Myrcia bella Leaf Extract Presents Hypoglycemic Activity via PI3k/Akt Insulin Signaling Pathway

PACAP ameliorates obesity-induced insulin resistance through FAIM/Rictor/AKT axis

Obesity and obesity-related insulin resistance have been a research hotspot. Pituitary adenylate cyclase activating polypeptide (PACAP) has emerged as playing a significant role in energy metabolism, holding promising potential for attenuating insulin resistance. However, the precise mechanism is not fully understood. Palmitic acid and a high-fat diet (HFD) were used to establish insulin resistance model in Alpha mouse liver 12 cell line and C57BL/6 mice, respectively. Subsequently, we assessed the effects of PACAP both in vivo and in vitro. Lentivirus vectors were used to explore the signaling pathway through which PACAP may ameliorate insulin resistance. PACAP was found to selectively bind to the PACAP type I receptor receptor and ameliorate insulin resistance, which was characterized by increased glycogen synthesis and the suppression of gluconeogenesis in the insulin-resistant cell model and HFD-fed mice. These effects were linked to the activation of the Fas apoptotic inhibitory molecule/rapamycin-insensitive companion of mammalian target of rapamycin/RAC-alpha serine/threonine-protein kinase (FAIM/Rictor/AKT) axis. Furthermore, PACAP ameliorated insulin resistance by increasing solute carrier family 2, facilitated glucose transporter members 2/4 and inhibiting gluconeogenesis-related proteins glucose 6-phosphatase catalytic subunit 1 and phosphoenolpyruvate carboxykinase 2 expression. Meanwhile, the phosphorylation of hepatic AKT/glycogen synthase kinase 3β was promoted both in vivo and in vitro by PACAP. Additionally, PACAP treatment decreased body weight, food intake and blood glucose levels in obese mice. Our study shows that PACAP ameliorated insulin resistance through the FAIM/Rictor/AKT axis, presenting it as a promising drug candidate for the treatment of obesity-related insulin resistance.

Exploring the Potential of Myrcia Genus Essential Oils: A Review of Biological Activities and Recent Advances

The present study provides a comprehensive analysis of the chemical composition of essential oils from species of the Myrcia genus and their applications. The compiled results highlight the chemical diversity and biological activities of these oils, emphasizing their potential importance for various therapeutic and industrial applications. The findings reveal that Myrcia essential oils present a variety of bioactive compounds, such as monoterpenes and sesquiterpenes, which demonstrate antimicrobial activities against a range of microorganisms, including Gram-positive and Gram-negative bacteria, as well as yeasts. Furthermore, this study highlights the phytotoxic activity of these oils, indicating their potential for weed control. The results also point to the insecticidal potential of Myrcia essential oils against a range of pests, showing their viability as an alternative to synthetic pesticides. Additionally, species of the genus Myrcia have demonstrated promising hypoglycemic effects, suggesting their potential in diabetes treatment. This comprehensive synthesis represents a significant advancement in understanding Myrcia essential oils, highlighting their chemical diversity and wide range of biological activities. However, the need for further research is emphasized to fully explore the therapeutic and industrial potential of these oils, including the identification of new compounds, understanding of their mechanisms of action, and evaluation of safety and efficacy in different contexts.

Potential Beneficial Effects and Pharmacological Properties of Ergosterol, a Common Bioactive Compound in Edible Mushrooms

Ergosterol is an important sterol commonly found in edible mushrooms, and it has important nutritional value and pharmacological activity. Ergosterol is a provitamin. It has been well established that edible mushrooms are an excellent food source of vitamin D2 because ergosterol is a precursor that is converted to vitamin D2 under ultraviolet radiation. The pharmacological effects of ergosterol, which include antimicrobial, antioxidant, antimicrobial, anticancer, antidiabetic, anti-neurodegenerative, and other activities, have also been reported. This review aims to provide an overview of the available evidence regarding the pharmacological effects of ergosterol and its underlying mechanisms of action. Their potential benefits and applications are also discussed.

Gut microbiome-mediated glucose and lipid metabolism mechanism of star apple leaf polyphenol-enriched fraction on metabolic syndrome in diabetic mice

BACKGROUND

Diabetes is a kind of metabolic syndrome (MetS) that seriously threatens human health globally. The leaf of star apple (Chrysophyllum cainito L.) is an incompletely explored folk medicine on diabetes. And, the effects and mechanisms on diabetes complicated glycolipid metabolism disorders are unknown till now.

PURPOSE

This study aimed to investigate the constituents of star apple leaf polyphenol enriched-fraction (SAP), and elucidate their treatment effects and mechanism on diabetes and accompanied other MetS.

METHODS

The components of SAP were tentatively identified by HPLC-Q-TOF-MS/MS. The antioxidant activity was determined by the scavenging of free radicals and hypoglycemic activities by inhibition of α-glucosidase in vitro. HepG2 cells were used for evaluating the alleviation effects of SAP on lipid accumulation. Streptozotocin and high-fat diet induced diabetic mice were grouped to evaluate the effects of different dosages of SAP. 16S rRNA was conducted to analysis gut microbiome-mediated glucose and lipid metabolism mechanism.

RESULTS

It showed that myricitrin was one of the main active constituents of SAP. SAP not only showed low IC50 on -glucosidase (24.427± 0.626 μg/mL), OH·(3.680± 0.054 μg/mL) and ABTS· (9.155±0.234 μg/mL), but significantly induced the lipid accumulation in HepG2 cells (p < 0.05). SAP at 200 mg/kg·day significantly decreased the blood glucose, insulin and oral glucose tolerance test value (p < 0.05). The insulin resistance indexes and oxidative stress were alleviated after administration. SAP not only attenuated hepatic lipid deposition, but also reversed the hepatic glycogen storage. 16S rRNA sequencing results revealed that the interaction between SAP and gut microbiota led to the positive regulation of beneficial bacteria including Akkermansia, Unspecified S24_7, Alistipes and Unspecified_Ruminococcaceae, which might be one of the mechanisms of SAP on MetS.

CONCLUSION

For the first time, this study explored the regulation effect of star apple leaf polyphenols on the hepatic glycolipid metabolism and studied the underlying mechanism from the view of gut microbiota. These findings indicated that SAP possesses great potential to serve as a complementary medicine for diabetes and associated MetS. It provided scientific evidence for folk complementary medicine on the treatment of diabetes-complicated multiple metabolic disorders.

Hypoglycemic effect and toxicity of the dry extract of Eugenia biflora (L.) DC. leaves

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Eugenia biflora (Myrtaceae) are traditionally used by Amazonian populations for the control of diabetes. However, their chemical composition has not yet been described and pharmacological evidence has not been reported.

OBJECTIVE

This study aimed to identify the chemical constituents and evaluate the hypoglycemic and toxic effect of the dry extract of the E. biflora leaves (DEEB).

MATERIALS AND METHODS

DEEB, obtained by infusion, was analyzed using LC-HRMS and NMR, whose the catechin flavonoid was quantified using NMR. The antidiabetic effect of DEEB was evaluated according to its inhibition of the enzymes α-amylase and α-glucosidase, as well as the content of total phenols, free radical scavengingand antiglycation activities, and its in vitro cell viability. Oral maltose tolerance and chronic multiple dose tests (28 days) in streptozotocin-induced diabetic mice (STZ) were performed. The hypoglycemic effect and toxicity of this extract were evaluated in the multiple dose assay. Biochemical parameters, hemolysis, and levels of the thiobarbituric acid reactive species in the liver were investigated and histopathological analyses of the kidneys and liver were performed.

RESULTS

Eight phenolic compounds were identified, with catechin (15.5 ± 1.7 mg g-1) being the majority compound and a possible chemical marker of DEEB. The extract showed inhibition activity of the enzyme α-glucosidase. Chronic administration of DEEB (50 mg/kg of body weight) reduced glucose levels in diabetic animals, similar to acarbose; however, DEEB (100 and 200 mg/kg bw) caused premature death of mice by D22 of the treatment. Our data indicate that one of the mechanisms of toxicity in DEEB may be related to the aggravation of oxidative stress in the liver. This histopathological study indicated that DEEB failed to minimize the progression of the toxicity of diabetes caused by STZ.

CONCLUSIONS

This study demonstrated the hypoglycemic potential of E. biflora leaves. However, the prolonged use of this tea can be harmful to its users due to its considerable toxicity, which needs to be better investigated.

Protective Mechanism of Fagopyrum esculentum Moench. Bee Pollen EtOH Extract Against Type II Diabetes in a High-Fat Diet/Streptozocin-Induced C57BL/6J Mice

Bee pollen is known as a natural nutrient storehouse and plays a key role in many biological processes. Based on the preliminary separation, identification, and characterization of the main active components of Fagopyrum esculentum Moench. bee pollen (FBP), the protective effects of F. esculentum bee pollen extract (FBPE) on high-fat-diet (HFD) and streptozocin (STZ) induced type II diabetes mellitus (T2DM) was evaluated in this study. The results revealed that FBPE contains 10 active compounds mainly including luteolin (9.46 g/kg), resveratrol (5.25 g/kg), kaemferol (3.67 g/kg), etc. The animal experiment results showed that FBPE could improve HFD-STZ induced T2DM mice. Moreover, the underlying mechanism of the above results could be: (i) FBPE could reduce the inflammation related to phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway, and (ii) the gut microbiota remodeling. The results of correlation analysis showed Candidatus Arthromitus and SMB53 indicated positive correlations to tumor necrosis factor-α (TNF-α); Coprococcus, Ruminocossus, and Odoribacteraceae reported negative correlations to transforming growth factor-β (TGF-β). That FBPE has an outstanding ability to improve T2DM and could be used as a kind of potential functional food for the prevention of T2DM.

Evaluation of Myrcia bella in murine osteosarcoma cells: Effect of the extract and enriched fractions of tannins and flavonoids

Myrcia bella Cambess (Myrtaceae) is an important and common plant, native to the Brazilian Cerrado, with cytotoxicity, antimicrobial, and antidiabetic properties. Therefore, the effects of crude hydroalcoholic extract (CE) and fractions of ellagitannins (ELT) and flavonoids (FV) from Myrcia bella leaves were evaluated in a UMR-106 murine osteosarcoma cells and MC3T3 (normal cell). Cell viability and migration, production of reactive oxygen species (ROS) and matrix metalloproteinase (MMP) -2 and -9 activities were evaluated. In general, CE (80 µg/mL), ELT (160 µg/mL) and FV (64 µg/mL) reduced cell viability (p < 0.05). FV (64 µg/mL) was more effective in inhibition of cell migration, ROS production, and MMP-2 activity when compared to CE and ELT. Myrcia bella a rich source of phenolic compounds and its fraction of flavonoids have cytotoxic effects on osteosarcoma cells, preserving the viability of normal osteoblasts. Due to its antioxidant capacity, flavonoid may be a new therapeutic strategy for cancer.

Chemical Composition and Antifungal Activity of Myrcia multiflora and Eugenia florida Essential Oils

The essential oils of three specimens of Myrcia multiflora (A, B and C) and Eugenia florida were extracted by hydrodistillation, and the chemical compositions from the essential oils were identified by gas chromatography and flame ionization detection (CG/MS and CG-FID). The fungicide potential of the EOs against five fungicide yeasts was assessed: Candida albicans INCQS-40175, C. tropicalis ATCC 6258, C. famata ATCC 62894, C. krusei ATCC 13803 and C. auris IEC-01. The essential oil of the specimen Myrcia multiflora (A) was characterized by the major compounds: α-bulnesene (26.79%), pogostol (21.27%) and δ-amorphene (6.76%). The essential oil of the specimen M. multiflora (B) was rich in (E)-nerolidol (44.4%), (E)-γ-bisabolene (10.64%) and (E,E)-α-farnesene (8.19%), while (E)-nerolidol (92.21%) was the majority of the specimen M. multiflora (C). The sesquiterpenes seline-3,11-dien-6-α-ol (12.93%), eremoligenol (11%) and γ-elemene (10.70%) characterized the chemical profile of the EOs of E. florida. The fungal species were sensitive to the essential oil of M. multiflora (B) (9-11 mm), and the lowest inhibitory concentration (0.07%) was observed in the essential oil of M. multiflora (A) against the yeasts of C. famata. Fungicidal action was observed in the essential oils of M. multiflora (A) against C. famata, with an MIC of 0.78 µL/mL and 3.12 µL/mL; C. albicans, with an MFC of 50 µL/mL and M. multiflora (C) against C. albicans; and C. krusei, with a MFC of 50 µL/mL.

Ursolic acid ameliorates adipose tissue insulin resistance in aged rats via activating the Akt-glucose transporter 4 signaling pathway and inhibiting inflammation

Ageing often results in insulin resistance (IR) and chronic inflammation, and adipose is one of the tissues in which inflammation and IR occur earliest during this process. The present study investigated the effect and underlying mechanisms of ursolic acid (UA) on adipose IR and inflammation in ageing rats. Specific pathogen-free male Sprague-Dawley rats were randomly divided into 4 groups: i) Young normal (young); ii) untreated ageing (aged); and groups supplemented with UA either iii) low-UA 10 mg/kg (UA-L) or iv) high-50 mg/kg (UA-H). Animals in the UA-treated groups received 10 or 50 mg/kg UA (suspended in 5% Gum Arabic solution). The rats in the corresponding aged group and young groups received vehicle (5% Gum Arabic) alone. All rats were intragastrically treated once daily by oral gavage for 7 weeks. The day before the experiment terminated, overnight fasting blood (~700 µl) was collected and plasma was prepared to measure biochemical indicators; western blotting was performed to analyze the expression of insulin signaling proteins [(insulin receptor substrate 1 (IRS-1), phosphorylated (p)-IRS-1, PI3K, glucose transporter 4 (GLUT4), Akt and p-Akt)] and inflammatory factors (NF-κB, IL-6 and IL-1β) in the epididymis white adipose tissue (eWAT). The results revealed that treatment with UA-H decreased eWAT weight, the ratio of eWAT weight/body weight, fasted insulin and triglyceride levels, the homeostasis model assessment of insulin resistance and adipose tissue insulin resistance index in ageing rats, indicating the amelioration of systemic and adipose tissue IR, compared with the aged group. Mechanistically, UA-H administration upregulated p-protein kinase B, the ratio of p-Akt to protein kinase B and total and cellular membrane GLUT4 protein levels in eWAT of ageing rats. Conversely, UA inhibited the increase in NF-κB expression and proinflammatory cytokines IL-6 and IL-1β. However, these alterations were not observed in the rats of the aged group. Taken together, the findings of the present study indicated that UA may ameliorate adipose IR, which is associated with activation of the Akt-GLUT4 signaling pathway and inhibition of inflammation in ageing rats. These data provide a basis for the development of effective and safe drugs or functional substances, such as UA, for the prevention and treatment of metabolic diseases.

Hypoglycemic active principles from the leaves of Bauhinia holophylla: Comprehensive phytochemical characterization and in vivo activity profile

Bauhinia holophylla leaves, also known as "pata-de-vaca", are traditionally used in Brazil to treat diabetes. Although the hypoglycemic activity of this medicinal plant has already been described, the active compounds responsible for the hypoglycemic activity have not yet been identified. To rapidly obtain two fractions in large amounts compatible with further in vivo assay, the hydroalcoholic extract of B. holophylla leaves was fractionated by Vacuum Liquid Chromatography and then purified by medium pressure liquid chromatography combined with an in vivo Glucose Tolerance Test in diabetic mice. This approach resulted in the identification of eleven compounds (1-11), including an original non-cyanogenic cyanoglucoside derivative. The structures of the isolated compounds were elucidated by nuclear magnetic resonance and high-resolution mass spectrometry. One of the major compounds of the leaves, lithospermoside (3), exhibited strong hypoglycemic activity in diabetic mice at the doses of 10 and 20 mg/kg b.w. and prevents body weight loss. The proton nuclear magnetic resonance (1H NMR) quantification revealed that the hydroalcoholic leaves extract contained 1.7% of lithospermoside (3) and 3.1% of flavonoids. The NMR analysis also revealed the presence of a high amount of pinitol (4) (9.5%), a known compound possessing in vivo hypoglycemic activity. The hypoglycemic properties of the hydroalcoholic leaves extract and the traditional water infusion extracts of the leaves of B. holophylla seem thus to be the result of the activity of three unrelated classes of compounds. Such results support to some extent the traditional use of Bauhinia holophylla to treat diabetes.

Momordica charantia silver nanoparticles modulate S/JAK/STAT and P13K/Akt/PTEN signalling pathways in the kidney of streptozotocin-induced diabetic rats

Objectives

Diabetes nephropathy (DN) is one of the complications of diabetes mellitus (DM) marked by gradual progressive loss of renal function. SOCS/JAK/STAT and PI3K/Akt/PTEN signalling pathways are among the chain of interactions implicated in the onset, progression and pathology of DN. Momordica charantia (bitter melon) is often used in folk medicine as therapy for DM due to its hypoglycemic properties. This study was designed to evaluate M. charantia silver nanoparticles' therapeutic effect on DN-induced by streptozotocin (STZ) in Wistar rats.

Methods

The M. charantia nanoparticles used was synthesized using the filtrate from the plant methanolic extract added to 1 mM concentration of aqueous silver nitrate. DM was induced in Wistar rats by intraperitoneal injection of STZ (65 mg/kg). The animals' treatment groups were divided into; Diabetic control (65 mg/kg STZ), Control, and groups treated with silver nitrate (10 mg/kg), M. charantia nanoparticles (50 mg/kg), metformin (100 mg/kg), and plant extract (100 mg/kg). Treatment was terminated after 11 days. RT-PCR determined renal mRNA expression of Akt, PI3k, PTEN, TGF-β, JAK2, STAT3, STAT5, SOCS3, SOCS4 and glucokinase (GCK). Consequently, characterized compounds from M. charantia identified from literatures were docked with PI3K, JAK2 and TGF-β and STAT3 to retrieve potential hits.

Results

Oral administration of M. charantia nanoparticles (50 mg/kg) to STZ-induced diabetic untreated rats significantly ((p < 0.05) down-regulated the mRNA expression of Akt, PI3k, TGF-β, JAK2, STAT3 and upregulated the mRNA expression of PTEN, SOCS3 and SOCS4, thus establishing the role of M. charantia nanoparticles in alleviating DN in diabetic rats. Additionally, there was a significant up-regulation of glucose metabolizing gene (glucokinase) upon administering M. charantia nanoparticles. Molecular docking results showed 12 compounds from bitter melon with docking score ranging from -6.114 kcal/mol to -8.221 kcal/mol that are likely to exert anti-diabetic properties.

Conclusion

Observation drawn from this study suggests that M. charantia nanoparticles ameliorate DN through regulation of SOCS/JAK/STAT and PI3K/Akt/PTEN signalling pathways.

Vochysia tucanorum Mart. butanol fraction presents antitumoral activity in vivo and prevents the installation of cachexia in solid Ehrlich tumor model

Background

Cancer is a multifactorial disease caused by uncontrolled proliferation of cells. About 50–80% of cancer patients develop cachexia, a complex metabolic syndrome associated with an increase of mortality and morbidity. However, there are no effective therapies in medical clinic for cancer cachexia. Vochysia tucanorum Mart. is a common three of the Brazilian “Cerrado”. The butanolic fraction of V. tucanorum (Fr-BuVt), very rich in triterpenes with various biological activities, might be interesting in being tested in cancer cachexia syndrome. Hence, the present study was undertaken to investigate the antitumoral activity of Fr-BuVt and its potential against cachexia development.

Methods

Ehrlich tumor was used as model of cancer cachexia. Ascitic Ehrlich tumor cells were collected, processed and inoculated subcutaneously in saline solution (1 × 10⁷/100 μl; ≥95% viability) for the obtention of solid Ehrlich carcinoma. After inoculation, solid Ehrlich carcinoma-bearing mice were treated by 14 consecutive days by gavage with Fr-BuVt (200 mg/kg). Body weight and tumor volume were measure during the treatment period. Tumors were removed, weighed and properly processed to measure the content and phosphorylation levels of key-proteins involved to apoptotic and proliferation process by Western Blot. Muscles and adipose tissues were removed for weighed. Serum was collected to cytokines levels and energetic blood markers measurements.

Results

The treatment with the Fr-BuVt (200 mg/kg, 14 days) decreased the solid Ehrlich tumor volume and weight besides increased the expression of the pro-apoptotic proteins caspase-3 and BAX, but also decreased the expression of the proteins involved in proliferation NFκB, mTOR and ERK. In addition, our data shows that the administration of Fr-BuVt was able to prevent the installation of cancer cachexia in Ehrlich carcinoma-bearing mice, since prevented the loss of body weight, as well as the loss of muscle and adipose tissue. Moreover, an improvement in some blood parameters such as decrease in cytokines TNF-α and IL-6 levels is observed.

Conclusions

The study revealed that Fr-BuVt has antitumoral activity and prevent installation of cancer cachexia in Ehrlich model. Therefore, Fr-BuVt may represent an alternative treatment for cancer cachexia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-020-03190-1.

Metabolomics of Myrcia bella Populations in Brazilian Savanna Reveals Strong Influence of Environmental Factors on Its Specialized Metabolism

Environmental conditions influence specialized plant metabolism. However, many studies aiming to understand these modulations have been conducted with model plants and/or under controlled conditions, thus not reflecting the complex interaction between plants and environment. To fully grasp these interactions, we investigated the specialized metabolism and genetic diversity of a native plant in its natural environment. We chose Myrcia bella due to its medicinal interest and occurrence in Brazilian savanna regions with diverse climate and soil conditions. An LC-HRMS-based metabolomics approach was applied to analyze 271 samples harvested across seven regions during the dry and rainy season. Genetic diversity was assessed in a subset of 40 samples using amplified fragment length polymorphism. Meteorological factors including rainfall, temperature, radiation, humidity, and soil nutrient and mineral composition were recorded in each region and correlated with chemical variation through multivariate analysis (MVDA). Marker compounds were selected using a statistically informed molecular network and annotated by dereplication against an in silico database of natural products. The integrated results evidenced different chemotypes, with variation in flavonoid and tannin content mainly linked to soil conditions. Different levels of genetic diversity and distance of populations were found to be correlated with the identified chemotypes. These observations and the proposed analytical workflow contribute to the global understanding of the impact of abiotic factors and genotype on the accumulation of given metabolites and, therefore, could be valuable to guide further medicinal exploration of native species.

Evaluation of Antidiabetic Effect of Ethanolic Leaves Extract of Becium grandiflorum Lam. (Lamiaceae) in Streptozotocin-Induced Diabetic Mice

BACKGROUND

Becium grandiflorum has been used traditionally for treatment of different ailments including diabetes mellitus although it lacks scientific evidence. Thus, the present study was aimed at evaluating the antidiabetic effect of Becium grandiflorum in streptozotocin (STZ)-induced diabetic mice.

METHODS

The antidiabetic activity of hydro-ethanolic (30:70) leaf extract of Becium grandiflorum was evaluated in STZ (45 mg/kg)-induced diabetic and normal mice. Antihyperglycemic, hypoglycemic, oral glucose tolerance and body weight change effects of the extract were assessed after administering three doses of the extract (200, 400 and 600 mg/kg), glibenclamide 5 mg/kg (reference drug) and 2% Tween 80 (vehicle). One-way analysis of variance and Tukey's post hoc test were used for data analysis.

RESULTS

All doses of the extract (200 mg/kg (p<0.05), 400 mg/kg (p<0.05) and 600 mg/kg (p<0.01)) and glibenclamide 5 mg/kg (p<0.001) showed statistically significant blood glucose level reduction in normal mice as compared to Tween 80. The hydroalcoholic extract at a dose of 200 mg/kg (p<0.05), 400 mg/kg (p<0.01) and 600 mg/kg (p<0.001) showed better blood glucose tolerance after 60, 120 and 180-minute treatment duration in normal mice as compared to negative control. In diabetic mice, Becium grandiflorum doses and the reference drug caused maximum reduction in blood glucose level at the end of the 15th day of treatment by 17.61%, 22.52%, 24.62% and 34.12%, respectively. The extract's doses and the standard drug showed significant (p<0.05) improvement in body weight while the diabetic control continued to lose their body weight.

CONCLUSION

Thus, Becium grandiflorum exhibits antihyperglycemic activity in STZ-induced diabetic mice, and shows improvement in oral glucose tolerance and body weight, which justifies the claimed use of the plant in ameliorating diabetes mellitus in Ethiopian folk medicine.

White sweet potato ameliorates hyperglycemia and regenerates pancreatic islets in diabetic mice

Background

White sweet potato (WSP) has many potential beneficial effects on metabolic control and on diabetes-related insulin resistance. The antihyperglycemic effects of Tainung No. 10 (TNG10), a variety of WSP in Taiwan, warrant investigation.

Objective

To investigate the antidiabetic activity of WSP (Ipomoea batatas L. TNG10) and the mechanisms for interventions using whole leaves or tubers of WSP in diabetic mice.

Design

Mice were co-administered with streptozotocin and nicotinamide to induce diabetes and then treated with an experimental diet including either 10% WSP tuber (10%-T) and 30% WSP tuber (30%-T) or 0.5% WSP leaf (0.5%-L) and 5% WSP leaf (5%-L). After 8 weeks’ treatment, their plasma glycemic parameters, lipid profiles, and inflammatory marker were analyzed. Their pancreases were removed for histopathologic image analysis; proteins were also extracted from their muscles for phosphoinositide 3-kinase pathway analysis.

Results

The 30%-T or 5%-L mice had lower plasma glucose, insulin, glucose area under the curve (AUC), homeostatic model assessment of insulin resistance (HOMA-IR), alanine transaminase, triglyceride, and tumor necrosis factor alpha levels. In all diabetic mice, their Langerhans’s area was reduced by 60%; however, after 30% WSP-T or 5% WSP-L diets, the mice demonstrated significant restoration of the Langerhans’s areas (approximately 30%). Only in 5%-L mice, slightly increased expression of insulin-signaling pathway-related proteins, phosphorylated insulin receptor and protein kinase B and membrane glucose transporter 4 was noted.

Conclusions

WSP has antihyperglycemic effects by inducing pancreatic islet regeneration and insulin resistance amelioration. Therefore, WSP has potential applications in dietary diabetes management.

Antidiabetic Activity of Extracts of Terminalia brownii Fresen. Stem Bark in Mice

Background

Diabetes mellitus is a chronic metabolic disorder that imposes a huge health and economic burden on societies. Because the currently available medications have many drawbacks, it is important to search for alternative therapies. Medicinal plants used in traditional medicines are ideal candidates. Hence, this study was undertaken to investigate the antidiabetic activity of crude extract and solvent fractions from the stem bark of Terminalia brownii Fresen. (Combretaceae) in mice.

Materials and Methods

The in vitro α-amylase inhibition assay was performed using the chromogenic 3, 5-dinitrosalicylic acid (DNSA) method while the antihyperglycemic activity was assessed using three mouse models: streptozotocin-induced diabetic mice, normoglycemic mice, and oral glucose challenged mice. Experimental diabetes was induced by a single intraperitoneal injection of streptozotocin at a dose of 150 mg/kg and animals with fasting blood glucose level (BGL) >200 mg/dL were considered diabetic. Glibenclamide (5 mg/kg) was used as a standard drug. Fasting BGL and body weight were used to assess the antidiabetic activity. The result was analyzed using GraphPad Prism software version 8 and one-way ANOVA followed by Tukey’s post hoc test with p<0.05 considered as statistically significant.

Results

The crude extract of T. brownii at all tested dose levels (250, 500 and 750 mg/kg) showed a significant BGL reduction in all the three animal models. Moreover, the ethyl acetate and aqueous fractions (at 500 mg/kg) significantly (p<0.01) reduced the BGL in the streptozotocin induced diabetic model. The crude extract and different solvent fractions also showed a dose-dependent in vitro α-amylase inhibitory activity and improvement of body weight.

Conclusion

T. brownii crude extract and its solvent fractions showed a significant antihyperglycemic activity in STZ induced diabetic mice, hypoglycemic activity and improvement of oral glucose tolerance in normal mice.

Hypoglycaemic activity of Bauhinia holophylla through GSK3-β inhibition and glycogenesis activation

CONTEXT

Bauhinia L. species, including Bauhinia holophylla (Bong.) Steud. (Fabaceae), have traditionally been used to treat diabetes. Bauhinia is a complex botanical genus, and the indiscriminate use of the diverse Bauhinia species is reflected in the experimental divergence of their medicinal potential.

OBJECTIVE

The hypoglycaemic and hypolipidaemic effects, molecular mechanism of action and phytochemical properties of an authentic extract of B. holophylla leaves were evaluated.

MATERIALS AND METHODS

A phytochemical study of a 70% EtOH extract was performed using FIA-ESI-IT-MS/MSn and HPLC-PAD-ESI-IT-MS. The extract (200 or 400 mg/kg b.w.) was administered for 14 days to streptozotocin-induced diabetic Swiss mice. Glucose tolerance and insulin sensitivity, blood parameters, gene and protein expression, and the in vivo and in vitro inhibition of intestinal glucosidases were assessed.

RESULTS

HPLC-PAD-ESI-IT-MS analysis identified flavonoid derivatives of quercetin, myricetin, luteolin and kaempferol. Treatment with 400 mg/kg of the extract reduced blood glucose (269.0 ± 32.4 mg/dL vs. 468.0 ± 32.2 mg/dL for diabetic animals), improved glucose tolerance, decreased cholesterol and triglyceride levels, and increased the mRNA expression of proteins involved in glucogenesis in the liver and muscle, such as PI3-K/Akt, GS, GSK3-β (ser-9), AMPK and Glut4. The activity of intestinal maltase was inhibited in vitro (IC50: 43.0 µg/mL for the extract compared to 516.4 µg/mL for acarbose) and in vivo.

DISCUSSION AND CONCLUSIONS

Treatment with B. holophylla was associated with a marked hypoglycaemic effect through the stimulation of glycogenesis and inhibition of gluconeogenesis and intestinal glucose absorption, without increasing basal insulinaemia.

PACAP ameliorates hepatic metabolism and inflammation through up-regulating FAIM in obesity

Obesity is considered a chronic inflammatory disease, the inflammatory factors, such as interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1) and small inducible cytokine A5 (RANTES), are elevated in obese individuals. Pituitary adenylate cyclase-activating polypeptide (PACAP) suppresses anti-inflammatory cytokines and ameliorates glucose and lipid metabolism. Our previous study showed that Fas apoptosis inhibitory molecule (FAIM) is a new mediator of Akt2 signalling, increases the insulin signalling pathway and lipid metabolism. In this study, we found that PACAP promoted the expression of FAIM protein in a human hepatocyte cell line (L02). Overexpression of FAIM with lentivirus suppressed the expression of the inflammatory factor interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1) and tumour necrosis factor alpha (TNF-α). Following treatment of obese mice with FAIM or PACAP for 2 weeks, inflammation was alleviated and the bodyweight and blood glucose levels were decreased. Overexpression of FAIM down-regulated the expression of adipogenesis proteins, including SREBP1, SCD1, FAS, SREBP2 and HMGCR, and up-regulated glycogen synthesis proteins, including Akt2 (Ser474) phosphorylation, GLUT2 and GSK-3β, in the liver of obese mice. However, down-regulation of FAIM with shRNA promotes obesity. Altogether, our data identified that FAIM mediates the function of PACAP in anti-inflammation, glucose regulation and lipid metabolism in obese liver.

Dietary chokeberry and dried jujube fruit attenuates high-fat and high-fructose diet-induced dyslipidemia and insulin resistance via activation of the IRS-1/PI3K/Akt pathway in C57BL/6 J mice

Background

The incidence of metabolic syndrome linked to dyslipidemia and insulin resistance has increased; thus, studies must be conducted to elucidate this phenomenon. The present study aimed to investigate the protective effects of chokeberry and dried jujube diet on high-fat and high-fructose diet-induced dyslipidemia in mice.

Methods

Male C57BL/6 J mice were divided into five groups: ND, mice fed normal diet and tap water; HFFD, mice fed 60% high-fat and 10% fructose diet (HFFD) in tap water; HFFD+C, mice fed HFFD with 1% chokeberry powder; HFFD+J, mice fed HFFD with 1% jujube fruit powder; and HFFD+M, mice fed HFFD with 0.5% chokeberry + 0.5% jujube fruit powder mixture.

Results

After 10 weeks of dietary treatment, chokeberry and dried jujube fruits reduced HFFD-induced weight gain and central obesity and decreased liver weight and abdominal and epididymal fat mass. Furthermore, such fruits attenuated HFFD-induced dyslipidemia; decreased triglyceride, total cholesterol, non-high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and very-low-density lipoprotein-cholesterol levels. Insulin resistance was improved via the consumption of dietary chokeberry and dried jujube fruits according to various indicators (serum insulin level, fasting blood glucose level, homeostatic model assessment-insulin resistance score, and oral glucose tolerance test value). These treatments were found to lower serum triglyceride levels. Moreover, the consumption of chokeberry and dried jujube changed the hepatic protein expression of insulin receptor, insulin receptor substrate 1, phosphoinositide 3-kinase, Akt, and catalase, which are associated with insulin resistance.

Conclusions

Chokeberry and dried jujube could be used in the management of dyslipidemia and insulin resistance associated with metabolic syndrome by reducing risk parameters in mice with HFFD.

Biological Activity and Pharmacological Application of Pectic Polysaccharides: A Review

Pectin is a polymer with a core of alternating α-1,4-linked d-galacturonic acid and α-1,2-l-rhamnose units, as well as a variety of neutral sugars such as arabinose, galactose, and lesser amounts of other sugars. Currently, native pectins have been compared to modified ones due to the development of natural medicines and health products. In this review, the results of a study of the bioactivity of pectic polysaccharides, including its various pharmacological applications, such as its immunoregulatory, anti-inflammatory, hypoglycemic, antibacterial, antioxidant and antitumor activities, have been summarized. The potential of pectins to contribute to the enhancement of drug delivery systems has been observed.

Glutamine Enhances the Hypoglycemic Effect of Insulin in L6 Cells via Phosphatidylinositol-3-Kinase (PI3K)/Protein Kinase B (AKT)/Glucose Transporter 4 (GLUT4) Signaling Pathway

Background

Diabetes mellitus (DM) is characterized by a decreased blood level of glutamine (Gln), which may contribute to the disturbance in the effect of insulin on skeletal muscle. Therefore, it is crucial to study how to improve the effect of insulin on skeletal muscle by increasing Gln. In the present study, we investigated the effect of Gln on the hypoglycemic action of insulin in skeletal muscle L6 cells at high glucose levels through the insulin signaling pathway and glycogen synthesis pathway.

Material/Methods

The L6 cells were cultured in and stimulated by Gln and insulin. The glutamine analogue, L-Gamma-Glutamyl-p-nitroanilide (GPNA), was used for verifying the effect of Gln. The expression of insulin signaling molecules, including phosphatidylinositol-3-kinase (PI3K), 3-phosphoinositide-dependent protein kinase-1 (PDK1), protein kinase B (AKT), protein kinase C zeta (PKCζ), and glucose transporter 4 (GLUT4), were detected by real-time PCR and Western blot analysis, GLUT4 translocation was observed by immunofluorescence staining, glycogen synthase kinase (GSK) was analyzed by Western blotting, and glucose uptake was measured by glucose oxidase method (GOD).

Results

The results demonstrated that Gln combined with insulin remarkably up-regulated PI3K and PDK1 and also increased AKT and PKCζ phosphorylation. The present study shows that Gln enhanced the impact of insulin on GLUT4 and its translocation. The results of glucose uptake and GSK phosphorylation further confirmed the hypoglycemic effect of Gln accompanied with insulin. The hypoglycemic effect of Gln was reversed by GPNA.

Conclusions

These findings suggest that Gln enhances the hypoglycemic role of insulin through the PI3K/AKT/GLUT4 signaling pathway and glycogen synthesis pathway.

Qualitative and Quantitative Analysis of Ethanolic Extract and Phenolic Fraction of Jatropha aethiopica (Euphorbiaceae) Leaves and Their Hypoglycemic Potential

Although Jatropha aethiopica, popularly known in Cuba as "mata diabetes", is used in salads and as a dietary supplement, its chemical composition and antidiabetic properties yet remains unclear. In this work, we evaluate the qualitative and quantitative composition of ethanolic extract (EE) and phenolic fraction (PF) of Jatropha aethiopica leaves and their hypoglycemic and hypolipidemic activity. Chemical fractionation of the ethanolic extract yielded nine compounds, which included protocatechuic acid (1), chlorogenic acid (2), caffeic acid (3), quercetin 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranolsyl-(1 → 6)]-β-d-galactopyranoside (4), a new kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 4)-[α-l-rhamnopyranolsyl-(1 → 6)]-β-d-galactopyranoside (5), kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranolsyl-(1 → 6)]-β-d-glucopyranoside (6), rutin (7), kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (8), and quercetin (9). The compounds (1, 4-7) were quantified by high-performance liquid chromatography photodiode array detection (HPLC-PDA) in both the ethanolic extract (62.65 ± 0.15 mg/g) and phenolic fraction (61.72 ± 0.23 mg/g). The results obtained show that both ethanolic extract and phenolic fraction contributed toward the improvement of glucose tolerance, which in turn led to a decline in the glucose levels. Remarkably, the ethanolic extract presented a relatively higher promising effect compared to metformin.

Regulatory Efficacy of Brown Seaweed Lessonia nigrescens Extract on the Gene Expression Profile and Intestinal Microflora in Type 2 Diabetic Mice

SCOPE

In this study, the antidiabetic activity of Lessonia nigrescens ethanolic extract (LNE) is investigated in streptozotocin (SZT)-induced type 2 diabetic mice fed with a high-sucrose/high-fat diet.

METHODS AND RESULTS

Ultra high performance liquid chromatography coupled with photo-DAD and electospray ionization-mass spectrometry (ESI-MS) is employed to analyze the major compounds in LNE. The components of the intestinal microflora in type 2 diabetic mice are analyzed by high-throughput next-generation 16S rRNA gene sequencing. Fasting blood glucose levels in diabetic mice are significantly decreased after LNE administration. The histology reveals that LNE could protect the cellular architecture of liver and kidney. LNE treatment significantly increases Bacteroidetes and decreases Firmicutes populations in intestinal microflora. Specifically, It could selectively enrich the amounts of beneficial bacteria, Barnesiella, as well as reduce the abundances of Clostridium and Alistipes. The increased gene and protein expression levels of phosphatidylinositol 3-kinase (PI3K) in the liver are observed in LNE treatment groups, while the expressions of c-Jun N-terminal kinase (JNK) are significantly downregulated.

CONCLUSION

The above findings suggest that LNE could be considered as a functional food for reducing blood glucose and regulating intestinal microflora.

Phytochemical Analysis and Antimicrobial Activity of Myrcia tomentosa (Aubl.) DC. Leaves

This work describes the isolation and structural elucidation of compounds from the leaves of Myrcia tomentosa (Aubl.) DC. (goiaba-brava) and evaluates the antimicrobial activity of the crude extract, fractions and isolated compounds against bacteria and fungi. Column chromatography was used to fractionate and purify the extract of the M. tomentosa leaves and the chemical structures of the compounds were determined using spectroscopic techniques. The antibacterial and antifungal activities were assessed using the broth microdilution method. The phytochemical investigation isolated 11 compounds: α-bisabolol, α-bisabolol oxide B, α-cadinol, β-sitosterol, n-pentacosane, n-tetracosane, quercetin, kaempferol, avicularin, juglanin and guaijaverin. The crude ethanolic extract and its fractions were tested against 15 bacteria and 9 yeasts. The crude extract inhibited the in vitro growth of yeasts at concentration of 4 to 32 μg/mL. The hexane, dichloromethane, ethyl acetate and aqueous fractions inhibited Candida sp. at concentrations of 4 to 256 μg/mL, whereas the Cryptococcus sp. isolates were inhibited only by the hexane and dichloromethane fractions in minimal inhibitory concentrations (MICs) at 16 to 64 μg/mL. The flavonoid quercetin-3-O-α-arabinofuranose (avicularin) was the most active compound, inhibiting Candida species in concentrations of 2 to 32 μg/mL. The MIC values suggest potential activity of this plant species against yeast.

The role of medicinal plants in the treatment of diabetes: a systematic review

INTRODUCTION

Diabetes is a serious metabolic disorder and plenty of medical plants are used in traditional medicines to treat diabetes. These plants have no side effects and many existing medicines are derived from the plants. The purpose of this systematic review is to study diabetes and to summarize the available treatments for this disease, focusing especially on herbal medicine.

METHODS

Required papers about diabetes and effective plants were searched from the databases, including Science direct, PubMed, Wiley, Scopus, and Springer. Keywords in this study are "medicinal plants", "diabetes", "symptom", "herbal", and "treatment". Out of the 490 collected articles (published in the period between 1995 and 2015), 450 were excluded due to non-relevance or lack of access to the original article.

RESULTS

Diabetes is mainly due to oxidative stress and an increase in reactive oxygen species that can have major effects. Many plants contain different natural antioxidants, in particular tannins, flavonoids, C and E vitamins that have the ability to maintain β-cells performance and decrease glucose levels in the blood.

CONCLUSION

According to published results, it can be said that medical plants are more affordable and have less side effects compared synthetic drugs, and are more effective in treatment of diabetes mellitus.

Antimutagenicity and induction of antioxidant defense by flavonoid rich extract of Myrcia bella Cambess. in normal and tumor gastric cells

ETHNOPHARMACOLOGICAL RELEVANCE

The Brazilian "Cerrado" is an important source of natural products, such as Myrcia bella Cambess (MB, also known as "mercurinho"). MB leaves are popularly used for the treatment of diabetes and gastrointestinal disorders; however, only its hypoglycemic activity has been experimentally described.

AIM OF THE STUDY

Because MB is used to treat gastrointestinal disorders, the present study characterized biological activities of hydroalcoholic MB extract in human normal and tumor gastric cells.

MATERIALS AND METHODS

Cytotoxic, antiproliferative, genotoxic and protective effects were evaluated, as well as the effects of the MB extract on gene expression.

RESULTS

The MB extract induced cytotoxicity in tumor cells at lower concentrations compared with normal cells as assessed by the MTT assay. Moreover, the MB extract induced necrosis based on acridine orange/ethidium bromide staining. An antiproliferative effect was evidenced through an arrest in the G2/M phase detected by flow cytometry and a decrease in the nuclear division index using the cytokinesis-block micronucleus cytome assay. Cells treated with MB extract combined with doxorubicin (DXR) showed increased NUBDs, which may be related to the gene amplification of CCND1. Antimutagenic effects were also observed and may be associated with the antioxidant activities detected using the CM-H2DCFDA probe.

CONCLUSIONS

Our findings showed the following: (a) high concentrations of MB induced cytotoxicity and cell death by necrosis; (b) its antiproliferative effect was associated with G2/M arrest; and (c) its antioxidant activity could be responsible for the observed antimutagenic effects and for protective effects against gastrointestinal disorders previously described to MB. Although these effects are not specific to normal or tumor cells, they provide a panel of biological activities for further exploration.

Ergosterol Alleviates Kidney Injury in Streptozotocin-Induced Diabetic Mice

Ergosterol (ERG) has been widely used in the development of novel drugs due to its unique physiological function. However, little is known about the protective effects of ERG on diabetes. Hence, the current study was designed to evaluate the positive role of ergosterol on streptozotocin- (STZ-) induced diabetes in mice. Oral glucose tolerance test (OGTT) was carried out to assess blood glucose level. Biochemical parameters such as uric acid, creatinine, serum insulin, triglycerides (TG), and total cholesterol (TC) were also measured. Pathological condition of kidney was examined by hematoxylin-eosin (H&E) staining. The expressions of PI3K, p-PI3K, Akt, p-Akt, NF-κBp65, p-NF-κBp65, IκBα, and p-IκBα were analyzed by western blot. ERG significantly reduced the concentrations of blood glucose, uric acid, creatinine, TG, and TC. Serum insulin was elevated with ERG treatment. In addition, renal pathologic changes of diabetes mice were also alleviated by ERG. Obtained data revealed that ERG restored the levels of PI3K/Akt/NF-κB signaling-related proteins in comparison with diabetes mice. Above all, it could be assumed that ERG might play a positive role in regulating STZ-induced diabetes through suppressing PI3K/Akt/NF-κB pathway.

Constituents and Pharmacological Activities of Myrcia (Myrtaceae): A Review of an Aromatic and Medicinal Group of Plants

Myrcia is one of the largest genera of the economically important family Myrtaceae. Some of the species are used in folk medicine, such as a group known as “pedra-hume-caá” or “pedra-ume-caá” or “insulina vegetal” (insulin plant) that it is used for the treatment of diabetes. The species are an important source of essential oils, and most of the chemical studies on Myrcia describe the chemical composition of the essential oils, in which mono- and sesquiterpenes are predominant. The non-volatile compounds isolated from Myrcia are usually flavonoids, tannins, acetophenone derivatives and triterpenes. Anti-inflammatory, antinociceptive, antioxidant, antimicrobial activities have been described to Myrcia essential oils, while hypoglycemic, anti-hemorrhagic and antioxidant activities were attributed to the extracts. Flavonoid glucosides and acetophenone derivatives showed aldose reductase and α-glucosidase inhibition, and could explain the traditional use of Myrcia species to treat diabetes. Antimicrobial and anti-inflammatory are some of the activities observed for other isolated compounds from Myrcia.

Effects of D-Pinitol on Insulin Resistance through the PI3K/Akt Signaling Pathway in Type 2 Diabetes Mellitus Rats

D-pinitol, a compound isolated from Pinaceae and Leguminosae plants, has been reported to possess insulin-like properties. Although the hypoglycemic activity of D-pinitol was recognized in recent years, the molecular mechanism of D-pinitol in the treatment of diabetes mellitus remains unclear. In this investigation, a model of type 2 diabetes mellitus (T2DM) with insulin resistance was established by feeding a high-fat diet (HFD) and injecting streptozocin (STZ) to Sprague-Dawley (SD) rats, targeting the exploration of more details of the mechanism in the therapy of T2DM. D-pinitol was administrated to the diabetic rats as two doses [30, 60 mg/(kg·body weight·day)]. The level of fasting blood glucose (FBG) was decreased 12.63% in the high-dosage group, and the ability of oral glucose tolerance was improved in D-pinitol-treated groups. The biochemical indices revealed that D-pinitol had a positive effect on hypoglycemic activity. Western boltting suggested that D-pinitol could promote the expression of the phosphatidylinositol-3-kinase (PI3K) p85, PI3Kp110, as well as the downstream target protein kinase B/Akt (at Ser473). Besides, D-pinitol inhibited the expression of glycogen synthesis kinase-3β (GSK-3β) protein and regulated the expression of glycogen synthesis (GS) protein and then accelerated the glycogen synthesis. Above all, D-pinitol played a positive role in regulating insulin-mediated glucose uptake in the liver through translocation and activation of the PI3K/Akt signaling pathway in T2DM rats.

Liraglutide Exerts Antidiabetic Effect via PTP1B and PI3K/Akt2 Signaling Pathway in Skeletal Muscle of KKAy Mice

Background. Liraglutide (a glucagon-like peptide 1 analog) was used for the treatment of type 2 diabetes (T2DM) which could produce glucose-dependent insulin secretion. Aim. The aim was to investigate whether liraglutide could improve myofibril and mitochondria injury in skeletal muscle and the mechanisms in diabetic KKAy mice. Method. We divided the male KKAy mice into 2 groups: liraglutide group (250 μg/kg/day liraglutide subcutaneous injection) and model group; meanwhile, the male C57BL/6J mice were considered as the control. After 6 weeks, the ultrastructure of skeletal muscle was observed by electron microscope. The gene expressions of protein tyrosine phosphatase 1B (PTP1B), phosphatidylinositol 3-kinase (PI3K), and glucose transporter type 4 (GLUT4) were determined by real-time PCR. The protein levels of the above molecules and phospho-Akt2 (p-Akt2) were measured by Western blot. Results. Liraglutide significantly ameliorated the injury of mitochondria by increasing the number (+441%) and the area (+113%) of mitochondria and mitochondrial area/100 µm(2) (+396%) in skeletal muscle of KKAy mice. The results of real-time PCR and Western blot showed that liraglutide downregulated PTP1B while it upregulated PI3K and GLUT4 (P < 0.01). The protein level of p-Akt2/Akt2 was also increased (P < 0.01). Conclusion. These results revealed that liraglutide could improve myofibril and mitochondria injury in skeletal muscle against T2DM via PTP1B and PI3K/Akt2 signaling pathway.