Allicin and Cancer Hallmarks.

Natural products, particularly medicinal plants, are crucial in combating cancer and aiding in the discovery and development of new therapeutic agents owing to their biologically active compounds. They offer a promising avenue for developing effective anticancer medications because of their low toxicity, diverse chemical structures, and ability to target various cancers. Allicin is one of the main ingredients in garlic (Allium sativum L.). It is a bioactive sulfur compound maintained in various plant sections in a precursor state. Numerous studies have documented the positive health benefits of this natural compound on many chronic conditions, including gastric, hepatic, breast, lung, cervical, prostate, and colon cancer. Moreover, allicin may target several cancer hallmarks or fundamental biological traits and functions that influence cancer development and spread. Cancer hallmarks include sustained proliferation, evasion of growth suppressors, metastasis, replicative immortality, angiogenesis, resistance to cell death, altered cellular energetics, and immune evasion. The findings of this review should provide researchers and medical professionals with a solid basis to support fundamental and clinical investigations of allicin as a prospective anticancer drug. This review outlines the anticancer role of allicin in each hallmark of cancer.

Bioavailability, Health Benefits, and Delivery Systems of Allicin: A Review.

Garlic has been used worldwide as a spice due to its pungent taste and flavor-enhancing properties. As a main biologically active component of the freshly crushed garlic extracts, allicin (diallyl thiosulfinate) is converted from alliin by alliinase upon damaging the garlic clove, which has been reported to have many potent beneficial biological functions. In this work, allicin formation, stability, bioavailability, and metabolism process are examined and summarized. The biological functions of allicin and potential underlying mechanisms are reviewed and discussed, including antioxidation, anti-inflammation, antidiabetic, cardioprotective, antineurodegenerative, antitumor, and antiobesity effects. Novel delivery systems of allicin with enhanced stability, encapsulation efficiency, and bioavailability are also evaluated, such as nanoparticles, gels, liposomes, and micelles. This study could provide a comprehensive understanding of the physiochemical properties and health benefits of allicin, with great potential for further applications in the food and nutraceutical industries.

Activation-Free Sulfonyl Fluoride Probes for Fragment Screening.

SuFEx chemistry is based on the unique reactivity of the sulfonyl fluoride group with a range of nucleophiles. Accordingly, sulfonyl fluorides label multiple nucleophilic amino acid residues, making these reagents popular in both chemical biology and medicinal chemistry applications. The reactivity of sulfonyl fluorides nominates this warhead chemotype as a candidate for an external, activation-free general labelling tag. Here, we report the synthesis and characterization of a small sulfonyl fluoride library that yielded the 3-carboxybenzenesulfonyl fluoride warhead for tagging tractable targets at nucleophilic residues. Based on these results, we propose that coupling diverse fragments to this warhead would result in a library of sulfonyl fluoride bits (SuFBits), available for screening against protein targets. SuFBits will label the target if it binds to the core fragment, which facilitates the identification of weak fragments by mass spectrometry.

Diversity oriented clicking delivers ß-substituted alkenyl sulfonyl fluorides as covalent human neutrophil elastase inhibitors.

Diversity Oriented Clicking (DOC) is a discovery method geared toward the rapid synthesis of functional libraries. It combines the best attributes of both classical and modern click chemistries. DOC strategies center upon the chemical diversification of core "SuFExable" hubs-exemplified by 2-Substituted-Alkynyl-1-Sulfonyl Fluorides (SASFs)-enabling the modular assembly of compounds through multiple reaction pathways. We report here a range of stereoselective Michael-type addition pathways from SASF hubs including reactions with secondary amines, carboxylates, 1H-1,2,3-triazole, and halides. These high yielding conjugate addition pathways deliver unprecedented ß-substituted alkenyl sulfonyl fluorides as single isomers with minimal purification, greatly enriching the repertoire of DOC and holding true to the fundamentals of modular click chemistry. Further, we demonstrate the potential for biological function - a key objective of click chemistry - of this family of SASF-derived molecules as covalent inhibitors of human neutrophil elastase.

Therapeutic Potential of Allicin and Aged Garlic Extract in Alzheimer's Disease.

Garlic, Allium sativum, has long been utilized for a number of medicinal purposes around the world, and its medical benefits have been well documented. The health benefits of garlic likely arise from a wide variety of components, possibly working synergistically. Garlic and garlic extracts, especially aged garlic extracts (AGEs), are rich in bioactive compounds, with potent anti-inflammatory, antioxidant and neuroprotective activities. In light of these effects, garlic and its components have been examined in experimental models of Alzheimer's disease (AD), the most common form of dementia without therapy, and a growing health concern in aging societies. With the aim of offering an updated overview, this paper reviews the chemical composition, metabolism and bioavailability of garlic bioactive compounds. In addition, it provides an overview of signaling mechanisms triggered by garlic derivatives, with a focus on allicin and AGE, to improve learning and memory.

Allicin as a Volatile or Nebulisable Antimycotic for the Treatment of Pulmonary Mycoses: In Vitro Studies Using a Lung Flow Test Rig.

Fungal infections of the lung are an increasing problem worldwide and the search for novel therapeutic agents is a current challenge due to emerging resistance to current antimycotics. The volatile defence substance allicin is formed naturally by freshly injured garlic plants and exhibits broad antimicrobial potency. Chemically synthesised allicin was active against selected fungi upon direct contact and via the gas phase at comparable concentrations to the pharmaceutically used antimycotic amphotericin B. We investigated the suppression of fungal growth by allicin vapour and aerosols in vitro in a test rig at air flow conditions mimicking the human lung. The effect of allicin via the gas phase was enhanced by ethanol. Our results suggest that allicin is a potential candidate for development for use in antifungal therapy for lung and upper respiratory tract infections.

A cascade reaction for regioselective construction of pyrazole-containing aliphatic sulfonyl fluorides.

A copper-catalyzed cascade reaction of α-diazocarbonyl compounds with ethenesulfonyl fluoride (ESF) is developed, affording a variety of highly functionalized pyrazolyl aliphatic sulfonyl fluorides in good to excellent yields (66-98%). This transformation features broad substrates, exclusive regioselectivity, high atom economy and operational simplicity, thus providing a straightforward method for the direct construction of pyrazole-containing aliphatic sulfonyl fluorides, which will provide great applicable value in medicinal chemistry and other related disciplines.

Anticancer potential of allicin: A review.

Phytochemicals have attracted attention in the oncological field because they are biologically friendly and have relevant pharmacological activities. Thanks to the intense and unique spicy aroma, garlic is one of the most used plants for cooking. Its consumption is correlated to health beneficial effects towards several chronic diseases, such as cancer, mainly attributable to allicin, a bioactive sulfur compound stored in different plant parts in a precursor form. The objective of this review is to present and critically discuss the chemistry and biosynthesis of allicin, its pharmacokinetic profile, its anticancer mechanisms and molecular targets, and its selectivity towards tumor cells. The research carried out so far revealed that allicin suppresses the growth of different types of tumors. In particular, it targets many signaling pathways associated with cancer development. Future research directions are also outlined to further characterize this promising natural product.

Progress in the Electrochemical Reactions of Sulfonyl Compounds.

Electrosynthesis has recently attracted more and more attention due to its great potential to replace chemical oxidants or reductants in molecule-electrode electron transfer. Sulfonyl compounds such as sulfonyl hydrazides, sulfinic acids (and their salts), sulfonyl halides have been discovered as practical precursors of several radicals. As electrochemical redox reactions can provide green and efficient pathways for the activation of sulfonyl compounds, studies for electrosynthesis have rapidly increased. Several types of radicals can be generated from anodic oxidation or cathodic reduction of sulfonyl compounds and can initiate fluoroalkylation, benzenesulfonylation, cyclization or rearrangement. In this Review, we summarize the electrosynthesis developments involving sulfonyl compounds mainly in the last decade.

A new method for C(sp2)-H sulfonylmethylation with glyoxylic acid and sodium sulfinates.

We herein describe a C4 sulfonylmethylation of pyrazol-5-amines with glyoxylic acid and sodium sulfinates. The reaction only needed water as a solvent, and it featured mild reaction conditions, simple operation, and high regioselectivity. Various C4 sulfonylmethylated pyrazol-5-amines were obtained in good to excellent yields. Moreover, this sulfonylmethylation method was applicable for C(sp2)-H sulfonylmethylation of other substrates such as enamines, indoles, and antipyrines by adding a catalyst and changing the solvent. Biological evaluation revealed that some products had antiproliferative activity against cancer cell lines.

Fatty Acyl Sulfonyl Fluoride as an Activity-Based Probe for Profiling Fatty Acid-Associated Proteins in Living Cells.

Fatty acids play fundamental structural, metabolic, functional, and signaling roles in all biological systems. Altered fatty acid levels and metabolism have been associated with many pathological conditions. Chemical probes have greatly facilitated biological studies on fatty acids. Herein, we report the development and characterization of an alkynyl-functionalized long-chain fatty acid-based sulfonyl fluoride probe for covalent labelling, enrichment, and identification of fatty acid-associated proteins in living cells. Our quantitative chemical proteomics show that this sulfonyl fluoride probe targets diverse classes of fatty acid-associated proteins including many metabolic serine hydrolases that are known to be involved in fatty acid metabolism and modification. We further validate that the probe covalently modifies the catalytically or functionally essential serine or tyrosine residues of its target proteins and enables evaluation of their inhibitors. The sulfonyl fluoride-based chemical probe thus represents a new tool for profiling the expression and activity of fatty acid-associated proteins in living cells.

Reactivity Analysis of New Multivalent Electrophilic Probes for Affinity Labeling of Carbohydrate Binding Proteins.

We have designed and synthesized six different multivalent electrophiles as carbohydrate affinity labeling probes. Evaluation of the reactivity of the electrophiles against peanut agglutinin (PNA) and Ricinus communis agglutinin (RCA) showed that p- and m-aryl sulfonyl fluoride are effective protein reactive groups that label carbohydrate binding lectins in a ligand-dependent fashion at a nanomolar probe concentration. Analysis of the selectivity of affinity labeling in the presence of excess BSA as a nonspecific protein indicated that m-arylsulfonyl fluoride is a more selective protein-reactive group, albeit with attenuated reactivity. Further analysis showed that the labeling efficiency of the multivalent electrophilic probes can be improved by employing reaction conditions involving 25 °C instead of typically employed 4 °C. Both isomers of arylsulfonyl fluoride groups together represent promising affinity labels for target identification studies that could serve as more efficient alternatives to photoreactive groups.

Allicin May Promote Reversal of T-Cell Dysfunction in Periodontitis via the PD-1 Pathway.

We evaluated the role of allicin in periodontitis using an in silico and in vitro design. An in silico docking analysis was performed to assess the plausible interactions between allicin and PD-L1. The cytokine profile of gingival crevicular fluid (GCF) samples obtained from periodontitis patients was estimated by cytometric bead array. CD3+ lymphocytes isolated from the peripheral blood were sorted and characterized using immunomagnetic techniques. Cultured and expanded lymphocytes were treated with the GCF samples to induce T-cell exhaustion. Optimum concentrations of allicin were added to exhausted lymphocytes to compare the expression of TIM-3 and LAG-3 gene expression at baseline and post-treatment. Allicin was found to bind to the PD-L1 molecule as revealed by the in-silico experiment, which is possibly an inhibitory interaction although not proven. GCF from periodontitis patients had significantly higher concentrations of TNF-α, CCL2, IL-6, IFN-γ, and CXCL8 than controls. GCF treatment of CD3+ lymphocytes from the periodontitis patients significantly increased expression of T-cell exhaustion markers TIM-3 and LAG-3. Allicin administration with GCF treatment resulted in significant lowering of the expression of exhaustion markers. Allicin may exert an immunostimulatory role and reverse immune-destructive mechanisms such as T-cell exhaustion.

Allium-Derived Compound Propyl Propane Thiosulfonate (PTSO) Attenuates Metabolic Alterations in Mice Fed a High-Fat Diet through Its Anti-Inflammatory and Prebiotic Properties.

BACKGROUND: Propyl propane thiosulfonate (PTSO) is an organosulfur compound from Allium spp. that has shown interesting antimicrobial properties and immunomodulatory effects in different experimental models. In this sense, our aim was to evaluate its effect on an experimental model of obesity, focusing on inflammatory and metabolic markers and the gut microbiota. METHODS AND RESULTS: Mice were fed a high-fat diet and orally treated with different doses of PTSO (0.1, 0.5 and 1 mg/kg/day) for 5 weeks. PTSO lessened the weight gain and improved the plasma markers associated with glucose and lipid metabolisms. PTSO also attenuated obesity-associated systemic inflammation, reducing the immune cell infiltration and, thus, the expression of pro-inflammatory cytokines in adipose and hepatic tissues (Il-1ẞ, Il-6, Tnf-α, Mcp-1, Jnk-1, Jnk-2, Leptin, Leptin R, Adiponectin, Ampk, Ppar-α, Ppar-γ, Glut-4 and Tlr-4) and improving the expression of different key elements for gut barrier integrity (Muc-2, Muc-3, Occludin, Zo-1 and Tff-3). Additionally, these effects were connected to a regulation of the gut microbiome, which was altered by the high-fat diet. CONCLUSION: Allium-derived PTSO can be considered a potential new tool for the treatment of metabolic syndrome.

A sulfonyl fluoride derivative inhibits EGFRL858R/T790M/C797S by covalent modification of the catalytic lysine.

The emergence of the C797S mutation in EGFR is a frequent mechanism of resistance to osimertinib in the treatment of non-small cell lung cancer (NSCLC). In the present work, we report the design, synthesis and biochemical characterization of UPR1444 (compound 11), a new sulfonyl fluoride derivative which potently and irreversibly inhibits EGFRL858R/T790M/C797S through the formation of a sulfonamide bond with the catalytic residue Lys745. Enzymatic assays show that compound 11 displayed an inhibitory activity on EGFRWT comparable to that of osimertinib, and it resulted more selective than the sulfonyl fluoride probe XO44, recently reported to inhibit a significant part of the kinome. Neither compound 11 nor XO44 inhibited EGFRdel19/T790M/C797S triple mutant. When tested in Ba/F3 cells expressing EGFRL858R/T790M/C797S, compound 11 resulted significantly more potent than osimertinib at inhibiting both EGFR autophosphorylation and proliferation, even if the inhibition of EGFR autophosphorylation by compound 11 in Ba/F3 cells was not long lasting.

Structure-activity relationship, in vitro and in vivo evaluation of novel dienyl sulphonyl fluorides as selective BuChE inhibitors for the treatment of Alzheimer's disease.

To discover novel scaffolds as leads against dementia, a series of δ-aryl-1,3-dienesulfonyl fluorides with α-halo, α-aryl and α-alkynyl were assayed for ChE inhibitory activity, in which compound A10 was identified as a selective BuChE inhibitor (IC50 = 0.021 µM for eqBChE, 3.62 µM for hBuChE). SAR of BuChE inhibition showed: (i) o- > m- > p-; -OCH3 > -CH3 > -Cl (-Br) for δ-aryl; (ii) α-Br > α-Cl, α-I. Compound A10 exhibited neuroprotective, BBB penetration, mixed competitive inhibitory effect on BuChE (Ki = 29 nM), and benign neural and hepatic safety. Treatment with A10 could almost entirely recover the Aß1-42-induced cognitive dysfunction to the normal level, and the assessment of total amount of Aß1-42 confirmed its anti-amyloidogenic profile. Therefore, the potential BuChE inhibitor A10 is a promising effective lead for the treatment of AD.

Allicin inclusions with α-cyclodextrin effectively masking its odor: Preparation, characterization, and olfactory and gustatory evaluation.

Allicin, a chemical found in functional foods, has a variety of beneficial bioactivities but the unpleasent odor and unstability hinder its applications. Isolating products from cyclodextrin (CD) complexation, using ß-CD and its derivatives, is usually a time and energy-consuming process. Herein, a high-efficiency and eco-friendly preparation method of an inclusion (allicin@α-CD) formed by allicin and α-CD was designed, which turned liquid allicin into crystal particles with high-speed stirring (10,000 r/min) at 25°C for 10 min in water. In vivo and in vitro masking evaluations showed that the inclusion particles could decrease the unpleasant odor of allicin. Molecular docking and experimental characterization results illustrated that the main reason of odor masking was due to the disulfide and thiocarbonyl groups of allicin being partially encapsulated by the cavity of α-CD. Compared with the physical mixture, the stability of allicin in allicin@α-CD at 60°C for 10 days was 33-fold improved. Overall, this efficient strategy of inclusion provided a promising approach for the industrialization of allicin-related formulations. PRACTICAL APPLICATION: In this study, an environmentally friendly method of α-CD inclusion without the use of organic reagents was designed to solidify and stabilize allicin, which effectively masked the unpleasant odor and taste of allicin. It has contributed greatly to improving the compliance of consumers and provided a new and effective approach to broaden the application of allicin.

Decatungstate-Catalyzed C(sp3)-H Sulfinylation: Rapid Access to Diverse Organosulfur Functionality.

Here we report the direct conversion of strong, aliphatic C(sp3)-H bonds into the corresponding alkyl sulfinic acids via decatungstate photocatalysis. This transformation has been applied to a diverse range of C(sp3)-rich scaffolds, including natural products and approved pharmaceuticals, providing efficient access to complex sulfur-containing products. To demonstrate the broad potential of this methodology for the divergent synthesis of pharmaceutically relevant molecules, procedures for the diversification of the sulfinic acid products into a range of medicinally relevant functional groups have been developed.

Exploration of the Reactivity of Multivalent Electrophiles for Affinity Labeling: Sulfonyl Fluoride as a Highly Efficient and Selective Label.

Here we explored the reactivity of a set of multivalent electrophiles cofunctionalized with a carbohydrate ligand on gold nanoparticles to achieve efficient affinity labeling for target protein analysis. Evaluation of the reactivity and selectivity of the electrophiles against three different cognate binding proteins identified arylsulfonyl fluoride as the most efficient protein-reactive group in this study. We demonstrated that multivalent arylsulfonyl fluoride probe 4 at 50 nm concentration achieved selective affinity labeling and enrichment of a model protein PNA in cell lysate, which was more effective than photoaffinity probe 1 with arylazide group. Labeling site analysis by LC-MS/MS revealed that the nanoparticle-immobilized arylsulfonyl fluoride group can target multiple amino acid residues around the ligand binding site of the target proteins. Our study highlights the utility of arylsulfonyl fluoride as a highly effective multivalent affinity label suitable for covalently capturing unknown target proteins.

Allicin ameliorates aluminium- and copper-induced cognitive dysfunction in Wistar rats: relevance to neuro-inflammation, neurotransmitters and Aß(1-42) analysis.

Alzheimer's disease (AD) is a multifactorial neurological disorder associated with neuropathological and neurobehavioral changes, like cognition and memory loss. Pathological hallmarks of AD comprise oxidative stress, formation of insoluble ß-amyloid (Aß) plaques, intracellular neurofibrillary tangles constituted by hyperphosphorylated tau protein (P-tau), neurotransmitters dysbalanced (DA, NE, 5-HT, GABA and Glutamate) and metal deposition. Chronic exposure to metals like aluminium and copper causes accumulation of Aß plaques, promotes oxidative stress, neuro-inflammation, and degeneration of cholinergic neurons results in AD-like symptoms. In the present study, rats were administered with aluminium chloride (200 mg/kg p.o) and copper sulfate (0.5 mg/kg p.o) alone and in combination for 28 days. Allicin (10 and 20 mg/kg i.p) was administered from day 7 to day 28. Spatial and recognition memory impairment analysis was performed using Morris water maze, Probe trial, and Novel Object Recognition test. Animals were sacrificed on day 29, brain tissue was isolated, and its homogenate was used for biochemical (lipid peroxidation, nitrite, and glutathione), neuro-inflammatory (IL-1ß, IL-6 and TNF- α), neurotransmitters (DA, NE, 5-HT, GABA and Glutamate), Aß(1-42) level, Al concentration estimation, and Na+/K+-ATPase activity. In the present study, aluminium chloride and copper sulfate administration increased oxidative stress, inflammatory cytokines release, imbalanced neurotransmitters' concentration, and promoted ß-amyloid accumulation and Na+/K+-ATPase activity. Treatment with allicin dose-dependently attenuated these pathological events via restoration of antioxidants, neurotransmitters concentration, and inhibiting cytokine release and ß-amyloid accumulation. Moreover, allicin exhibited the neuroprotective effect through antioxidant, anti-inflammatory, neurotransmitters restoration, attenuation of neuro-inflammation and ß-amyloid-induced neurotoxicity.