Unfolding Mechanism and Fibril Formation Propensity of Human Prion Protein in the Presence of Molecular Crowding Agents.

The pathological process of prion diseases implicates that the normal physiological cellular prion protein (PrPC) converts into misfolded abnormal scrapie prion (PrPSc) through post-translational modifications that increase ß-sheet conformation. We recently demonstrated that HuPrP(90-231) thermal unfolding is partially irreversible and characterized by an intermediate state (ß-PrPI), which has been revealed to be involved in the initial stages of PrPC fibrillation, with a seeding activity comparable to that of human infectious prions. In this study, we report the thermal unfolding characterization, in cell-mimicking conditions, of the truncated (HuPrP(90-231)) and full-length (HuPrP(23-231)) human prion protein by means of CD and NMR spectroscopy, revealing that HuPrP(90-231) thermal unfolding is characterized by two successive transitions, as in buffer solution. The amyloidogenic propensity of HuPrP(90-231) under crowded conditions has also been investigated. Our findings show that although the prion intermediate, structurally very similar to ß-PrPI, forms at a lower temperature compared to when it is dissolved in buffer solution, in cell-mimicking conditions, the formation of prion fibrils requires a longer incubation time, outlining how molecular crowding influences both the equilibrium states of PrP and its kinetic pathways of folding and aggregation.

Structural characterization of PHOX2B and its DNA interaction shed light on the molecular basis of the +7Ala variant pathogenicity in CCHS.

An expansion of poly-alanine up to +13 residues in the C-terminus of the transcription factor PHOX2B underlies the onset of congenital central hypoventilation syndrome (CCHS). Recent studies demonstrated that the alanine tract expansion influences PHOX2B folding and activity. Therefore, structural information on PHOX2B is an important target for obtaining clues to elucidate the insurgence of the alanine expansion-related syndrome and also for defining a viable therapy. Here we report by NMR spectroscopy the structural characterization of the homeodomain (HD) of PHOX2B and HD + C-terminus PHOX2B protein, free and in the presence of the target DNA. The obtained structural data are then exploited to obtain a structural model of the PHOX2B-DNA interaction. In addition, the variant +7Ala, responsible for one of the most frequent forms of the syndrome, was analysed, showing different conformational proprieties in solution and a strong propensity to aggregation. Our data suggest that the elongated poly-alanine tract would be related to disease onset through a loss-of-function mechanism. Overall, this study paves the way for the future rational design of therapeutic drugs, suggesting as a possible therapeutic route the use of specific anti-aggregating molecules capable of preventing variant aggregation and possibly restoring the DNA-binding activity of PHOX2B.

Molecular interactions between a diphenyl scaffold and PED/PEA15: Implications for type II diabetes therapeutics targeting PED/PEA15 - Phospholipase D1 interaction.

In a recent study, we have identified BPH03 as a promising scaffold for the development of compounds aimed at modulating the interaction between PED/PEA15 (Phosphoprotein Enriched in Diabetes/Phosphoprotein Enriched in Astrocytes 15) and PLD1 (phospholipase D1), with potential applications in type II diabetes therapy. PED/PEA15 is known to be overexpressed in certain forms of diabetes, where it binds to PLD1, thereby reducing insulin-stimulated glucose transport. The inhibition of this interaction reestablishes basal glucose transport, indicating PED as a potential target of ligands capable to recover glucose tolerance and insulin sensitivity. In this study, we employ computational methods to provide a detailed description of BPH03 interaction with PED, evidencing the presence of a hidden druggable pocket within its PLD1 binding surface. We also elucidate the conformational changes that occur during PED interaction with BPH03. Moreover, we report new NMR data supporting the in-silico findings and indicating that BPH03 disrupts the PED/PLD1 interface displacing PLD1 from its interaction with PED. Our study represents a significant advancement toward the development of potential therapeutics for the treatment of type II diabetes.

Characterization of Complexes between Imidacloprid and ß-Cyclodextrin: Evaluation of the Toxic Activity in Algae and Rotifers.

The development of new formulations can be driven by the knowledge of host-guest complexes using cyclodextrins which have the ability to include guest molecules within their hydrophobic cavities, improving the physicochemical properties of the guest. To rationally explore new pesticide formulations, the effects of cyclodextrins on the properties of such guest molecules need to be explored. Imidacloprid is a neonicotinoid systemic insecticide used worldwide. In this study, the inclusion complexes of Imidacloprid (IMI) with ß-cyclodextrin (ß-CD) were prepared in the solid state by co-precipitation and the physical mixing method, with a stoichiometry of 1:1 and 1:2 molar ratios. The obtained products, Imidacloprid:ß-cyclodextrin inclusion complex (IMI:ß-CD), were characterized in the solid state by Fourier transform-infrared (FT-IR) spectroscopy and X-ray powder diffractometry (XRD). In solution, the 1:1 stoichiometry for the inclusion complexes was established by the Job plot method, and the binding constant of IMI:ß-CD was determined by UV-vis titration. The toxicity was determined in producers and primary consumers of the freshwater trophic chain, the green alga Raphidocelis subcapitata and the rotifer Brachionus calyciflorus, respectively. The results indicated that Imidacloprid forms inclusion complexes with CDs showing improved physicochemical properties compared to free Imidacloprid. The formation of the inclusion complex reduced the chronic toxicity in rotifers when IMI concentrations were close to those of environmental concern (tenths/hundredths of micromoles/L). Therefore, CD inclusion complexes could provide important advantages to be considered for the future industrial production of new formulations.

Inclusions of Pesticides by ß-Cyclodextrin in Solution and Solid State: Chlorpropham, Monuron, and Propanil.

Persistence and degradation are important factors in determining the safe use of such synthetic products, and numerous studies have been addressed to develop pesticide remediation methods aimed at ameliorating these features. In this frame, the use of different cyclodextrins (CDs) molecules has attracted considerable attention due to their well-known non-toxic nature, limited environmental impact, and capability to reduce the environmental and health risks of pesticides. CDs appear to be a valuable tool for the elimination of pesticides from polluted areas as well as for better pesticide formulations that positively influence their hydrolysis or degradation. The present work investigates the interaction between ß-cyclodextrins and three commonly used pesticides (i.e., chlorpropham, monuron, and propanil) both in solution and in the solid state by means of UV-Vis, FT-IR, and X-ray powder diffractometry. We show that such interactions result in all three cases in the formation of inclusion complexes with a 1:1 stoichiometry and binding constants (Kb) of 369.9 M-1 for chlorpropham, 292.3 M-1 for monuron, and 298.3 M-1 for propanil. We also report the energy-minimized structures in silico for each complex. Our data expand and complement the available literature data in indicating CDs as a low-cost and very effective tool capable of modulating the properties that determine the environmental fate of pesticides.

Copper (I) or (II) Replacement of the Structural Zinc Ion in the Prokaryotic Zinc Finger Ros Does Not Result in a Functional Domain.

A strict interplay is known to involve copper and zinc in many cellular processes. For this reason, the results of copper's interaction with zinc binding proteins are of great interest. For instance, copper interferences with the DNA-binding activity of zinc finger proteins are associated with the development of a variety of diseases. The biological impact of copper depends on the chemical properties of its two common oxidation states (Cu(I) and Cu(II)). In this framework, following the attention addressed to unveil the effect of metal ion replacement in zinc fingers and in zinc-containing proteins, we explore the effects of the Zn(II) to Cu(I) or Cu(II) replacement in the prokaryotic zinc finger domain. The prokaryotic zinc finger protein Ros, involved in the horizontal transfer of genes from A. tumefaciens to a host plant infected by it, belongs to a family of proteins, namely Ros/MucR, whose members have been recognized in different bacteria symbionts and pathogens of mammals and plants. Interestingly, the amino acids of the coordination sphere are poorly conserved in most of these proteins, although their sequence identity can be very high. In fact, some members of this family of proteins do not bind zinc or any other metal, but assume a 3D structure similar to that of Ros with the residues replacing the zinc ligands, forming a network of hydrogen bonds and hydrophobic interactions that surrogates the Zn-coordinating role. These peculiar features of the Ros ZF domain prompted us to study the metal ion replacement with ions that have different electronic configuration and ionic radius. The protein was intensely studied as a perfectly suited model of a metal-binding protein to study the effects of the metal ion replacement; it appeared to tolerate the Zn to Cd substitution, but not the replacement of the wildtype metal by Ni(II), Pb(II) and Hg(II). The structural characterization reported here gives a high-resolution description of the interaction of copper with Ros, demonstrating that copper, in both oxidation states, binds the protein, but the replacement does not give rise to a functional domain.

High-Resolution Conformational Analysis of RGDechi-Derived Peptides Based on a Combination of NMR Spectroscopy and MD Simulations.

The crucial role of integrin in pathological processes such as tumor progression and metastasis formation has inspired intense efforts to design novel pharmaceutical agents modulating integrin functions in order to provide new tools for potential therapies. In the past decade, we have investigated the biological proprieties of the chimeric peptide RGDechi, containing a cyclic RGD motif linked to an echistatin C-terminal fragment, able to specifically recognize αvß3 without cross reacting with αvß5 and αIIbß3 integrin. Additionally, we have demonstrated using two RGDechi-derived peptides, called RGDechi1-14 and ψRGDechi, that chemical modifications introduced in the C-terminal part of the peptide alter or abolish the binding to the αvß3 integrin. Here, to shed light on the structural and dynamical determinants involved in the integrin recognition mechanism, we investigate the effects of the chemical modifications by exploring the conformational space sampled by RGDechi1-14 and ψRGDechi using an integrated natural-abundance NMR/MD approach. Our data demonstrate that the flexibility of the RGD-containing cycle is driven by the echistatin C-terminal region of the RGDechi peptide through a coupling mechanism between the N- and C-terminal regions.

Structural and dynamical determinants of a ß-sheet-enriched intermediate involved in amyloid fibrillar assembly of human prion protein.

The conformational conversion of the cellular prion protein (PrPC) into a misfolded, aggregated and infectious scrapie isoform is associated with prion disease pathology and neurodegeneration. Despite the significant number of experimental and theoretical studies the molecular mechanism regulating this structural transition is still poorly understood. Here, via Nuclear Magnetic Resonance (NMR) methodologies we investigate at the atomic level the mechanism of the human HuPrP(90-231) thermal unfolding and characterize the conformational equilibrium between its native structure and a ß-enriched intermediate state, named ß-PrPI. By comparing the folding mechanisms of metal-free and Cu2+-bound HuPrP(23-231) and HuPrP(90-231) we show that the coupling between the N- and C-terminal domains, through transient electrostatic interactions, is the key molecular process in tuning long-range correlated µs-ms dynamics that in turn modulate the folding process. Moreover, via thioflavin T (ThT)-fluorescence fibrillization assays we show that ß-PrPI is involved in the initial stages of PrP fibrillation, overall providing a clear molecular description of the initial phases of prion misfolding. Finally, we show by using Real-Time Quaking-Induced Conversion (RT-QuIC) that the ß-PrPI acts as a seed for the formation of amyloid aggregates with a seeding activity comparable to that of human infectious prions.

Host and Viral Zinc-Finger Proteins in COVID-19.

An unprecedented effort to tackle the ongoing COVID-19 pandemic has characterized the activity of the global scientific community over the last two years. Hundreds of published studies have focused on the comprehension of the immune response to the virus and on the definition of the functional role of SARS-CoV-2 proteins. Proteins containing zinc fingers, both belonging to SARS-CoV-2 or to the host, play critical roles in COVID-19 participating in antiviral defenses and regulation of viral life cycle. Differentially expressed zinc finger proteins and their distinct activities could thus be important in determining the severity of the disease and represent important targets for drug development. Therefore, we here review the mechanisms of action of host and viral zinc finger proteins in COVID-19 as a contribution to the comprehension of the disease and also highlight strategies for therapeutic developments.

Structural characterization of the thermal unfolding pathway of human VEGFR1 D2 domain.

Folding stability is a crucial feature of protein evolution and is essential for protein functions. Thus, the comprehension of protein folding mechanisms represents an important complement to protein structure and function, crucial to determine the structural basis of protein misfolding. In this context, thermal unfolding studies represent a useful tool to get a molecular description of the conformational transitions governing the folding/unfolding equilibrium of a given protein. Here, we report the thermal folding/unfolding pathway of VEGFR1D2, a member of the immunoglobulin superfamily by means of a high-resolution thermodynamic approach that combines differential scanning calorimetry with atomic-level unfolding monitored by NMR. We show how VEGFR1D2 folding is driven by an oxidatively induced disulfide pairing: the key event in the achievement of its functional structure is the formation of a small hydrophobic core that surrounds a disulfide bridge. Such a 'folding nucleus' induces the cooperative transition to the properly folded conformation supporting the hypothesis that a disulfide bond can act as a folding nucleus that eases the folding process.

Screening a Molecular Fragment Library to Modulate the PED/PEA15-Phospholipase D1 Interaction in Cellular Lysate Environments.

The overexpression of PED/PEA15, the phosphoprotein enriched in diabetes/phosphoprotein enriched in the astrocytes 15 protein (here referred simply to as PED), observed in some forms of type II diabetes, reduces the transport of insulin-stimulated glucose by binding to the phospholipase D1 (PLD1). The inhibition of the PED/PLD1 interaction was shown to restore basal glucose transport, indicating PED as a pharmacological target for the development of drugs capable of improving insulin sensitivity and glucose tolerance. We here report the identification and selection of PED ligands by means of NMR screening of a library of small organic molecules, NMR characterization of the PED/PLD1 interaction in lysates of cells expressing PLD1, and modulation of such interactions using BPH03, the best selected ligand. Overall, we complement the available literature data by providing detailed information on the structural determinants of the PED/PLD1 interaction in a cellular lysate environment and indicate BPH03 as a precious scaffold for the development of novel compounds that are able to modulate such interactions with possible therapeutic applications in type II diabetes.

Probing the helical stability in a VEGF-mimetic peptide.

The analysis of the forces governing helix formation and stability in peptides and proteins has attracted considerable interest in order to shed light on folding mechanism. We analyzed the role of hydrophobic interaction, steric hindrance and chain length on i, i + 3 position in QK peptide, a VEGF mimetic helical peptide. We focused on position 10 of QK, occupied by a leucine, as previous studies highlighted the key role of the Leu7-Leu10 interaction in modulating the helix formation and inducing an unusual thermodynamic stability. Leu10 has been replaced by hydrophobic amino acids with different side-chain length, hydrophobicity and steric hindrance. Ten peptides were, hence, synthesized and analyzed combining circular dichroism, calorimetry and NMR spectroscopy. We found that helical content and thermal stability of peptide QK changed when Leu10 was replaced. Interestingly, we observed that the changes in the helical content and thermal stability were not always correlated and they depend on the type of interaction (strength and geometry) that could be established between Leu7 and the residue in position 10.

The change of conditions does not affect Ros87 downhill folding mechanism.

Downhill folding has been defined as a unique thermodynamic process involving a conformations ensemble that progressively loses structure with the decrease of protein stability. Downhill folders are estimated to be rather rare in nature as they miss an energetically substantial folding barrier that can protect against aggregation and proteolysis. We have previously demonstrated that the prokaryotic zinc finger protein Ros87 shows a bipartite folding/unfolding process in which a metal binding intermediate converts to the native structure through a delicate barrier-less downhill transition. Significant variation in folding scenarios can be detected within protein families with high sequence identity and very similar folds and for the same sequence by varying conditions. For this reason, we here show, by means of DSC, CD and NMR, that also in different pH and ionic strength conditions Ros87 retains its partly downhill folding scenario demonstrating that, at least in metallo-proteins, the downhill mechanism can be found under a much wider range of conditions and coupled to other different transitions. We also show that mutations of Ros87 zinc coordination sphere produces a different folding scenario demonstrating that the organization of the metal ion core is determinant in the folding process of this family of proteins.

Substitution of the Native Zn(II) with Cd(II), Co(II) and Ni(II) Changes the Downhill Unfolding Mechanism of Ros87 to a Completely Different Scenario.

The structural effects of zinc replacement by xenobiotic metal ions have been widely studied in several eukaryotic and prokaryotic zinc-finger-containing proteins. The prokaryotic zinc finger, that presents a bigger ßßßαα domain with a larger hydrophobic core with respect to its eukaryotic counterpart, represents a valuable model protein to study metal ion interaction with metallo-proteins. Several studies have been conducted on Ros87, the DNA binding domain of the prokaryotic zinc finger Ros, and have demonstrated that the domain appears to structurally tolerate Ni(II), albeit with important structural perturbations, but not Pb(II) and Hg(II), and it is in vitro functional when the zinc ion is replaced by Cd(II). We have previously shown that Ros87 unfolding is a two-step process in which a zinc binding intermediate converts to the native structure thorough a delicate downhill folding transition. Here, we explore the folding/unfolding behaviour of Ros87 coordinated to Co(II), Ni(II) or Cd(II), by UV-Vis, CD, DSC and NMR techniques. Interestingly, we show how the substitution of the native metal ion results in complete different folding scenarios. We found a two-state unfolding mechanism for Cd-Ros87 whose metal affinity Kd is comparable to the one obtained for the native Zn-Ros87, and a more complex mechanism for Co-Ros87 and Ni-Ros87, that show higher Kd values. Our data outline the complex cross-correlation between the protein-metal ion equilibrium and the folding mechanism proposing such an interplay as a key factor in the proper metal ion selection by a specific metallo-protein.

Zinc Fingers.

Zinc finger (ZF) domains, that represent the majority of the DNA-binding motifs in eukaryotes, are involved in several processes ranging from RNA packaging to transcriptional activation, regulation of apoptosis, protein folding and assembly, and lipid binding. While their amino acid composition varies from one domain to the other, a shared feature is the coordination of a zinc ion, with a structural role, by a different combination of cysteines and histidines. The classical zinc finger domain (also called Cys2His2) that represents the most common class, uses two cysteines and two histidines to coordinate the metal ion, and forms a compact ßßα architecture consisting in a ß-sheet and an α-helix. GAG-knuckle resembles the classical ZF, treble clef and zinc ribbon are also well represented in the human genome. Zinc fingers are also present in prokaryotes. The first prokaryotic ZF domain found in the transcriptional regulator Ros protein was identified in Agrobacterium tumefaciens. It shows a Cys2His2 metal ion coordination sphere and folds in a domain significantly larger than its eukaryotic counterpart arranged in a ßßßαα topology. Interestingly, this domain does not strictly require the metal ion coordination to achieve the functional fold. Here, we report what is known on the main classes of eukaryotic and prokarotic ZFs, focusing our attention to the role of the metal ion, the folding mechanism, and the DNA binding. The hypothesis of a horizontal gene transfer from prokaryotes to eukaryotes is also discussed.

Structural Insight of the Full-Length Ros Protein: A Prototype of the Prokaryotic Zinc-Finger Family.

Ros/MucR is a widespread family of bacterial zinc-finger (ZF) containing proteins that integrate multiple functions such as virulence, symbiosis and/or cell cycle transcription. NMR solution structure of Ros DNA-binding domain (region 56-142, i.e. Ros87) has been solved by our group and shows that the prokaryotic ZF domain shows interesting structural and functional features that differentiate it from its eukaryotic counterpart as it folds in a significantly larger zinc-binding globular domain. We have recently proposed a novel functional model for this family of proteins suggesting that they may act as H-NS-'like' gene silencers. Indeed, the N-terminal region of this family of proteins appears to be responsible for the formation of functional oligomers. No structural characterization of the Ros N-terminal domain (region 1-55) is available to date, mainly because of serious solubility problems of the full-length protein. Here we report the first structural characterization of the N-terminal domain of the prokaryotic ZF family examining by means of MD and NMR the structural preferences of the full-length Ros protein from Agrobacterium tumefaciens.

Polypseudorotaxanes of Pluronic® F127 with Combinations of α- and ß-Cyclodextrins for Topical Formulation of Acyclovir.

Acyclovir (ACV) is one of the most used antiviral drugs for the treatment of herpes simplex virus infections and other relevant mucosal infections caused by viruses. Nevertheless, the low water solubility of ACV limits both its bioavailability and antiviral performance. The combination of block copolymer micelles and cyclodextrins (CDs) may result in polypseudorotaxanes with tunable drug solubilizing and gelling properties. However, the simultaneous addition of various CDs has barely been investigated yet. The aim of this work was to design and characterize ternary combinations of Pluronic® F127 (PF127), αCD and ßCD in terms of polypseudorotaxane formation, rheological behavior, and ACV solubilization ability and controlled release. The formation of polypseudorotaxanes between PF127 and the CDs was confirmed by FT-IR spectroscopy, X-ray diffraction, and NMR spectroscopy. The effects of αCD/ßCD concentration range (0-7% w/w) on copolymer (6.5% w/w) gel features were evaluated at 20 and 37 °C by rheological studies, resulting in changes of the copolymer gelling properties. PF127 with αCD/ßCD improved the solubilization of ACV, maintaining the biocompatibility (hen's egg test on the chorio-allantoic membrane). In addition, the gels were able to sustain acyclovir delivery. The formulation prepared with similar proportions of αCD and ßCD provided a slower and more constant release. The results obtained suggest that the combination of Pluronic with αCD/ßCD mixtures can be a valuable approach to tune the rheological features and drug release profiles from these supramolecular gels.

The curious case of opossum prion: a physicochemical study on copper(ii) binding to the bis-decarepeat fragment from the protein N-terminal domain.

The opossum is a peculiar model of immunity to prion diseases. Here we scrutinised the bis-decarepeat peptide sequence of the opossum prion (Op_bis-deca) protein by a multitechnique approach, with a combined experimental (potentiometry, UV-visible, circular dichroism, NMR and EPR spectroscopy, quartz crystal microbalance with dissipation monitoring and confocal microscopy) and simulation (DFT calculations) approach. Results showed that the macrochelate structures formed upon the binding to Cu(ii) by the analogous bis-octarepeat peptide sequence of human prion (Hu_bis-octa) are not found in the case of Op_bis-deca. At physiological pH and equimolar amount of copper ions, the [CuLH-2] is the major species formed by Op_bis-deca. In this species one imidazole and two amide nitrogen atoms are involved in metal coordination and its stability constant value is lower than that of the analogous species formed by Hu_bis-octa, due to the presence of an extra proline residue. Moreover, the study on the interaction of the peptides or the peptide/Cu(ii) complexes with the model cell membranes made of supported lipid bilayers disclosed different levels of interaction, monitored by the viscoelastic changes of the membranes, which exhibited a similar viscoelastic response at the interface of the two complexes, while in the absence of Cu(ii), the Hu_bis-octa/SLB interface was more viscoelastic than the Op_bis-deca one.

Coordination of a bis-histidine-oligopeptide to Re(i) and Ga(iii) in aqueous solution.

The utilization of isotopes of transition metals for the development of novel therapeutic or diagnostic compounds is limited by the fact that they must be stabilized by chelating systems in coordination complexes. Important roles in the targeting approach are played by the tricarbonyl complexes of Technetium(i) and Rhenium(i) because they can be readily conjugated to biomolecules to form stable probes. Additionally, 67Ga and 68Ga isotopes of gallium are considered an obvious alternative to 99mTc (M. D. Bartholomä, A. S. Louie, J. F. Valliant and J. Zubieta, Chem. Rev., 2010, 110, 2903-2920) for SPECT and PET applications. We have previously reported the characterization of the peptide CCK8 decorated with a bis-histidine-based chelator (pHis2) labeled with 99mTc-tricarbonyl. In order to study the molecular properties of the histidine-based chelator pHis2, we here present the characterization in solution of its complexes with the metals Re(i) and Ga(iii) using potentiometry and NMR. We detail the solution equilibria reporting pHis2 acid-base behavior, the coordination properties of pHis2 toward fac-[Re(H2O)3(CO)3]+ and Ga(iii) and the atomic details of the formed complexes. Interestingly, two different metal coordination modes were found highlighting the plasticity of this bifunctional chelator.

Therapeutic Perspectives of Molecules from Urtica dioica Extracts for Cancer Treatment.

A large range of chronic and degenerative diseases can be prevented through the use of food products and food bioactives. This study reports the health benefits and biological activities of the Urtica dioica (U. dioica) edible plant, with particular focus on its cancer chemopreventive potential. Numerous studies have attempted to investigate the most efficient anti-cancer therapy with few side effects and high toxicity on cancer cells to overcome the chemoresistance of cancer cells and the adverse effects of current therapies. In this regard, natural products from edible plants have been assessed as sources of anti-cancer agents. In this article, we review current knowledge from studies that have examined the cytotoxic, anti-tumor and anti-metastatic effects of U. dioica plant on several human cancers. Special attention has been dedicated to the treatment of breast cancer, the most prevalent cancer among women and one of the main causes of death worldwide. The anti-proliferative and apoptotic effects of U. dioica have been demonstrated on different human cancers, investigating the properties of U. dioica at cellular and molecular levels. The potent cytotoxicity and anti-cancer activity of the U. dioica extracts are due to its bioactive natural products content, including polyphenols which reportedly possess anti-oxidant, anti-mutagenic and anti-proliferative properties. The efficacy of this edible plant to prevent or mitigate human cancers has been demonstrated in laboratory conditions as well as in experimental animal models, paving the way to the development of nutraceuticals for new anti-cancer therapies.