diet-induced obese mice

Theaflavins (TFs) are the characteristic components of black tea and have been widely acknowledged for their health benefits. The current study aimed to investigate the effects and mechanism of TFs, TF1, TF2a and TF3 on glycolipid metabolism in obese mice induced by a high-fat diet (HFD). Mice were randomly divided into seven groups (n = 8 per group) as follows: low-fat diet (LFD), HFD, HFD + metformin (Met, 100 mg kg^-1 d^-1), HFD + TFs (TFs, 200 mg kg^-1 d^-1), HFD + TF1 (TF1, 100 mg kg^-1 d^-1), HFD + TF2a (TF2a, 100 mg kg^-1 d^-1), and HFD + TF3 (TF3, 100 mg kg^-1 d^-1). All groups were studied for 9 weeks continuously. The levels of serum glucose, insulin, TC, TG, LDL and HLD in the plasma, lipid accumulation in the liver, and injury of the liver were investigated. In addition, the effects of TFs and their monomers on the SIRT6/AMPK/SREBP-1/FASN pathway were also evaluated. The results showed that oral administration of TFs, TF1, TF2a and TF3 not only dramatically suppressed weight gain, reduced blood glucose level, and ameliorated insulin resistance but also obviously lowered the levels of serum TC, TG and LDL, suppressed the activities of ALT and AST, and ameliorated hepatic damage in mice fed a HFD when compared to the HFD group. Western blot analysis showed that TFs, TF1, TF2a and TF3 treatments increased the expression of SIRT6 and suppressed the expression levels of SREBP-1 and FASN significantly in mice fed a HFD as compared to the HFD group. The phosphorylation of AMPK in mice fed a HFD was obviously elevated by TF2a and TF3 when compared to the HFD group. These results proved for the first time that TF1, TF2a and TF3 improved the glucolipid metabolism of mice fed a HFD, and activated the SIRT6/AMPK/SREBP-1/FASN signaling pathway to inhibit the synthesis and accumulation of lipids in the liver to ameliorate obesity in mice fed a HFD. These findings indicate that TFs, TF1, TF2a and TF3 as the main functional components of black tea might potentially be used as a food additive for improving glycolipid metabolism and ameliorating obesity, and TF3 may be the best choice.

Protective effect of sinomenine against inflammation and oxidative stress in gestational diabetes mellitus in female rats via TLR4/MyD88/NF-κB signaling pathway

Gestational diabetes mellitus (GDM) is a dangerous complication of pregnancy which is induced via dysfunction in glucose metabolism during pregnancy. Sinomenine (SM) has already proved an antidiabetic effect against streptozotocin (STZ)-induced diabetes mellitus (DM) in rats. In this protocol, we examined the protective effect of SM against STZ-induced GDM in rats. Wistar rats were divided into three groups and STZ (40 mg/kg) was used to induce GDM. At the end of the experimental protocol, bodyweight, pub weight, and survival rate were estimated. Blood glucose level (BGL), fasting insulin (FINS), free fatty acid (FFA), Hemoglobin A1C (HbA1c), and C-peptide were measured. Lipid, antioxidant, inflammatory cytokines, and inflammatory mediators were also determined. RT-PCR was used for estimation of the role of TLR4/MyD88/NF-κB signaling pathway. SM treatment significantly (p < .001) reduced BGL, hepatic glycogen, and improved the levels of FINS, C-peptide, FFA, and HbA1c. SM significantly (p < .001) suppressed the levels of total cholesterol (TC), low-density lipoprotein (LDL), triglycerides (TG), coronary artery index (CAI), very low-density lipoprotein (VLDL), atherogenic index (AI), and boosted high-density lipoprotein (HDL) levels. SM significantly (p < .001) decreased the lipid peroxidation (LPO) level and enhanced glutathione peroxidase (GPx), total antioxidant capacity (TAC), glutathione S-transferase (GST), superoxide dismutase (SOD), respectively. It reduced the levels of inflammatory cytokines including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and inflammatory mediators viz., nuclear kappa B factors (NF-κB). SM significantly (p < .001) reduced the mRNA expression of Myd88, NLRP3, TLR4, and NF-κB, which were boosted in the GDM group rats. These findings suggest that SM could be a probable drug to be used for treating GDM via inhibition of the TLR4 signaling pathway. PRACTICAL APPLICATIONS: It is well known that gestational diabetes mellitus (GDM) is a dangerous health problem during the pregnancy. SM reduced the glucose level; boosted the level of fasting insulin (FINS) and bodyweight. SM significantly improved the number of pubs and their survival rates. SM suppressed oxidative stress and inflammation via activation of TLR4/MyD88/NF-κB signaling pathway. According to our research, SM can be used as a preventive drug in the treatment of GDM during pregnancy.

Chebulagic acid attenuates HFD/streptozotocin induced impaired glucose metabolism and insulin resistance via up regulations of PPAR γ and GLUT 4 in type 2 diabetic rats

The aim of the present study was to evaluate the effects of chebulagic acid on enzymes involved in carbohydrate metabolism in high-fat diet/streptozotocin-induced diabetic rats. Diabetes was induced in albino male Wistar rats by feeding them with a high-fat diet comprising of 84.3% standard laboratory rat chow, 5% lard, 10% yolk powder, 0.2% cholesterol, and 5% bile salt for 2 weeks. After 2 weeks, the animals were kept in an overnight fast and injected with a low dose of streptozotocin (35 mg/kg, dissolved in 0.1 M sodium citrate buffer, pH 4.5). At the end of the experimental periods, the blood glucose, plasma insulin, hemoglobin, glycated hemoglobin levels, homeostatic model of insulin resistance, glycogen content, glycogen synthase, glycogen phosphorylase were measured in high-fat diet and streptozotocin-induced diabetic rats whereas the glucose metabolic enzymes such as hexokinase, glucose 6 phosphate dehydrogenase, glucose 6 phosphatase, fructose 1,6 bisphosphatase and protein expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) and Glucose transporter 4 (GLUT4) were analyzed. Administration of chebulagic acid to HFD/STZ -induced diabetic rats for 30 days significantly decreased the levels of plasma glucose, homeostatic model assessment of insulin resistance, glycogen phosphorylase and glycosylated hemoglobin and increased the levels of insulin, glycogen content and glycogen synthase. On the other hand, the altered activity of carbohydrate metabolic enzymes, PPAR-γ and GLUT4 were brought back to near-normal levels on treatment with chebulagic acid. The effect produced by chebulagic acid on various parameters was comparable to that of metformin.

Anti-damage effect of theaflavin-3'-gallate from black tea on UVB-irradiated HaCaT cells by photoprotection and maintaining cell homeostasis

Keratinocytes are rich in lipids and are the main sensitive cells to ultraviolet (UV) rays. Theaflavins are the core functional components of black tea and are known as the "soft gold" in tea. In this study, ultraviolet-B (UVB) irradiation caused apoptosis and necrosis of human epidermal keratinocytes (HaCaT). EGCG and the four theaflavins had anti-UVB damage activity, among which theaflavin-3'-gallate (TF3'G) had the best activity. The results of biophysical and molecular biology experiments showed that TF3'G has anti-damage effects on UVB-irradiated HaCaT cells through the dual effects of photoprotection and maintenance of cell homeostasis. That is, TF3'G preincubation could absorb UV rays, reduce the accumulation of aging-related heterochromatin (SAHF) formation, increase mitochondrial membrane potential, downregulate NF-κB inflammation pathways, inhibit the formation of cytotoxic aggregates, and protect biological macromolecules Structure, etc. The accumulation of conjugated π bonds and the balance benzoquinone are the core functional structure of TF3'G with high efficiency and low toxicity. The study indicates that TF3'G has the potential to inhibit the photoaging and intrinsic aging of skin cells.

Aging and diabetes drive the COVID-19 forwards; unveiling nature and existing therapies for the treatment

Human SARS Coronavirus-2 (SARS-CoV-2) has infected more than 170 million people worldwide and resulted in more than 3.5 million deaths so far. The infection causes Coronavirus disease (COVID-19) in people of all age groups, notably diabetic and old age people, at a higher risk of infectivity and fatality. Around 35% of the patients who have died of the disease were diabetic. The infection is associated with weakening immune response, chronic inflammation, and potential direct pancreatic impairment. There seems to be a three-way association of the SARS-CoV-2 infection with diabetes and aging. The COVID-19 infection causes metabolism complications, which may induce diabetes and accelerate aging in healthy individuals. How does diabetes elevate the likelihood of the infection is not clearly understood. we summarize mechanisms of accelerated aging in COVID-19 and diabetes, and the possible correlation of these three diseases. Various drug candidates under different stages of pre-clinical or clinical developments give us hope for the development of COVID-19 therapeutics, but there is no approved drug so far to treat this disease. Here, we explored the potential of anti-diabetic and anti-aging natural compounds for the COVID-19 treatment. We have also reviewed different therapeutic strategies with plant-based natural products that may be used to cure patients infected with SARS-CoV-2 and post-infection syndrome.

The ameliorative activity of Chrysobalanus orbicularis in streptozotocin-induced type II diabetes mellitus rat model

Chrysobalanus orbicularis is a medicinal plant present in West Africa in the Itsekiri speaking part of Nigeria. It is used conventionally in diabetes mellitus management. This research investigates the ameliorative activity of the aqueous leaf extract of C. orbicularis in a streptozotocin-induced diabetic rat model. Freshly prepared streptozotocin (40 mg/kg body weight [BW]) was administered intraperitoneally to induce diabetes. Three diabetic groups were placed on aqueous leaf extract of C. orbicularis at 11.076, 22.134, and 44.268 mg/kg BW respectively; a group was placed on metformin (44.28 mg/kg BW), and the other two groups were the diabetic control and normal control. The experiment lasted for 28 days, thereafter, fasting blood glucose levels and body weight variations were recorded. Also, glycogen level, antioxidant enzyme, hexokinase and glucose-6-phosphatase activities, malonaldehyde (MDA) as well as glucose transporters 2 and 4 levels were analyzed using standard procedures. Diabetic rats administered aqueous extract of C. orbicularis leaf significantly (p < 0.05) decreased the fasting blood glucose and MDA levels, and glucose-6-phosphatase activity. In addition, administration of aqueous extract of C. orbicularis leaf to diabetic rats demonstrated a momentous increase in liver glycogen level, superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, glutathione transferase, and hexokinase activities as well as GLUT-2 and GLUT-4 levels. The data from this study suggest that the aqueous extract of C. orbicularis leaf may be beneficial in the management of diabetic mellitus and its secondary effects.

Theaflavin protects against oxalate calcium-induced kidney oxidative stress injury via upregulation of SIRT1

Renal tubular cell injury induced by calcium oxalate (CaOx) is a critical initial stage of kidney stone formation. Theaflavin (TF) has been known for its strong antioxidative capacity; however, the effect and molecular mechanism of TF against oxidative stress and injury caused by CaOx crystal exposure in kidneys remains unknown. To explore the potential function of TF on renal crystal deposition and its underlying mechanisms, experiments were conducted using a CaOx nephrocalcinosis mouse model established by glyoxylate intraperitoneal injection, and HK-2 cells were subjected to calcium oxalate monohydrate (COM) crystals, with or without the treatment of TF. We discovered that TF treatment remarkably protected against CaOx-induced kidney oxidative stress injury and reduced crystal deposition. Additionally, miR-128-3p expression was decreased and negatively correlated with SIRT1 level in mouse CaOx nephrocalcinosis model following TF treatment. Moreover, TF suppressed miR-128-3p expression and further abolished its inhibition on SIRT1 to attenuate oxidative stress in vitro. Mechanistically, TF interacted with miR-128-3p and suppressed its expression. In addition, miR-128-3p inhibited SIRT1 expression by directly binding its 3'-untranslated region (UTR). Furthermore, miR-128-3p activation partially reversed the acceerative effect of TF on SIRT1 expression. Taken together, TF exhibits a strong nephroprotective ability to suppress CaOx-induced kidney damage through the recovery of the antioxidant defense system regulated by miR-128-3p/SIRT1 axis. These findings provide novel insights for the prevention and treatment of renal calculus.

Antioxidant activities of Dhanwantaram Kashayam -an Ayurvedic poly herbal formulation alleviates diabetic complications in rats

Purpose

Phytochemicals of ethno medicines are being developed as effective drugs with minimum or no toxic side effects. Dhanwantaram Kashayam (DK) is a polyherbal formulation used as a potent general health tonic and is found to have antioxidant activities, but there are no proper scientific studies on its possible benefits. In this study we investigated the antioxidant and antidiabetic properties of DK and trying to explore the possibility of employing DK for the treatment of diseases like diabetes mellitus caused by the imbalance in Reactive Oxygen Species (ROS).

Methods

We investigated the effect of DK on normal and rat model of diabetes. Rats were fed with DK for 21 days. Fasting blood glucose level, haemoglobin, glycosylated hemoglobin, non enzymatic antioxidants like vitamin C, vitamin E, reduced glutathione, and MDA were evaluated.

Results

DK was found to ameliorate the disease symptoms of diabetes. A significant decrease in non enzymatic antioxidants - vitamin C, vitamin E, reduced glutathione and an increase in MDA and fasting blood glucose level was observed in diabetic rats. Administration of DK resulted significant increase in non enzymatic antioxidant levels both in diabetic and normal rats and a decrease in MDA, fasting blood glucose, glycosylated hemoglobin and HOMA-IR index was observed.

Conclusion

This study reveals the protective role of DK in diabetic condition through its antioxidant and antihyperglycemic activity. Our results strongly indicate the possibility of DK being developed as a potent antidiabetic drug. DK could be an alternative in the treatment of diseases with ROS imbalance to expensive and toxic synthetic 'medicines'.

Theaflavin ameliorates renal ischemia/reperfusion injury by activating the Nrf2 signalling pathway in vivo and in vitro

Studies have demonstrated that oxidaive stress-induced apoptosis may be the main pathogenic mechanism of renal ischemia/reperfusion (I/R) injury. Theaflavin, a polyphenolic compound extracted from black tea, has been proven to exert strong antioxidant biological function. The objective of the present study was to investigate the potential role of theaflavin on renal I/R injury and its potential molecular mechanism both in vitro and in vivo. C57/BL6 J mice were used to create a model of I/R injury wherein mice were ligated with bilateral renal pedicles for 45 min, and then reperfused for 24 h. A hypoxia/reoxygenation (H/R) model of TCMK-1 cells was used to simulate I/R in vitro. Theaflavin were administered to the treatment group first and then established the model. Kidney Injury Molecule-1 (KIM-1), serum creatinine, urea nitrogen, and 24-h urinary protein levels were evaluated and changes in mitochondrial membrane potential and the ultrastructure of mitochondria were observed. Cell viability, oxidative stress damage, and apoptosis were assessed. The expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target genes HO-1 and NQO1 were evaluated. Our results revealed that pretreatment with theaflavin significantly inhibited I/R- and H/R-induced renal injury and cell apoptosis. Theaflavin improved mitochondrial dysfunction by attenuating mitochondrial damage and promoting mitochondrial membrane potential. Theaflavin pretreatment significantly reduced malondialdehyde content, while enhancing superoxide dismutase activity in vivo and in vitro. It also reduced oxidative stress and apoptosis mainly by upregulating Nrf2 and its downstream targets in TCMK-1 cells. Thus, theaflavin exerted a protective effect against renal I/R injury by inhibiting oxidative stress and apoptosis via activation of the Nrf2-NQO1/HO-1 pathway as well as correcting mitochondrial dysfunction, thereby presenting its potential as a clinical therapeutic in cases of acute kidney injury.

Theaflavins decrease skeletal muscle wasting in disuse atrophy induced by hindlimb suspension in mice

We previously found that a single dose of theaflavins induced skeletal muscle metabolic changes. In this study, we examined the effect of theaflavins on disuse muscle atrophy model mice by hindlimb suspension. Mice were assigned to 4 groups; ground-vehicle, ground-theaflavins, suspension-vehicle, and suspension-theaflavins, dosed with theaflavins (250 mg/kg/day) for 2 weeks. The peak of myotube size of cross sectional area was significantly moved to the smaller side in the suspension-vehicle group compared with the ground-vehicle group, and these shifts were significantly reduced by the treatment with theaflavins in both soleus and extensor digitorum longus. The level of phosphorylated eukaryotic translation initiation factor 4E-binding protein (4EBP)-1, located downstream of the Akt/mTOR pathway, was significantly different between suspension-vehicle and suspension-theaflavins in soleus. The ratio of forkhead box O (FoxO) 3a to phosphorylated FoxO3a significantly increased in soleus or tended to rise in extensor digitorum longus of suspension-vehicle group compared with ground-vehicle. In contrast, these changes were not observed in suspension-theaflavins group. These results suggested that theaflavins inhibited the progress of disuse muscle atrophy through modulation of protein metabolism.

A Genome-Wide Association Study Identifies the Association between the 12q24 Locus and Black Tea Consumption in Japanese Populations

Several genome-wide association studies (GWASs) have reported the association between genetic variants and the habitual consumption of foods and drinks; however, no association data are available regarding the consumption of black tea. The present study aimed to identify genetic variants associated with black tea consumption in 12,258 Japanese participants. Data on black tea consumption were collected by a self-administered questionnaire, and genotype data were obtained from a single nucleotide polymorphism array. In the discovery GWAS, two loci met suggestive significance (p < 1.0 × 10^-6). Three genetic variants (rs2074356, rs144504271, and rs12231737) at 12q24 locus were also significantly associated with black tea consumption in the replication stage (p < 0.05) and during the meta-analysis (p < 5.0 × 10^-8). The association of rs2074356 with black tea consumption was slightly attenuated by the additional adjustment for alcohol drinking frequency. In conclusion, genetic variants at the 12q24 locus were associated with black tea consumption in Japanese populations, and the association is at least partly mediated by alcohol drinking frequency.

Alpha-Mangostin Improves Cardiac Hypertrophy and Fibrosis and Associated Biochemical Parameters in High-Fat/High-Glucose Diet and Low-Dose Streptozotocin Injection-Induced Type 2 Diabetic Rats

PURPOSE

The aim of present study was to analyze the effect of alpha-mangostin on cardiac hypertrophy and fibrosis and biochemical parameters in high-fat/high-glucose diet and low-dose streptozotocin injection (HF/HG/STZ)-induced type 2 diabetic rats.

METHODS

Diabetes was induced in male Wistar rats by giving a combination of high-fat/high-glucose (HF/HG) diet for 3 weeks and followed by low-dose streptozotocin intraperitoneal injection (STZ; 35 mg/kg) at Week-3 and the HF/HG diet was continued until 8 weeks. The diabetic rats were then divided into four groups (each, n=6): untreated diabetic group (HF/HG/STZ); diabetic group treated with metformin 200 mg/kg/day (HF/HG/STZ+Metformin); diabetic group treated with alpha-mangostin 100 mg/kg/day (HF/HG/STZ+AM100); and diabetic group treated with alpha-mangostin 200 mg/kg/day (HF/HG/STZ+AM200) and all were given by oral gavage for 8 weeks. We also included a control group (C) treated with AM200 (C+AM200). The role of alpha-mangostin was assessed through its effect on blood glucose levels, HOMA-IR, blood pressure, body weight, pro-inflammatory cytokines in cardiac tissue, serum aminotransferases (ALT and AST), lipid profiles (cholesterol and triglyceride), blood urea nitrogen (BUN), uric acid, cardiac hypertrophy and fibrosis.

RESULTS

Diabetic rats treated with alpha-mangostin in both doses for 8 weeks showed decrease in blood glucose levels, HOMA-IR, and blood pressure. Alpha-mangostin treatment also prevented HF/HG/STZ-induced changes in the activities of ALT, AST, BUN, uric acid, lipid profiles, and pro-inflammatory cytokines, which were comparable with the standard drug metformin, while alpha-mangostin did not show any significant effects on control rats (p>0.05). The cardiac hypertrophy and fibrosis were also attenuated in diabetic rats treated with alpha-mangostin in both doses.

CONCLUSION

These data suggest that administration of alpha-mangostin can effectively attenuate diabetes-induced alteration in cardiac hypertrophy and fibrosis as well as biochemical parameters in HF/HG/STZ rats.

Consumption of Terpenoids-Rich Padina pavonia Extract Attenuates Hyperglycemia, Insulin Resistance and Oxidative Stress, and Upregulates PPARγ in a Rat Model of Type 2 Diabetes

Seaweeds are rich in structurally diverse bioactive compounds with promising therapeutic effects. This study aimed to isolate and identify terpenes from the brown alga Padina pavonia and to investigate its antidiabetic activity, pointing to the possible involvement of peroxisome proliferator-activated receptor (PPAR)γ. Type 2 diabetes was induced by feeding rats a high fat diet (HFD) for 4 weeks followed by injection of 35 mg/kg streptozotocin (STZ). The diabetic rats received P. pavonia extract (PPE; 50, 100 and 200 mg/kg) for 4 weeks and samples were collected for analyses. HFD/STZ-induced rats showed hyperglycemia, dyslipidemia, impaired glucose tolerance, decreased insulin, and increased HbA1c and HOMA-IR. PPE ameliorated hyperglycemia and dyslipidemia, and improved glucose tolerance and insulin sensitivity in diabetic rats. Treatment with PPE increased hepatic hexokinase activity and glycogen, suppressed glucose-6-phosphatase, fructose-1,6-biphosphatase, and glycogen phosphorylase, and attenuated oxidative stress, inflammation, and liver injury and lipid infiltration in HFD/STZ-induced rats. In addition, PPE boosted antioxidants and upregulated PPARγ gene and protein expression in the liver of diabetic rats. Phytochemical investigation resulted in the isolation of six terpenes from PPE and in silico analysis revealed their binding affinity toward PPARγ. In conclusion, P. pavonia-derived terpenes attenuated hyperglycemia, dyslipidemia, oxidative stress, and inflammation, and improved insulin sensitivity and carbohydrate metabolism in type 2 diabetic rats. These beneficial effects are mediated via PPARγ activation. However, further studies to explore the exact mechanisms underlying the antidiabetic effect of PPE are recommended.