Antidiabetic effect of total flavonoids from Sanguis draxonis in type 2 diabetic rats

K. J, Goh KW, Desai SM, H. L. K, Ramu R. Characterization of Lactobacillus spp. as Probiotic and Antidiabetic Potential Isolated from Boza, Traditional Fermented Beverage in Turkey

Boza, a cereal-based beverage popular in southeast Europe, is fortified with probiotics and is believed to positively impact the composition of the gut microflora. This investigation focused on fermented cereal-based beverage boza to identify strains of probiotic Lactobacillus spp. capable of inhibiting carbohydrate-hydrolysing enzymes α-glucosidase (AG) and α-amylase (AA). The isolated bacterial strains underwent a comprehensive assessment, including biochemical, molecular, and probiotic trait analyses such as tolerance survivability, adhesion, safety, and health-promoting attributes. We evaluated the inhibitory potential of the supernatant, cell lysate, and intact cells of Lactobacillus spp. Molecular analysis has revealed that isolates RAMULAB30 and RAMULAB29 exhibit a significant genetic similarity (>97%) to Lacticaseibacillus paracasei and Limosilactobacillus fermentum, respectively. These findings are documented in the NCBI database. They exhibited significant resistance to gastrointestinal and intestinal fluids, also indicating their potential for adhesion. Additionally, the isolates showed a significant antibacterial activity, particularly against Micrococcus luteus. They showed resistance to vancomycin and methicillin antibiotics but were more susceptible to streptomycin and ampicillin. Furthermore, the strains demonstrated antioxidant properties. To ensure their safety, a haemolytic assay was conducted despite their general recognition as safe (GRAS) status. The study primarily aimed to evaluate the inhibitory effects of the extract on enzymes AG and AA. Bacterial isolates demonstrated a significant inhibitory activity against both enzyme AG (32%-67% inhibition) and enzyme AA (18%-46% inhibition) in different forms, including supernatant (CS), lysed extract (CE), and intact cell (IC). These findings underscore the potential of bacterial isolates to inhibit the enzyme activity effectively. Furthermore, the L. fermentum RAMULAB29 and L. paracasei RAMULAB30 strains exhibit remarkable antidiabetic potential. Food products incorporating these strains have promising prospects as nutraceuticals, providing improved health benefits.

Loureirin B ameliorates cholestatic liver fibrosis via AKT/mTOR/ATG7-mediated autophagy of hepatic stellate cells

AIM OF THE STUDY

Chronic cholestasis leads to liver fibrosis, which lacks effective treatment. In this study, we investigated the role and mechanisms of action of loureirin B (LB) in cholestatic liver fibrosis.

MATERIALS AND METHODS

Bile duct ligation (BDL)-induced hepatic fibrosis mice were used as in vivo models. Transforming growth factor-β1 (TGF-β1)-pretreated HSC-T6 cells were used to explore the mechanism by which LB attenuates liver fibrosis in vitro. RNA sequencing, quantitative PCR (qPCR), western blotting, immunohistochemistry and immunofluorescence were performed to detect the fibrosis markers and measure autophagy levels. Flow cytometry, cell counting kit-8 (CCK-8) assay, and 5'-ethynyl-2'-deoxyuridine (EdU) assay were conducted to detect cell proliferation and viability. GFP-RFP-LC3 adenovirus, autophagy-related protein 7 (ATG7) siRNA, and bafilomycin A1 (BafA1) were used to verify autophagic flux.

RESULTS

Our results showed that LB ameliorates liver injury, inhibits collagen deposition, and decreases the expressions of fibrosis-related markers in BDL-induced mouse livers. In vitro, we found that LB inhibited proliferation and migration, promoted apoptosis, and inhibited the activation of HSC-T6 cells pretreated with TGF-β1. RNA sequencing analysis of HSC-T6 cells showed that LB treatment predominantly targeted autophagy-related pathways. Further protein analysis indicated that LB downregulated the expression of phosphorylated AKT (p-AKT) and phosphorylated mTOR (p-mTOR), and upregulated LC3-II, p62, and ATG7 both in vivo and in vitro. Intriguingly, ATG7 inactivation reversed the antifibrotic effects of LB on HSC-T6 cells.

CONCLUSIONS

LB can improve BDL-induced liver fibrosis by inhibiting the activation and proliferation of HSCs and is expected to be a promising antifibrotic drug.

The Discovery and Development of Glucagon-Like Peptide-1 Receptor Agonists

Diabetes mellitus has become a serious life-threatening disease. As one of the new drugs for the treatment of diabetes, GLP-1 receptor agonists have attracted a lot of attention. Compared with traditional hypoglycemic drugs, GLP-1 receptor agonists have good safety and tolerability. To a certain extent, they overcome the problem of the short half-life of natural GLP-1 in vivo and can exist stably in patients for a long time, achieving good results in the treatment of diabetes, as well as improving the symptoms of some complications. The GLP-1 receptor agonists in the market are all peptide drugs. Compared with peptide drugs, small molecule agonists have the advantages of low cost and oral administration. In this article, we review the recent research progress of GLP-1 receptor agonists.

Radical oxygen species: an important breakthrough point for botanical drugs to regulate oxidative stress and treat the disorder of glycolipid metabolism

Background: The incidence of glycolipid metabolic diseases is extremely high worldwide, which greatly hinders people's life expectancy and patients' quality of life. Oxidative stress (OS) aggravates the development of diseases in glycolipid metabolism. Radical oxygen species (ROS) is a key factor in the signal transduction of OS, which can regulate cell apoptosis and contribute to inflammation. Currently, chemotherapies are the main method to treat disorders of glycolipid metabolism, but this can lead to drug resistance and damage to normal organs. Botanical drugs are an important source of new drugs. They are widely found in nature with availability, high practicality, and low cost. There is increasing evidence that herbal medicine has definite therapeutic effects on glycolipid metabolic diseases. Objective: This study aims to provide a valuable method for the treatment of glycolipid metabolic diseases with botanical drugs from the perspective of ROS regulation by botanical drugs and to further promote the development of effective drugs for the clinical treatment of glycolipid metabolic diseases. Methods: Using herb*, plant medicine, Chinese herbal medicine, phytochemicals, natural medicine, phytomedicine, plant extract, botanical drug, ROS, oxygen free radicals, oxygen radical, oxidizing agent, glucose and lipid metabolism, saccharometabolism, glycometabolism, lipid metabolism, blood glucose, lipoprotein, triglyceride, fatty liver, atherosclerosis, obesity, diabetes, dysglycemia, NAFLD, and DM as keywords or subject terms, relevant literature was retrieved from Web of Science and PubMed databases from 2013 to 2022 and was summarized. Results: Botanical drugs can regulate ROS by regulating mitochondrial function, endoplasmic reticulum, phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT), erythroid 2-related factor 2 (Nrf-2), nuclear factor κB (NF-κB), and other signaling pathways to improve OS and treat glucolipid metabolic diseases. Conclusion: The regulation of ROS by botanical drugs is multi-mechanism and multifaceted. Both cell studies and animal experiments have demonstrated the effectiveness of botanical drugs in the treatment of glycolipid metabolic diseases by regulating ROS. However, studies on safety need to be further improved, and more studies are needed to support the clinical application of botanical drugs.

Hydroethanolic Extract of A. officinarum Hance Ameliorates Hypertension and Causes Diuresis in Obesogenic Feed-Fed Rat Model

Alpinia officinarum Hance (Zingiberaceae) has been used widely in traditional Chinese and Ayurvedic medicines. Its folkloric uses include relieving stomach ache, treating cold, improving the circulatory system, and reducing swelling. Its effectiveness and mechanism of antihypertension in obesity-induced hypertensive rats have not been studied yet as per our knowledge. This study has been designed to provide evidence of underlying mechanisms to the medicinal use of A. officinarum as a cardiotonic using an obesity-induced hypertension model in rats. Chronic administration of A. officinarum caused a marked reduction in the body weight gain and Lee index of rats compared to the obesogenic diet-fed rats. Its administration also caused attenuation in blood pressure (systolic, diastolic, and mean), serum total cholesterol, triglyceride, and leptin, while an increase in serum HDL and adiponectin levels was noticed. The catalase and superoxide dismutase enzymatic activities were found to be remarkable in the serum of A. officinarum-treated animal groups. A. officinarum showed mild to moderate diuretic, hepatoprotective, and reno-protective effects. The A. officinarum-treated group showed less mRNA expression of 3-hydroxy-3-methylglutaryl-CoA reductase while the mRNA expression of peroxisome proliferator-activated receptor and mRNA expression of cholesterol 7 alpha-hydroxylase were raised in comparison to the hypertensive group of rats evaluated by quantitative real-time polymerase chain reaction. These findings show that A. officinarum possesses antihypertensive and diuretic activities, thus providing a rationale to the medicinal use of A. officinarum in cardiovascular ailments.

Effects of streptozotocin and S-allyl-L-cysteine on motility, plasma membrane integrity, and mitochondrial activity of boar spermatozoa

This study investigated the effects of streptozotocin (STZ) and S-allyl-L-cysteine (SAC) on motility, plasma membrane integrity, and mitochondrial activity of the boar sperm. STZ (0, 10, 50, and 100 μM) and SAC (0, 1, 5, 25, and 100 μM) were treated alone and co-treated in the fresh boar semen. The motility, plasma membrane integrity, and mitochondrial activity of sperm were analyzed at 3, 6, and 9 h after incubation. Boar semen was collected using the gloved-hand method from ten crossbred male pigs, and age of experimental ten male pigs is 24~27 months. The sperm plasma membrane integrity was analyzed using Live/Dead sperm kit. Mitochondrial activity was analyzed using rhodamine 123 and PI double-staining method. Additionally, sperm motility was evaluated according to standard method. Sperm motility, plasma membrane integrity, and mitochondrial activity were decreased in an STZ concentration-dependent manner (P < 0.05) and also were decreased by 10 μM STZ in all incubation times (P < 0.05). The motility, plasma membrane integrity, and mitochondrial activity of the sperm were increased at 5 μM SAC treatment, whereas it was decreased at 100 μM treatment. In addition, sperm motility, plasma membrane integrity, and mitochondrial activity were increased when co-treated with 50 μM STZ and 5 μM SAC group at 9 h after incubation (P < 0.05). Based on our results, STZ has a deleterious effect on sperm characteristics, and SAC can protect sperm motility, viability, and function of the sperm exposed to STZ.

Progress in the discovery of naturally occurring anti-diabetic drugs and in the identification of their molecular targets

Diabetes mellitus (DM), a chronic metabolic disease, severely affects patients' life and intensively increases risks of developing other diseases. It is estimated that 0.4 billion individuals worldwide are subjected to diabetes, especially type 2 diabetes mellitus. At present, although various synthetic drugs for diabetes such as Alogliptin and Rosiglitazone, etc. have been used to manage diabetes, some of them showed severe side effects. Given that the pathogenesis of type 2 diabetes mellitus, natural occurring drugs are beneficial alternatives for diabetes therapy with low adverse effects or toxicity. Recently, more and more plant-derived extracts or compounds were evaluated to have anti-diabetic activities. Their anti-diabetic mechanisms involve certain key targets like α-glucosidase, α-amylase, DPP-4, PPAR γ, PTP1B, and GLUT4, etc. Here, we summarize the newly found anti-diabetic (type 2 diabetes mellitus) natural compounds and extracts from 2011-2017, and give the identification of their molecular targets. This review could provide references for the research of natural agents curing type 2 diabetes mellitus (T2DM).

Assessment of anti-diabetic activity of peanut shell polyphenol extracts

The present study aimed to evaluate the anti-diabetic property of peanut shell polyphenol extracts (PSPEs). Diabetic rats were oral-administrated with PSPE at doses of 50, 100, and 200 mg/kg body weight (BW) per day for 28 consecutive days, with metformin (Met) as a positive control. The results showed that, similar to the Met treatment, administration of PSPE caused significant decreases in food intake, water intake, fasting blood glucose, total cholesterol, triglyceride, low-density lipoprotein cholesterol, and methane dicarboxylic aldehyde in serum, and significant increases in BW, insulin level, high-density lipoprotein cholesterol, superoxide dismutase, glutathione, and liver glycogen. Further, glucose tolerance was markedly improved in the PSPE-treated diabetic groups. Histopathological results showed that PSPE improved cellular structural and pathological changes in liver, kidney, and pancreatic islets. Collectively, the results indicated that the hypoglycemic effects of PSPE on high-fat diet/streptozotocin (HFD/STZ)-induced diabetes are comparable to Met, though their exact mechanism actions are still under investigation. Therefore, the current study suggests that PSPE could be a potential health-care food supplement in the management of diabetes.

Method development and application for multi-component quantification in rats after oral administration of Longxuetongluo Capsule by UHPLC-MS/MS

Although wide applications towards ischemic stroke in clinic, the therapeutic materials of Longxuetongluo Capsule (LTC) that is composed of total phenolic extract of Chinese dragon's blood, are still largely unclear. Exposure pattern characterization of those drug-derived components in vivo, notably in circulation system has been recommended as a viable approach to disclose the effective components of a given herbal medicine. Herein, we aimed to develop a robust method being capable of multi-component quantification in either rat plasma or tissues following oral administration of LTC, and to clarify the kinetic profiles of 11 primary drug-derived phenolic derivatives. Proteins precipitation was carried out for the plasma as well as homogenized tissue samples with acetonitrile. Chromatographic separations were achieved using UHPLC equipped with a shim-pack XR-ODS II column, and confidence-enhanced detection was accomplished through the joint employment of selected-reaction monitoring and tandem mass spectrometry (SRM-MS/MS) on a hybrid triple quadrupole-linear ion trap mass spectrometer. Diverse validation assays proved the method to be sensitive, precise, and rapid for simultaneous determination of those 11 components. Pharmacokinetic and tissue distribution investigations were subsequently conducted in rat after a single 500 mg/kg oral dose. Rapid absorption (T_max, 11.53-68.27 min) and elimination (T_1/2, 6.893-57.90 min) occurred for all analytes-of-interest. Extensive occurrences were observed for 7,4'-dihydroxy-5-methoxyhomoisoflavanone (C_max, 340.0 ng/mL), thevetiaflavone (C_max, 42.86 ng/mL), 5,7,4'-trihydroxyhomoisoflavanone (C_max, 41.55 ng/mL), and pterostilbene (C_max, 25.49 ng/mL) in plasma. Significant distributions occurred for all analytes in the liver as well as kidney, and several compounds could be found in brain. The findings described are envisioned to provide promising information for the in-depth clarification of the therapeutic entities, and also to offer a practical approach for therapeutic drug monitoring of LTC in clinic.

Identification of bioactive heterocyclic compounds from mulberry and their protective effect against streptozotocin-induced apoptosis in INS-1 cells

A phytochemical investigation of the MeOH extracts from mulberries (the fruit of Morus alba L.) led to the identification of six heterocyclic compounds (1‑6). These compounds were screened to detect whether they protected pancreatic INS‑1 cells from streptozotocin (STZ)‑induced cytotoxicity. Compound 3 was the most effective at preventing STZ‑induced cytotoxicity and the production of reactive oxygen species (ROS) in INS‑1 cells. In addition, compound 3 effectively prevented apoptosis induced by STZ in INS‑1 cells. Compound 3 also prevented STZ‑mediated cleavage of caspase‑8, caspase‑3 and poly (ADP‑ribose) polymerase and increased the expression of B‑cell lymphoma‑2 (Bcl‑2), an anti‑apoptotic Bcl‑2 family protein. In conclusion, the results of the present study indicate that compound 3 extracted from the fruit of M. alba was highly effective in preventing type 1 diabetes mellitus and may be a novel treatment option.

Amelioration of streptozotocin‑induced pancreatic β cell damage by morin: Involvement of the AMPK‑FOXO3‑catalase signaling pathway

Pancreatic β cells are sensitive to oxidative stress, which is one of the predominant causes of cell damage and the emergence of diabetes. The identification of effective therapeutic strategies to protect pancreatic cells from oxidative stress has increased interest in the screening of antioxidants from natural products. The present study aimed to investigate the protective effects of morin against streptozotocin (STZ)‑induced cell damage in a rat insulinoma cell line (RINm5F pancreatic β cells) and to identify the underlying mechanisms. The results indicated that morin inhibited the increase in intracellular reactive oxygen species, attenuated the activity of poly (ADP‑ribose) polymerase, restored intracellular nicotinamide adenine dinucleotide levels and reduced the apoptotic cell death of STZ‑treated pancreatic β cells. Treatment with morin significantly upregulated catalase in pancreatic β cells, and ameliorated the STZ‑induced loss of catalase at the genetic, protein and enzymatic level. In further experiments, morin induced the phosphorylation of 5' adenosine monophosphate‑activated protein kinase (AMPK), which subsequently promoted the translocation of forkhead box O3 (FOXO3) to the nucleus. Specific small interfering RNAs (siRNAs) against AMPK and FOXO3 suppressed morin‑induced catalase expression. Furthermore, catalase‑specific siRNA abolished the protective effects of morin against STZ‑stimulated cell death. Taken together, these results indicated that morin protected RINm5F cells from STZ‑induced cell damage by triggering the phosphorylation of AMPK, thus resulting in subsequent activation of FOXO3 and induction of catalase.

Loureirin B promotes insulin secretion through inhibition of KATP channel and influx of intracellular calcium

The development of new diabetes drugs continues to be explored. Loureirin B, a flavonoid, extracted from Dracaena cochinchinensis, has been confirmed to increase insulin secretion and decrease blood glucose levels. For searching the promotion of insulin secretion with the treatment of loureirin B, experiments were employed based on cell experiments and computational methods. First, promotion of insulin secretion was dependent on extracellular glucose concentration. At the genetic level, loureirin B enhanced the relative mRNA level of Pdx-1 and MafA. Meanwhile the intracellular level of ATP increased due to the continuous absorption of glucose. Further experiments showed that the currents of K_ATP channel on Ins-1 cells were inhibited and the voltage-dependent calcium channels were subsequently activated. The increase of Cx43 protein expression might mediate the Ca²⁺ to the intracellular. Through computational simulation, we hypothesized that loureirin B might interact with K_ATP channels to promote insulin secretion. In conclusion, it could be concluded that loureirin B promoted insulin secretion mainly through increasing mRNA level of Pdx-1, MafA, intracellular ATP level, inhibiting the K_ATP current, influx of Ca²⁺ to the intracellular.

Apigenin attenuates streptozotocin-induced pancreatic β cell damage by its protective effects on cellular antioxidant defense

Pancreatic beta cells are very sensitive to oxidative stress, which is one of the major causes of cell damages in diabetes. Growing interest has focused on the development of effective therapeutics to protect pancreatic cells from oxidative stress and searching for potentially protective antioxidants for treating diabetes. Apigenin, a plant-derived flavonoid, was investigated to determine whether it could protect rat insulinoma cell lines (RINm5F pancreatic beta cells) against streptozotocin (STZ)-induced oxidative damages and the mechanisms implicated. Our results showed that STZ treatment could induce oxidative stress and consequent cytotoxic effects in RINm5F cells. Pretreatment with apigenin effectively decreased the intracellular reactive oxygen species (ROS) production, attenuated cellular DNA damage, diminished lipid peroxidation, relieved protein carbonylation, and restored the cell apoptosis of pancreatic beta cells stressed by STZ. Our further experiments demonstrated that the beneficial effects of apigenin were related to ameliorate the loss of antioxidant enzymes of the STZ-treated cells in the level of gene transcription, protein expression, and enzyme activity. That suggested apigenin was not only a free radical scavenger but also a regulator to antioxidant defenses of pancreatic cells. Taken all together, our findings suggested that apigenin could attenuate the STZ-induced oxidative damages in pancreatic beta cells and might serve as a novel agent for the treatment of diabetes.

Flavonoids

Diabetes Mellitus is one of the major healthcare problems faced by the society today and has become alarmingly epidemic in many parts of the world. Despite enormous knowledge and technology advancement, available diabetes therapeutics only provide symptomatic relief by reducing blood glucose level, thereby, just slows down development and progression of diabetes and its associated complications. Thus, the need of the day is to develop alternate strategies that can not only prevent the progression but also reverse already “set-in” diabetic complications. Many flavonoids are reported, traditionally as well as experimentally, to be beneficial in averting diabetes and lowering risk of its accompanying complications. In the present chapter we have convened different flavonoids beneficial in diabetes and comorbid complications and discussed their mechanisms of action. Further, we conclude that coupling current therapeutics with flavonoids might provide exceptional advantage in the management of diabetes and its complications.

Applicability of Isolates and Fractions of Plant Extracts in Murine Models in Type II Diabetes: A Systematic Review

Type II diabetes mellitus is one of the most common public health problems worldwide. Its increasing prevalence in several countries and the difficult metabolic control of individuals with the disease justify studying strategies for primary prevention. The population has sought alternative and cheaper ways to treat the disease, including the use of plants considered medicinal by the population. In this study, we carried out a systematic review on the applicability of isolates and fractions of plant extracts in animal models in type II diabetes. A literature search was performed in MEDLINE/PubMed and Scopus databases. Studies using other experimental animals (horses, rabbits, and monkeys) and humans as well as articles in Chinese, German, and Russian were excluded. We assessed the quality of the studies included by using the criteria described in the ARRIVE guidelines. In general, the animals that received fractions or isolates presented reduced blood glucose levels, normalization of body weight and plasma insulin levels, and reduced total triglycerides and cholesterol. In addition, we observed wide variation among the analyzed parameters, which hindered comparison between the studies found. In further studies, standardized reports and experimental design would help to establish comparable study groups and advance the overall knowledge, thus facilitating translatability from animal data to human clinical conditions.

Radical scavenging potentials of single and combinatorial herbal formulations in vitro

Reactive oxygen and nitrogen species (RONS) are involved in deleterious/beneficial biological processes. The present study sought to investigate the capacity of single and combinatorial herbal formulations of Acanthus montanus, Emilia coccinea, Hibiscus rosasinensis, and Asystasia gangetica to act as superoxide radicals (SOR), hydrogen peroxide (HP), nitric oxide radical (NOR), hydroxyl radical (HR), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical antagonists using in vitro models. The herbal extracts were single herbal formulations (SHfs), double herbal formulations (DHfs), triple herbal formulations (THfs), and a quadruple herbal formulation (QHf). The phytochemical composition and radical scavenging capacity index (SCI) of the herbal formulations were measured using standard methods. The flavonoids were the most abundant phytochemicals present in the herbal extracts. The SCI50 defined the concentration (μg/mL) of herbal formulation required to scavenge 50% of the investigated radicals. The SHfs, DHfs, THfs, and QHf SCI50 against the radicals followed the order HR > SOR > DPPH radical > HP > NOR. Although the various herbal formulations exhibited ambivalent antioxidant activities in terms of their radical scavenging capabilities, a broad survey of the results of the present study showed that combinatorial herbal formulations (DHfs, THfs, and QHf) appeared to exhibit lower radical scavenging capacities than those of the SHfs in vitro.

Antidiabetic andantioxidant properties, and α-amylase and α-glucosidase inhibition effects of triterpene saponins from Piper auritum

Bioactivity-guided fractionation of methanol extracts from leaves of Piper auritum produced four triterpenoid saponin compounds 1-4. Structures were established based on interpretation of mass spectrometry (MS), nuclear magnetic resonance (NMR) data. 21-(p-methoxycinnamoyl)-olean-12-ene-28oic cid-3-O-α-L-arabinopyranosyl-(1→2)-β-D-glucopyranoside (1) and olean-12-ene-28 methyl ester-3-O-α-L-arabinofuranosyl-(1→2)-β-D-glucopyranoside (2) were orally administered to diabetic mice at dosage of 10 mg/kg of body weight per day for 30 days and resultant biochemical parameters were studied. Both compounds significantly (p<0.05) decreased serum glucose, total cholesterol, and triglyceride levels, compared with controls. Low density lipoprotein and high density lipoprotein cholesterol levels were ameliorated. The effects of lipid peroxidation and oxidative stress in the liver, pancreas, and kidney were reversed, with reductions insulin resistance and stimulation of insulin production. β-Glucosidase activities were studied in vitro. Compounds 1 and 2 can be used to improve glucose and lipid metabolism and to reduce the imbalance between generation of reactive oxygen species and scavenging enzyme activities for prevention of diabetic complications.

Anti-Diabetic, Anti-Oxidant and Anti-Hyperlipidemic Activities of Flavonoids from Corn Silk on STZ-Induced Diabetic Mice

Corn silk is a well-known ingredient frequently used in traditional Chinese herbal medicines. This study was designed to evaluate the anti-diabetic, anti-oxidant and anti-hyperlipidemic activities of crude flavonoids extracted from corn silk (CSFs) on streptozotocin (STZ)-induced diabetic mice. The results revealed that treatment with 300 mg/kg or 500 mg/kg of CSFs significantly reduced the body weight loss, water consumption, and especially the blood glucose (BG) concentration of diabetic mice, which indicated their potential anti-diabetic activities. Serum total superoxide dismutase (SOD) and malondialdehyde (MDA) assays were also performed to evaluate the anti-oxidant effects. Besides, several serum lipid values including total cholesterol (TC), triacylglycerol (TG), low density lipoprotein cholesterol (LDL-C) were reduced and the high density lipoprotein cholesterol level (HDL-C) was increased. The anti-diabetic, anti-oxidant and anti-hyperlipidemic effect of the CSFs suggest a potential therapeutic treatment for diabetic conditions.

Analgesic effect of total flavonoids from Sanguis draxonis on spared nerve injury rat model of neuropathic pain

BACKGROUND

Sanguis draxonis (SD) is a kind of red resin obtained from the wood of Dracaena cochinchinensis (Lour.) S. C. Chen (D. cochinchinensis). The active components of total flavonoids from SD (SDF) have analgesic effect.

AIM

The aim of this study is to evaluate the analgesic effects and potential mechanism of SDF on mechanical hypersensitivity induced by spared nerve injury (SNI) model of neuropathic pain in the rat.

METHODS

SNI model in rats was established and then the rats were treated with SDF intragastric administration for 14 days. Paw withdrawal mechanical threshold (PMWT) in response to mechanical stimulation was measured by von Frey filaments on day 1 before operation and days 1, 3, 5, 7, 9, 11, 14 after operation, respectively. After 14 days, we measured the levels of nitric oxide (NO), nitric oxide synthase (NOS), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-10 (IL-10) in the spinal dorsal horn. In addition, the expression of fibroblast growth factor receptor 3 (FGFR3), phosphorylated cyclic AMP response element-binding protein (p-CREB) and glial fibrillary acidic protein (GFAP) of the spinal dorsal horn was evaluated by western blotting and an immunofluorescence histochemical method, respectively.

RESULTS

Intragastric administration of SDF (100, 200, 400 mg/kg) alleviated significantly SNI-induced mechanical hypersensitivity, as PMWT increased in a dose-dependent manner. Moreover, SDF not only reduced the level of NO, NOS, TNF-α and IL-1β, but also upregulated the level of IL-10 in the spinal dorsal horn of SNI rats. At the same time, SDF (100, 200, 400 mg/kg) could inhibit the expression of FGFR3, GFAP and p-CREB in the spinal dorsal horn.

CONCLUSION

SDF has potentially reduced mechanical hypersensitivity induced by SNI model of neuropathic pain which may be attributed to inhibition of astrocytic function (like release pro-inflammatory cytokines) and NO release as well as p-CREB activation in the spinal dorsal horn.

Tetrapleura tetraptera spice attenuates high-carbohydrate, high-fat diet-induced obese and type 2 diabetic rats with metabolic syndrome features

BACKGROUND

Tetrapleura tetraptera, a seasoning and nutritive spice is also used in western African folk medicine in the management of wide variety of diseases including diabetes, inflammation and hypertension. Flavonoids and saponins are some abundant secondary metabolic constituents in the fruits of this plant. This study aimed at evaluating the potential therapeutic action of the polyphenol-rich hydroethanolic extract (HET) of this fruit in experimentally induced obese and type 2 diabetic rats (T2DM) with characteristic metabolic syndrome (MetS).

METHODS

MetS was induced in rats by high-carbohydrate, high-fat diet and administration of low-dose streptozotocin. Then different oral doses of HET (200 and 400 mg/kg) were administered to T2DM rats for 28 days. A standard antidiabetic drug, metformin (300 mg/kg), was used for comparison. The body weight, systolic blood pressure, oxidative stress and metabolic parameters were then assessed to evaluate the effect of HET on MetS.

RESULTS

HET reduced weight gain, fasting blood glucose and plasma insulin levels as well as homeostasis model assessment of insulin resistance (HOMA-IR) and alleviated obesity and T2DM associated oxidative stress and hypertension in rats. Moreover, a significantly hypolipidemic property and an attenuation of liver injury and tissue steatosis was observed after HET administration. HET further demonstrated its anti-inflammation effect via down regulation of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), leptin and an increase in adiponectin. The HET exhibited dose-dependent effects which were comparable to that of metformin.

CONCLUSIONS

The present study thereby demonstrates the anti-insulin resistance, antilipidemic, anti-obesity, hypotensive and anti-inflammatory properties of HET; hence it has the potential to be further developed for the management of MetS such as obesity, T2DM and hypertension.

Loureirin B, an essential component of Sanguis Draxonis, inhibits Kv1.3 channel and suppresses cytokine release from Jurkat T cells

Sanguis draxonis (SD), also known as “Dragon’s Blood”, is a traditional herb medicine that has been used to treat a variety of complications with unknown mechanisms. Recent studies show that SD displays immunosuppressive activities and improves symptoms of type I diabetes in animal models. However, the mechanisms underlying SD’s immunosuppressive actions are not completely understood. The voltage-gated Kv1.3 channel plays a critical role in the pathogenesis of autoimmune diseases by regulating the functions of both T cells and B cells. Here we investigated the effect of SD and one of its active components loureirin B (LrB) on Kv1.3. Both SD and LrB inhibited Kv1.3-mediated currents, produced a membrane depolarization, and reduced Ca²⁺ influx in Jurkat T cells. In addition, application of LrB inhibited phytohemagglutinin (PHA)-induced IL-2 release from activated Jurkat T cells. Furthermore, point mutations in the selective filter region significantly reduced the inhibitory effect of LrB on Kv1.3. The results of these experiments provide evidence that LrB is a channel blocker of Kv1.3 by interacting with amino acid residues in its selective filter region. Direct inhibition of Kv1.3 in T cells by SD and LrB might be the cellular and molecular basis of SD-mediated immunosuppression.

Anti-adipogenic and Pro-osteoblastogenic Activities of Spergularia marina Extract

For decades, Spergularia marina, a local food that is popular in South Korea, has been regarded as a nutritious source of amino acids, vitamins, and minerals. While several halophytes are reported to possess distinct bioactivities, S. marina has yet to be promoted as a natural source of bioactives. In this study, the effects of S. marina on the adipogenic differentiation of 3T3-L1 fibroblasts and the osteoblastic differentiation of MC3T3-E1 pre-osteoblasts and C2C12 myoblast cells were evaluated. The anti-adipogenic effect of S. marina was assessed by measuring lipid accumulation and adipogenic differentiation marker expression. S. marina treatment significantly reduced lipid accumulation and notably decreased the gene levels of peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein α, and sterol regulatory element binding protein 1c. In addition, S. marina enhanced osteoblast differentiation, as indicated by increased alkaline phosphatase activity and increased levels of osteoblastogenesis indicators, namely bone morphogenetic protein-2, osteocalcin, and type I collagen. In conclusion, S. marina could be a source of functional food ingredients that improve osteoporosis and obesity. Further studies, including activity-based fractionation, will elucidate the mechanism of action and active ingredients of S. marina, which would provide researchers with a better understanding of the nutraceutical and therapeutic applications of S. marina.

Diazepam potentiates the antidiabetic, antistress and anxiolytic activities of metformin in type-2 diabetes mellitus with cooccurring stress in experimental animals

Psychological stress is considered as one of the limiting factors in the management of type-2 diabetes mellitus (T2DM). Therefore, the basic objective of the present study was to evaluate the antidiabetic effect of metformin, diazepam, and their combination in cooccurring T2DM and stress condition (DMS). T2DM was induced in the male rats by administering streptozotocin (45 mg/kg, i.p.) and nicotinamide (110 mg/kg, i.p.) with time lag of 15 min. Rats were subjected to two sessions of cold restraint stress paradigm for one hour on the sixth and seventh day after streptozotocin injection. Administration of metformin (25 mg/kg, p.o.) and diazepam (1 mg/kg, p.o.) in combination from the seventh to thirteenth day after streptozotocin injection showed better improvement in glucose tolerance and insulin sensitivity compared to monotherapy of either drug. In addition, the combination significantly attenuated DMS-induced hyperglycemia, hypertriglyceridaemia, hypercorticosteronemia, anxiety-like behavior, and insulin resistance through modulating insulin signaling pathway in the liver compared to monotherapy. Further, improvement of mitochondrial function, integrity, and oxidative stress in hippocampus, hypothalamus, prefrontal cortex, striatum, amygdala, and nucleus accumbens was observed with the combination. Therefore, metformin in combination with diazepam may be a better therapeutic option in the management of T2DM with cooccurring stress condition.

Pharmacological characterization of different fractions of Calotropis procera (Asclepiadaceae) in streptozotocin induced experimental model of diabetic neuropathy

ETHNOPHARMACOLOGICAL RELEVANCE

Calotropis procera (Ait.) R.Br. is one of an ancient traditional shrub, which has been used for the treatment of diabetes, pain and inflammation for thousands of years in India. The root extract of Calotropis procera has been widely used by the tribal׳s of district Udaipur, Rajasthan (India) for treatment of diabetes mellitus and its associated complications like diabetic neuropathy. The present study was performed to explore the protective effect of root, stem and leaf extracts of Calotropis procera in diabetes and diabetic neuropathy against tactile allodynia, mechanical hyperalgesia and thermal hyperalgesia in streptozotocin induced diabetic rats.

MATERIALS AND METHODS

Diabetes and peripheral neuropathy were induced in Wistar rats by injection of streptozotocin (45 mg/kg/intraperitoneally). The roots, stem and leaves of Calotropis procera were sequentially extracted with petroleum ether, chloroform, ethyl acetate and methanol. All the extracts were assessed by oral administration at 100 and 250 mg/kg in streptozotocin diabetic rats. The following compounds were used as positive controls: insulin NPH (1 IU/kg/day), metformin (500 mg/kg/day), glibenclamide (2.5 mg/kg/day) and a combination of acarbose (20 mg/kg/day) with methylcobalamine (500 µg/kg/day). In contrast, the streptozotocin induced untreated diabetic rats termed as negative control. Thermal hyperalgesia, mechanical hyperalgesia and tactile allodynia were evaluated in all groups of streptozotocin diabetic rats to assess the extent of neuropathy by Eddy׳s hot plate, tail immersion, Randall-Selitto and Von Frey hair tests. The basal nociceptive thresholds were assessed in week 4 of post streptozotocin injection. All groups received their treatment on a regular basis from 28 to 42 days following a confirmation of diabetic neuropathy. The nociceptive thresholds were assessed in all groups in week 5 and 6. The histopathology of pancreas and biochemical estimations of plasma insulin and glycosylated haemoglobin (HbA1C%) levels were also performed in week 6 of post streptozotocin injection.

RESULTS

The negative control rats developed diabetes and diabetic neuropathy after 6 week of streptozotocin administration distinguished by significant (p<0.01) hyperalgesia and tactile allodynia with enhanced HbA1C% level compared to normoglycemic rats. Chronic administration of root methanol, stem methanol and leaf ethyl-acetate extracts of Calotropis procera for 2 weeks at 100 and 250 mg/kg doses significantly (p<0.01) attenuated the diabetes induced mechanical hyperalgesia, thermal hyperalgesia, tactile allodynia and HbA1C% level in streptozotocin diabetic rats as compared to negative control rats. Further, the root methanol extract of Calotropis procera in 100mg/kg dose showed the regeneration capability of β cells in the histology of pancreas with significant (p<0.01) improvement in plasma insulin level in streptozotocin diabetic rats compared to negative control rats.

CONCLUSION

Root methanol extract of Calotropis procera (100mg/kg) has shown ameliorative effect in diabetic neuropathy which may be attributed by its multiple actions including potent hypoglycemic and antioxidant.