Evaluation of antidiabetic effect of total calystegines extracted from Hyoscyamus albus

Dereplication of calystegines in food plants and wild Solanum Brazilian fruits

Calystegines are potent glycosidase inhibitors with therapeutic potential and are constituents of food and feed with potential toxic effects. This study aims to target calystegines and other nitrogenous substances in food plants. Hydroalcoholic extracts from Solanum tuberosum, Ipomoea batatas, S. lycocarpum, and fruit from S. lycopersicum, S. aethiopicum, S. paniculatum, S. crinitum, and S. acanthodes were analyzed by liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using an acidic HILIC column. The dereplication approach included data processing using MZMine2, FBMN-GNPS, and structure elucidation and interpretation of the organized data. The calystegines A3, A5, B2, and C1 were identified, and several potential new calystegine analogues: three may correspond to new calystegines of the A-group, one glycosyl derivative of calystegine A3, and two glycosyl derivatives of the B-group. These findings help to direct the search for new calystegines. In addition, the dereplication approach enabled the annotation of 22 other nitrogen compounds.

Withania frutescens (L.) Pauquy, a valuable Mediterranean shrub containing bioactive withanolides

The bushy plant Withania frutescens (L.) Pauquy is well distributed in the West-Mediterranean area, notably in the south of Spain, Algeria and Morocco where is it is used traditionally for the treatment of various human diseases, including diabetes. Unlike the two major species W. somnifera and W. coagulans extensively studied, the genomically close species W. frutescens has been much less investigated. Nevertheless, this shrub species displays a comparable phytochemical profile and marked antioxidant and anti-inflammatory properties, at the origin of reported pharmacological effects and its traditional uses. Here we have analyzed the diversity of biological effects reported with leaves and root extracts of W. frutescens. Hydroalcoholic extracts prepared from the aerial parts of the plant have revealed antihyperglycemic and cell-protective activities along with antimicrobial and anticorrosive effects. The extracts contained diverse polyphenolic compounds and a few alkaloids (calystegines) but most of the observed effects have been attributed to the presence of withanolides which are modified C28 ergostane-type steroids. Our analysis focused in part on specific withanolides found in W. frutescens, in particular an unusual 3-O-sulfated withanolide considered as a potential pro-drug of the major active compound withaferin A (WA) and a lead compound for the development of a potential drug candidate. The mechanism of action of this sulfated WA analogue is discussed. Altogether, our unprecedented extensive analysis of W. frutescens highlighted the pharmacological potential of this atypical medicinal plant. By analogy with the major cultivated Withania species, the market potential of little-known plant is underlined.

LC/MS-MS Analysis of Phenolic Compounds in Hyoscyamus albus L. Extract: In Vitro Antidiabetic Activity, In Silico Molecular Docking, and In Vivo Investigation against STZ-Induced Diabetic Mice

This study aimed to investigate the chemical composition and antidiabetic properties of cultivated Hyoscyamus albus L. The ethanol extract was analyzed using LC-MS/MS, and 18 distinct phenolic compounds were identified. Among these, p-coumaric acid (6656.8 ± 3.4 µg/g), gallic acid (6516 ± 1.7 µg/g), luteolin (6251.9 ± 1.3 µg/g), apigenin (6209.9 ± 1.1 µg/g), and rutin (5213.9 ± 1.3 µg/g) were identified as the most abundant polyphenolic molecules. In the in vitro antidiabetic experiment, the ability of the plant extract to inhibit α-glucosidase and α-amylase activities was examined. The results indicated that the extract from H. albus L. exhibited a higher inhibitory effect on α-amylase compared to α-glucosidase, with an IC50 of 146.63 ± 1.1 µg/mL and 270.43 ± 1.1 µg/mL, respectively. Docking simulations revealed that luteolin, fisetin, and rutin exhibited the most promising inhibitory activity against both enzymes, as indicated by their high contrasting inhibition scores. To further investigate the in vivo antidiabetic effects of H. albus L., an experiment was conducted using STZ-induced diabetic mice. The results demonstrated that the plant extract effectively reduced the levels of cholesterol and triglycerides. These findings suggest that H. albus L. may have therapeutic potential for managing hyperlipidemia, a common complication associated with diabetes. This highlights its potential as a natural remedy for diabetes and related conditions.

Calystegines Improve the Metabolic Activity of Human Adipose Derived Stromal Stem Cells (ASCs) under Hyperglycaemic Condition through the Reduction of Oxidative/ER Stress, Inflammation, and the Promotion of the AKT/PI3K/mTOR Pathway

Hyperglycaemia and its resulting glucotoxicity are among the most prominent hallmarks of diabetes mellitus (DM) development. Persistent hyperglycaemia further leads to oxidative stress via mitochondrial dysfunction and subsequent ER stress onset, while associated hyperlipidaemia triggers the adipose tissue to secrete pro-inflammatory cytokines. In this study, the effect of calystegines has been investigated in an experimental model of hyperglycaemia induced on human ASCs cells. Different cellular pathways including apoptosis, oxidative and ER stress, inflammation as well as Pi3K/AKT/mTOR metabolic-associated axis have been evaluated by means on RT-qPCR, western blot, and flow cytometry techniques. Treatment of HuASCs cells with calystegines strongly promoted the hyperglycaemic cells survival and significantly diminished oxidative stress, mitochondrial dynamics failure and ER stress, while improving the endogenous cellular antioxidant defenses. Interestingly, nortropane alkaloids efficiently prevented the hyperglycaemia-mediated inflammatory response, as evidenced by the regulation of the pro- and anti-inflammatory response in HuASCs cells. Finally, we evidenced that calystegines may exert their protective effect on HuASCs cells metabolic functions through the restoration of the defective PI3K/AKT/mTOR pathway. Overall, the present investigation demonstrated that calystegines possess important abilities to protect HuASCs against hyperglycaemia-induced cellular dysfunction, and it evidenced that the observed effects are associated to the promotion of PI3K/AKT/mTOR pathway.

High throughput virtual screening and molecular dynamics simulation analysis of phytomolecules against BfmR of Acinetobacter baumannii: anti-virulent drug development campaign

Acinetobacter baumannii is a notorious multidrug resistant bacterium responsible for several hospital acquired infections assisted by its capacity to develop biofilms. A. baumannii BfmR (RstA), a response regulator from the BfmR/S two-component signal transduction system, is the major controller of A. baumannii biofilm development and formation. As a result, BfmR represents a novel target for anti-biofilm treatment against A. baumannii. The discovery of the high-resolution crystal structure of BfmR provides a good chance for computational screening of its probable inhibitors. Therefore, in this study we aim to search new, less toxic, and natural BfmR inhibitors from 8450 phytomolecules available in the Indian Medicinal Plants, Phytochemistry and Therapeutic (IMPPAT) database by analyzing molecular docking against BfmR (PDB ID: 6BR7). Out of these 8450 phytomolecules 6742 molecules were successfully docked with BfmR with the docking score range -6.305 kcal/mol to +5.120 kcal/mol. Structure based-molecular docking (SB-MD) and ADMET (absorption, distribution, metabolism, excretion, & toxicity) profile examination revealed that Norepinephrine, Australine, Calystegine B3, 7,7 A-Diepialexine, and Alpha-Methylnoradrenaline phytocompounds strongly binds to the active site residues of BfmR. Furthermore, molecular dynamics simulation (MDS) studies for 100 ns and the binding free energy (MM/GBSA) analysis elucidated the binding mechanism of Calystegine B3, 7,7 A-Diepialexine, and Alpha-Methylnoradrenaline to BfmR. In summary, these phytocompounds seems to have the promising molecules against BfmR, and thus necessitates further verification by both in vitro and in vivo experiments. HighlightsBfmR plays a key role in biofilm development and exopolysaccharide (EPS) synthesis in A. baumannii.Computational approach to search for promising BfmR inhibitors from IMPAAT database.The lead phytomolecules such as Calystegine B3, 7,7 A-Diepialexine, and Alpha-Methylnoradrenaline displayed significant binding with BfmR active site.The outcome of BfmR binding phytomolecules has broadened the scope of hit molecules validation.Communicated by Ramaswamy H. Sarma.

Herbal Medicines Targeting the Improved β-Cell Functions and β-Cell Regeneration for the Management of Diabetes Mellitus

There is an increasing trend of investigating natural bioactive compounds targeting pancreatic β-cells for the prevention/treatment of diabetes mellitus (DM). With the exploration of multiple mechanisms by which β-cells involve in the pathogenesis of DM, herbal medicines are gaining attention due to their multitasking ability as evidenced by traditional medicine practices. This review attempts to summarize herbal medicines with the potential for improvement of β-cell functions and regeneration as scientifically proven by in vivo/in vitro investigations. Furthermore, attempts have been made to identify the mechanisms of improving the function and regeneration of β-cells by herbal medicines. Relevant data published from January 2009 to March 2020 were collected by searching electronic databases “PubMed,” “ScienceDirect,” and “Google Scholar” and studied for this review. Single herbal extracts, polyherbal mixtures, and isolated compounds derived from approximately 110 medicinal plants belonging to 51 different plant families had been investigated in recent years and found to be targeting β-cells. Many herbal medicines showed improvement of β-cell function as observed through homeostatic model assessment-β-cell function (HOMA-β). Pancreatic β-cell regeneration as observed in histopathological and immunohistochemical studies in terms of increase of size and number of functional β-cells was also prominent. Increasing β-cell mass via expression of genes/proteins related to antiapoptotic actions and β-cell neogenesis/proliferation, increasing glucose-stimulated insulin secretion via activating glucose transporter-2 (GLUT-2) receptors, and/or increasing intracellular Ca²⁺ levels were observed upon treatment of some herbal medicines. Some herbal medicines acted on various insulin signaling pathways. Furthermore, many herbal medicines showed protective effects on β-cells via reduction of oxidative stress and inflammation. However, there are many unexplored avenues. Thus, further investigations are warranted in elucidating mechanisms of improving β-cell function and mass by herbal medicines, their structure-activity relationship (SAR), and toxicities of these herbal medicines.

Hyoscyamus albus nortropane alkaloids reduce hyperglycemia and hyperinsulinemia induced in HepG2 cells through the regulation of SIRT1/NF-kB/JNK pathway

BACKGROUND

Chronic superphysiological glucose and insulin concentrations are known to trigger several tissue and organ failures, including insulin resistance, oxidative stress and chronic low-grade inflammation. Hence, the screening for molecules that may counteract such conditions is essential in current existing therapeutic strategies, thereby the use of medicinal plant derivatives represents a promising axis in this regard.

METHODS

In this study, the effect of a selected traditional medicinal plant, Hyoscyamus albus from which, calystegines have been isolated, was investigated in an experimental model of hyperinsulinemia and hyperglycemia induced on HepG2 cells. The mRNA and protein expression levels of different insulin signaling, gluconeogenic and inflammatory pathway- related molecules were examined. Additionally, cell viability and apoptosis, oxidative stress extent and mitochondrial dysfunctions were assayed using flow cytometric and qRT-PCR techniques.

RESULTS

Treatment of IR HepG2 cells with calystegines strongly protected the injured cells from apoptosis, oxidative stress and mitochondrial integrity loss. Interestingly, nortropane alkaloids efficiently regulated the impaired glucose metabolism in IR HepG2 cells, through the stimulation of glucose uptake and the modulation of SIRT1/Foxo1/G6PC/mTOR pathway, which is governing the hepatic gluconeogenesis. Furthermore, the alkaloidal extract restored the defective insulin signaling pathway, mainly by promoting the expression of Insr at the mRNA and protein levels. What is more, treated cells exhibited significant mitigated inflammatory response, as evidenced by the modulation and the regulation of the NF- κB/JNK/TLR4 axis and the downstream proinflammatory cytokines recruitment.

CONCLUSION

Overall, the present investigation demonstrates that calystegines from Hyoscyamus albus provide cytoprotection to the HepG2 cells against insulin/glucose induced insulin resistance and apoptosis due to the regulation of SIRT1/Foxo1/G6PC/mTOR and NF-κB/JNK/TLR4 signaling pathways. Video Abstract.

Natural Alkaloids and Diabetes Mellitus: A Review

BACKGROUND

The use of herbal therapies for treatment and management of diabetes mellitus and complications associated with this chronic condition is increasing. Plants contain a bounty of phytochemicals that have been proven to be protective by reducing the risk of various ailments and diseases, including alkaloids. Moreover, alkaloids are known to be among the oldest natural products used by humans for highlighting drugs that play crucial roles as therapeutic agents. The reason for this expanding interest and uses of alkaloids as a part of plant natural compounds-based treatments is that a significant proportion of diabetic patients do not respond very well to conventional therapeutic medication. Furthermore, other explanations to this fact are the cost of medication, side-effects, accessibility, and availability of health facilities and drugs and the inefficiency of these medicines in certain cases.

OBJECTIVE

In this study we aimed to review the literature on the valuable effects of herbs and plants and their isolated alkaloids compounds as medication for management of diabetes, a prevalent risk factor for several other disorders and illnesses.

METHODS

In the current review, PubMed, ScienceDirect, Springer and google scholar databases were used and the criterion for inclusion was based on the following keywords and phrases: diabetes, hyperglycemia, complications of diabetes, alkaloids, antidiabetic alkaloids, hypoglycemic alkaloids, alkaloids and complications of diabetes mellitus, mechanisms of action and alkaloids.

RESULTS

In the current review, we demonstrate that alkaloids in the form of extracts and isolated molecules obtained from a large variety of species demonstrated their efficiency for improving raises in blood glucose either in animal models via experimental studies or in human subjects via clinical trials. Medicinal species as chillies (Capsicum annuum), turmeric (Curcuma longa), barberry (Berberis vulgaris) and cress (Lepidium sativum) are among the most common and therapeutic plants used for controlling diabetes that were the subject of several experimental and clinical investigations. Whereas, isolated alkaloids such as berberine, capsaicin and trigonelline have received more interest in this field. Interestingly, the therapeutic impact of alkaloids against blood glucose pathogenesis is mediated through a variety of signaling cascades and pathways, via inhibiting or stimulating diversity of systems such as inhibition of α-glucosidase enzyme, blockade of PTP- 1B, deactivation of DPP-IV, increasing insulin sensitivity and modulating the oxidative stress.

CONCLUSION

Based on the findings of the present review, alkaloids could be used as preventive and curative agents in the case of endocrine disorders, particularly diabetes and could play a promoting function for the discovery of new antidiabetic agents.

A review of Algerian medicinal plants used in the treatment of diabetes

ETHNOPHARMACOLOGICAL RELEVANCE

Plants are traditionally used in Algeria to treat many disorders, including diabetes mellitus. Knowledge of the plants that are used may provide insight on their properties, for further exploration. This study reviewed all the available published and unpublished reports concerning the use of herbal medicines in the treatment of diabetes in Algeria.

AIM OF THE STUDY

To describe the plants used in Algeria to treat diabetes, as reported in the literature.

MATERIAL AND METHODS

Systematic review of ethnobotanical papers published in the medical literature, from literature databases (Pubmed, Web of Science), as well as Google, for English, French and Arabic -language publication, and a manual search of local libraries and bookshops, as well as the university repository of PhD and master's theses. The reference lists of the papers retrieved were also examined for further papers.

RESULTS

Many plants are cited in the ethnobotanical surveys, but only very few pharmacological studies were found. In the ethnobotanical surveys, 171 plants were reported, from 58 families of which the most often cited were Asteraceae, Lamiaceae and Apiaceae. The plants with the best evidence of use and activity are: Anabasis articulata (Forssk.) Moq., Trigonella foenum-graecum L., Centaurium erythraea Rafn, Artemisia herba-alba Asso, Marrubium vulgare L., Agathophora alopecuroides (Delile) Fenzl ex Bunge, Anabasis articulata (Forssk.) Moq., Hammada elegans (Bunge) Botsch., Helianthemum kahiricum Delile, Salsola baryosma (Schult.) Dandy, Salsola vermiculata L., Olea europaea L.

CONCLUSION

Traditional herbal medicines are still very much used in Algeria to control diabetes. However they are generally poorly characterized and none have been properly tested in man. There is a need for systematic evaluation of the more commonly used plants to confirm their antidiabetic activity, identify possible mechanimss of action, and recommend best use.

Nortropane alkaloids as pharmacological chaperones in the rescue of equine adipose-derived mesenchymal stromal stem cells affected by metabolic syndrome through mitochondrial potentiation, endoplasmic reticulum stress mitigation and insulin resistance alleviation

OBJECTIVES

Equine metabolic syndrome (EMS) refers to a cluster of associated abnormalities and metabolic disorders, including insulin resistance and adiposity. The numerous biological properties of mesenchymal stem cells (MSCs), including self-renewal and multipotency, have been the subject of many in-depth studies, for the management of EMS; however, it has been shown that this cell type may be affected by the condition, impairing thus seriously their therapeutic potential. Therefore, an attempt to rescue EMS adipose-derived stem cells (ASCs) with calystegines (polyhydroxylated alkaloids) that are endowed with strong antioxidant and antidiabetic abilities was performed.

METHODS

ASCs isolated from EMS horses were subsequently treated with various concentrations of total calystegines. Different parameters were then assessed using flow cytometry, confocal as well as SE microscopy, and RT-qPCR.

RESULTS

Our results clearly demonstrated that calystegines could improve EqASC viability and proliferation and significantly reduce apoptosis, via improvement of mitochondrial potentiation and functionality, regulation of pro- and anti-apoptotic pathways, and suppression of ER stress. Furthermore, nortropanes positively upregulated GLUT4 and IRS transcripts, indicating a possible sensitizing or mimetic effect to insulin. Most interesting finding in this investigation lies in the modulatory effect of autophagy, a process that allows the maintenance of cellular homeostasis; calystegines acted as pharmacological chaperones to promote cell survival.

CONCLUSION

Obtained data open new perspectives in the development of new drugs, which may improve the metabolic dynamics of cells challenged by MS.

Overview of available toxicity data for calystegines

Calystegines are polyhydroxylated nortropane alkaloids that have been found in various solanaceous foods, in particular in potatoes and aubergines. The biological activity and potential toxicity of calystegines are associated with their capacity to inhibit glycosidases and block carbohydrate metabolism inducing lysosomal storage toxicity. The present report summarises the retrieved information on the possible toxicity of calystegines. Only few in vivo short‐term toxicological studies in rodents on individual calystegines or mixtures of calystegines were retrieved. Overall, these studies are insufficient to conclude on the possible chronic toxicity effects of calystegines in humans, in particular considering the short duration of the studies and potential lower sensitivity of rats and mice to glycosidase inhibitors, compared to other species such as goats and guinea pigs. Several studies and case reports were retrieved on the toxic effects induced in livestock or experimental animals following consumption or administration of plants containing calystegines. However, the concurrent presence of other alkaloids, in particular swainsonine, did not allow using these studies to draw conclusions on the toxicity of calystegines. Since no experimental data on genotoxicity of calystegines were retrieved, in silico predicting models were applied to identify possible alert for genotoxicity of five calystegines recently detected in food. In most of the cases, the outcome of the computational predictions indicated no alerts for genotoxicity; however, the low reliability of the results prevents a firm conclusion on the genotoxic potential of the substances. Overall, the available data do not allow drawing conclusions on the possible toxic effects of calystegines in humans or in livestock, and more data in relevant experimental models would be necessary to characterise the toxic profile of this group of substances.