Ethnobotanical Uses and Pharmacological Activities of Moroccan Ephedra Species.

Ephedra species are among the most popular herbs used in traditional medicine for a long time. The ancient Chinese medical book "Treatise on Febrile Diseases" refers to the classic traditional Chinese medicine prescription Ge Gen decoction, which consists of seven herbs, including an Ephedra species. Ephedra species are utilized all over the world to treat symptoms of the common cold and coughs, and to combat major human diseases, such as asthma, cancers, diabetes, cardiovascular and digestive disorders, and microbial infections. This study aimed at identifying specific Ephedra species used traditionally in Morocco for therapeutic purposes. The plant parts, their preparation process, and the treated pathologies were identified and analyzed. The results revealed five ethnobotanically important species of Ephedra: Ephedra alata Decne, Ephedra altissima Desf., Ephedra distachya L., Ephedra fragilis Desf., and Ephedra nebrodensis Tineo. These species are used traditionally in Morocco for treating people with diabetes, cancer, rheumatism, cold and asthma, hypertension, influenza virus infection, and respiratory ailments. In addition, they are occasionally used as calefacient agents, to regulate weight, or for capillary care. Few studies have underlined the antibacterial and antioxidant activities of some of these Moroccan Ephedra species, but little information is available regarding the natural products at the origin of the bioactivities. Further phytochemical investigations and clinical data are encouraged to better support the use of these plants.

Activity of pyridyl-pyrazolone derivatives against Trypanosoma cruzi.

New affordable drugs are needed for the treatment of infection with the protozoan parasite Trypanosoma cruzi responsible for the Chagas disease (CD). Only two old drugs are currently available, nifurtimox and benznidazole (Bz) but they exhibit unwanted side effects and display a weak activity in the late chronic phase of the disease. In this context, we evaluated the activity of a series of aryl-pyrazolone derivatives against T cruzi, using both bloodstream trypomastigote and intracellular amastigote forms of the parasite. The test compounds originate from a series of anticancer agents targeting the immune checkpoint ligand PD-L1 and bear an analogy with known anti-trypanosomal pyrazolones. A first group of 6 phenyl-pyrazolones was tested, revealing the activity of a single pyridyl-pyrazolone derivative. Then a second group of 8 compounds with a common pyridyl-pyrazolone core was evaluated. The in vitro testing process led to the identification of two non-cytotoxic and highly potent molecules against the intracellular form of T. cruzi, with an activity comparable to Bz. Moreover, one compound revealed an activity largely superior to that of Bz against bloodstream trypomastigotes, while being non-cytotoxic (selectivity index >1000). Unfortunately, the compound showed little activity in vivo, most likely due to its very limited plasma stability. However, the study opens novel perspectives for the design of new anti-trypanosomal products and the mechanism of action of the compounds is discussed.

Limonoids isolated from Chisocheton ceramicus Miq. and the antiadipogenic mechanism of action of ceramicine B.

Different types of limonoids have been isolated from plants of the Chisocheton genus, notably from the species Chisocheton ceramicus Miq. which is largely distributed in the Indonesian archipelago and Malaysia region. A variety of natural products have been found in the bark of the tree and characterized as antimicrobial and/or antiproliferative agents. The isolated limonoids include chisomicines A-E, proceranolide, and a few other compounds. A focus is made on a large series of limonoids designated ceramicines A to Z including derivatives with antiparasitic activities, antioxidant, antimelanogenic, and antiproliferative effects and/or acting as regulators of lipogenesis. The lead compound in the series is ceramicine B functioning as a potent inhibitor of lipid droplet accumulation (LDA). Extracts from Chisocheton ceramicus and ceramicines have shown anti-LDA effects, with little or no cytotoxic effects. Ceramicine B is the most active compound functioning as a regulator of lipid storage in cells and tissues. Ceramicine B is a transcriptional repressor of peroxisome proliferator-activated receptor γ (PPARγ) and an inhibitor of phosphorylation of the transcription factor FoxO1, acting via an upstream molecular target. Targeting of glycogen synthase kinase-3ß is proposed, based on the analogy with structurally related limonoids known to target this enzyme, and supported by a molecular docking analysis. The target and pathway implicated in ceramicine B activity are discussed. The analysis shed light on ceramicine B as a natural product precursor for the design of novel compounds capable of reducing LDA in cells and of potential interest for the treatment of obesity, liver diseases, and other pathologies.

Insights into the Mechanism of Action of the Degraded Limonoid Prieurianin.

Limonoids are extremely diversified in plants, with many categories of products bearing an intact, rearranged or fragmented oxygenated scaffold. A specific subgroup of fragmented or degraded limonoids derives from the tetranortriterpenoid prieurianin, initially isolated from the tree Trichilia prieuriana but also found in other plants of the Meliaceae family, including the more abundant species Aphanamixis polystachya. Prieurianin-type limonoids include about seventy compounds, among which are dregeanin and rohitukin. Prieurianin and analogs exhibit insecticidal, antimicrobial, antiadipogenic and/or antiparasitic properties but their mechanism of action remains ill-defined at present. Previous studies have shown that prieurianin, initially known as endosidin 1, stabilizes the actin cytoskeleton in plant and mammalian cells via the modulation of the architecture and dynamic of the actin network, most likely via interference with actin-binding proteins. A new mechanistic hypothesis is advanced here based on the recent discovery of the targeting of the chaperone protein Hsp47 by the fragmented limonoid fraxinellone. Molecular modeling suggested that prieurianin and, to a lesser extent dregeanin, can form very stable complexes with Hsp47 at the protein-collagen interface. Hsp-binding may account for the insecticidal action of the product. The present review draws up a new mechanistic portrait of prieurianin and provides an overview of the pharmacological properties of this atypical limonoid and its chemical family.

Synthesis, Molecular Electron Density Theory Study, Molecular Docking, and Pharmacological Evaluation of New Coumarin-Sulfonamide-Nitroindazolyl-Triazole Hybrids as Monoamine Oxidase Inhibitors.

Inhibitors of monoamine oxidases (MAOs) are of interest for the treatment of neurodegenerative disorders and other human pathologies. In this frame, the present work describes different synthetic strategies to obtain MAO inhibitors via the coupling of the aminocoumarin core with arylsulfonyl chlorides followed by copper azide-alkyne cycloaddition, leading to coumarin-sulfonamide-nitroindazolyl-triazole hybrids. The nitration position on the coumarin moiety was confirmed through nuclear magnetic resonance spectroscopy and molecular electron density theory in order to elucidate the molecular mechanism and selectivity of the electrophilic aromatic substitution reaction. The coumarin derivatives were evaluated for their inhibitory potency against monoamine oxidases and cholinesterases. Molecular docking calculations provided a rational binding mode of the best compounds in the series with MAO A and B. The work identified hybrids 14a-c as novel MAO inhibitors, with a selective action against isoform B, of potential interest to combat neurological diseases.

A systematic review of spirostanol saponins and anticancer natural products isolated from Tacca plantaginea (Hance) Drenth.

The plant genus Tacca comprises twenty species including Tacca plantaginea, essentially distributed in the Indo-China region. Medicinal preparations from the rhizomes are used traditionally to treat gastrointestinal ailments, stomach aches and inflammatory disorders. A variety of bioactive molecules have been isolated from T. plantaginea, including potent anticancer steroids such as the taccanolides which interfere with microtubules dynamic. Other efficient anticancer natural products have been isolated from the plant, in particular a series of diosgenin/yamogenin-type sapogenins including taccaoside (monodesmosidic) and taccaoside A (bidesmosidic). Taccaoside A displays marked anticancer properties through two complementary mechanisms: a direct action on cancer stem cells via HRas and Pi3K/Akt signaling and an indirect immunomodulatory action via activation of cytotoxic T cells. A similar mechanism of action has been invoked with a total saponin extract from Schizocapsa plantaginea Hance (synonym to T. plantaginea) and the saponin SSPH 1. This saponin reduced tumor growth in mice through stimulation of cytotoxic T lymphocytes. Other bioactive products have been isolated from T. plantaginea, including withanolide-type steroids (plantagiolides, chantriolides), diarylheptanoids (plantagineosides) and different saponins (diosbulbisides, lieguonins). The discussion centers around the mechanism of action of spirostanol saponins, with the objective to promote their study as immuno-active anticancer agents.

Pharmacological properties of extracts and prenylated isoflavonoids from the fruits of Osage orange (Maclura pomifera (Raf.) C.K.Schneid.).

Osage orange trees (Maclura pomifera (Raf.) C.K.Schneid.) are distributed worldwide, particularly in south-east states of the USA. They produce large quantities of strong yellow fruits, bigger than oranges, but these fruits are inedible, with an acid milky juice which is little consumed by birds and insects. Extracts prepared from Osage orange fruits (hedge apple) have revealed a range of pharmacological properties of interest in human and veterinary medicine. In addition, Osage orange extracts can be used in agriculture and aquaculture, and as dyeing agent for the textile industry. Extracts contain potent antioxidant compounds, notably the isoflavonoids pomiferin and auriculasin, together with other terpenoids and flavonoids. The structural characteristics and pharmacological properties of the major prenylated isoflavones isolated from M. pomifera are discussed here, with a focus on the two phenolic compounds osajin and warangalone, and the two catechol analogues pomiferin and auriculasin. The mechanisms at the origin of their potent antioxidant and anti-inflammatory effects are presented, notably inhibition of xanthine oxidase, phosphodiesterase 5A and kinases such as RKS2 and kRAS. Osajin and auriculasin display marked anticancer properties, owing to their ability to inhibit tumor cell proliferation, migration and tumor angiogenesis. Different molecular mechanisms are discussed, including osajin­copper complexation and binding to quadruplex DNA. An overview of the mechanism of action of the prenylated isoflavones from Osage orange is presented, with the objective to promote their knowledge and to raise opportunities to better exploit the fruits of Osage orange, abundant but largely neglected at present.

Covalent binding of withanolides to cysteines of protein targets.

Withanolides represent an important category of natural products with a steroidal lactone core. Many of them contain an α,ß-unsaturated carbonyl moiety with a high reactivity toward sulfhydryl groups, including protein cysteine thiols. Different withanolides endowed with marked antitumor and anti-inflammatory have been shown to form stable covalent complexes with exposed cysteines present in the active site of oncogenic kinases (BTK, IKKß, Zap70), metabolism enzymes (Prdx-1/6, Pin1, PHGDH), transcription factors (Nrf2, NFκB, C/EBPß) and other structural and signaling molecules (GFAP, ß-tubulin, p97, Hsp90, vimentin, Mpro, IPO5, NEMO, …). The present review analyzed the covalent complexes formed through Michael addition alkylation reactions between six major withanolides (withaferin A, physalin A, withangulatin A, 4ß-hydroxywithanolide E, withanone and tubocapsanolide A) and key cysteine residues of about 20 proteins and the resulting biological effects. The covalent conjugation of the α,ß-unsaturated carbonyl system of withanolides with reactive protein thiols can occur with a large set of soluble and membrane proteins. It points to a general mechanism, well described with the leading natural product withaferin A, but likely valid for most withanolides harboring a reactive (electrophilic) enone moiety susceptible to react covalently with cysteinyl residues of proteins. The multiplicity of reactive proteins should be taken into account when studying the mechanism of action of new withanolides. Proteomic and network analyses shall be implemented to capture and compare the cysteine covalent-binding map for the major withanolides, so as to identify the protein targets at the origin of their activity and/or unwanted effects. Screening of the cysteinome will help understanding the mechanism of action and designing cysteine-reactive electrophilic drug candidates.

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.

Interaction of Norsecurinine-Type Oligomeric Alkaloids with α-Tubulin: A Molecular Docking Study.

The medicinal plant Securinega virosa (Roxb ex. Willd) Baill., also known as Flueggea virosa (Roxb. ex Willd.) Royle, is commonly used in traditional medicine in Africa and Asia for the management of diverse pathologies, such as parasite infections, diabetes, and gastrointestinal diseases. Numerous alkaloids have been isolated from the twigs and leaves of the plant, notably a variety of oligomeric indolizidine alkaloids derived from the monomers securinine and norsecurinine which both display anticancer properties. The recent discovery that securinine can bind to tubulin and inhibit microtubule assembly prompted us to investigate the potential binding of two series of alkaloids, fluevirosines A-H and fluevirosinine A-J, with the tubulin dimer by means of molecular modeling. These natural products are rare high-order alkaloids with tri-, tetra-, and pentameric norsecurinine motifs. Despite their large size (up to 2500 Å3), these alkaloids can bind easily to the large drug-binding cavity (about 4800 Å3) on α-tubulin facing the ß-tubulin unit. The molecular docking analysis suggests that these hydrophobic macro-alkaloids can form stable complexes with α/ß-tubulin. The tubulin-binding capacity varies depending on the alkaloid size and structure. Structure-binding relationships are discussed. The docking analysis identifies the trimer fluevirosine D, tetramer fluevirosinine D, and pentamer fluevirosinine H as the most interesting tubulin ligands in the series. This study is the first to propose a molecular target for these atypical oligomeric Securinega alkaloids.

A molecular docking exploration of the large extracellular loop of tetraspanin CD81 with small molecules.

Tetraspanin CD81 is a transmembrane protein used as a co-receptor by different viruses and implicated in some cancer and inflammatory diseases. The design of therapeutic small molecules targeting CD81 lags behind monoclonal antibodies and peptides but different synthetic and natural products binding to CD81 have been identified. We have investigated the interaction between synthetic compounds and CD81, considering both the cholesterol-bound full-length receptor and a truncated protein corresponding to the large extracellular loop (LEL) of the tetraspanin. They represent the closed and open conformations of the protein, respectively. Stable complexes were characterized with bi-aryl compounds (notably the quinolinone-benzothiazole 6) and atypical molecules bearing a 1-amino-boraadamantane scaffold well adapted to interact with CD81 (5a-d). In each case, the mode of binding to CD81 was analyzed, the binding sites identified and the molecular contacts determined. The narrow intra-LEL binding site of CD81 can accommodate the elongated bi-aryl 6 but not a series of isosteric compounds with a bis(bicyclic) scaffold. The bora-adamantane derivatives appeared to bind well to CD81, but essentially to the external surface of the protein loop. The binding selectivity of the compounds was assessed comparing binding to the LEL of tetraspanins CD81, CD9 and Tspan15. A net preference for CD81 over CD9 was evidenced, but the LEL of Tspan15 also provided a suitable binding site for the compounds, notably for the bora-adamantane derivatives. This work provides an aid to the identification and design of tetraspanin-binding small molecules, underlining the distinct behavior of the open and closed conformation of the protein for drug binding. Supplementary Information: The online version contains supplementary material available at 10.1007/s40203-024-00203-6.

Implication of Rac1 GTPase in molecular and cellular mitochondrial functions.

Rac1 is a member of the Rho GTPase family which plays major roles in cell mobility, polarity and migration, as a fundamental regulator of actin cytoskeleton. Signal transduction by Rac1 occurs through interaction with multiple effector proteins, and its activity is regulated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). The small protein is mainly anchored to the inner side of the plasma membrane but it can be found in endocellular compartments, notably endosomes and cell nuclei. The protein localizes also into mitochondria where it contributes to the regulation of mitochondrial dynamics, including both mitobiogenesis and mitophagy, in addition to signaling processes via different protein partners, such as the proapoptotic protein Bcl-2 and chaperone sigma-1 receptor (σ-1R). The mitochondrial form of Rac1 (mtRac1) has been understudied thus far, but it is as essential as the nuclear or plasma membrane forms, via its implication in regulation of oxidative stress and DNA damages. Rac1 is subject to diverse post-translational modifications, notably to a geranylgeranylation which contributes importantly to its mitochondrial import and its anchorage to mitochondrial membranes. In addition, Rac1 contributes to the mitochondrial translocation of other proteins, such as p53. The mitochondrial localization and functions of Rac1 are discussed here, notably in the context of human diseases such as cancers. Inhibitors of Rac1 have been identified (NSC-23766, EHT-1864) and some are being developed for the treatment of cancer (MBQ-167) or central nervous system diseases (JK-50561). Their effects on mtRac1 warrant further investigations. An overview of mtRac1 is provided here.

Fissistigma oldhamii (Hemsl.) Merr.: Ethnomedicinal, Phytochemistry, and Pharmacological Aspects.

The species Fissistigma oldhamii (Hemsl.) Merr. (Annonaceae) has long been used as a traditional herbal medicine in China to treat diverse human diseases. Decoctions from the roots of the plant (Gua Fù Mù) are used to treat body pain and inflammatory pathologies, such as rheumatic syndromes, sciatica, and osteoarthritis. The phytochemical content of the plant and the associated pharmacological activities have been analyzed. Seventy natural products were identified in the different parts of the plants, namely, the roots, stems, leaves, fruits, and seeds. The compounds comprise many tri- and tetracyclic alkaloids (aporphine-type), anthraquinones, terpenoids, flavonoids, and others. The pharmacological properties of these molecules were analyzed to point out the anti-inflammatory, antioxidant, anticancer, and/or antimicrobial effects, together with the underlying modulated pathways and molecular targets in some cases. The panel of phytoconstituents present in F. oldhamii extracts is large, with the majority of bioactive products identified in the roots and stems. Multiple molecules can contribute to the anti-inflammatory properties of the extracts. Network pharmacology analyses of the phytoconstituents are needed to better delineate the effective components and their targets.

Mechanism of action of glycyrrhizin against Plasmodium falciparum

Extracts of the plant Glycyrrhiza glabra (licorice) are used in traditional medicine to treat malaria. The main active components are the saponin glycyrrhizin (GLR) and its active metabolite glycyrrhetinic acid (GA) which both display activities against Plasmodium falciparum. We have identified three main mechanisms at the origin of their anti-plasmodial activity: (i) drug-induced disorganisation of membrane lipid rafts, (ii) blockade of the alarmin protein HMGB1 and (iii) potential inhibition of the detoxifying enzyme glyoxalase 1 (GLO-1) considered as an important drug target for malaria. Our analysis shed light on the mechanism of action of GLR against P. falciparum.

In vitro measurement of enzymatic markers as a tool to detect mouse cardiomyocytes injury

Primary cultures of cardiomyocytes represent a useful model for analyzing cardiac cell biology as well as pathogenesis of several cardiovascular disorders. Our aim was to standardize protocols for determining the damage of cardiac cells cultured in vitro by measuring the creatine kinase and its cardiac isotype and lactate dehydrogenase activities in the supernatants of mice cardiomyocytes submitted to different protocols of cell lysis. Our data showed that due to its higher specificity, the cardiac isotype creatine kinase was the most sensitive as compared to the others studied enzymatic markers, and can be used to monitor and evaluate cardiac damage in in vitro assays.