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Topic Review
Green Tea Catechins
Green tea and green tea catechins have been shown to be strongly inhibitory to cancer formation in rodents. They are believed to do this by altering cells after they have been initiated on the path toward cancer. Green tea and green tea catechin prevention of cancer in humans has been hard to detect. We discuss that the reason for this difference is likely to be the digestive tract microbiome. If green tea catechins are to be continue to be tested for cancer prevention properties in humans it will be necessary to take into account variable digestive tract microbiome metabolism in people so the dose can be optimized for each person thus avoiding toxicity. 
  • 769
  • 03 Nov 2020
Topic Review
Biological Activity of Flavones, Flavonols, and Aurones
Flavonoids are a widely distributed group of natural polyphenolic compounds that are found in plants usually in glycosylated form and have been shown to possess a wide range of biological activities, including antioxidant, anti-inflammatory, antibacterial, antiviral, and anticancer properties, making them an attractive target for synthesis and further research.
  • 769
  • 12 Sep 2023
Topic Review
Folic Acid Antimetabolites
Antimetabolites of folic acid represent a large group of drugs and drug candidates, including those for cancer chemotherapy. Antimetabolites, which are antagonists of natural metabolites, belong to a group of highly efficient anticancer drugs. Based on the chemical structure, these groups can be divided into several sub-groups, such as non-natural amino-acids or peptides, including phospha-analogues, analogues of purine and pyrimidine bases, such as competitors in the synthesis of the nucleic acids, as well as vitamin actions including folic acid, hormones, coenzymes, and other substrates responsible for the normal functioning of cells and tissues of the human body.
  • 766
  • 29 Dec 2022
Topic Review
Jatropha Curcas Biodiesel
J. Curcas is a small and medium sized fern tree, rising to around 5–7 m tall, belonging to the Euphorbiaceae genus, consisting of approximately 800 species, around 321 genera. Jatropha is an herb immune to famine, with a lifespan of around fifty years. It is also called physic nut and Ratanjayot. J. Curcas will generate 2000 L/ha of oil annually. JCL oil is transesterified primarily into (m)ethyl esters (biofuels) and glycerol. One of the greatest challenges of the 21st century is to fulfill the growing energy needs sustainably and cost-effectively. Among the different sources of energy, biodiesel is one of the alternative energy sources that has tremendous potential to become a major mainstream renewable energy mix. Jatropha is an important raw input for biodiesel that provides an ecological and sustainable solution for emerging greenhouse gas emissions over the other biomass feedstock. 
  • 761
  • 09 Jul 2021
Topic Review
Xanthones, A Promising Anti-Inflammatory Scaffold
Inflammation is the body’s self-protective response to multiple stimulus, from external harmful substances to internal danger signals released after trauma or cell dysfunction. Many diseases are considered to be related to inflammation, such as cancer, metabolic disorders, aging, and neurodegenerative diseases.  Xanthones, a unique scaffold with a 9H-Xanthen-9-one core structure, widely exist in natural sources. Till now, over 250 xanthones were isolated and identified in plants from the families Gentianaceae and Hypericaceae. Many xanthones have been disclosed with anti-inflammatory properties on different models, either in vitro or in vivo.
  • 759
  • 17 Nov 2021
Topic Review
Synthesis of Squaraine Dyes
Squaraine dye is a popular class of contrast near-infrared (NIR) dyes. Squaraine dyes have shown the ability to be modified with various heterocycles. The indole moiety is the most notable heterocycle incorporated in squaraine dyes.
  • 758
  • 26 Sep 2023
Topic Review
Vanillin Production from Lignin
Vanillin, one of the most widely used and appreciated flavoring agents worldwide, is the main constituent of vanilla bean extract, obtained from the seed pods of various members belonging to the Orchidaceae family. Due to the great demand in the food confectionery industry, as well as in the perfume industry, medicine, and more, the majority of vanillin used today is produced synthetically, and only less than one percent of the world’s vanilla flavoring market comes directly from the traditional natural sources. The increasing global demand for vanillin requires alternative and overall sustainable new production methods, and the recovery from biobased polymers, like lignin, is an environmentally friendly alternative to chemical synthesis. 
  • 747
  • 01 Feb 2024
Topic Review
Heteroaromatic N-Oxides in Asymmetric Catalysis
Chiral heteroaromatic N-oxides can work as powerful electron-pair donors, providing suitable electronic environments in the transition state formed within the reaction. The nucleophilicity of the oxygen atom in N-oxides, coupled with a high affinity of silicon to oxygen, represent ideal properties for the development of synthetic methodology based on nucleophilic activation of organosilicon reagents.
  • 746
  • 28 Apr 2022
Topic Review
Secondary Metabolites of Purpureocillium lilacinum
Fungi can synthesize a wealth of secondary metabolites, which are widely used in the exploration of lead compounds of pharmaceutical or agricultural importance. Beauveria, Metarhizium, and Cordyceps are the most extensively studied fungi in which a large number of biologically active metabolites have been identified. However, relatively little attention has been paid to Purpureocillium lilacinum. P. lilacinum are soil-habituated fungi that are widely distributed in nature and are very important biocontrol fungi in agriculture, providing good biological control of plant parasitic nematodes and having a significant effect on Aphidoidea, Tetranychus cinnbarinus, and Aleyrodidae. At the same time, it produces secondary metabolites with various biological activities such as anticancer, antimicrobial, and insecticidal. 
  • 745
  • 13 Jan 2022
Topic Review
Intramolecular Cyclization
3,n-fused (n = 4–7) tricyclic indoles are pervasive motifs, embedded in a variety of biologically active molecules and natural products. Thus, numerous catalytic methods have been developed for the synthesis of these skeletons.
  • 744
  • 29 Jun 2023
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
Charge-Compensated Derivatives of Nido-Carborane
Compared with organic analogs, onium derivatives of nido-carborane have increased stability due to the stabilizing electron-donor action of the boron cage. Charge-compensated derivatives are considered according to the type of heteroatom bonded to a boron atom.
  • 727
  • 07 Mar 2023
Topic Review
Bridging Ligand Containing Terpyridine (bpat)
Synthesis strategy of a terpyridine bridging ligand was explained.
  • 725
  • 20 Feb 2021
Topic Review
Direct Synthesis of Functionalized Azahelicenes
As azahelicenes are helicenes bearing one or more nitrogen atom(s) in the molecular framework, parent azahelicenes can be functionalized on carbon atoms by exploiting the presence of the electron-withdrawing nitrogen atom. Moreover, they can be transformed into quaternary salts, whose properties are quite different from those of the parent azahelicenes in terms of the solubility and electronic properties. The synthesis of helicenes can be obtained following different strategies, namely (a) oxidative photocyclization, (b) Diels–Alder reactions, (c) Friedel–Crafts reactions, and (d) metal-mediated reactions. Strategies (a) and (d) have been mainly used to obtain the direct synthesis of functionalized azahelicenes by using appropriate starting materials, bearing functional side substituents compatible with the reaction to be performed.
  • 724
  • 20 Apr 2022
Topic Review
Marine Sponges of the Genus Callyspongia
In this entry, information about the common metabolites of the Callyspongia genus were grouped, as well as studies of the biological activity of these compounds. Through NMR data, 212 metabolites were identified from genus Callyspongia (15 species and Callyspongia sp.), belonging to classes such as polyacetylenes, terpenoids, steroids, alkaloids, polyketides, simple phenols, phenylpropanoids, nucleosides, cyclic peptides, and cyclic depsipep-tides. A total of 109 molecules have been reported with bioactive activity, mainly cytotoxic and antimicrobial (antibacterial and antifungal) action. 
  • 720
  • 16 Dec 2021
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
Sweet Boron
Boron neutron capture therapy (BNCT) is a binary type of radiotherapy for the treatment of cancer. Due to recent developments of neutron accelerators and their installation in some hospitals, BNCT is on the rise worldwide and is expected to have a significant impact on patient treatments. Therefore, there is an increasing need for improved boron delivery agents. 
  • 702
  • 03 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
Synthesis of Fluorescent Five- and Six-Membered Ring Azaheterocycles
The synthesis of fluorescent azaheterocycles continues to arouse strong interest due to their great potential for application as sensors and biosensors, luminophores on in the construction of Organic Light-Emitting Diode (OLED) devices, laser and other semiconductor devices, as well as to their potential biological properties as antimicrobial, antifungal, anticancer, antituberculosis antioxidant and anti-HIV agents. The advantages of the azaheterocyclic fluorophores, such as small size, enriched photostability, a wide and tunable spectral range, and, frequently, high brightness, are the reason why these fluorophores are preferred and used in various medical application. Probe structure can be modified to adjust excitation and emission wavelengths, target-binding affinity, chemical reactivity, and subcellular localization.
  • 696
  • 09 Oct 2022
Topic Review
Haloanisoles in Wine
Haloanisoles in wine have devastating effects on the aroma and quality of the wine. 2,4,6-trichloroanisole (TCA) was discovered and coined as “cork taint” in 1982. There are many more haloanisoles that contribute to these musty odors, including 2,4,6-Tribromoanisiole (TBA), 2,3,4,6-tetrachloroanisole (TeCA), and pentachloroanisole (PCA). While TCA, TeCA, and PCA can all be traced back to the cork, TBA’s phenol precursor is ubiquitous in building material as a fire retardant, making it a much larger vector. All haloanisoles have the ability to aerosolize and resettle onto surfaces in the winery, making this a very difficult problem to eliminate. 
  • 695
  • 23 Mar 2023
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