Corosolic acid isolated from Eriobotrya japonica leaves reduces glucose level in human hepatocellular carcinoma cells, zebrafish and rats

Corosolic acid enhances oxidative stress-induced apoptosis and senescence in pancreatic cancer cells by inhibiting the JAK2/STAT3 pathway

BACKGROUND

Pancreatic cancer (PC) is a fatal human malignancy with a poor prognosis. Corosolic acid (CRA) is a triterpenoid, has been reported to have inhibitory effects on tumor growth. However, the role of CRA on PC has not been explored. Here, we aimed to uncover the molecular mechanisms of CRA in PC progression.

METHODS

Cell viability, lactate dehydrogenase (LDH) release, cell apoptosis and senescence were detected by cell counting kit-8 (CCK-8), LDH, flow cytometry and senescence associated-β-galactosidase (SA-β-gal) assay. Levels of relevant proteins and oxidative stress (OS) markers were evaluated by Western blot and enzyme-linked immunosorbent assay (ELISA). A xenograft tumor model was established to explore the in vivo effects of CRA on PC.

RESULTS

We found that CRA inhibited PC cell viability and promoted LDH release in a dose-dependent manner, but had no significant effect on human normal pancreatic ductal epithelial cells HPDE6C7. CRA increased OS-induced cell apoptosis and senescence in HAPC and SW1990 cells. And CRA decreased the levels of anti-apoptotic protein Bcl-2, and elevated the expression of pro-apoptotic protein Bax and senescence-associated proteins P21 and P53. Besides, CRA decreased tumor growth in xenograft models. Furthermore, CRA inactivated the Janus kinase-2 (JAK2)/Signal Transducer and Activator of Transcription 3 (STAT3) signaling pathway in HAPC and SW1990 cells. Functional experiments demonstrated that activation of the JAK2/STAT3 pathway by the JAK2 activator coumermycin A1 (C-A1) or the STAT3 activator colivelin (col) reduced the contribution effect of OS, apoptosis and senescence by CRA.

CONCLUSION

Taken together, our findings indicated that CRA exerted anti-cancer effects in PC by inhibiting the JAK2/STAT3 pathway.

Effects of Dietary Protein Levels on Sheep Gut Metabolite Profiles during the Lactating Stage

Diet-associated characteristics such as dietary protein levels can modulate the gut's primary or secondary metabolites, leading to effects on the productive performance and overall health of animals. Whereas fecal metabolite changes are closely associated with gut metabolome, this study aimed to see changes in the rumen metabolite profile of lactating ewes fed different dietary protein levels. For this, eighteen lactating ewes (approximately 2 years old, averaging 38.52 ± 1.57 kg in their initial body weight) were divided into three groups (n = 6 ewes/group) by following the complete randomized design, and each group was assigned to one of three low-protein (D_I), medium-protein (D_m), and high-protein (D_h) diets containing 8.58%, 10.34%, and 13.93% crude protein contents on a dry basis, respectively. The fecal samples were subjected to untargeted metabolomics using ultra-performance liquid chromatography (UPLC). The metabolomes of the sheep fed to the high-protein-diet group were distinguished as per principal-component analysis from the medium- and low-protein diets. Fecal metabolite concentrations as well as their patterns were changed by feeding different dietary protein levels. The discriminating metabolites between groups of nursing sheep fed different protein levels were identified using partial least-squares discriminant analysis. The pathway enrichment revealed that dietary protein levels mainly influenced the metabolism-associated pathways (n = 63 and 39 in positive as well as negative ionic modes, respectively) followed by protein (n = 15 and 8 in positive as well as negative ionic modes, respectively) and amino-acid (n = 14 and 7 in positive as well as negative ionic modes, respectively) synthesis. Multivariate and univariate analyses showed comparative changes in the fecal concentrations of metabolites in both positive and negative ionic modes. Major changes were observed in protein metabolism, organic-acid biosynthesis, and fatty-acid oxidation. Pairwise analysis and PCA reveal a higher degree of aggregation within the D-h group than all other pairs. In both the PCA and PLS-DA plots, the comparative separation among the D_h/D_m, D_h/D_I, and D_m/D_I groups was superior in positive as well as negative ionic modes, which indicated that sheep fed higher protein levels had alterations in the levels of the metabolites. These metabolic findings provide insights into potentiated biomarker changes in the metabolism influenced by dietary protein levels. The target identification may further increase our knowledge of sheep gut metabolome, particularly regarding how dietary protein levels influence the molecular mechanisms of nutritional metabolism, growth performance, and milk synthesis of sheep.

Active peptides with hypoglycemic effect obtained from hemp (Cannabis sativa L) protein through identification, molecular docking, and virtual screening

Hemp (Cannabis sativa L) seeds are rich in proteins of high nutritional value, which makes the study of beneficial properties of hemp seed proteins and peptides, such as hypotensive and hypoglycemic effects, increasingly attractive. The present results confirm the good processability and stability of the hemp protein hydrolysate obtained by enzymatic hydrolysis of non-dehulled hemp seed meal (NDHM). Six peptides with potential hypoglycemic activity were obtained by ethanol-graded precipitation, Nano LC-Q-Orbitrap-MS/MS mass spectrometry, and computerized virtual screening. Further, validation experiments for in vitro synthesis showed that TGLGR, SPVI, FY, and FR exhibited good α-glucosidase inhibitory activity, respectively. Animal experiments showed that the hemp protein peptides modulated blood glucose and blood lipids in hyperglycemic rats. These results indicate that hemp protein peptides can reduce blood glucose levels in hyperglycemic rats, suggesting that hemp proteins may be a promising natural source for the prevention and treatment of hyperglycemia.

Aflatoxin B1-induced early developmental hepatotoxicity in larvae zebrafish

Aflatoxin B1 (AFB1) is a ubiquitous mycotoxin that causes oxidative damage in various organs. At present, the research studies on AFB1 are primarily focused on its effects on the terrestrial environment and animals. However, its toxicity mechanism in aquatic environments and aquatic animals has not been largely explored. Thus, in this study, zebrafish was used as a model to study the toxicity mechanism of AFB1 on the liver of developing larvae. The results showed that AFB1 exposure inhibited liver development and promoted fat accumulation in the liver. Transcriptome sequencing analysis showed that AFB1 affected liver redox metabolism and oxidoreductase activity. KEGG analysis showed that AFB1 inhibited the expression of gsto1, gpx4a, mgst3a, and idh1 in the glutathione metabolizing enzyme gene pathway, resulting in hepatic oxidative stress. At the same time, AFB1 also inhibited the expression of acox1, acsl1b, pparα, fabp2, and cpt1 genes in peroxidase and PPAR metabolic pathways, inducing hepatic steatosis and lipid droplet accumulation. Antioxidant N-Acetyl-l-cysteine (NAC) preconditioning up-regulated gsto1, gpx4a and idh1 genes, and improved the AFB1-induced lipid droplet accumulation in the liver. In summary, AFB1 induced hepatic oxidative stress and steatosis, resulting in abnormal liver fat metabolism and accumulation of cellular lipid droplets. NAC could be used as a potential preventative drug to improve AFB1-induced fat accumulation.

Aflatoxin B1 exposure induced developmental toxicity and inhibited muscle development in zebrafish embryos and larvae

The prevalence of aflatoxin B1 (AFB1), one of the most toxic mycotoxins that contaminates feedstock and food is increasing worldwide. AFB1 can cause various health problems in humans and animals, as well as direct embryotoxicity. However, the direct toxicity of AFB1 on embryonic development, especially foetal foetus muscle development, has not been studied in depth. In the present study, we used zebrafish embryos as a model to study the mechanism of the direct toxicity of AFB1 to the foetus, including muscle development and developmental toxicity. Our results showed that AFB1 caused motor dysfunction in zebrafish embryos. In addition, AFB1 induces abnormalities in muscle tissue architecture, which in turn causes abnormal muscle development in larvae. Further studies found that AFB1 destroyed the antioxidant capacity and tight junction complexes (TJs), causing apoptosis in zebrafish larvae. In summary, AFB1 may induce developmental toxicity and inhibit muscle development through oxidative damage, apoptosis and disruption of TJs in zebrafish larvae. Our results revealed the direct toxicity effects of AFB1 on the development of embryos and larvae, including inhibition of muscle development and triggering neurotoxicity, induction of oxidative damage, apoptosis and disruption of TJs, and fills the gap in the toxicity mechanism of AFB1 on foetal development.

The Combination of Natural Molecules Naringenin, Hesperetin, Curcumin, Polydatin and Quercetin Synergistically Decreases SEMA3E Expression Levels and DPPIV Activity in In Vitro Models of Insulin Resistance

Type 2 diabetes mellitus (T2DM) is a disease characterized by a prolonged hyperglycemic condition caused by insulin resistance mechanisms in muscle and liver, reduced insulin production by pancreatic β cells, and a chronic inflammatory state with increased levels of the pro-inflammatory marker semaphorin 3E. Phytochemicals present in several foods have been used to complement oral hypoglycemic drugs for the management of T2DM. Notably, dipeptidyl peptidase IV (DPPIV) inhibitors have demonstrated efficacy in the treatment of T2DM. Our study aimed to investigate, in in vitro models of insulin resistance, the ability of the flavanones naringenin and hesperetin, used alone and in combination with the anti-inflammatory natural molecules curcumin, polydatin, and quercetin, to counteract the insulin resistance and pro-inflammatory molecular mechanisms that are involved in T2DM development. Our results show for the first time that the combination of naringenin, hesperetin, curcumin, polydatin, and quercetin (that mirror the nutraceutical formulation GliceFen^®, Mivell, Italy) synergistically decreases expression levels of the pro-inflammatory gene SEMA3E in insulin-resistant HepG2 cells and synergistically decreases DPPIV activity in insulin-resistant Hep3B cells, indicating that the combination of these five phytochemicals is able to inhibit pro-inflammatory and insulin resistance molecular mechanisms and could represent an effective innovative complementary approach to T2DM pharmacological treatment.

New insights into the oxidative damage and antioxidant defense mechanism in Manila clams (Ruditapes philippinarum) exposed to 8:2 polyfluoroalkyl phosphate diester stress

8:2 perfluoroalkyl phosphate diester (8:2 diPAP) is the main precursor of perfluoroalkyl carboxylic acids, and it has been detected in a wide range of environments. In this study, conventional biochemical and histopathological analyses and transcriptome methods were used to investigate the accumulation and oxidative stress of 8:2 diPAP in Manila clams (Ruditapes philippinarum) as well as the clam's defense mechanisms for the first time. The hepatopancreas was the main target organ for 8:2 diPAP accumulation; the concentration reached 484.0 ± 15.5 ng/g after 7 days of exposure to 10 μg/L of 8:2 diPAP, which was 2-100 times higher than that found in other organs. 8:2 diPAP accumulation resulted in significant lipid peroxidation, and the change in malondialdehyde content was highly correlated with 8:2 diPAP accumulation (r > 0.8). The antioxidant enzymes catalase and peroxidase were significantly activated at 7 days of exposure. Although the levels subsequently returned to normal, this restoration was unable to prevent damage. Histopathological analysis showed that 8:2 diPAP exposure resulted in inflammatory damage to the hepatopancreas, which failed to resolve during the recovery period. Transcriptomic analyses showed that the expression of differentially expressed genes had different degrees of positive/negative correlation with antioxidant indicators, and they were significantly enriched in cell death regulatory pathways such as autophagy, apoptosis, and necrosis. The core factor expression results indicated that 8:2 diPAP exposure induced activation of the organismal autophagy factor followed by a shift towards apoptosis. In addition, pathways related to amino acid metabolism and energy metabolism were involved in determining the cell fate of Manila clams. Overall, these results indicated that 8:2 diPAP induced peroxidation of membrane lipids, disturbed physiological processes, and ultimately initiated programmed cell death in Manila clams. The findings of this study provide new insights into the mechanism of toxicity of 8:2 diPAP exposure in marine bivalves.

A plant-derived glucocorticoid receptor modulator with potency to attenuate the side effects of glucocorticoid therapy

BACKGROUND AND PURPOSE

Continuous efforts have been made to move towards maintaining the beneficial anti-inflammatory functions of glucocorticoids (GCs) while minimizing side effects. Here, we investigated the selective glucocorticoid receptor (GR) modulator-like properties of a plant-derived compound caesaldekarin e (CA-e).

EXPERIMENTAL APPROACH

The therapeutic efficacy of CA-e was evaluated in several mouse models, including dextran sulfate sodium-induced colitis, ovalbumin-induced lung allergic inflammation, imiquimod-induced psoriasis-like skin inflammation and skin atrophy. The action of CA-e targeting the GR was analysed using molecular docking, cellular thermal shift assays and microscale thermophoresis. Other methods included DNA-protein pull-down assays and mass spectrometry.

KEY RESULTS

CA-e selectively inhibited positive GC response element ((+) GRE)-mediated direct transactivation while maintaining and even enhancing the anti-inflammatory effects of treatment with dexamethasone. CA-e, alone and in combination with dexamethasone, efficiently alleviated inflammation in several mouse models with milder side effects compared with dexamethasone alone. Mechanistically, CA-e inhibited the formation of dimers by binding to the dimerization interface located in the ligand-binding domain of GR and facilitated embryonic ectoderm development that is involved in the regulation of transcriptional repression to compete for binding to (+) GRE, eventually leading to the repression of (+) GRE-regulated genes. In addition, CA-e repressed NF-κB-dependent genes by enhancing the interaction between GR and p65.

CONCLUSIONS AND IMPLICATIONS

Our results reveal that CA-e is a novel GR modulator with strong potency to attenuate the side effects of GC therapy and can be used as a potential molecular tool for deciphering GR signalling.

Integrating experimental model, LC-MS/MS chemical analysis, and systems biology approach to investigate the possible antidiabetic effect and mechanisms of Matricaria aurea (Golden Chamomile) in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a heterogeneous disease with numerous abnormal targets and pathways involved in insulin resistance, low-grade inflammation, oxidative stress, beta cell dysfunction, and epigenetic factors. Botanical drugs provide a large chemical space that can modify various targets simultaneously. Matricaria aurea (MA, golden chamomile) is a widely used herb in Middle Eastern communities for many ailments, including diabetes mellitus, without any scientific basis to support this tradition. For the first time, this study aimed to investigate the possible antidiabetic activity of MA in a type 2 diabetic rat model, identify chemical constituents by LC-MS/MS, and then elucidate the molecular mechanism(s) using enzyme activity assays, q-RTPCR gene expression analysis, network pharmacology analysis, and molecular docking simulation. Our results demonstrated that only the polar hydroethanolic extract of MA had remarkable antidiabetic activity. Furthermore, it improved dyslipidemia, insulin resistance status, ALT, and AST levels. LC-MS/MS analysis of MA hydroethanolic extract identified 62 compounds, including the popular chamomile flavonoids apigenin and luteolin, other flavonoids and their glycosides, coumarin derivatives, and phenolic acids. Based on pharmacokinetic screening and literature, 46 compounds were chosen for subsequent network analysis, which linked to 364 candidate T2DM targets from various databases and literature. The network analysis identified 123 hub proteins, including insulin signaling and metabolic proteins: IRS1, IRS2, PIK3R1, AKT1, AKT2, MAPK1, MAPK3, and PCK1, inflammatory proteins: TNF and IL1B, antioxidant enzymes: CAT and SOD, and others. Subsequent filtering identified 40 crucial core targets (major hubs) of MA in T2DM treatment. Functional enrichment analyses of the candidate targets revealed that MA targets were mainly involved in the inflammatory module, energy-sensing/endocrine/metabolic module, and oxidative stress module. q-RTPCR gene expression analysis showed that MA hydroethanolic extract was able to significantly upregulate PIK3R1 and downregulate IL1B, PCK1, and MIR29A. Moreover, the activity of the antioxidant hub enzymes was substantially increased. Molecular docking scores were also consistent with the networks’ predictions. Based on experimental and computational analysis, this study revealed for the first time that MA exerted antidiabetic action via simultaneous modulation of multiple targets and pathways, including inflammatory pathways, energy-sensing/endocrine/metabolic pathways, and oxidative stress pathways.

Corosolic acid sensitizes ferroptosis by upregulating HERPUD1 in liver cancer cells

Primary liver cancer is the third leading cause of cancer death in the world, and the lack of effective treatments is the main reason for the high mortality. Corosolic acid (CA) has been proved to have antitumor activity. In this study, we found that CA can sensitize liver cancer cells to ferroptosis, which is a regulated form of cell death characterized by iron-dependent lipid peroxides reaching lethal levels. Here, we revealed that CA can inhibit glutathione (GSH) synthesis via HERPUD1, decreasing the cellular GSH level and causing liver cancer cells to become more sensitive to ferroptosis. Mechanistically, further studies found that HERPUD1 reduced the ubiquitination of the GSS-associated E3 ubiquitin ligase MDM2, which promoted ubiquitination of GSS, thereby inhibiting GSH synthesis to increase ferroptosis susceptibility. Importantly, a mouse xenograft model also demonstrated that CA inhibits tumor growth via HERPUD1. Collectively, our findings suggesting that CA is a candidate component for the development of treatments against liver cancer.

Recent Advances Regarding the Molecular Mechanisms of Triterpenic Acids: A Review (Part II)

Triterpenic acids are a widespread class of phytocompounds which have been found to possess valuable therapeutic properties such as anticancer, anti-inflammatory, hepatoprotective, cardioprotective, antidiabetic, neuroprotective, lipolytic, antiviral, and antiparasitic effects. They are a subclass of triterpenes bearing a characteristic lipophilic structure that imprints unfavorable in vivo properties which subsequently limit their applications. The early investigation of the mechanism of action (MOA) of a drug candidate can provide valuable information regarding the possible side effects and drug interactions that may occur after administration. The current paper aimed to summarize the most recent (last 5 years) studies regarding the MOA of betulinic acid, boswellic acid, glycyrrhetinic acid, madecassic acid, moronic acid, and pomolic acid in order to provide scientists with updated and accessible material on the topic that could contribute to the development of future studies; the paper stands as the sequel of our previously published paper regarding the MOA of triterpenic acids with therapeutic value. The recent literature published on the topic has highlighted the role of triterpenic acids in several signaling pathways including PI3/AKT/mTOR, TNF-alpha/NF-kappa B, JNK-p38, HIF-α/AMPK, and Grb2/Sos/Ras/MAPK, which trigger their various biological activities.

Effects of dexmedetomidine on cognitive dysfunction and neuroinflammation via the HDAC2/HIF-1α/PFKFB3 axis in a murine model of postoperative cognitive dysfunction

Inhibition of histone deacetylase (HDAC) may be a useful approach in the treatment of disorders characterized by cognitive dysfunction. Dexmedetomidine (DEX), an α2-adrenoceptor (α2-AR) agonist, has demonstrated neuroprotective effects. Here, we attempted to investigate the protective effects of DEX on postoperative cognitive dysfunction (POCD) involving HDAC2. Male C57BL/6 mice were selected to develop a POCD model, where HDAC2, HIF-1α, and PFKFB3 expression was quantified. DEX was administered before POCD modeling. Then the cognitive function of POCD mice was evaluated with the open field and Y-maze tests. Meanwhile, lipopolysaccharide (LPS) was employed to induce BV-2 microglial cells to simulate the inflammatory response. The contents of TNF-α, IL-6, and IL-10 were measured by enzyme-linked immunosorbent assay (ELISA) in mouse serum and BV-2 cell supernatant. Abundant expression of HDAC2, HIF-1α, and PFKFB3 was confirmed in POCD mice (p < 0.05). Cognitive dysfunction in POCD mice could be alleviated following pharmacological inhibition of HDAC2 by FK228 (p < 0.05). Mechanistically, HDAC2 upregulated HIF-1α and PFKFB3 and promoted the secretion of inflammatory factors in LPS-exposed BV-2 cells (p < 0.05). DEX attenuated neuroinflammation and the resulting cognitive dysfunction by decreasing HDAC2 expression and HIF-1α-dependent PFKFB3 upregulation in POCD mice (p < 0.05). In conclusion, DEX-regulated HDAC2 may play an inhibitory role in mice with POCD through regulation of the HIF-1α/PFKFB3 axis.

Characterization of Promising Cytotoxic Metabolites from Tabebuia guayacan Hemsl.: Computational Prediction and In Vitro Testing

Genus Tabebuia is famous for its traditional uses and valuable phytoconstituents. Our previous investigation of Tabebuia species noted the promising anticancer activity of T. guayacan Hemsl. leaves extract, however, the mechanism underlying the observed anticancer activity is still unexplored. The current research was designed to explore the phytochemical content as well as to address the phytoconstituent(s) responsible for the recorded anticancer activity. Accordingly, sixteen compounds were isolated, and their structures were elucidated using different spectroscopic techniques. The drug-likeness of the isolated compounds, as well as their binding affinity with four anticancer drug target receptors: CDK-2/6, topoisomerase-1, and VEGFR-2, were evaluated. Additionally, the most promising compounds were in vitro evaluated for inhibitory activities against CDK-2/6 and VEGFR-2 enzymes using kinase assays method. Corosolic acid (3) and luteolin-7-O-β-glucoside (16) were the most active inhibitors against CDK-2 (−13.44 kcal/mol) and topoisomerase 1 (−13.83 kcal/mol), respectively. Meanwhile, quercetin 3-O-β-xyloside (10) scored the highest binding free energies against both CDK-6 (−16.23 kcal/mol) as well as against VEGFR-2 protein targets (−10.39 kcal/mol). Molecular dynamic simulation indicated that quercetin 3-O-β-xyloside (10) exhibited the least fluctuations and deviations from the starting binding pose with RMSD (2.6 Å). Interestingly, in vitro testing results confirmed the potent activity of 10 (IC₅₀ = 0.154 µg/mL) compared to IC₅₀ = 0.159 µg/mL of the reference drug ribociclib. These findings suggest the three noted compounds (3, 10, and 16) for further in vivo anticancer studies.

Corosolic acid and its structural analogs: A systematic review of their biological activities and underlying mechanism of action

BACKGROUND

The corosolic acid (CA), also known as plant insulin, is a pentacyclic triterpenoid extracted from plants such as Lagerstroemia speciosa. It has been shown to have anti-diabetic, anti-inflammatory and anti-tumor effects. Its structural analogs ursolic acid (UA), oleanolic acid (OA), maslinic acid (MA), asiatic acid (AA) and betulinic acid (BA) display similar individual pharmacological activities to those of CA. However, there is no systematic review documenting pharmacological activities of CA and its structural analogues. This study aims to fill this gap in literature.

PURPOSE

This systematic review aims to summarize the medical applications of CA and its analogues.

METHODS

A systematic review summarizes and compares the extraction techniques, pharmacokinetic parameters, and pharmacological effects of CA and its structural analogs. Hypoglycemic effect is one of the key inclusion criteria for searching Web of Science, PubMed, Embase and Cochrane databases up to October 2020 without language restrictions. 'corosolic acid', 'ursolic acid', 'oleanolic acid', 'maslinic acid', 'asiatic acid', 'betulinic acid', 'extraction', 'pharmacokinetic', 'pharmacological' were used to extract relevant literature. The PRISMA guidelines were followed.

RESULTS

At the end of the searching process, 140 articles were selected for the systematic review. Information of CA and five of its structural analogs including UA, OA, MA, AA and BA were included in this review. CA and its structural analogs are pentacyclic triterpenes extracted from plants and they have low solubilities in water due to their rigid scaffold and hydrophobic properties. The introduction of water-soluble groups such as sugar or amino groups could increase the solubility of CA and its structural analogs. Their biological activities and underlying mechanism of action are reviewed and compared.

CONCLUSION

CA and its structural analogs UA, OA, MA, AA and BA are demonstrated to show activities in lowering blood sugar, anti-inflammation and anti-tumor. Their oral absorption and bioavailability can be improved through structural modification and formulation design. CA and its structural analogs are promising natural product-based lead compounds for further development and mechanistic studies.

Recent development in zebrafish model for bioactivity and safety evaluation of natural products

The zebrafish is a species of freshwater fish, popular in aquariums and laboratories. Several advantageous features have facilitated zebrafish to be extensively utilized as a valuable vertebrate model in the lab. It has been well-recognized that natural products possess multiple health benefits for humans. With the increasing demand for natural products in the development of functional foods, nutraceuticals, and natural cosmetics, the zebrafish has emerged as an unprecedented tool for rapidly and economically screening and identifying safe and effective substances from natural products. This review first summarized the key factors for the management of zebrafish in the laboratory, followed by highlighting the current progress on the establishment and applications of zebrafish models in the bioactivity evaluation of natural products. In addition, the zebrafish models used for assessing the potential toxicity or health risks of natural products were involved as well. Overall, this review indicates that zebrafish are promising animal models for the bioactivity and safety evaluation of natural products, and zebrafish models can accelerate the discovery of novel natural products with potential health functions.

Targeting the crosstalk between canonical Wnt/β-catenin and inflammatory signaling cascades: A novel strategy for cancer prevention and therapy

Emerging scientific evidence indicates that inflammation is a critical component of tumor promotion and progression. Most cancers originate from sites of chronic irritation, infections and inflammation, underscoring that the tumor microenvironment is largely orchestrated by inflammatory cells and pro-inflammatory molecules. These inflammatory components are intimately involved in neoplastic processes which foster proliferation, survival, invasion, and migration, making inflammation the primary target for cancer prevention and treatment. The influence of inflammation and the immune system on the progression and development of cancer has recently gained immense interest. The Wnt/β-catenin signaling pathway, an evolutionarily conserved signaling strategy, has a critical role in regulating tissue development. It has been implicated as a major player in cancer development and progression with its regulatory role on inflammatory cascades. Many naturally-occurring and small synthetic molecules endowed with inherent anti-inflammatory properties inhibit this aberrant signaling pathway, making them a promising class of compounds in the fight against inflammatory cancers. This article analyzes available scientific evidence and suggests a crosslink between Wnt/β-catenin signaling and inflammatory pathways in inflammatory cancers, especially breast, gastrointestinal, endometrial, and ovarian cancer. We also highlight emerging experimental findings that numerous anti-inflammatory synthetic and natural compounds target the crosslink between Wnt/β-catenin pathway and inflammatory cascades to achieve cancer prevention and intervention. Current challenges, limitations, and future directions of research are also discussed.

Novel Phytochemical Constituents and their Potential to Manage Diabetes

BACKGROUND

Diabetes is a chronic disease affecting a large population worldwide and stands as one of the major global health challenges to be tackled. According to World Health Organization, about 400 million are having diabetes worldwide and it is the seventh leading cause of deaths in 2016. Plant-based natural products have been in use from ancient times as ethnomedicine for the treatment of several diseases, including diabetes. As a result of that, there are several reports on plant-based natural products displaying antidiabetic activity. In the current review, such antidiabetic potential compounds reported from all plant sources along with their chemical structures are collected, presented and discussed. These kinds of reports are essential to pool the available information to one source, followed by statistical analysis and screening to check the efficacy of all known compounds in a comparative sense. This kind of analysis can give rise to a few potential compounds from hundreds, which can further be screened through in vitro and in vivo studies, and human trails leading to the drug development.

METHODS

Phytochemicals, along with their potential antidiabetic property, were classified according to their basic chemical skeleton. The chemical structures of all the compounds with antidiabetic activities were elucidated in the present review. In addition to this, the distribution and their other remarkable pharmacological activities of each species are also included.

RESULTS

The scrutiny of literature led to the identification of 44 plants with antidiabetic compounds (70) and other pharmacological activities. For the sake of information, the distribution of each species in the world is given. Many plant derivatives may exert anti-diabetic properties by improving or mimicking insulin production or action. Different classes of compounds including sulfur compounds (1-4), alkaloids (5-11), phenolic compounds (12-17), tannins (18-23), phenylpropanoids (24-27), xanthanoids (28-31), amino acid (32), stilbenoid (33), benzofuran (34), coumarin (35), flavonoids (36-49) and terpenoids (50-70) were found to be potential active compounds for antidiabetic activity. Of the 70 listed compounds, majorly 17 compounds are obtained from triterpenoids, 13 from flavonoids and 7 from alkaloids. Among all the 44 plant species, the maximum number (7) of compounds were isolated from Lagerstroemia speciosa followed by Momordica charantia (6) and S. oblonga with 5 compounds.

CONCLUSION

This is the first paper to summarize the established chemical structures of phytochemicals that have been successfully screened for antidiabetic potential and their mechanisms of inhibition. The reported compounds could be considered as potential lead molecules for the treatment of type-2 diabetes. Further, molecular and clinical trials are required to select and establish therapeutic drug candidates.

Activation of Insulin Signaling by Botanical Products

Type 2 diabetes (T2D) is a worldwide health problem, ranked as one of the leading causes for severe morbidity and premature mortality in modern society. Management of blood glucose is of major importance in order to limit the severe outcomes of the disease. However, despite the impressive success in the development of new antidiabetic drugs, almost no progress has been achieved with regard to the development of novel insulin-sensitizing agents. As insulin resistance is the most eminent factor in the patho-etiology of T2D, it is not surprising that an alarming number of patients still fail to meet glycemic goals. Owing to its wealth of chemical structures, the plant kingdom is considered as an inventory of compounds exerting various bioactivities, which might be used as a basis for the development of novel medications for various pathologies. Antidiabetic activity is found in over 400 plant species, and is attributable to varying mechanisms of action. Nevertheless, relatively limited evidence exists regarding phytochemicals directly activating insulin signaling, which is the focus of this review. Here, we will list plants and phytochemicals that have been found to improve insulin sensitivity by activation of the insulin signaling cascade, and will describe the active constituents and their mechanism of action.

Ultrasonic-microwave assisted extraction of total triterpenoid acids from Corni Fructus and hypoglycemic and hypolipidemic activities of the extract in mice

Triterpene acids, the main component of Corni Fructus, could improve diabetes mellitus, for which the underlying hypoglycemic mechanism is still unclear, in patients. In this study, total triterpenoid acids were extracted by ultrasonic-microwave assisted extraction optimized by the response surface methodology. The extract was then purified with an X-5 macroporous resin, and the yield of total triterpenoid acids increased to 281.24 mg g^-1 as compared with the 35.71 mg g^-1 obtained by unassisted extraction. The contents of five components were determined by ultrafast performance liquid chromatography. In addition, the hypoglycemic and hypolipidemic activities of total triterpenoid acids in diabetic mice induced by streptozotocin and a high fat diet were studied. The results indicated that all parameters (oral glucose tolerance, insulin resistance and liver damage) related to diabetes were significantly improved by total triterpenoid acids. Furthermore, total triterpenoid acids significantly recovered the expression level of AMP-activated protein kinase and its downstream proteins, including acetyl-CoA carboxylase, carnitine palmityltransferase-1, peroxisome proliferator-activated receptor alpha, sterol regulatory element-binding protein 1c and fatty acid synthase. Altogether, total triterpenoid acids could ameliorate hyperlipidemia and hyperglycemia in diabetic mice, probably by activating the AMP-activated protein kinase-peroxisome proliferator-activated receptor signaling pathway and inhibiting the sterol regulatory element-binding protein 1c and fatty acid synthase signaling pathways. Therefore, total triterpene acids, isolated from Corni Fructus which is a prevailing health food, could be a functional food ingredient with therapeutic and commercial values.

Epigenetic Regulation of NRF2/KEAP1 by Phytochemicals

Epigenetics has provided a new dimension to our understanding of nuclear factor erythroid 2–related factor 2/Kelch-like ECH-associated protein 1 (human NRF2/KEAP1 and murine Nrf2/Keap1) signaling. Unlike the genetic changes affecting DNA sequence, the reversible nature of epigenetic alterations provides an attractive avenue for cancer interception. Thus, targeting epigenetic mechanisms in the corresponding signaling networks represents an enticing strategy for therapeutic intervention with dietary phytochemicals acting at transcriptional, post-transcriptional, and post-translational levels. This regulation involves the interplay of histone modifications and DNA methylation states in the human NFE2L2/KEAP1 and murine Nfe2l2/Keap1 genes, acetylation of lysine residues in NRF2 and Nrf2, interaction with bromodomain and extraterminal domain (BET) acetyl “reader” proteins, and non-coding RNAs such as microRNA (miRNA) and long non-coding RNA (lncRNA). Phytochemicals documented to modulate NRF2 signaling act by reversing hypermethylated states in the CpG islands of NFE2L2 or Nfe2l2, via the inhibition of DNA methyltransferases (DNMTs) and histone deacetylases (HDACs), through the induction of ten-eleven translocation (TET) enzymes, or by inducing miRNA to target the 3′-UTR of the corresponding mRNA transcripts. To date, fewer than twenty phytochemicals have been reported as NRF2 epigenetic modifiers, including curcumin, sulforaphane, resveratrol, reserpine, and ursolic acid. This opens avenues for exploring additional dietary phytochemicals that regulate the human epigenome, and the potential for novel strategies to target NRF2 signaling with a view to beneficial interception of cancer and other chronic diseases.

Network pharmacology-based study of the mechanisms of action of anti-diabetic triterpenoids from Cyclocarya paliurus

Diabetes is a complex illness requiring long-term therapy. Cyclocarya paliurus, a recently confirmed new food resource, shows significant hypoglycemic and hypolipidemic effects in type II diabetes. Triterpenoid saponins are considered as the effective medicinal components of C. paliurus and are useful for the treatment of diabetes mellitus. However, little is known regarding their specific mechanism of actions. In this study, we used active ingredient screening and target prediction techniques to determine the components of C. paliurus responsible for its anti-diabetic effects as well as their targets. In addition, we used bioinformatics technology and molecular docking analysis to determine the mechanisms underlying their anti-diabetic effects. A total of 39 triterpenes were identified through a literature search and 1 triterpene compound by experiments. In all, 33 potential target proteins associated with 36 pathways were predicted to be related to diabetes. Finally, 7 compounds, 15 target proteins, and 15 signaling pathways were found to play important roles in the therapeutic effects of C. paliurus against diabetes. These results provide a theoretical framework for the use of C. paliurus against diabetes. Moreover, molecular docking verification showed that more than 90% of the active ingredients had binding activity when tested against key target proteins, and a literature search showed that the active ingredients identified had anti-diabetic effects, indicating that the results were highly reliable.

Active ingredient screening and target prediction techniques were used to determine the components of Cyclocarya paliurus responsible for its anti-diabetic effects as well as their targets.