Momordica charantia (Bitter Melon) reduces obesity-associated macrophage and mast cell infiltration as well as inflammatory cytokine expression in adipose tissues

Kaguacidine A: a novel spirohydantoin-containing cucurbitane glycoside from vines of Momordica charantia L

The spirohydantoin-containing cucurbitane-type triterpenoid, kaguacidine A (1), was isolated and purified from 95% ethanol extract of vines of Momordica charantia L. (Cucurbitaceae). Its unprecedented chemical structure, a spirohydantoin substituent at C-23 of cucurbitane, was elucidated by extensive spectroscopic analyses, including HRESIMS, IR, optical rotation, 1 D- and 2 D-NMR spectra. The possible biosynthetic pathway is deduced and may be attributed to the metabolic activity of microbial symbionts in M. charantia L. Compound 1 was evaluated for anti-inflammatory activity against LPS-induced NO production in RAW 264.7 cells and anti-proliferative activity against four cancer cell lines, including HEp-2, MCF-7, Hep-G2, and WiDr. Compound 1 showed moderate anti-inflammatory activity with an IC50 value of 18.5 ± 0.4 μg/mL and weak anti-proliferative activity against MCF-7, HEp-2, Hep-G2, and WiDr with IC50 values of >40, 33.8 ± 0.6, 31.0 ± 0.7, and 27.0 ± 0.7 μM, respectively.

Research progress in the treatment of an immune system disease-type 1 diabetes-by regulating the intestinal flora with Chinese medicine and food homologous drugs

Type 1 diabetes (T1D) is a specific autoimmune disease related to genetic and autoimmune factors. Recent studies have found that the intestinal flora is one of the important environmental factors in the development of T1D. The gut microbiota is the largest microbiota in the human body and has a significant impact on material and energy metabolism. Related studies have found that the intestinal floras of T1D patients are unbalanced. Compared with normal patients, the abundance of beneficial bacteria is reduced, and various pathogenic bacteria are significantly increased, affecting the occurrence and development of diabetes. Medicinal and food homologous traditional Chinese medicine (TCM) has a multicomponent, multitarget, and biphasic regulatory effect. Its chemical composition can increase the abundance of beneficial bacteria, improve the diversity of the intestinal flora, reduce blood sugar, and achieve the purpose of preventing and treating T1D by regulating the intestinal flora and its metabolites. Therefore, based on a review of T1D, intestinal flora, and TCM derived from medicine and food, this review describes the relationship between T1D and the intestinal flora, as well as the research progress of TCM interventions for T1D through regulation of the intestinal flora. Medicine and food homologous TCM has certain advantages in treating diabetes and regulating the intestinal flora. It can be seen that there is still great research space and broad development prospects for the treatment of diabetes by regulating the intestinal flora with drug and food homologous TCM.

The metabolic effect of Momordica charantia cannot be determined based on the available clinical evidence: a systematic review and meta-analysis of randomized clinical trials

Several studies have shown that Momordica charantia L. (Cucurbitaceae, bitter melon) has beneficial effects on metabolic syndrome (MetS) parameters and exerts antidiabetic, anti-hyperlipidemic, and anti-obesity activities. Since the findings of these studies are contradictory, the goal of this systematic review and meta-analysis was to assess the efficacy of bitter melon in the treatment of metabolic syndrome, with special emphasis on the anti-diabetic effect. Embase, Cochrane, PubMed, and Web of Science databases were searched for randomized controlled human trials (RCTs). The meta-analysis was reported according to the PRISMA statement. The primary outcomes of the review are body weight, BMI, fasting blood glucose, glycated hemoglobin A1c, systolic blood pressure, diastolic blood pressure, serum triglyceride, HDL, LDL, and total cholesterol levels. Nine studies were included in the meta-analysis with 414 patients in total and 4-16 weeks of follow-up. In case of the meta-analysis of change scores, no significant effect could be observed for bitter melon treatment over placebo on fasting blood glucose level (MD = -0.03; 95% CI: -0.38 to 0.31; I2 = 34%), HbA1c level (MD = -0.12; 95% CI: -0.35 to 0.11; I2 = 56%), HDL (MD = -0.04; 95% CI: -0.17 to 0.09; I2 = 66%), LDL (MD = -0.10; 95% CI: -0.28 to 0.08; I2 = 37%), total cholesterol (MD = -0.04; 95% CI: -0.17 to 0.09; I2 = 66%,), body weight (MD = -1.00; 95% CI: -2.59-0.59; I2 = 97%), BMI (MD = -0.42; 95% CI: -0.99-0.14; I2 = 95%), systolic blood pressure (MD = 1.01; 95% CI: -1.07-3.09; I2 = 0%) and diastolic blood pressure levels (MD = 0.24; 95% CI: -1.04-1.53; I2 = 0%). Momordica treatment was not associated with a notable change in ALT, AST, and creatinine levels compared to the placebo, which supports the safety of this plant. However, the power was overall low and the meta-analyzed studies were also too short to reliably detect long-term metabolic effects. This highlights the need for additional research into this plant in carefully planned clinical trials of longer duration.

Promising roles of Zingiber officinale roscoe, Curcuma longa L., and Momordica charantia L. as immunity modulators against COVID-19: A bibliometric analysis

Zingiber officinale, Curcuma longa, and Momordica charantia are medicinal plants that are commonly used in the form of herbal tea, which is formulated to strengthen the immune system, especially against COVID-19 infection. Excellent antioxidant, anti-inflammatory, and immunostimulatory properties have been reported for their bioactive compounds, which have been shown to aid in stimulating immune systems as well as lowering the risk of severe COVID-19 such as lung injury. Yet, no bibliometric study on the subject is available. Hence, the purpose of this study is to quantitatively examine the existing articles related to the therapeutic potential of these three herbs, as well as their mechanisms of action in combating the SARS-CoV-2 virus. A total of 121 papers were retrieved from Scopus database up to 14^th March 2023. The bibliometric analysis was conducted using VOSviewer software. Based on the literature search, Z. officinale was the most researched plant. India appeared as the most prolific country, with the highest number of articles contributed by two authors from India (Rathi, R. and Gayatri Devi, R.). In terms of keywords, the plants were associated with immune modulation, management of symptoms, antioxidant, anti-inflammatory and antiviral activities. Several important bioactive compounds were responsible for these effects such as gingerol, paradol, shogaol, curcumin, calebin A, momordicoside, karaviloside and cucurbitadienol. These compounds were hypothesized to prevent and cure COVID-19 by regulating inflammatory response, downregulating oxidative stress and modulating immunostimulatory activity. This review paper therefore supports the potential of Z. officinale, C. longa, and M. charantia to be formulated as a herbal blend for treating and preventing COVID-19 infection.

Antioxidant Activities of Natural Compounds from Caribbean Plants to Enhance Diabetic Wound Healing

Diabetic wound healing is a global medical challenge. Several studies showed that delayed healing in diabetic patients is multifactorial. Nevertheless, there is evidence that excessive production of ROS and impaired ROS detoxification in diabetes are the main cause of chronic wounds. Indeed, increased ROS promotes the expression and activity of metalloproteinase, resulting in a high proteolytic state in the wound with significant destruction of the extracellular matrix, which leads to a stop in the repair process. In addition, ROS accumulation increases NLRP3 inflammasome activation and macrophage hyperpolarization in the M1 pro-inflammatory phenotype. Oxidative stress increases the activation of NETosis. This leads to an elevated pro-inflammatory state in the wound and prevents the resolution of inflammation, an essential step for wound healing. The use of medicinal plants and natural compounds can improve diabetic wound healing by directly targeting oxidative stress and the transcription factor Nrf2 involved in the antioxidant response or the mechanisms impacted by the elevation of ROS such as NLRP3 inflammasome, the polarization of macrophages, and expression or activation of metalloproteinases. This study of the diabetic pro-healing activity of nine plants found in the Caribbean highlights, more particularly, the role of five polyphenolic compounds. At the end of this review, research perspectives are presented.

Anti-adipogenic activities of pheophorbide a and pyropheophorbide a isolated from wild bitter gourd (Momordica charantia L. var. abbreviata Seringe) in vitro

BACKGROUND

The wild bitter gourd (WBG) is a commonly consumed vegetable in Asia that has antioxidant and hypoglycemic properties. The present study aimed to investigate the anti-adipogenic activities of isolated compounds from WBG on 8-day differentiated cultures of 3 T3-L1 adipocytes that were then stained with Oil Red O (ORO) or diamidino-2-phenylindole (DAPI).

RESULTS

ORO stains of the methanol extracts of de-seeded HM86 cultivar of WBG (WBG-M) and the ethyl acetate fractions (WBG-M-EA) showed anti-adipogenic activities against differentiated adipocytes. Two chlorophyll-degraded compounds, pheophorbide a (1) and pyropheophorbide a (2), were isolated from WBG-M-EA. Treatments with 1 (5, 10, and 20 μmol L^-1 ) and 2 (2.5, 5, and 10 μmol L^-1 ) showed dose-dependent reductions in lipid accumulations and reduced nuclear DAPI stains in differentiated 3 T3-L1 adipocytes. The concentrations for 50% inhibition against lipid accumulations of 1 and 2, respectively, were 16.05 and 7.04 μmol L^-1 . Treatments with 1 and 2 showed enhanced lactate dehydrogenase release in the first 4-day cell mitotic clonal expansions during the differentiating cultural processes, although the effect was less on the non-differentiating cultural processes. Thus, 1 and 2 were more toxic to differentiating adipocytes than to non-differentiated pre-adipocytes, which partly resulted in anti-adipogenic activities with lowered lipid accumulations.

CONCLUSION

Both 1 and 2 showed anti-adipogenic activities in cell models. These chlorophyll-degraded compounds commonly exist in several vegetables during storage or edible seaweeds, which will provide resources for further investigations aiming to test anti-obesity in animal studies. © 2022 Society of Chemical Industry.

Associations of the Mediterranean-Style Dietary Pattern Score with Coronary Artery Calcification and Pericardial Adiposity in a Sample of US Adults

Several studies have identified improvements in the risks of cardiovascular disease in adults following a Mediterranean dietary pattern. However, data are scarce on its association with coronary artery calcification (CAC) and pericardial adiposity (PAT) in US adults with and without diabetes. To address this gap, we conducted a case-control study using baseline data from the Coronary Artery Calcification in Type 1 Diabetes (CACTI) study [n = 1255; Type 1 Diabetes (T1D): n = 563; non-Diabetes Mellitus (non-DM): n = 692]. Participants completed a validated food frequency questionnaire, fasting (12 h overnight fast) biochemical analyses, and a physical examination including anthropometric measures. CAC and PAT were measured using electron beam-computed tomography. Logistic regression models were used to examine the associations of the Mediterranean-Style Dietary Pattern Score (MSDPS) with CAC (presence or absence), and linear regression models were applied to PAT analyses. In all of the adjusted models, no significant associations with CAC were found. For PAT, an increasing MSDPS was consistently associated with its lower volume in models adjusted for age, sex, diabetes status, total calories, and body mass index (all p < 0.05). The association between MSDPS and PAT was attenuated after adjusting for serum lipids and physical activity. In conclusion, the baseline data from the CACTI study show that a greater adherence to MSDPS is associated with a lower PAT volume and provide evidence that the Mediterranean dietary pattern is associated with lower cardiovascular risk markers.

Four cucurbitane glycosides taimordisins A–D with novel furopyranone skeletons isolated from the fruits of Momordica charantia

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Four new cucurbitane-type triterpenoids glycosides were isolated from the fresh fruit of Momordica charantia and determined by NMR, HRESIMS, and biosynthesis.

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Taimordisins A and B possess rare bicyclic-fused and trifuso-centro-fused ring systems at side chain of the cucurbitane-type triterpenoids at the first time.

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Taimordisins A-D showed the inhibition of NO production by LPS-stimulated in RAW264.7 macrophage cells.

Four novel triterpene glycosides, taimordisins A–D (1–4), were discovered from fresh fruits of Taiwanese Momordica charantia. The chemical framework and relative stereochemistry of these four natural products were isolated, purified, and determined by using various separation and spectroscopy techniques. Each of them features a unique bicyclic-fused or trifuso-centro-fused ring system. Notably, 1 and 2 are cucurbitane-based compounds possessing a new C-24 and C-2″ carbon–carbon linkage with 5-hydroxy-2-(hydroxymethyl)tetrahydro-4H-pyran-4-one and 6-(hydroxymethyl)tetrahydro-4H-pyran-3,4,4-triol units, respectively, and represented an unprecedented molecular skeleton. In terms of biosynthesis, they all originate from a common precursor 3-hydroxycucurbita-5,24-dien-19-al-7,23-di-O-β-glucopyranoside. Of two sugar moieties, the one at 23-O-β-glucopyranoside grants each individual congener uniqueness likely through microbial symbiont-mediated intramolecular transformation into two major types of furo[2,3-b]pyranone and furo[3,2-c]pyranone derivatives. These new products possess desirable anti-inflammatory biological activities in addition to being generally regarded as safe.

Transcriptome and metabolome changes induced by bitter melon (Momordica charantia)- intake in a high-fat diet induced obesity model

Background and aim

Metabolic syndrome (MetS) is a complex disease of physiological imbalances interrelated to abnormal metabolic conditions, such as abdominal obesity, type II diabetes, dyslipidemia and hypertension. In the present pilot study, we investigated the nutraceutical bitter melon (Momordica charantia L) -intake induced transcriptome and metabolome changes and the converging metabolic signaling networks underpinning its inhibitory effects against MetS-associated risk factors.

Experimental procedure

Metabolic effects of lyophilized bitter melon juice (BMJ) extract (oral gavage 200 mg/kg/body weight-daily for 40 days) intake were evaluated in diet-induced obese C57BL/6J male mice [fed-high fat diet (HFD), 60 kcal% fat]. Changes in a) serum levels of biochemical parameters, b) gene expression in the hepatic transcriptome (microarray analysis using Affymetrix Mouse Exon 1.0 ST arrays), and c) metabolite abundance levels in lipid-phase plasma [liquid chromatography mass spectrometry (LC-MS)-based metabolomics] after BMJ intervention were assessed.

Results and conclusion

BMJ-mediated changes showed a positive trend towards enhanced glucose homeostasis, vitamin D metabolism and suppression of glycerophospholipid metabolism. In the liver, nuclear peroxisome proliferator-activated receptor (PPAR) and circadian rhythm signaling, as well as bile acid biosynthesis and glycogen metabolism targets were modulated by BMJ (p < 0.05). Thus, our in-depth transcriptomics and metabolomics analysis suggests that BMJ-intake lowers susceptibility to the onset of high-fat diet associated MetS risk factors partly through modulation of PPAR signaling and its downstream targets in circadian rhythm processes to prevent excessive lipogenesis, maintain glucose homeostasis and modify immune responses signaling.

Moderate l-lactate administration suppresses adipose tissue macrophage M1 polarization to alleviate obesity-associated insulin resistance

As a crucial metabolic intermediate, l-lactate is involved in redox balance, energy balance, and acid-base balance in organisms. Moderate exercise training transiently elevates plasma l-lactate levels and ameliorates obesity-associated type 2 diabetes. However, whether moderate l-lactate administration improves obesity-associated insulin resistance remains unclear. In this study, we defined 800 mg/kg/day as the dose of moderate l-lactate administration. In mice fed with a high-fat diet (HFD), moderate l-lactate administration for 12 weeks was shown to alleviate weight gain, fat accumulation, and insulin resistance. Along with the phenotype alterations, white adipose tissue thermogenesis was also found to be elevated in HFD-fed mice. Meanwhile, moderate l-lactate administration suppressed the infiltration and proinflammatory M1 polarization of adipose tissue macrophages (ATMs) in HFD-fed mice. Furthermore, l-lactate treatment suppressed the lipopolysaccharide-induced M1 polarization of bone marrow-derived macrophages (BMDMs). l-lactate can bind to the surface receptor GPR132, which typically drives the downstream cAMP-PKA signaling. As a nutrient sensor, AMP-activated protein kinase (AMPK) critically controls macrophage inflammatory signaling and phenotype. Thus, utilizing inhibitors of the kinases PKA and AMPK as well as siRNA against GPR132, we demonstrated that GPR132-PKA-AMPKα1 signaling mediated the suppression caused by l-lactate treatment on BMDM M1 polarization. Finally, l-lactate addition remarkably resisted the impairment of lipopolysaccharide-treated BMDM conditional media on adipocyte insulin sensitivity. In summary, moderate l-lactate administration suppresses ATM proinflammatory M1 polarization through activation of the GPR132-PKA-AMPKα1 signaling pathway to improve insulin resistance in HFD-fed mice, suggesting a new therapeutic and interventional approach to obesity-associated type 2 diabetes.

Immunomodulatory effects and associated mechanisms of Momordica charantia and its phytochemicals

Momordica charantia L. (M. charantia), which is a member of the Cucurbitaceae family and widely distributed in tropical and subtropical regions, has been consumed as a vegetable and also used as herbal medicine for thousands of years worldwide.

Fabrication of electrochemical biosensor composed of multi-functional DNA 4 way junction for TNF-α detection in human serum

Tumor necrosis factor (TNF-α) is a representative cytokine family known to induce multiple signaling cascades leading to various cellular responses, such as cell death, survival, and differentiation. It has been reported that blocking the action of TNF-α in various diseases can improve disease prognosis. Therefore, it is important to monitor TNF-α in patient plasma and properly regulate its action. In this study, we report a label-free electrochemical biosensor consisting of a multifunctional DNA 4-way junction (MF-4WJ) for TNF-α detection in human serum. MF-4WJ does not require additional labeling and signal amplification processes. The electrochemical properties of functionalized MF-4WJ were evaluated by cyclic voltammetry (CV) in the presence of Ag⁺ intercalated between the mismatched sequences of MF-aptamers as redox-active species. Afterward, CV was carried out to evaluate the performance of the fabricated biosensor. The proposed label-free electrochemical biosensor was able to effectively detect TNF-α in a dynamic range of 0.15 pg/ml to 150 ng/ml. Limit of detection (LOD) was at 0.07 pg/ml in HEPES. Moreover, it was confirmed that even in 10% diluted human serum, TNF-α could be detected in an excellent dynamic range of 0.15 pg/ml to ∼ 15 ng/ml and LOD was at 0.14 pg/ml in 10% diluted human serum.

A triterpenoid-enriched extract of bitter melon leaves alleviates hepatic fibrosis by inhibiting inflammatory responses in carbon tetrachloride-treated mice

Liver fibrosis is a progression of chronic liver disease characterized by excess deposition of fibrillary collagen. The aim of this study was to investigate the protective effect of a triterpenoid-enriched extract (TEE) from bitter melon leaves against carbon tetrachloride (CCl₄)-induced hepatic fibrosis in mice. Male ICR mice received TEE (100 or 150 mg kg^-1) by daily oral gavage for one week before starting CCl₄ administration and throughout the entire experimental period. After intraperitoneal injection of CCl₄ for nine weeks, serum and liver tissues of the mice were collected for biochemical, histopathological and molecular analyses. Our results showed that TEE supplementation reduced CCl₄-induced serum aspartate aminotransferase and alanine aminotransferase activities. Histopathological examinations revealed that CCl₄ administration results in hepatic fibrosis, while TEE supplementation significantly suppressed hepatic necroinflammation and collagen deposition. In addition, TEE supplementation decreased α-smooth muscle actin (α-SMA)-positive staining and protein levels of α-SMA and transforming growth factor-β1. TEE-supplemented mice had lower mRNA expression levels of interleukin-6, tumor necrosis factor-α, and toll-like receptor 4. Moreover, TEE (150 mg kg^-1) supplementation significantly reduced intrahepatic inflammatory Ly6C⁺ monocyte infiltration. We demonstrated that TEE could ameliorate hepatic fibrosis by regulating inflammatory cytokine secretion and α-SMA expression in the liver to reduce collagen accumulation.

JD419, a Staphylococcus aureus Phage With a Unique Morphology and Broad Host Range

Phage therapy represents a possible treatment option to cure infections caused by multidrug-resistant bacteria, including methicillin and vancomycin-resistant Staphylococcus aureus, to which most antibiotics have become ineffective. In the present study, we report the isolation and complete characterization of a novel phage named JD219 exhibiting a broad host range able to infect 61 of 138 clinical strains of S. aureus tested, which included MRSA strains as well. The phage JD419 exhibits a unique morphology with an elongated capsid and a flexible tail. To evaluate the potential of JD419 to be used as a therapeutic phage, we tested the ability of the phage particles to remain infectious after treatment exceeding physiological pH or temperature. The activity was retained at pH values of 6.0–8.0 and below 50°C. As phages can contain virulence genes, JD419’s complete genome was sequenced. The 45509 bp genome is predicted to contain 65 ORFs, none of which show homology to any known virulence or antibiotic resistance genes. Genome analysis indicates that JD419 is a temperate phage, despite observing rapid replication and lysis of host strains. Following the recent advances in synthetic biology, JD419 can be modified by gene engineering to remove prophage-related genes, preventing potential lysogeny, in order to be deployed as a therapeutic phage.

Jayaprakasha G, S. Patil B. Anti-Inflammatory, Antidiabetic Properties and In Silico Modeling of Cucurbitane-Type Triterpene Glycosides from Fruits of an Indian Cultivar of Momordica charantia L

Diabetes mellitus is a chronic disease and one of the fastest-growing health challenges of the last decades. Studies have shown that chronic low-grade inflammation and activation of the innate immune system are intimately involved in type 2 diabetes pathogenesis. Momordica charantia L. fruits are used in traditional medicine to manage diabetes. Herein, we report the purification of a new 23-O-β-d-allopyranosyl-5β,19-epoxycucurbitane-6,24-diene triterpene (charantoside XV, 6) along with 25ξ-isopropenylchole-5(6)-ene-3-O-β-d-glucopyranoside (1), karaviloside VI (2), karaviloside VIII (3), momordicoside L (4), momordicoside A (5) and kuguaglycoside C (7) from an Indian cultivar of Momordica charantia. At 50 µM compounds, 2–6 differentially affected the expression of pro-inflammatory markers IL-6, TNF-α, and iNOS, and mitochondrial marker COX-2. Compounds tested for the inhibition of α-amylase and α-glucosidase enzymes at 0.87 mM and 1.33 mM, respectively. Compounds showed similar α-amylase inhibitory activity than acarbose (0.13 mM) of control (68.0–76.6%). Karaviloside VIII (56.5%) was the most active compound in the α-glucosidase assay, followed by karaviloside VI (40.3%), while momordicoside L (23.7%), A (33.5%), and charantoside XV (23.9%) were the least active compounds. To better understand the mode of binding of cucurbitane-triterpenes to these enzymes, in silico docking of the isolated compounds was evaluated with α-amylase and α-glucosidase.

The Effect of Momordica charantia in the Treatment of Diabetes Mellitus: A Review

In recent years, many studies of Momordica charantia (MC) in the treatment of diabetes mellitus (DM) and its complications have been reported. This article reviewed the effect and mechanism of MC against diabetes, including the results from in vitro and in vivo experiments and clinical trials. The common side effects of MC were also summarized. We hope that it might open up new ideas for further mechanism exploration and clinical application as well as provide a scientific theoretical basis for the development of drugs or foods derived from MC.

Inhibiting NF-κB Signaling Activation Reduces Retinal Neovascularization by Promoting a Polarization Shift in Macrophages

Purpose

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling is involved in regulating tumor angiogenesis and metastasis; however, the exact mechanism of action in retinal neovascularization (RNV) remains unclear. The purpose of this study was to determine the role and underlying mechanism of NF-κB in regulating RNV in retinal neovascularization mice.

Methods

Expression levels of NF-κB signaling were detected by immunofluorescence staining and western blotting in retinas of oxygen-induced retinopathy (OIR) mice. OIR mice were treated with either pyrrolidinedithiocarbamate (PDTC), a NF-κB signaling inhibitor, or PBS, and retinal flat-mounts were performed to quantify the area of RNV and the recruitment of retinal macrophages by immunofluorescence staining. Macrophage polarization detected by flow cytometric analysis and the expression of macrophage polarization-associated genes were evaluated by immunofluorescence staining, quantitative RT-PCR, and western blotting.

Results

Expression levels of phosphorylated IκBα (p-IκBα) and p-p65 increased in OIR mice. Inhibiting NF-κB signaling activation by PDTC significantly reduced RNV. After treatment with PDTC, a reduction in the quantity of macrophages was observed: M1 polarized macrophages decreased, and M2 polarized macrophages increased; the expression of M1 macrophage-associated cytokines decreased and M2 macrophage-associated cytokines increased in the retinas of OIR mice.

Conclusions

Blocking activation of NF-κB signaling reduces RNV by promoting polarization of M1 macrophages to M2 macrophages in OIR mice.

Momordica charantia Suppresses Inflammation and Glycolysis in Lipopolysaccharide-Activated RAW264.7 Macrophages

Macrophage activation is a key event that triggers inflammatory response. The activation is accompanied by metabolic shift such as upregulated glucose metabolism. There are accumulating evidences showing the anti-inflammatory activity of Momordica charantia. However, the effects of M. charantia on inflammatory response and glucose metabolism in activated macrophages have not been fully established. The present study aimed to examine the effect of M. charantia in modulating lipopolysaccharide (LPS)-induced inflammation and perturbed glucose metabolism in RAW264.7 murine macrophages. The results showed that LPS-induced NF-κB (p65) nuclear translocation was inhibited by M. charantia treatment. In addition, M. charantia was found to reduce the expression of inflammatory genes including IL6, TNF-α, IL1β, COX2, iNOS, and IL10 in LPS-treated macrophages. Furthermore, the data showed that M. charantia reduced the expression of GLUT1 and HK2 genes and lactate production (-28%), resulting in suppression of glycolysis. Notably, its effect on GLUT1 gene expression was found to be independent of LPS-induced inflammation. A further experiment also indicated that the bioactivities of M. charantia may be attributed to its key bioactive compound, charantin. Taken together, the study provided supporting evidences showing the potential of M. charantia for the treatment of inflammatory disorders.

Crosstalk Between Mast Cells and Adipocytes in Physiologic and Pathologic Conditions

Excessive fatty acids and glucose uptake support the infiltration of adipose tissue (AT) by a variety of immune cells including neutrophils, pro-inflammatory M1 macrophages, and mast cells (MCs). These cells promote inflammation by releasing pro-inflammatory mediators. The involvement of MCs in AT biology is supported by their accumulation in the AT of obese individuals along with significantly higher serum levels of MC-derived tryptase. AT-resident MCs under the influence of locally derived adipokines such as leptin become activated and release pro-inflammatory cytokines including TNFα that worsens the inflammatory state. MCs support angiogenesis in AT by releasing chymase and inducing preadipocyte differentiation and also the proliferation of adipocytes through 15-deoxy-delta PGJ2/PPARγ interaction. Additionally, they contribute to the remodeling of the AT extracellular matrix (ECM) and play a role in the recruitment and activation of leukocytes. MC degranulation has been linked to brown adipocyte activation, and evidence indicates an important link between MCs and the appearance of BRITE/beige adipocytes in white AT. Cell crosstalk between MCs and AT-resident cells, mainly adipocytes and immune cells, shows that these cells play a critical role in the regulation of AT homeostasis and inflammation.

Electrochemical ELISA Protein Biosensing in Undiluted Serum Using a Polypyrrole-Based Platform

An electrochemical enzyme-linked immunosorbent assay (ELISA) biosensor platform using electrochemically prepared ~11 nm thick carboxylic functionalized popypyrrole film has been developed for bio-analyte measurement in undiluted serum. Carboxyl polypyrrole (PPy-COOH) film using 3-carboxy-pyrrol monomer onto comb-shaped gold electrode microarray (Au) was prepared via cyclic voltammetry (CV). The prepared Au/PPy-COOH was then utilized for electrochemical ELISA platform development by immobilizing analyte-specific antibodies. Tumor necrosis factor-alpha (TNF-α) was selected as a model analyte and detected in undiluted serum. For enhanced performance, the use of a polymeric alkaline phosphatase tag was investigated for the electrochemical ELISA. The developed platform was characterized at each step of fabrication using CV, electrochemical impedance spectroscopy and atomic force microscopy. The bioelectrodes exhibited linearity for TNF-α in the 100 pg/mL-100 ng/mL range when measured in spiked serum, with limit of detection of 78 pg/mL. The sensor showed insignificant signal disturbance from serum proteins and other biologically important proteins. The developed platform was found to be fast and specific and can be applicable for testing and measuring various biologically important protein markers in real samples.

mcIRBP-19 of Bitter Melon Peptide Effectively Regulates Diabetes Mellitus (DM) Patients' Blood Sugar Levels

This study was conducted to test the effectiveness of a particular bitter melon peptide (BMP), with a specific sequence of 19 amino acids (mcIRBP-19), in regulating diabetic patients' blood glucose. In order to test the product with the specially processed BMP, a total of 142 diabetic patients were solicited as study subjects, of which 64 were assigned to an experiment group and 78 to a control group. Biochemical data were compared with a paired t-test to verify the significance of changes over different time periods. The clinical results showed that BMP started to improve the subjects' glycated hemoglobin (HbA1c) levels at the end of the second month (T2), with mean values being significantly lowered from 7.8 ± 1.4% (T0) to 7.5 ± 1.4% (T2) (p = 0.004). The values reduced continuously, eventually reaching 7.4 ± 1.1% (p = 0.000) at the end of the experiment (T3). HbA1c levels for the control group were 7.5 ± 1.2% in T0 and 7.5 ± 1.1% (T3), and not significantly different (p = 0.852) over the same period. This study provides clinical evidence that helps to verify the effectiveness of the new BMP product in regulating diabetic patients' blood sugar levels.

Identification of chemotypes in bitter melon by metabolomics: a plant with potential benefit for management of diabetes in traditional Chinese medicine

INTRODUCTION

Bitter melon (Momordica charantia, Cucurbitaceae) is a popular edible medicinal plant, which has been used as a botanical dietary supplement for the treatment of diabetes and obesity in Chinese folk medicine. Previously, our team has proved that cucurbitanes triterpenoid were involved in bitter melon's anti-diabetic effects as well as on increasing energy expenditure. The triterpenoids composition can however be influenced by changes of varieties or habitats.

OBJECTIVES

To clarify the significance of bioactive metabolites diversity among different bitter melons and to provide a guideline for selection of bitter melon varieties, an exploratory study was carried out using a UHPLC-HRMS based metabolomic study to identify chemotypes.

METHODS

Metabolites of 55 seed samples of bitter melon collected in different parts of China were profiled by UHPLC-HRMS. The profiling data were analysed with multivariate (MVA) statistical methods. Principle component analysis (PCA) and hierarchical cluster analysis (HCA) were applied for sample differentiation. Marker compounds were identified by comparing spectroscopic data with isolated compounds, and additional triterpenes were putatively identified by propagating annotations through a molecular network (MN) generated from UHPLC-HRMS & MS/MS metabolite profiling.

RESULTS

PCA and HCA provided a good discrimination between bitter melon samples from various origins in China. This study revealed for the first time the existence of two chemotypes of bitter melon. Marker compounds of those two chemotypes were identified at different MSI levels. The combined results of MN and MVA demonstrated that the two chemotypes mainly differ in their richness in cucurbitane versus oleanane triterpenoid glycosides (CTGs vs. OTGs).

CONCLUSION

Our finding revealed a clear chemotype distribution of bioactive components across bitter melon varieties. While bioactivities of individual CTGs and OTGs still need to be investigated in more depth, our results could help in future the selection of bitter melon varieties with optimised metabolites profile for an improved management of diabetes with this popular edible Chinese folk medicine.

Momordica charantia, a Nutraceutical Approach for Inflammatory Related Diseases

Momordica charantia, commonly called bitter melon, is a plant belonging to Cucurbitaceae family known for centuries for its pharmacological activities, and nutritional properties. Due to the presence of many bioactive compounds, some of which possess potent biological actions, this plant is used in folk medicine all over the world for the treatment of different pathologies, mainly diabetes, but also cancer, and other inflammation-associated diseases. It is widely demonstrated that M. charantia extracts contribute in lowering glycaemia in patients affected by type 2 diabetes. However, the majority of existing studies on M. charantia bioactive compounds were performed only on cell lines and in animal models. Therefore, because the real impact of bitter melon on human health has not been thoroughly demonstrated, systematic clinical studies are needed to establish its efficacy and safety in patients. Besides, both in vitro and in vivo studies have demonstrated that bitter melon may also elicit toxic or adverse effects under different conditions. The aim of this review is to provide an overview of anti-inflammatory and anti-neoplastic properties of bitter melon, discussing its pharmacological activity as well as the potential adverse effects. Even if a lot of literature is available about bitter melon as antidiabetic drug, few papers discuss the anti-inflammatory and anti-cancer properties of this plant.

Role of Gut Microbiota in the Pharmacological Effects of Natural Products

Increasing evidence has demonstrated that natural products derived from traditional Chinese medicine, such as ginseng, berberine, and curcumin, possess a wide variety of biological activities on gut microbiota, which may cause changes in the composition of intestinal microbiota, microbial metabolites, intestinal tight junction structure, and mucosal immunology. These changes will eventually result in the exertion of the pharmacological effects by treatment with these natural products. In this review, we will discuss how gut microbiota is influenced by commonly used natural products. Furthermore, our findings are expected to provide novel insight into how these untargeted natural products function via gut microbiota.

Momordica charantia (bitter melon) modulates adipose tissue inflammasome gene expression and adipose-gut inflammatory cross talk in high-fat diet (HFD)-fed mice

Systemic and tissue-specific inflammation has a profound influence on regulation of metabolism, and therefore, strategies to reduce inflammation are of special interest in prevention and treatment of obesity and type 2 diabetes (T2D). Antiobesity and antidiabetic properties of Momordica charantia (bitter melon, BM) have been linked to its protective effects on inflammation and gut microbial dysbiosis. We investigated the mechanisms by which freeze-dried BM juice reduces adipose inflammation in mice fed a 60% high-fat diet (HFD) for 16 weeks. Although earlier studies indicated that BM inhibited recruitment of macrophages (Mφ) infiltration in adipose tissue of rodents and reduced NF-kB and IL-1β secretions, the mechanisms remain unknown. We demonstrate that freeze-dried BM juice inhibits recruitment of Mφ into adipose tissue and its polarization to inflammatory phenotype possibly due to reduction of sphingokinase 1 (SPK1) mRNA in HFD-fed mice. Furthermore, reduction of IL-1β secretion by freeze-dried BM juice in the adipose tissue of HFD-fed mice is correlated to alleviation of NLRP3 inflammasome components and their downstream signaling targets. We confirm previous observations that BM inhibited inflammation of colon and gut microbial dysbiosis in HFD-fed mice, which in part may be associated with the observed anti-inflammatory effects in adipose tissue if HFD-fed mice. Overall, functional foods such as BM may offer potential dietary interventions that may impact sterile inflammatory diseases such as obesity and T2D.

Beneficial Effects of an Aged Black Garlic Extract in the Metabolic and Vascular Alterations Induced by a High Fat/Sucrose Diet in Male Rats

Aged black garlic (ABG) is a functional food with antioxidant and anti-inflammatory properties. Recent studies also report its beneficial metabolic effects in a context of obesity or diabetes, although the mechanisms involved are poorly understood. The aim of this work was to analyze the effects of an ABG extract in the vascular and metabolic alterations induced by a high-fat/sucrose diet in rats. For this purpose, male Sprague–Dawley rats were fed either a standard chow (controls; n = 12) or a high-fat/sucrose diet (HFD; n = 24) for 16 weeks. From week 8 on, half of the HFD rats were treated with a commercial ABG extract concentrated in S-allyl cysteine and melanoidins (ABG10+®; 250 mg/kg daily by gavage; 5 mL/kg). ABG10+®-treated rats showed lower mean caloric intake, body weight, triglycerides, low density lipoprotein cholesterol (LDL-c), insulin and leptin serum concentrations and higher high density lipoprotein cholesterol (HDL-c) and adiponectin serum concentrations than non-treated rats. In the hypothalamus, ABG10+® treatment induced an increase in the gene expression of proopiomelanocortin (POMC) and a decrease in leptin receptor (ObR) mRNA levels. No significant changes were found in visceral adipose tissue except for an overexpression of β3-adrenergic receptor (β3-ADR) in ABG-treated rats. In subcutaneous adipose tissue, ABG10+® treatment decreased adipose weight and downregulated the gene expression of PPAR-γ, LPL, ObR and HSL. In brown adipose tissue, an overexpression of InsR, GLUT-4, UCP-1 and β3-ADR in ABG10+®-treated rats was found, whereas PPAR-γ mRNA levels were significantly decreased. Regarding vascular function, ABG10+® treatment attenuated the obesity-induced vasoconstriction in response to potassium chloride both in presence/absence of perivascular adipose tissue (PVAT). On the contrary, aorta segments from ABG-treated rats showed and improved relaxation in response to acetylcholine only when PVAT was present, with this fact possible being related to the decreased gene expression of proinflammatory cytokines in this tissue. In conclusion, ABG10+® administration partially improves the metabolic and vascular alterations induced by a high-fat/high-sucrose diet in rats through modifications in the gene expression of proteins and neuropeptides involved in inflammation, fat metabolism and food intake regulation. Further studies are required to assess the bioavailability of ABG between rats and humans.

Momordica charantia Inhibits Inflammatory Responses in Murine Macrophages via Suppression of TAK1

Momordica charantia known as bitter melon is a representative medicinal plant reported to exhibit numerous pharmacological activities such as antibacterial, antidiabetic, anti-inflammatory, anti-oxidant, antitumor, and hypoglycemic actions. Although this plant has high ethnopharmacological value for treating inflammatory diseases, the molecular mechanisms by which it inhibits the inflammatory response are not fully understood. In this study, we aim to identify the anti-inflammatory mechanism of this plant. To this end, we studied the effects of its methanol extract (Mc-ME) on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Specifically, we evaluated nitric oxide (NO) production, mRNA expression of inflammatory genes, luciferase reporter gene activity, and putative molecular targets. Mc-ME blocked NO production in a dose-dependent manner in RAW264.7 cells; importantly, no cytotoxicity was observed. Moreover, the mRNA expression levels of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 were decreased by Mc-ME treatment in a dose-dependent manner. Luciferase assays and nuclear lysate immunoblotting analyses strongly indicated that Mc-ME decreases the levels of p65 [a nuclear factor (NF)-[Formula: see text]B subunit] and c-Fos [an activator protein (AP)-1 subunit]. Whole lysate immunoblotting assays, luciferase assays, and overexpression experiments suggested that transforming growth factor [Formula: see text]-activated kinase 1 (TAK1) is targeted by Mc-ME, thereby suppressing NF-[Formula: see text]B and AP-1 activity via downregulation of extracellular signal-regulated kinases (ERKs) and AKT. These results strongly suggest that Mc-ME exerts its anti-inflammatory activity by reducing the action of TAK1, which also affects the activation of NF-[Formula: see text]B and AP-1.

Comparison of Methods for Analyzing Human Adipose Tissue Macrophage Content

OBJECTIVE

The relationship between inflammation, obesity, and adverse metabolic conditions is associated with adipose tissue macrophages (ATM). This study compared the measurements of human ATM using flow cytometry, immunohistochemistry (IHC), and real-time polymerase chain reaction (RT-PCR) of ATM markers.

METHODS

A new software program (AMCounter) was evaluated to help measure ATM using IHC, and this was compared to flow cytometry and RT-PCR.

RESULTS

IHC had good intraindividual reproducibility for total (CD68), proinflammatory (CD14), and anti-inflammatory (CD206) ATM. The AMCounter improved interreader agreement and was more time efficient. Flow cytometry had acceptable intraindividual reproducibility for the percentage of CD68⁺ cells that were CD14⁺ or CD206⁺ , but not for ATMs per gram of tissue. ATMs per gram of tissue was much greater using IHC than flow cytometry. The flow cytometry and IHC measures of ATM from the same biopsies were not correlated. There were statistically significant correlations between RT-PCR CD68 and IHC CD68, CD14, and CD206 ATMs per 100 adipocytes. Also of interest were statistically significant correlations between RT-PCR CD68 and IHC CD68, CD14, and adipose flow cytometry measures of CD68⁺ , CD68⁺ /CD14⁺ , and CD68⁺ /CD206⁺ ATMs per gram of tissue.

CONCLUSIONS

The AMCounter software helps provide reproducible and efficient measures of IHC ATMs. Flow cytometry, IHC, and RT-PCR measures of adipose inflammation provide somewhat different information.

Recent Advances in Momordica charantia: Functional Components and Biological Activities

Momordica charantia L. (M. charantia), a member of the Cucurbitaceae family, is widely distributed in tropical and subtropical regions of the world. It has been used in folk medicine for the treatment of diabetes mellitus, and its fruit has been used as a vegetable for thousands of years. Phytochemicals including proteins, polysaccharides, flavonoids, triterpenes, saponins, ascorbic acid and steroids have been found in this plant. Various biological activities of M. charantia have been reported, such as antihyperglycemic, antibacterial, antiviral, antitumor, immunomodulation, antioxidant, antidiabetic, anthelmintic, antimutagenic, antiulcer, antilipolytic, antifertility, hepatoprotective, anticancer and anti-inflammatory activities. However, both in vitro and in vivo studies have also demonstrated that M. charantia may also exert toxic or adverse effects under different conditions. This review addresses the chemical constituents of M. charantia and discusses their pharmacological activities as well as their adverse effects, aimed at providing a comprehensive overview of the phytochemistry and biological activities of M. charantia.

Effectiveness of Antihyperglycemic Effect of Momordica charantia: Implication of T-Cell Cytokines

BACKGROUND/OBJECTIVE

We investigate the effect of antidiabetic Momordica charantia fruit juice on T cells' differentiation, through plasmatic cytokine quantification in type 1 diabetic rats (T1D).

METHODS

Male Wistar rats were rendered diabetic by the injection of five low doses of streptozotocin. Then, animals were treated with Momordica charantia fruit juice for 28 consecutive days. Plasmatic levels of Th1 interleukin- (IL-) 02 and interferon- (IFN-) γ, Th2 (IL-4), and regulatory (IL-10) cytokines were determined in rats.

RESULTS

We observed that fruit juice induced a significant decrease in blood glucose of T1D rats. Besides, the concentrations of IL-2 and IFN-γ significantly increased while those of IL-4 and IL-10 diminished in diabetic rats compared to control animals. Interestingly, after treatment with Momordica charantia fruit juice, IL-4 and IL-10 levels significantly increased in diabetic rats, while IL-2 and IFN-γ concentrations decreased, suggesting a Th2 phenotype in these animals. Phytochemical analysis of the fruit juice revealed the presence of tannins, flavonoids, and coumarins, compounds which possess antioxidant activity.

CONCLUSION

This study shows that Momordica charantia fruit juice, by lowering the hyperglycemia, induced a shift of proinflammatory Th1 phenotype in T1D rats towards a favorable anti-inflammatory Th2 status. These effects might be due to the presence of antioxidant compounds in the juice and confirms the use of this plant in the treatment of autoimmune type 1 diabetes.

New Insights into the Mechanisms of Chinese Herbal Products on Diabetes: A Focus on the "Bacteria-Mucosal Immunity-Inflammation-Diabetes" Axis

Diabetes, especially type 2, has been rapidly increasing all over the world. Although many drugs have been developed and used to treat diabetes, side effects and long-term efficacy are of great challenge. Therefore, natural health product and dietary supplements have been of increasing interest alternatively. In this regard, Chinese herbs and herbal products have been considered a rich resource of product development. Although increasing evidence has been produced from various scientific studies, the mechanisms of action are lacking. Here, we have proposed that many herbal monomers and formulae improve glucose homeostasis and diabetes through the BMID axis; B represents gut microbiota, M means mucosal immunity, I represents inflammation, and D represents diabetes. Chinese herbs have been traditionally used to treat diabetes, with minimal side and toxic effects. Here, we reviewed monomers such as berberine, ginsenoside, M. charantia extract, and curcumin and herbal formulae such as Gegen Qinlian Decoction, Danggui Liuhuang Decoction, and Huanglian Wendan Decoction. This review was intended to provide new perspectives and strategies for future diabetes research and product.

Response of gut microbiota and inflammatory status to bitter melon (Momordica charantia L.) in high fat diet induced obese rats

ETHNOPHARMACOLOGICAL RELEVANCE

Bitter melon (Momordica charantia L.) is rich in a variety of biologically active ingredients, and has been widely used in traditional Chinese medicine (TCM) to treat various diseases, including type 2 diabetes and obesity.

AIM OF THE STUDY

We aimed to investigate how bitter melon powder (BMP) could affect obesity-associated inflammatory responses to ameliorate high-fat diet (HFD)-induced insulin resistance, and investigated whether its anti-inflammatory properties were effected by modulating the gut microbiota.

MATERIALS AND METHODS

Obese SD rats (Sprague-Dawley rats, rattus norregicus) were randomly divided into four groups: (a) normal control diet (NCD) and distilled water, (b) HFD and distilled water, (c) HFD and 300mg BMP/kg body weight (bw), (d) HFD and 10mg pioglitazone (PGT)/kg bw.

RESULTS

We observed remarkable decreases in the fasting glucose, fasting insulin, HOMA-IR index, serum lipid levels, and cell sizes of epididymal adipose tissues in the BMP and PGT groups after 8 weeks. BMP could significantly improve the proinflammatory cytokine tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), anti-inflammatory cytokine interleukin-10 (IL-10), and local endotoxin levels compared to the HFD group (p<0.05). BMP suppressed the activation of nuclear factor-κB (NF-κB) by inhibiting inhibitor of NF-κB alpha (IκBα) degradation and phosphorylation of c-Jun N-terminal kinase/ p38 mitogen-activated protein kinases (JNK/p38 MAPKs) in adipose tissue. Sequencing results illustrated that BMP treatment markedly decreased the proportion of the endotoxin-producing opportunistic pathogens and increased butyrate producers.

CONCLUSIONS

These results demonstrate that BMP ameliorates insulin sensitivity partly via relieving the inflammatory status in the system and in white adipose tissues of obese rats, and is associated with a proportional regulation of specific gut microbiota.

1H NMR-based metabolic study reveals the improvements of bitter melon (Momordica charantia) on energy metabolism in diet-induced obese mouse

CONTEXT

Obesity can be ameliorated by some natural products such as polyphenol, flavones and saponin. As a typical medicinal plant, Momordica charantia L. (Cucurbitaceae) (bitter melon, BM) contains these natural chemicals and reduces diet-induced obesity in mice.

OBJECTIVE

This study evaluates the metabolic effects of dietary BM supplement, investigates a global metabolic profile and determines associated perturbations in metabolic pathways.

MATERIALS AND METHODS

Male C57BL/6 mice were fed with low-fat diet (LFD), high-fat diet (HFD) and HFD supplemented with 5% BM based on 37.6 g/kg body weight in average for 12 weeks, respectively. Then energy metabolism was quantified using PhenoMaster/LabMaster. The spectroscopy of urine was acquired by nuclear magnetic resonance and latent biomarkers were identified. Pattern recognition analysis was used to discriminate associated metabolic profiles.

RESULTS

Dietary BM supplement reduced body weight gain (-0.15-fold, p < 0.01) and blood glucose levels (-0.19-fold, p < 0.01) in HFD-fed mice. Meanwhile, the levels of energy metabolism were enhanced (0.08-0.11-fold, p < 0.01). According to pattern recognition analysis, dietary BM supplement changed metabolic profiles in HFD-fed mice and the modified profiles were similar to those in LFD-fed mice. Finally, the mapping of metabolic pathways showed that dietary BM supplement primarily affected glucose metabolism-associated pathways.

DISCUSSION AND CONCLUSION

The results indicated that BM improves weight loss in diet-induced obesity and elevate energy expenditure in HFD-fed mice. The pattern recognition with metabolic study may be used as a noninvasive detection method to assess the effects of dietary BM supplement on mouse energy metabolism.

Metabolomics Reveals that Momordica charantia Attenuates Metabolic Changes in Experimental Obesity

Momordica charantia L., also known as bitter melon, has been shown to ameliorate obesity and insulin resistance. However, metabolic changes regulated by M. charantia in obesity are not clearly understood. In this study, serums obtained from obese and M. charantia-treated mice were analyzed by using gas and liquid chromatography-mass spectrometry, and multivariate statistical analysis was performed by Orthogonal partial least squares discriminant analysis. The results from this study indicated that body weight fat and insulin levels of obese mice are dramatically suppressed by 8 weeks of dietary supplementation of M. charantia. Metabolomic data revealed that overproductions of energy and nutrient metabolism in obese mice were restored by M. charantia treatment. The antiinflammatory and inhibition of insulin resistance effect of M. charantia in obesity was illustrated with the restoration of free fatty acids and eicosanoids. The findings achieved in this study further strengthen the therapeutic value of using M. charantia to treat obesity. Copyright © 2016 John Wiley & Sons, Ltd.

Luteolin reduces obesity-associated insulin resistance in mice by activating AMPKα1 signalling in adipose tissue macrophages

AIMS/HYPOTHESIS

Inflammatory polarisation of adipose tissue macrophages (ATMs) plays a critical role in the development of obesity-associated metabolic diseases such as insulin resistance and diabetes. Our previous study indicated that dietary luteolin (LU) could prevent the establishment of insulin resistance in mice fed a high-fat diet (HFD). Here, we further investigated the effects of LU, which is a natural flavonoid, on pre-established insulin resistance and obesity-associated ATM polarisation in mice.

METHODS

Five-week-old C57/BL6 mice were fed on a low-fat diet or HFD for 20 weeks, with some mice receiving supplementation with 0.01% LU from weeks 1 or 10 of the HFD to assess the actions of LU on insulin resistance and ATM polarisation. Furthermore, the role of LU in metabolic-dysfunction-associated macrophage phenotypes was investigated in vitro.

RESULTS

Dietary LU supplementation, either for 20 weeks or from weeks 10 to 20 of an HFD, significantly improved insulin resistance in HFD-fed mice. In addition, inflammatory macrophage infiltration and polarisation were suppressed in mouse epididymal adipose tissues. Furthermore, LU treatment directly reversed lipopolysaccharide-stimulated and metabolism-regulated molecules, and induced inflammatory polarisation in mouse RAW264.7 cells and peritoneal cavity resident macrophages. Finally, using the selective AMP-activated protein kinase (AMPK) inhibitor compound C and Ampkα1 (also known as Prkaa1) silencing with siRNA, we found that LU activated AMPKα1 in macrophages to inhibit their inflammatory polarisation and enhanced insulin signals in adipocytes that were stimulated with macrophage-conditioned media.

CONCLUSIONS/INTERPRETATION

Dietary LU ameliorated insulin resistance in diet-induced obese mice by promoting AMPKα1 signalling in ATMs.

Irisin improves perivascular adipose tissue dysfunction via regulation of the heme oxygenase-1/adiponectin axis in diet-induced obese mice

AIMS

To determine whether irisin could improve perivascular adipose tissue (PVAT) dysfunction via regulation of the heme oxygenase-1 (HO-1)/adiponectin axis in obesity.

MATERIALS AND METHODS

C57BL/6 mice were given chow or a high-fat diet (HFD) with or without treatment with irisin. The concentration-dependent responses of the thoracic aorta with or without PVAT (PVAT+ or PVAT-) to phenylephrine were studied in an organ bath. Protein levels of HO-1 and adiponectin were determined by western blot. UCP-1, Cidea, and TNF-α gene expression in PVAT were analyzed by real-time PCR.

RESULTS

Treatment of obese mice with irisin improved glucose and lipid metabolism, reduced plasma levels of TNF-α and malondialdehyde, and increased plasma adiponectin levels (P<0.01). The anti-contractile effects of PVAT were attenuated in HFD mice and this attenuation was restored in HFD mice treated with irisin (P<0.05). Incubation of aortas (PVAT+) with the HO-1 inhibitor and adiponectin receptor blocking peptide in irisin-treated HFD mice abolished the beneficial effects of irisin on PVAT function. The same results were also observed in HFD mice treated with irisin ex vivo. Treatment of HFD mice with irisin significantly enhanced protein levels of HO-1 and adiponectin, and reduced superoxide production and TNF-α expression in PVAT. Irisin treatment enhanced brown adipocyte markers UCP-1 and Cidea expression in PVAT from HFD mice.

CONCLUSION

Irisin improved the anti-contractile properties of PVAT from the thoracic aorta in diet-induced obese mice. The mechanism for protective effects of irisin appeared to be related to upregulation of the HO-1/adiponectin axis in PVAT and browning of PVAT.

Interleukin-17A neutralization alleviated ocular neovascularization by promoting M2 and mitigating M1 macrophage polarization

Neovascularization (NV), as a cardinal complication of several ocular diseases, has been intensively studied, and research has shown its close association with inflammation and immune cells. In the present study, the role of interleukin-17A (IL-17A) in angiogenesis in the process of ocular NV both in vivo and in vitro was investigated. Also, a paracrine role of IL-17A was demonstrated in the crosstalk between endothelial cells and macrophages in angiogenesis. In the retinas of mice with retinopathy of prematurity, the IL-17A expression increased significantly at postnatal day 15 (P15) and P18 during retinal NV. Mice given IL-17A neutralizing antibody (NAb) developed significantly reduced choroidal NV and retinal NV. Studies on vascular endothelial growth factor (VEGF) over-expressing mice suggested that IL-17A modulated NV through the VEGF pathway. Furthermore, IL-17A deficiency shifted macrophage polarization toward an M2 phenotype during retinal NV with significantly reduced M1 cytokine expression compared with wild-type controls. In vitro assays revealed that IL-17A treated macrophage supernatant gave rise to elevated human umbilical vascular endothelial cell proliferation, tube formation and VEGF receptor 1 and receptor 2 expression. Therefore, IL-17A could potentially serve as a novel target for treating ocular NV diseases. The limitation of this study involved the potential mechanisms, such as which transcription accounted for macrophage polarization and how the subsequent cytokines were modulated when macrophages were polarized. Further studies need to be undertaken to definitively determine the extent to which IL-17A neutralizing anti-angiogenic activity depends on macrophage modulation compared with anti-VEGF treatment.

Bitter melon: a panacea for inflammation and cancer

Nature is a rich source of medicinal plants and their products that are useful for treatment of various diseases and disorders. Momordica charantia, commonly known as bitter melon or bitter gourd, is one of such plants known for its biological activities used in traditional system of medicines. This plant is cultivated in all over the world, including tropical areas of Asia, Amazon, east Africa, and the Caribbean and used as a vegetable as well as folk medicine. All parts of the plant, including the fruit, are commonly consumed and cooked with different vegetables, stir-fried, stuffed or used in small quantities in soups or beans to give a slightly bitter flavor and taste. The plant is reported to possess anti-oxidant, anti-inflammatory, anti-cancer, anti-diabetic, anti-bacterial, anti-obesity, and immunomodulatory activities. The plant extract inhibits cancer cell growth by inducing apoptosis, cell cycle arrest, autophagy and inhibiting cancer stem cells. The plant is rich in bioactive chemical constituents like cucurbitane type triterpenoids, triterpene glycosides, phenolic acids, flavonoids, essential oils, saponins, fatty acids, and proteins. Some of the isolated compounds (Kuguacin J, Karaviloside XI, Kuguaglycoside C, Momordicoside Q-U, Charantin, α-eleostearic acid) and proteins (α-Momorcharin, RNase MC2, MAP30) possess potent biological activity. In the present review, we are summarizing the anti-oxidant, anti-inflammatory, and anti-cancer activities of Momordica charantia along with a short account of important chemical constituents, providing a basis for establishing detail biological activities of the plant and developing novel drug molecules based on the active chemical constituents.

One new 19-nor cucurbitane-type triterpenoid from the stems of Momordica charantia

One new 19-nor cucurbitane-type triterpenoid (3β,9β,25-trihydroxy-7β-methoxy-19-nor-cucurbita-5,23(E)-diene) (1), together with other six known cucurbitane-type triterpenoids (2-7), were isolated from the stems of Momordica charantia L. The chemical structure of 1 was elucidated by extensive 1D NMR and 2D NMR (HSQC, HMBC, COSY and ROESY), MS experiments. Using MTT assay, compound 1 exhibited weak cytotoxicity against HL-60, A-549, and SK-BR-3 cell lines with the IC50 values at 27.3, 32.7 and 26.6 μM, respectively.

Preventive effects of bitter melon (Momordica charantia) against insulin resistance and diabetes are associated with the inhibition of NF-κB and JNK pathways in high-fat-fed OLETF rats

Bitter melon (BM; Momordica charantia) has been used as a treatment method for various diseases including cancer and diabetes. The objective of this study was to investigate whether BM has preventive effects against insulin resistance and diabetes and to identify the underlying mechanism by which BM ameliorates insulin resistance in obese and diabetic rats. The rats were separated into three groups as follows: (a) high-fat (HF) diet control, (b) HF diet and 1% BM and (c) HF diet and 3% BM. After 6 weeks of assigned treatments, body weight and food intake were not altered by BM administration. Bitter melon treatment significantly improved glucose tolerance and insulin sensitivity. The levels of proinflammatory cytokines were significantly down-regulated in liver, muscle and epididymal fats from BM-treated rats. The activation of nuclear factor-κB (NF-κB) in the liver and muscle was decreased by BM compared with HF controls. The 3% BM supplementation significantly increased the levels of phospho-insulin receptor substrate-1 (Tyr612) and phospho-Akt (Ser473). It also significantly decreased the levels of phospho-NF-κB (p65) (Ser536) and phospho-c-Jun N-terminal kinase (JNK) (Thr183/Tyr185) in liver, muscle and epididymal fats. The findings of this study indicate that BM exerted preventive effects against insulin resistance and diabetes through the modulation of NF-κB and JNK pathways. Therefore, BM may be useful in the prevention of insulin resistance and diabetes.

The effect of Momordica charantia intake on the estrogen receptors ESRα/ESRβ gene levels and apoptosis on uterine tissue in ovariectomy rats

Estrogen or combinational hormone therapy can protect to menopausal symptoms but exogenous estrogen therapy has some potential risks which in turns lead to the appearance of various diseases. In recent years plants with high phytoestrogen content are recommended as therapeutic agents for postmenopausal hormonal treatment. In this research, we investigated the effects of Momordica charantia (MC) on the estrogen production and E2 as well as anti-oxidative and anti-apoptotic role on the ovariectomy rat model. The rats were ovariectomized and fed on 2 g/kg of fruit extra of MC for 30 days by gavage. 17-β estradiol (E2) and 8-OHdG levels in serum, markers of oxidative damage of ROS and ESRα, ESRβ and NF-kB gene levels were measured in uterus horn tissue. Caspase-3, caspase-9, TNF-α, IL-6, IL-10, Bcl-2 and Nf-kB proteins expression were assessed by western blotting. Structural changes in tissue were examined with H&E staining. MC administration also stimulated the E2 production and ESRα/ESRβ gene levels and the inhibited oxidative damage. Furthermore, MC treatment enhanced anti-apoptotic and anti-inflammatory process and tissue regeneration. Data herein support that MC directly regulates uterine estrogen response and may serve as a new phytoestrogenic substance for the treatment of post-menopausal symptoms.