s-allylcysteine and Inflammation

Alzheimer's disease (AD) is the most common form of dementia in the older people and 7(th) leading cause of death in the United States. Deposition of amyloid-beta (Aβ) plaques, hyperphosphorylation of microtubule associated protein tau (MAPT), neuroinflammation and cholinergic neuron loss are the major hallmarks of AD. Deposition of Aβ peptides, which takes place years before the clinical onset of the disease can trigger hyperphophorylation of tau proteins and neuroinflammation, and the latter is thought to be primarily involved in neuronal and synaptic damage seen in AD. To date, four cholinesterase inhibitors or ChEI (tacrine, rivastigmine, donepezil and galantamine) and a partial NMDA receptor antagonist (memantine) are the only approved treatment options for AD. However, these drugs fail to completely cure the disease, which warrants a search for newer class of targets that would eventually lead to effective drugs for the treatment of AD. In addition to selected pharmacological agents, botanical and medicinal plant extracts are also being investigated. Apart from its culinary use, garlic (Allium sativum) is being used to treat several ailments like cancer and diabetes. Herein we have discussed the effects of a specific 'Aged Garlic Extract' (AGE) and one of its active ingredients, S-allyl-L-cysteine (SAC) in restricting several pathological cascades related to the synaptic degeneration and neuroinflammatory pathways associated with AD. Thus, based on the reported positive preliminary results reviewed herein, further research is required to develop the full potential of AGE and/or SAC into an effective preventative strategy for AD.

Topics: Alzheimer Disease; Cysteine; Garlic; Humans; Inflammation; Nerve Degeneration; Plant Extracts

Topics: Aged; Antigens, Neoplasm; Chondrocytes; Cysteine; Female; Humans; Inflammation; JNK Mitogen-Activated Protein Kinases; Male; Middle Aged; Mitogen-Activated Protein Kinases; NF-E2-Related Factor 2; Osteoarthritis; Signal Transduction; Toll-Like Receptor 4

In the present study, we evaluated the therapeutic potentiality of S-allylcysteine (SAC) in streptozotocin (STZ)-nicotinamide (NAD)-induced diabetic nephropathy (DN) in experimental rats.. SAC was orally administered for 45 days to rats with STZ-NAD-induced DN; a metformin-treated group was included for comparison. Effect of SAC on body weight, organ weight, blood glucose, levels of insulin, glycated haemoglobin, and renal biochemical markers was determined. Body composition by total body electrical conductivity (TOBEC) and dual-X ray absorptiometry (DXA), kidney antioxidant analysis, real-time polymerase chain reaction, and western blot analysis of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), nuclear factor kappa B (NF-κB), interleukin (IL)-6, and tumor necrosis factor (TNF)-α; histopathological and scanning electron microscope (SEM) analysis of the kidneys were performed in both control and experimental rats.. SAC treatment showed significantly decreased levels of blood glucose, glycated haemoglobin, creatinine, albumin, AST, ALT, creatinine kinase, lactate dehydrogenase, and expressions of NF-κB, IL-6, and TNF-α compared with DN control rats. Furthermore, SAC administration to DN rats significantly improved body composition and antioxidant defense mechanism which was confirmed by the upregulation of mRNA and protein expressions of antioxidant genes.. Thus, SAC showed adequate therapeutic effect against DN by downregulation of inflammatory factors and attenuation of oxidative stress. Histological and SEM observations also indicated that SAC treatment notably reverses renal damage and protects the kidneys from hyperglycemia-mediated oxidative damage.

Topics: Animals; Antineoplastic Agents; Antioxidants; Cysteine; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Disease Models, Animal; Inflammation; Male; Niacinamide; Oxidative Stress; Rats; Rats, Wistar; Streptozocin

Sepsis is a serious and life-threatening medical condition with a higher rate of patients' morbidity and mortality and with complications such as acute kidney injury (AKI). S-allyl cysteine (SAC) is the active constituent of the medicinal plant garlic (Allium sativum) with multiple beneficial effects including anti-inflammatory and antioxidant properties. In this research, we tried to determine the protective effect of SAC pretreatment in a mouse model of AKI. To induce AKI, lipopolysaccharide (LPS) was injected once (10 mg/kg, i.p.) and SAC was administered at doses of 25, 50, or 100 mg/kg (p.o.) 1 h before LPS. Treatment of LPS-challenged C56BL/6 animals with SAC lowered serum level of creatinine and blood urea nitrogen (BUN), partially restored renal oxidative stress-related biomarkers including malondialdehyde (MDA), glutathione (GSH), and activity of superoxide dismutase (SOD) and catalase in addition to improvement of mitochondrial membrane potential (MMP). Furthermore, SAC was capable to bring renal nuclear factor-kappaB (NF-κB), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), toll-like receptor 4 (TLR4), cyclooxygenase-2 (COX2), tumor necrosis factor α (TNFα), interleukin-1β (IL-1β), interleukin-6 (IL-6), Annexin V, and DNA fragmentation partially back to their control levels. Additionally, SAC pretreatment was capable to exert a protective effect, as shown histologically by lower tubular injury and pathologic changes in the kidney. In summary, SAC is capable to alleviate LPS-induced AKI through mitigation of renal oxidative stress, inflammation, and apoptosis in addition to preservation of mitochondrial integrity and its favorable effect exhibits a dose-dependent pattern.

Topics: Acute Kidney Injury; Animals; Anti-Inflammatory Agents; Apoptosis; Creatinine; Cysteine; Disease Models, Animal; Garlic; Humans; Inflammation; Kidney; Lipopolysaccharides; Male; Malondialdehyde; Membrane Potential, Mitochondrial; Mice; Mice, Inbred C57BL; Oxidative Stress; Sepsis; Signal Transduction

Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal lung disease characterized by inflammation, multifocal fibrotic lesions and excessive collagen deposition with limited therapies. As a major bioactive compound in garlic, S-allyl-l-cysteine (SAC) is a neuroprotective drug candidate to prevent cognitive decline, however, its anti-pulmonary fibrotic activity remains unknown. Here, we investigated whether SAC could attenuate bleomycin (BLM)-induced pulmonary fibrosis and inflammation in mice. Our results showed that SAC dose-dependently reduced the infiltration of inflammatory cells, pulmonary lesions and collagen deposition in BLM treated mice with downregulated mRNA expression levels of fibrotic genes including alpha smooth muscle actin (α-SMA), fibronectin, collagen I and collagen III as well as the protein level of α-SMA. In addition, SAC could also reduce the mRNA expression of inflammatory mediators such as TNF-α and iNOS. Furthermore, higher phosphorylation of AKT and NF-κB p65 in IPF patient samples and murine samples was verified by immunohistochemistry while SAC could decrease the phosphorylation level of AKT and NF-κB p65 in mice stimulated with BLM. These findings, for the first time, indicate that SAC might mediate AKT/NF-κB signaling pathway to inhibit BLM-induced pulmonary fibrosis and support the potential role of SAC as an anti-pulmonary fibrosis agent.

Topics: Actins; Animals; Bleomycin; Collagen; Cysteine; Dose-Response Relationship, Drug; Fibronectins; Gene Expression; Inflammation; Inflammation Mediators; Mice; Mice, Inbred C57BL; NF-kappa B; Phosphorylation; Proto-Oncogene Proteins c-akt; Pulmonary Fibrosis; RNA, Messenger; Signal Transduction

Diabetes mellitus (DM) is associated with learning, memory, and cognitive deficits. S-allyl cysteine (SAC) is the main organosulfur bioactive molecule in aged garlic extract with anti-diabetic, antioxidant, anti-inflammatory and nootropic property. This research was conducted to evaluate the efficacy of SAC on alleviation of learning and memory deficits in streptozotocin (STZ)-diabetic rats and to explore involvement of toll-like receptor 4 (TLR4), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), nuclear factor-kappa B (NF-κB), and heme oxygenase 1 (HO-1) signaling cascade. Male Wistar rats were divided into control, diabetic, SAC-treated diabetic, and glibenclamide-treated diabetic (positive control) groups. SAC was administered at a dose of 150mg/kg for seven weeks. Treatment of diabetic rats with SAC lowered serum glucose, improved spatial recognition memory in Y maze, discrimination ratio in novel object recognition task, and restored step-through latency (STL) in passive avoidance paradigm. In addition, SAC reduced acetylcholinesterase activity, lipid peroxidation marker malondialdehyde (MDA) and augmented antioxidant defensive system including superoxide dismutase (SOD), catalase and reduced glutathione (GSH) in hippocampal lysate. Meanwhile, SAC lowered hippocampal NF-kB, TLR4, and TNFα and prevented reduction of Nrf2 and heme oxygenase-1 (HO-1) in diabetic rats. Taken together, chronic SAC treatment could ameliorate cognitive deficits in STZ-diabetic rats through modulation of Nrf2/NF-κB/TLR4/HO-1, and acetylcholinesterase and attenuation of associated oxidative stress and neuroinflammation.

Topics: Acetylcholinesterase; Animals; Avoidance Learning; Biomarkers; Cognition; Cysteine; Diabetes Mellitus, Experimental; Discrimination, Psychological; Hippocampus; Inflammation; Lipid Peroxidation; Male; Maze Learning; Oxidative Stress; Rats; Rats, Wistar

The anti-neuroinflammatory capacities of raw and steamed garlic extracts as well as five organosulfur compounds (OSCs) were examined in lipopolysaccharide (LPS)-stimulated BV2 microglia. According to those results, steaming pretreatment blocked the formation of alliinase-catalyzed OSCs such as allicin and diallyl trisulfide (DATS) in crushed garlic. Raw garlic, but not steamed garlic, dose-dependently attenuated the production of LPS-induced nitric oxide (NO), interleukin-1β (IL-1β), tumor necrosis factor (TNF)-α, and monocyte chemoattractant protein-1 (MCP-1). DATS and diallyl disulfide at 200 and 400 μM, respectively, displayed significant anti-neuroinflammatory activity. Meanwhile, even at 1 mM, diallyl sulfide, S-allyl cysteine and alliin did not display such activity. Inhibition of nuclear factor-κB activation was the mechanism underlying this protective effect of raw garlic and DATS. Analysis results indicated that the anti-neuroinflammatory capacity of raw garlic is due to the alliin-derived OSCs. Importantly, DATS is a highly promising therapeutic candidate for treating inflammation-related neurodegenerative diseases.

Topics: Allium; Allyl Compounds; Animals; Cell Line; Chemokine CCL2; Cysteine; Disulfides; Garlic; Inflammation; Interleukin-1beta; Lipopolysaccharides; Mice; Microglia; Neurodegenerative Diseases; NF-kappa B; Nitric Oxide; Plant Extracts; Sulfides; Sulfur Compounds; Tumor Necrosis Factor-alpha

Oxidative stress and inflammatory damage play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. The present study examined the hypothesis that S-allyl cysteine (SAC), organosulfur compounds found in garlic extract, would reduce oxidative stress-associated brain injury after middle cerebral artery occlusion (MCAO). To test this hypothesis, male Wistar rats were subjected to MCAO for 2 hours and 22-hour reperfusion. S-allyl cysteine was administered (100 mg/kg, b.wt.) intraperitoneally 30 minutes before the onset of ischemia and after the ischemia at the interval of 0, 6, and 12 hours. After 24 hours of reperfusion, rats were tested for neurobehavioral activities and were killed for the infarct volume, estimation of lipid peroxidation, glutathione content, and activity of antioxidant enzymes (glutathione peroxidase, glutathione reductase, catalase, and superoxide dismutase). S-allyl cysteine treatment significantly reduced ischemic lesion volume, improved neurologic deficits, combated oxidative loads, and suppressed neuronal loss. Behavioral and biochemical alterations observed after MCAO were further associated with an increase in glial fibrillary acidic protein and inducible nitric oxide expression and were markedly inhibited by the treatment with SAC. The results suggest that SAC exhibits exuberant neuroprotective potential in rat ischemia/reperfusion model. Thus, this finding of SAC-induced adaptation to ischemic stress and inflammation could suggest a novel avenue for clinical intervention during ischemia and reperfusion.

Topics: Allium; Animals; Antioxidants; Behavior, Animal; Brain Ischemia; Cerebrum; Cysteine; Glial Fibrillary Acidic Protein; Infarction, Middle Cerebral Artery; Inflammation; Male; Nervous System Diseases; Neuroprotective Agents; Nitric Oxide; Oxidative Stress; Phytotherapy; Plant Extracts; Rats; Rats, Wistar; Reperfusion Injury