Revitalizing allicin for cancer therapy: advances in formulation strategies to enhance bioavailability, stability, and clinical efficacy.

The main objective of this review is to highlight the therapeutic potential of allicin, a defense molecule in garlic known for its diverse health benefits, and address the key challenges of its bioavailability and stability. The research further aims to evaluate various formulation strategies and nanotechnology-based delivery systems that can resolve these issues and improve allicin's clinical efficacy, especially in cancer therapy. We conducted a comprehensive review of the available literature and previous studies, focusing on the therapeutic properties of allicin, its bioavailability, stability issues, and novel formulation strategies. We assessed the mechanism of action of allicin in cancer, including its effects on signaling pathways, cell cycle, apoptosis, autophagy, and tumor development. We also evaluated the outcomes of both in vitro and in vivo studies on different types of cancers, such as breast, cervical, colon, lung, and gastric cancer. Despite allicin's significant therapeutic benefits, including cardiovascular, antihypertensive, cholesterol-lowering, antimicrobial, antifungal, anticancer, and immune-modulatory activity, its clinical utility is limited due to poor stability and unpredictable bioavailability. Allicin's bioavailability in the gastrointestinal tract is dependent on the activity of the enzyme alliinase, and its stability can be affected by various conditions like gastric acid and intestinal enzyme proteases. Recent advances in formulation strategies and nanotechnology-based drug delivery systems show promise in addressing these challenges, potentially improving allicin's solubility, stability, and bioavailability. Allicin offers substantial potential for cancer therapy, yet its application is hindered by its instability and poor bioavailability. Novel formulation strategies and nanotechnology-based delivery systems can significantly overcome these limitations, enhancing the therapeutic efficacy of allicin. Future research should focus on refining these formulation strategies and delivery systems, ensuring the safety and efficacy of these new allicin formulations. Clinical trials and long-term studies should be carried out to determine the optimal dosage, assess potential side effects, and evaluate their real-world applicability. The comparative analysis of different drug delivery approaches and the development of targeted delivery systems can also provide further insight into enhancing the therapeutic potential of allicin.

Combating Black Fungus: Using Allicin as a Potent Antifungal Agent against Mucorales.

Invasive fungal (IF) diseases are a leading global cause of mortality, particularly among immunocompromised individuals. The SARS-CoV-2 pandemic further exacerbated this scenario, intensifying comorbid IF infections such as mucormycoses of the nasopharynx. In the work reported here, it is shown that zygomycetes, significant contributors to mycoses, are sensitive to the natural product allicin. Inhibition of Mucorales fungi by allicin in solution and by allicin vapor was demonstrated. Mathematical modeling showed that the efficacy of allicin vapor is comparable to direct contact with the commercially available antifungal agent amphotericin B (ampB). Furthermore, the study revealed a synergistic interaction between allicin and the non-volatile ampB. The toxicity of allicin solution to human cell lines was evaluated and it was found that the half maximal effective concentration (EC50) of allicin was 25-72 times higher in the cell lines as compared to the fungal spores. Fungal allicin sensitivity depends on the spore concentration, as demonstrated in a drop test. This study shows the potential of allicin, a sulfur-containing defense compound from garlic, to combat zygomycete fungi. The findings underscore allicin's promise for applications in infections of the nasopharynx via inhalation, suggesting a novel therapeutic avenue against challenging fungal infections.

Allicin Alleviates Mitochondrial Dysfunction in Acrylamide-Induced Rat Kidney Involving the Regulation of SIRT1.

Acrylamide (AA), commonly formed in carbohydrate-rich thermally processed foods, exerts harmful effects on the kidney. Allicin, from crushed garlic cloves, exhibits strong biological activities. In the current study, the protection mechanisms of allicin against AA-caused nephrotoxicity were comprehensively examined using an in vivo rat model based on previous research that allicin plays a key role in improving renal function. The results showed that allicin attenuated histological changes of the kidney and ameliorated renal function. Damaged mitochondrial structures, upregulated voltage-dependent anion channel 1 expression, and decreased membrane potential and adenosine 5'-triphosphate levels were observed after AA treatment. Surprisingly, allicin notably reversed the adverse effects. Further, allicin effectively restored mitochondrial function via modulating mitochondrial biogenesis and dynamics, which might be associated with the upregulated expression of sirtuin 1 (SIRT1). Meanwhile, allicin dramatically activated the SIRT1 activity and subsequently inhibited p53 acetylation, prevented the translocation of cytochrome c to the cytoplasm, and reduced the caspase expression, thus further inhibiting mitochondrial apoptosis caused by AA. In summary, the relieving effect of allicin on AA-caused nephrotoxicity lies in its inhibition of mitochondrial dysfunction and mitochondrial apoptosis.

[Advances in cardiovascular protection effects and mechanisms of allicin].

Cardiovascular diseases(CVD) with high morbidity and mortality pose severe threats to human life. Allicin, a main active ingredient of garlic, possesses multiple pharmaceutical activities. It not only exerts cardioprotective effects but also prevents the risk factors for CVD. Allicin exerts cardioprotective effects via a variety of mechanisms, including inhibiting oxidative stress, apoptosis, autophagy, and inflammatory responses, regulating lipid metabolism and gut microbiota, inducing hydrogen sulfide production, and dilating vessels. Despite the valuable cardioprotective effects, the instability of allicin has hindered the basic research and clinical application. This paper reviews the progress in the cardioprotective effects and mechanisms of allicin in the last decade and summarizes the methods to improve the stability of allicin. In addition, this review provides a reference for further research and development of allicin in cardiovascular protection.

Current studies and potential future research directions on biological effects and related mechanisms of allicin.

Allicin, a thiosulfonate extract from freshly minced garlic, has been reported to have various biological effects on different organs and systems of animals and human. It can reduce oxidative stress, inhibit inflammatory response, resist pathogen infection and regulate intestinal flora. In addition, dozens of studies also demonstrated allicin could reduce blood glucose level, protect cardiovascular system and nervous system, and fight against cancers. Allicin was widely used in disease prevention and health care. However, more investigations on human cohort study are needed to verify the biological or clinical effects of allicin in the future. In this review, we summarized the biological effects of allicin from previous outstanding and valuable studies and provided useful information for future studies on the health effects of allicin.

Natural Compound Allicin Containing Thiosulfinate Moieties as Transmembrane Protein 16A (TMEM16A) Ion Channel Inhibitor for Food Adjuvant Therapy of Lung Cancer.

Cancer is one of the most serious malignant diseases, and chemotherapy is cancer's main clinical treatment method. However, chemotherapy inevitably produces drug resistance, and side effects accompany them. Adjuvant therapy is an effective way to enhance chemotherapeutic drug sensitivity and reduce side effects. This study found allicin, garlic's active ingredient, is an inhibitor of transmembrane protein 16A (TMEM16A), a novel drug target of lung adenocarcinoma. Allicin concentration-dependently inhibited TMEM16A currents with an IC50 of 24.35 ± 4.14 µM. Allicin thiosulfinate moieties bound with R535A/E624A/E633A residues of TMEM16A blocked the ion transport function and downregulated TMEM16A protein expression affecting the mitogen-activated protein kinase signal transduction. Then, allicin reduced the viability and migration of LA795 cells, and induced cell apoptosis. Moreover, multitarget combination administration results indicated that the therapeutic effect of 3.56 mg/kg allicin and 3 mg/kg cisplatin combined administration was superior to the superposition of the two drugs alone, demonstrating that the anticancer effects of allicin and cisplatin were synergistic. In addition, low-concentration combined administration also avoided the side effects of cisplatin in mice. Based on the good tumor suppressor effect and high biosafety of allicin and cisplatin combination in vivo, allicin can be used for food adjuvant therapy of cisplatin chemotherapy.

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.

Cellular Mechanisms Underlying the Cardioprotective Role of Allicin on Cardiovascular Diseases.

Cardiovascular diseases (CVDs) are a group of diseases in which the common denominator is the affection of blood vessels, heart tissue, and heart rhythm. The genesis of CVD is complex and multifactorial; therefore, approaches are often based on multidisciplinary management and more than one drug is used to achieve the optimal control of risk factors (dyslipidemia, hypertension, hypertrophy, oxidative stress, endothelial dysfunction, inflammation). In this context, allicin, a sulfur compound naturally derived from garlic, has shown beneficial effects on several cardiovascular risk factors through the modulation of cellular mechanisms and signaling pathways. Effective pharmacological treatments for CVD or its risk factors have not been developed or are unknown in clinical practice. Thus, this work aimed to review the cellular mechanisms through which allicin exerts its therapeutic effects and to show why it could be a therapeutic option for the prevention or treatment of CVD and its risk factors.

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.

Anti-inflammatory and Anti-bacterial Effects of Allicin-coated Tracheal Tube on Trachea Mucosa.

BACKGROUND/AIM: Allicin has been known to improve wound healing via antimicrobial and anti-inflammatory properties. The aim of this study was to evaluate whether an allicin-coated tracheal tube can prevent tracheal stenosis through improving wound healing after tracheal injury. MATERIALS AND METHODS: Allicin-coated silicone tracheal tube (t-tube) was prepared by the polydopamine-mediated coating method. Tracheal mucosa was injured, and an allicin-coated t-tube was placed into the trachea to evaluate mucosal changes until designated time point. Anti-inflammatory, anti-bacterial and cytotoxic effects of allicin were also investigated in in vitro. RESULTS: Allicin- coated silicone was not cytotoxic, and it showed anti-inflammatory and anti-bacterial effects in in vitro analysis. The use of allicin-coated t-tube in a rabbit model showed favorable mucosal healing with significant decrease of proinflammatory cytokines compared to the non-coated tube group. The allicin-coated tube showed obvious decreased number of cocci-shaped bacterial attached to the tube surface. From the histological point of view, the allicin- coated tube showed faster regeneration of the normal respiratory epithelial structure compared to the non-coated group. CONCLUSION: Allicin-coated t-tube showed anti-inflammatory and anti-bacterial effects on injured tracheal mucosa. We suggest that allicin-coated t-tube can be used for promoting physiological wound healing to prevent laryngotracheal stenosis.

Kinetics of bactericidal potency with synergistic combination of allicin and selected antibiotics.

Synergistic therapy against the resurgence of bacterial pathogenesis is a modern trend for antibacterial chemotherapy. The phytochemical allicin, found in garlic extract is a commendable antimicrobial agent that can be used in synergistic combination with modern antibiotics. Determination of optimal antibacterial combination for the target species is vital for maximizing efficacy, lowering toxicity, total eradication of the bacterial cells and minimization of the risk of resistance generation. In this present investigation, Hill function-based pharmacodynamics models were employed to elaborate various time-kill kinetics parameters. The bactericidal potency of the synergistic combinations of allicin and individual antibiotic was assessed in comparison to their monotherapy application viz. using sole allicin and sole antibiotics (levofloxacin, ciprofloxacin, oxytetracycline, rifaximin, ornidazole and azithromycin) on actively growing Bacillus subtilis and Escherichia coli bacteria. Here, all the synergistic combinations showed significantly better (t-test p-value < 0.05) killing effect and biofilm reduction potential compared to their respective monotherapy application, where the highest killing effect was observed with rifaximin-allicin combination (kill rate was more than 5.5 h-1). Moreover, the average inhibition potential to protein denaturation by the synergistic combination group was significantly higher (3.4 fold) than the sole antibiotic's group manifests reduction in the dose-related toxicity. The potential of synergism between antibiotics and allicin combination demonstrated greater killing efficiency at significantly lower concentration compared to monotherapy with increased kill rates in all cases.

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.

Allicin protects porcine oocytes against LPS-induced defects during maturation in vitro.

Lipopolysaccharide (LPS), the main virulence factor of gram-negative bacteria, severely impairs the function of the female reproductive system. It has especially harmful effects on oocytes and subsequent embryonic development. The use of active plant substances to ameliorate the damage caused by LPS exposure is a strategy worthy of attention. In this study, porcine oocytes were used to investigate the protective effects and underlying mechanisms of allicin, an extract derived from garlic, on LPS-exposed oocytes in vitro. Our data indicated that supplementation with 1 µM allicin significantly attenuated the LPS-mediated reductions in the first polar body extrusion rate and the subsequent blastocyst formation rate. Allicin also mitigated the abnormalities in spindle assembly, chromosome alignment, actin polymerization, and cortical granule distribution caused by LPS exposure. Furthermore, allicin restored reactive oxygen species (ROS), early apoptosis and autophagy to normal physiological levels in LPS-exposed oocytes. In conclusion, our findings confirm that allicin can protect oocytes against LPS-induced damage. The results of this study will help promote the application of plant-derived bioactive substances to ameliorate oocyte maturation defects.

Allicin Improves Intestinal Epithelial Barrier Function and Prevents LPS-Induced Barrier Damages of Intestinal Epithelial Cell Monolayers.

Gut barrier disruption is the initial pathogenesis of various diseases. We previously reported that dietary allicin improves tight junction proteins in the endoplasmic reticulum stressed jejunum. However, whether the allicin benefits the gut barrier within mycotoxin or endotoxin exposure is unknown. In the present study, IPEC-J2 cell monolayers within or without deoxynivalenol (DON) or lipopolysaccharide (LPS) challenges were employed to investigate the effects of allicin on intestinal barrier function and explore the potential mechanisms. Results clarified that allicin at 2 µg/mL increased the viability, whereas the allicin higher than 10 µg/mL lowered the viability of IPEC-J2 cells via inhibiting cell proliferation. Besides, allicin increased trans-epithelial electric resistance (TEER), decreased paracellular permeability, and enhanced ZO-1 integrity of the IPEC-J2 cell monolayers. Finally, allicin supplementation prevented the LPS-induced barrier damages via activating Nrf2/HO-1 pathway-dependent antioxidant system. In conclusion, the present study strongly confirmed allicin as an effective nutrient to improve intestinal barrier function and prevent bacterial endotoxin-induced barrier damages.

Pharmacoinformatics and hypothetical studies on allicin, curcumin, and gingerol as potential candidates against COVID-19-associated proteases.

Medicinal plants have been known to provide the essential raw material for the majority of antiviral drugs. This study demonstrated the putative inhibitory potential of curcumin, allicin, and gingerol towards cathepsin K, COVID-19 main protease, and SARS-CoV 3 C-like protease. The pharmacokinetic properties were predicted through the SwissADME server while the corresponding binding affinity of the selected phytocompounds towards the proteins was computed using PyRx-Python Prescription 0.8 and the binding free energy were computed based on conventional molecular dynamics using LARMD server. The ADMET properties revealed all the drugs possess drug-like properties. Curcumin has the highest binding affinities with all the selected proteases while allicin has the lowest binding affinities towards the proteases. Moreover, it was observed that curcumin exhibited the highest binding free energy of -17.90 ± 0.23,  -18.21 ± 0.25, and -9.67 ± 0.08 kcal/mol for Cathepsin K, COVID-19 main protease, and SARS-CoV 3 C-like protease, respectively. Based on the activities of the phytocompounds against coronavirus target proteases involved in the viral entry as evident from the results, the study, therefore, suggests that these phytocompounds could be valuable for the development of drugs useful for the prevention of coronavirus entry and replication.Communicated by Ramaswamy H. Sarma.

Evaluation of Allicin Against Alveolar Echinococcosis In Vitro and in a Mouse Model.

PURPOSE: At present, the chemotherapy for alveolar echinococcosis (AE) is mainly based on albendazole (ABZ). However, more than 20% of patients fail chemotherapy. Therefore, new and more effective treatments are urgently needed. Allicin has been reported to have antibacterial and antiparasitic effects. The objectives of the present study were to investigate the in vivo and in vitro efficacy of allicin against Echinococcus multilocularis (E. multilocularis). METHODS: The effects of allicin on protoscolex survival and structural changes were evaluated in vitro. The 4-week-old BALB/c male mice used for in vivo modelling underwent inoculation of E. multilocularis protoscoleces by intraperitoneal injection, followed by intragastric administration of allicin for 6 weeks. Then, the effects of allicin on lymphocyte subsets, metacestode growth and host tissue matrix metalloproteinase 2 (MMP2)/MMP9 expression around metacestodes in mice were evaluated. The toxicity of allicin was further evaluated in vivo and in vitro. RESULTS: Att 40 µg/mL, allicin showed a killing effect on protoscoleces in vitro and treatment resulted in the destruction of protoscolex structure. Molecular docking showed that allicin could form hydrogen bonds with E. multilocularis cysteine enzymes. After 6 weeks of in vivo allicin treatment, the spleen index of mice was increased and the weight of metacestodes was reduced. Allicin increased the proportion of CD4+ T cells and decreased the proportion of CD8+ T cells in the peripheral blood and spleen. Pathological analysis of the metacestodes showed structural disruption of the germinal and laminated layers after allicin treatment. In addition, allicin inhibited the expression of MMP2 and MMP9 in metacestode-surrounding host tissues. At 160 µg/mL, allicin had no significant toxicity to normal hepatocytes but could inhibit hepatoma cell proliferation. At 30 mg/kg, allicin had no significant hepatorenal toxicity in vivo. CONCLUSION: These results suggest that allicin exerts anti-E. multilocularis effects in vitro and in vivo and can enhance immune function in mice, with the potential to be developed as a lead compound against echinococcosis.

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 induces cell cycle arrest and apoptosis of breast cancer cells in vitro via modulating the p53 pathway.

BACKGROUND: The tumor suppressor protein p53 is a most promising target for the development of anticancer drugs. Allicin (diallylthiosulfinate) is one of the most active components of garlic (Alliium sativum L.) and possesses a variety of health-promoting properties with pharmacological applications. However, whether allicin plays an anti-cancer role against breast cancer cells through the induction of p53-mediated apoptosis remains unknown. METHODS AND RESULTS: In this study, we investigate the anti-breast cancer effect of allicin in vitro by using MCF-7 and MD-MBA-231 cells. We found that allicin reduces cell viability, induces apoptosis and cell cycle arrest in both cells. Allicin activated p53 and caspase 3 expressions in both cells but produced different effects on the expression of p53-related biomarkers. In MDA-MB-231 cells, allicin up-regulated the mRNA and protein expression of A1BG and THBS1 while down-regulated the expression of TPM4. Conversely, the mRNA and protein expression of A1BG, THBS1 and TPM4 were all reduced in MCF-7 cells. Hence, allicin induces cell cycle arrest and apoptosis in breast cancer cells through p53 activation but it effects on the expression of p53-related biomarkers were dependent upon the specific type of breast cancer involved. CONCLUSIONS: These findings suggest that allicin induces apoptosis and regulates biomarker expression in breast cancer cell lines through modulating the p53 signaling pathway. Furthermore, our results promote the utility of allicin as compound for further studies as an anticancer drug targeting p53.

Potential Therapeutic Effects of Natural Plant Compounds in Kidney Disease.

BACKGROUND: The blockade of the progression or onset of pathological events is essential for the homeostasis of an organism. Some common pathological mechanisms involving a wide range of diseases are the uncontrolled inflammatory reactions that promote fibrosis, oxidative reactions, and other alterations. Natural plant compounds (NPCs) are bioactive elements obtained from natural sources that can regulate physiological processes. Inflammation is recognized as an important factor in the development and evolution of chronic renal damage. Consequently, any compound able to modulate inflammation or inflammation-related processes can be thought of as a renal protective agent and/or a potential treatment tool for controlling renal damage. The objective of this research was to review the beneficial effects of bioactive natural compounds on kidney damage to reveal their efficacy as demonstrated in clinical studies. METHODS: This systematic review is based on relevant studies focused on the impact of NPCs with therapeutic potential for kidney disease treatment in humans. RESULTS: Clinical studies have evaluated NPCs as a different way to treat or prevent renal damage and appear to show some benefits in improving OS, inflammation, and antioxidant capacity, therefore making them promising therapeutic tools to reduce or prevent the onset and progression of KD pathogenesis. CONCLUSIONS: This review shows the promising clinical properties of NPC in KD therapy. However, more robust clinical trials are needed to establish their safety and therapeutic effects in the area of renal damage.