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Topic Review
Inflammasome Regulation for IBD
Inflammasomes are multiprotein complexes formed to regulate the maturation of pro-inflammatory caspases, in response to intracellular or extracellular stimulants. Accumulating studies showed that the inflammasomes are implicated in the pathogenesis of inflammatory bowel disease (IBD), although their activation is not a decisive factor for the development of IBD. Inflammasomes and related cytokines play an important role in the maintenance of gut immune homeostasis, while its overactivation might induce excess immune responses and consequently cause tissue damage in the gut. Emerging studies provide evidence that some genetic abnormalities might induce enhanced NLRP3 inflammasome activation and cause colitis. In these cases, the colonic inflammation can be ameliorated by blocking NLRP3 activation or its downstream cytokine IL-1β. A number of natural products were shown to play a role in preventing colon inflammation in various experimental colitis models. On the other hand, lack of inflammasome function also causes intestinal abnormalities.
  • 736
  • 21 Apr 2021
Topic Review
Biological Effects of Natural Acylated Flavonoids
Acylated flavonoids are widely distributed natural metabolites in medicinal plants and foods with several health attributes. Flavonoids are secondary metabolites that are widely distributed in planta, and they are well recognized for their health benefits, viz., anticancer, antioxidant, anti-inflammatory, antiviral, and as neuro- and cardio-protective effects. Flavonoids are phytochemicals comprising a benzopyrone ring bearing a phenolic or poly-phenolic group at different positions, classified based on their chemical structure, degree of unsaturation, and oxidation of carbon ring, viz., anthoxanthins (flavanone and flavanol), flavanones, flavanonols, flavans, chalcones, anthocyanidins, and isoflavonoids.
  • 734
  • 14 Sep 2022
Topic Review
Chitosan-Based Particles for Biomedical Applications
Marine-derived chitosan (CS) is a cationic polysaccharide widely studied for its bioactivity, which is mostly attached to its primary amine groups. CS is able to neutralize reactive oxygen species (ROS) from the microenvironments in which it is integrated, consequently reducing cell-induced oxidative stress. It also acts as a bacterial peripheral layer hindering nutrient intake and interacting with negatively charged outer cellular components, which lead to an increase in the cell permeability or to its lysis. Its biocompatibility, biodegradability, ease of processability (particularly in mild conditions), and chemical versatility has fueled CS study as a valuable matrix component of bioactive small-scaled organic drug-delivery systems, with current research also showcasing CS’s potential within tridimensional sponges, hydrogels and sutures, blended films, nanofiber sheets and fabric coatings.
  • 731
  • 30 Jun 2021
Topic Review
Redox-Active Metal Ions
Redox-active metal ions, Cu(I/II) and Fe(II/III), are essential biological molecules for the normal functioning of the brain, including oxidative metabolism, synaptic plasticity, myelination, and generation of neurotransmitters.
  • 730
  • 06 Aug 2021
Topic Review
Synthesis of Metabolite of Resveratrol by Beauveria bassiana
Resveratrol is a well-known dietary polyphenol because it has a variety of beneficial biological activities. The fungus Beauveria bassiana is one of the most frequently used microorganisms for the biotransformation of polyphenols. Recently, resvebassianol A (2), a glycosylated metabolite of resveratrol by B. bassiana, was isolated and structurally elucidated. It was demonstrated to exhibit antioxidant, regenerative, and anti-inflammatory activities with no cytotoxicity. Here, we report the first total synthesis of resvebassianol A, 4'-O-β-(4'"-O-methylglucopyranosyl)resveratrol (2), and its regiomer, 3-O-β-(4 -O-methylglucopyranosyl)resveratrol (3). Key reactions include (i) the construction of a stilbene core via a novel Heck reaction of aryl halides and styrenes, and (ii) glycosylation with unnatural methylglucopyranosyl bromide. The glycosylation step was carefully optimized by varying the bases and solvents. Resveratrol metabolites 2 and 3 were obtained at 7.5% and 6.3% of the overall yield, respectively.
  • 727
  • 25 Oct 2021
Topic Review
Extremophilic Fungi from Marine Environments
Marine environments are underexplored terrains containing fungi that produce a diversity of natural products given unique environmental pressures and nutrients. While bacteria are commonly the most studied microorganism for natural products in the marine world, marine fungi are also abundant but remain an untapped source of bioactive metabolites. Given that their terrestrial counterparts have been a source of many blockbuster antitumor agents and anti-infectives, including camptothecin, the penicillins, and cyclosporin A, marine fungi also have the potential to produce new chemical scaffolds as leads to potential drugs. Fungi are more phylogenetically diverse than bacteria and have larger genomes that contain many silent biosynthetic gene clusters involved in making bioactive compounds. However, less than 5% of all known fungi have been cultivated under standard laboratory conditions. While the number of reported natural products from marine fungi is steadily increasing, their number is still significantly lower compared to those reported from their bacterial counterparts.
  • 727
  • 29 Mar 2022
Topic Review
Bone Metastases
Bone metastasis remains a major cause of death in cancer patients, and current therapies for bone metastatic disease are mainly palliative. Bone metastases arise after cancer cells have colonized the bone and co-opted the normal bone remodeling process.
  • 723
  • 27 Apr 2021
Topic Review
Insights into the Pharmacological Effects of Flavonoids
Flavonoids are widely occurring secondary metabolites of plants. Currently, there is a trend of article numbers increasing, which focuses on the computer modeling of flavonoid interactions with biological targets. Such studies help to accumulatethe data on lead compounds that can find medicinal implementation, including COVID-19. Flavanonol taxifolin demonstrated wound-healing activity. Luteolin, apigenin, and wogonin, which can be classified as flavones, show induced neutrophil apoptosis and have potential as neutrophil apoptosis-inducing anti-inflammatory, proresolution agents.
  • 722
  • 10 Jun 2022
Topic Review
Sources and Absorption of Resveratrol
Polyphenols are secondary metabolites produced by plants and also found in many natural products, such as fruit and vegetables, and their derivatives, such as tea, coffee, olive oil, and wine. Polyphenols are well known for their antioxidant properties, which confer to them health-beneficial effects. Among them, resveratrol is probably one of the most investigated molecules. It was first described in 1940 by Michio Takaoka, a Japanese student who was investigating extracts from traditional medicinal plants and called it “resveratrol” because the molecule had been extracted from the roots of Veratrum grandiflorum (white hellebore) and presented the skeleton of resorcinol in its molecular structure. The extract from this plant was exploited for treating several allergic and inflammatory diseases, among others. However, this molecule did not attract much interest until 1997, when Jang and colleagues published an article regarding its cancer chemopreventive activity. Resveratrol is the common name for 3,5,4′-trihydroxy-trans-stilbene, a natural phytoalexin derived from phenylpropanoids, that is synthesized in plants under stress conditions, such as infections or UV exposure. 
  • 719
  • 14 Dec 2021
Topic Review
Regenerative Medicine Bioconjugated Hydrogel Scaffolds
Materials used for regenerative medicine purposes pose a series of challenges in terms of biocompatibility, adaptability and functionality. A way to design functional and compatible materials that mimic soft tissue is to exploit synthetic hydrogels. To widen their activity scope, hydrogels can be coupled with molecular cues to promote tissue regeneration or trigger regeneration processes. Within this entry we asses the criteria to choose the design of a bioconjugated for regenerative medicine purposes, giving relevant examples from the current literature.
  • 718
  • 21 Oct 2020
Topic Review
Metal-Based Chemotherapeutic Treatments
Herein we provides an overview of the various research approaches we have explored in recent years to improve metal-based agents for cancer or infection treatments. Although cisplatin, carboplatin, and oxaliplatin remain the cornerstones in tumor chemotherapy, the discovery and approval of novel inorganic anticancer drugs is a very slow process. Analogously, although a few promising inorganic drugs have found clinical application against parasitic or bacterial infections, their use remains relatively limited. Moreover, the discovery process is often affected by small therapeutic enhancements that are not attractive for the pharmaceutical industry. However, the availability of increasing mechanistic information for the modes of action of established inorganic drugs is fueling the exploration of various approaches for developing effective inorganic chemotherapy agents. Through a series of examples, some from our own research experience, we focus our attention on a number of promising strategies, including (1) drug repurposing, (2) the simple modification of the chemical structures of approved metal-based drugs, (3) testing novel drug combinations, and (4) newly synthesized complexes coupling different anticancer drugs. Accordingly, we aim to suggest and summarize a series of reliable approaches that are exploitable for the development of improved and innovative treatments.
  • 717
  • 25 May 2021
Topic Review
The Tetrahydrofuran Motif in Marine Lipids and Terpenes
Heterocycles are particularly common moieties within marine natural products. Specifically, tetrahydrofuranyl rings are present in a variety of compounds which present complex structures and interesting biological activities. Focusing on terpenoids, a high number of tetrahydrofuran-containing metabolites have been isolated. They show promising biological activities, making them potential leads for novel antibiotics, antikinetoplastid drugs, amoebicidal substances, or anticancer drugs. Thus, they have attracted the attention of the synthetics community and numerous approaches to their total syntheses have appeared.
  • 716
  • 28 Oct 2022
Topic Review
Metal-Promoted Heterocyclization
The recent formulation, production, and ongoing administration of vaccines represent a starting point in the battle against SARS-CoV-2, but they cannot be the only aid available. In this regard, the use of drugs capable to mitigate and fight the virus is a crucial aspect of the pharmacological strategy. Among the plethora of approved drugs, a consistent element is a heterocyclic framework inside its skeleton. Heterocycles have played a pivotal role for decades in the pharmaceutical industry due to their high bioactivity derived from anticancer, antiviral, and anti-inflammatory capabilities. In this context, the development of new performing and sustainable synthetic strategies to obtain heterocyclic molecules has become a key focus of scientists.
  • 713
  • 09 Jul 2021
Topic Review
Principles of pH-Responsive Drug Delivery
The paradigm of drug carriers’ usage to overcome the non-specific distribution of therapeutic agents in the body, including chemotherapeutic substances that exert severe toxic stress on healthy tissues, has been actively developed. One of the main pillars of this paradigm is the increased or even selective accumulation of drug delivery systems (DDSs) carrying therapeutic agents in tumor interstitium harnessing the differences between normal and cancer tissues properties. Thus, structural features of tumors, such as hypervascularization, vascular pathologies, and impaired functionality of lymphatic drainage, can be utilized to differentiate tumors from healthy tissues and selectively accumulate drug carriers. In particular, tumor-surrounding vessels are characterized by defects in the endothelial layer lining the blood vessel wall, represented by wide fenestrations (up to several microns) and other features that lead to an increase in the permeability of this barrier for small objects, making the effective extravasation of nanosized carriers from the bloodstream to tumor interstitium possible. Methods of selective therapy via the systemic administration of therapeutic agents based on increased permeability of the tumor vessels’ wall, known under the general name of the EPR effect, have become widespread and have inspired the creation of a large number of vehicles proposed for the delivery of chemotherapeutic agents. In summary, the EPR effect implies the extravasation of nanosized drug carriers through endothelial fenestra and their retention in the interstitial volume of the tumor due to dysfunctional lymphatic drainage.
  • 712
  • 01 Jun 2023
Topic Review
G-Quadruplex Structures in Plants
G-quadruplex (G4) oligonucleotides are higher-order DNA and RNA secondary structures of enormous relevance due to their implication in several biological processes and pathological states in different organisms.  Plants offer a cornucopia of phytocompounds that, in many cases, are effective in binding and modulating the thermal stability of G4s and, on the other hand, contain almost unexplored G4 motifs in their genome that could inspire new biotechnological strategies.
  • 708
  • 10 Nov 2022
Topic Review
Artificial Intelligence for COVID-19 De Novo Drug Design
Artificial intelligence (AI) refers to machines, mainly computers, working like humans. In AI, machines execute tasks such as speech recognition, solving problems, and learning. Machines can work and act like humans if they have enough instruction and knowledge. Drug development is a costly and time-consuming business, and only a minority of approved drugs generate returns exceeding the research and development costs. As a result, there is a huge drive to make drug discovery cheaper and faster. With modern algorithms and hardware, it is not too surprising that the new technologies of artificial intelligence and other computational simulation tools can help drug developers.
  • 706
  • 28 Mar 2022
Topic Review
Technical Features of Polysaccharide-Based Hydrogels in Drug Delivery
Hydrogels are a form of highly hydrophilic biomaterials with three-dimensional architecture that can retain a significant amount of water and swell without disintegrating. Hydrogels can be either synthetic, natural, or hybrid forms. Natural polymer hydrogels are those derived from naturally sourced polymers, including polysaccharides, polynucleotides, and proteins. Neutral, cationic, and anionic categories describe the chemical properties of natural sources of polymers. These polymers are easily accessible, ubiquitous, affordable, non-toxic, renewable, and have other appealing biological features.
  • 701
  • 22 Dec 2022
Topic Review
Pyrroloiminoquinones
Pyrroloiminoquinones are a group of cytotoxic alkaloids most commonly isolated from marine sponges. Structurally, they are based on a tricyclic pyrrolo[4,3,2-de]quinoline core and encompass marine natural products such as makaluvamines, tsitsikammamines and discorhabdins.
  • 697
  • 22 Dec 2022
Topic Review
Quinazoline Based HDAC Dual Inhibitors
Quinazolines are the most versatile, ubiquitous and privileged nitrogen bearing heterocyclic compounds with a wide array of biological and pharmacological applications. Most of the anti-cancer agents featuring quinazoline pharmacophore have shown promising therapeutic activity. Histone deacetylases (HDACs) have emerged as an important anti-cancer target in the recent years given its role in cellular growth, gene regulation, and metabolism.
  • 695
  • 20 Jun 2022
Topic Review
Phytochemicals of the Genus Maytenus
The genus Maytenus is a member of the Celastraceae family, of which several species have long been used in traditional medicine. Between 1976 and 2021, nearly 270 new compounds have been isolated and elucidated from the genus Maytenus. Among these, maytansine and its homologues are extremely rare in nature. Owing to its unique skeleton and remarkable bioactivities, maytansine has attracted many synthetic endeavors in order to construct its core structure.
  • 693
  • 09 Aug 2021
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