Neuroprotective effects of garlic a review

Examining the role of antioxidant supplementation in mitigating oxidative stress markers in Alzheimer's disease: a comprehensive review

Alzheimer's disease is a devastating neurodegenerative disorder that affects millions of people worldwide. One of the key pathological features of Alzheimer's disease is oxidative stress, which is characterized by an imbalance between the production of reactive oxygen species and the body's ability to neutralize them with antioxidants. In recent years, there has been growing interest in the potential role of antioxidant supplementation in mitigating oxidative stress markers in Alzheimer's disease. This review paper aims to provide a comprehensive overview of the current research on antioxidant supplementation in Alzheimer's disease and its effects on oxidative stress markers. The paper will examine the underlying mechanisms of oxidative stress in Alzheimer's disease, the potential benefits of antioxidant supplementation, and the challenges and limitations of using antioxidants as a therapeutic strategy.

Comparative study of antioxidant activities of Allium sativum (a novel variety, HG17) and Allium ampeloprasum (SMG): Revealing the higher potential of HG17 and analyzing its phytochemicals

Garlic, belonging to the genus Allium, is renowned for its rich antioxidant potential. Snow Mountain garlic (SMG) (Allium ampeloprasum) has been traditionally used for medicinal purposes because of its higher antioxidant potential. Considering its potential in medical therapies, we compared the antioxidant activity of SMG with a novel variety of Allium sativum, Hisar garlic 17 (HG17). Comparative antioxidant activity data (2,2-diphenyl-1-picrylhydrazyl and 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) revealed the higher antioxidant activity of HG17 than SMG, which prompted us to conduct a comprehensive phytochemical investigation to elucidate the factors contributing to antioxidant potential of HG17. To get a detailed antioxidant and phytoconstituents profiling, we differentially extracted HG17 by processing it in different forms (fresh, dry, heated, and aged) with two solvents (50% methanol and n-butanol). Our data (antioxidant activities, total phenolics, and flavonoids) showed that dry garlic methanolic extract (DgM) had maximum potential than other HG17 forms/solvents, which concludes that different extraction techniques had direct impact on the phenolics/flavonoids and antioxidant potential of the extracts. Further, phytochemical analysis of HG17 extracts by high resolution liquid chromatograph mass spectrometer quadrupole time of flight validated the maximum potential of DgM. LCMS revealed the presence of garcimangosone C, osmanthuside A, and protoaphin aglucone polyphenols exclusively in DgM compared to other HG17 extracts, which possibly contributing in its high antioxidant potential. The overall differential extraction and LCMS data of HG17 strongly depict that it may be used as an alternative of SMG under diverse medical applications. HG17 higher antioxidant potential and rich array of unique phytochemicals make it valuable for food and pharmaceutical industries to integrate into functional foods/therapeutics. PRACTICAL APPLICATION: Garlic unique phytochemical composition and its remarkable ability to scavenge different radicals make it valuable therapeutic asset to mitigate diseases associated with oxidative stress. SMG is well known for its anti-arthritic and anti-inflammatory properties. HG17 showed higher antioxidant potential than SMG and can be used as an alternative of SMG for anti-arthritic properties.

Unraveling potential neuroprotective mechanisms of herbal medicine for Alzheimer's diseases through comprehensive molecular docking analyses

Alzheimer's disease (AD) continues to be a worldwide health concern, demanding innovative therapeutic approaches. This study investigates the neuroprotective potential of herbal compounds by scrutinizing their interactions with Beta-Secretase-1 (BACE1). Through comprehensive molecular docking analyses, three compounds, Masticadienonic acid (ΔG: -9.6 kcal/mol), Hederagenin (ΔG: -9.3 kcal/mol), and Anthocyanins (ΔG: -8.1 kcal/mol), emerge as promising BACE1 ligands, displaying low binding energies and strong affinities. ADME parameter predictions, drug-likeness assessments, and toxicity analyses reveal favorable pharmacokinetic profiles for these compounds. Notably, Masticadienonic Acid exhibits optimal drug-likeness (-3.3736) and negligible toxicity concerns. Hederagenin (drug-likeness: -5.3272) and Anthocyanins (drug-likeness: -6.2041) also demonstrate promising safety profiles. Furthermore, pharmacophore modeling elucidates the compounds' unique interaction landscapes within BACE1's active site. Masticadienonic acid showcases seven hydrophobic interactions and a hydrogen bond acceptor interaction with Thr232. Hederagenin exhibits a specific hydrogen bond acceptor interaction with Trp76, emphasizing its selective binding. Anthocyanins reveal a multifaceted engagement, combining hydrophobic contacts and hydrogen bond interactions with key residues. In conclusion, Masticadienonic acid, Hederagenin, and Anthocyanins stand out as promising candidates for further experimental validation, presenting a synergistic balance of efficacy and safety in combating AD through BACE1 inhibition.

The nutritional value, bioactive availability and functional properties of garlic and its related products during processing

Garlic, a common culinary spice, is cultivated and used around the globe. Consumption of garlic and its supplements reduces the risk of diabetes and cardiovascular disease and boosts the immune system with antibacterial, antifungal, anti-aging, and anti-cancer properties. Diallyl sulfide, diallyl disulfide, triallyl trisulfide, phenolics, flavonoids, and others are the most commercially recognized active ingredients in garlic and its products. In recent years, global demand for medicinal or functional garlic has surged, introducing several products such as garlic oil, aged garlic, black garlic, and inulin into the market. Garlic processing has been demonstrated to directly impact the availability of bioactive ingredients and the functionality of products. Depending on the anticipated functional qualities, it is also recommended that one or a combination of processing techniques be deemed desirable over the others. This work describes the steps involved in processing fresh garlic into products and their physicochemical alterations during processing. Their nutritional, phytochemical, and functional properties are also reviewed. Considering the high demand for functional food, this review has been compiled to provide guidance for food producers on the industrial utilization and suitability of garlic for new product development.

Phytochemical Profiles and Biological Studies of Selected Botanical Dietary Supplements Used in the United States

Based on their current wide bioavailability, botanical dietary supplements have become an important component of the United States healthcare system, although most of these products have limited scientific evidence for their use. The most recent American Botanical Council Market Report estimated for 2020 a 17.3% increase in sales of these products when compared to 2019, for a total sales volume of $11,261 billion. The use of botanical dietary supplements products in the United States is guided by the Dietary Supplement Health and Education Act (DSHEA) from 1994, enacted by the U.S. Congress with the aim of providing more information to consumers and to facilitate access to a larger number of botanical dietary supplements available on the market than previously. Botanical dietary supplements may be formulated for and use only using crude plant samples (e.g., plant parts such as the bark, leaves, or roots) that can be processed by grinding into a dried powder. Plant parts can also be extracted with hot water to form an "herbal tea." Other preparations of botanical dietary supplements include capsules, essential oils, gummies, powders, tablets, and tinctures. Overall, botanical dietary supplements contain bioactive secondary metabolites with diverse chemotypes that typically are found at low concentration levels. These bioactive constituents usually occur in combination with inactive molecules that may induce synergy and potentiation of the effects observed when botanical dietary supplements are taken in their different forms. Most of the botanical dietary supplements available on the U.S. market have been used previously as herbal remedies or as part of traditional medicine systems from around the world. Their prior use in these systems also provides a certain level of assurance in regard to lower toxicity levels. This chapter will focus on the importance and diversity of the chemical features of bioactive secondary metabolites found in botanical dietary supplements that are responsible for their applications. Many of the active principles of botanical dietary substances are phenolics and isoprenoids, but glycosides and some alkaloids are also present. Biological studies on the active constituents of selected botanical dietary supplements will be discussed. Thus, the present chapter should be of interest for both members of the natural products scientific community, who may be performing development studies of the products available, as well as for healthcare professionals who are directly involved in the analysis of botanical interactions and evaluation of the suitability of botanical dietary supplements for human consumption.

Herbal Therapeutics for Alzheimer's Disease: Ancient Indian Medicine System from the Modern Viewpoint

Alzheimer's is a chronic neurodegenerative disease where amyloid-beta (Aβ) plaques and neurofibrillary tangles are formed inside the brain. It is also characterized by progressive memory loss, depression, neuroinflammation, and derangement of other neurotransmitters. Due to its complex etiopathology, current drugs have failed to completely cure the disease. Natural compounds have been investigated as an alternative therapy for their ability to treat Alzheimer's disease (AD). Traditional herbs and formulations which are used in the Indian ayurvedic system are rich sources of antioxidant, anti-amyloidogenic, neuroprotective, and anti-inflammatory compounds. They promote quality of life by improving cognitive memory and rejuvenating brain functioning through neurogenesis. A rich knowledge base of traditional herbal plants (Turmeric, Gingko, Ashwagandha, Shankhpushpi, Giloy, Gotu kola, Garlic, Tulsi, Ginger, and Cinnamon) combined with modern science could suggest new functional leads for Alzheimer's drug discovery. In this article Ayurveda, the ancient Indian herbal medicine system based on multiple clinical and experimental, evidence have been reviewed for treating AD and improving brain functioning. This article presents a modern perspective on the herbs available in the ancient Indian medicine system as well as their possible mechanisms of action for AD treatment. The main objective of this research is to provide a systematic review of herbal drugs that are easily accessible and effective for the treatment of AD.

The Phytochemistry and Pharmacology of Tulbaghia, Allium, Crinum and Cyrtanthus: ‘Talented’ Taxa from the Amaryllidaceae

Amaryllidaceae is a significant source of bioactive phytochemicals with a strong propensity to develop new drugs. The genera Allium, Tulbaghia, Cyrtanthus and Crinum biosynthesize novel alkaloids and other phytochemicals with traditional and pharmacological uses. Amaryllidaceae biomolecules exhibit multiple pharmacological activities such as antioxidant, antimicrobial, and immunomodulatory effects. Traditionally, natural products from Amaryllidaceae are utilized to treat non-communicable and infectious human diseases. Galanthamine, a drug from this family, is clinically relevant in treating the neurocognitive disorder, Alzheimer’s disease, which underscores the importance of the Amaryllidaceae alkaloids. Although Amaryllidaceae provide a plethora of biologically active compounds, there is tardiness in their development into clinically pliable medicines. Other genera, including Cyrtanthus and Tulbaghia, have received little attention as potential sources of promising drug candidates. Given the reciprocal relationship of the increasing burden of human diseases and limited availability of medicinal therapies, more rapid drug discovery and development are desirable. To expedite clinically relevant drug development, we present here evidence on bioactive compounds from the genera Allium, Tulgbaghia, Cyrtanthus and Crinum and describe their traditional and pharmacological applications.

Bioactive Compounds and Their Derivatives: An Insight into Prospective Phytotherapeutic Approach against Alzheimer’s Disease

Alzheimer's disease (AD) is a common neurodegenerative brain disorder that causes cellular response alterations, such as impaired cholinergic mechanism, amyloid-beta (Aβ) AD aggregation, neuroinflammation, and several other pathways. AD is still the most prevalent form of dementia and affects many individuals across the globe. The exact cause of the disorder is obscure. There are yet no effective medications for halting, preventing, or curing AD's progress. Plenty of natural products are isolated from several sources and analyzed in preclinical and clinical settings for neuroprotective effects in preventing and treating AD. In addition, natural products and their derivatives have been promising in treating and preventing AD. Natural bioactive compounds play an active modulatory role in the pathological molecular mechanisms of AD development. This review focuses on natural products from plant sources and their derivatives that have demonstrated neuroprotective activities and maybe promising to treat and prevent AD. In addition, this article summarizes the literature pertaining to natural products as agents in the treatment of AD. Rapid metabolism, nonspecific targeting, low solubility, lack of BBB permeability, and limited bioavailability are shortcomings of most bioactive molecules in treating AD. We can use nanotechnology and nanocarriers based on different types of approaches.

Antioxidants in Alzheimer's Disease: Current Therapeutic Significance and Future Prospects

Alzheimer's disease (AD) rate is accelerating with the increasing aging of the world's population. The World Health Organization (WHO) stated AD as a global health priority. According to the WHO report, around 82 million people in 2030 and 152 million in 2050 will develop dementia (AD contributes 60% to 70% of cases), considering the current scenario. AD is the most common neurodegenerative disease, intensifying impairments in cognition, behavior, and memory. Histopathological AD variations include extracellular senile plaques' formation, tangling of intracellular neurofibrils, and synaptic and neuronal loss in the brain. Multiple evidence directly indicates that oxidative stress participates in an early phase of AD before cytopathology. Moreover, oxidative stress is induced by almost all misfolded protein lumps like α-synuclein, amyloid-β, and others. Oxidative stress plays a crucial role in activating and causing various cell signaling pathways that result in lesion formations of toxic substances, which foster the development of the disease. Antioxidants are widely preferred to combat oxidative stress, and those derived from natural sources, which are often incorporated into dietary habits, can play an important role in delaying the onset as well as reducing the progression of AD. However, this approach has not been extensively explored yet. Moreover, there has been growing evidence that a combination of antioxidants in conjugation with a nutrient-rich diet might be more effective in tackling AD pathogenesis. Thus, considering the above-stated fact, this comprehensive review aims to elaborate the basics of AD and antioxidants, including the vitality of antioxidants in AD. Moreover, this review may help researchers to develop effectively and potentially improved antioxidant therapeutic strategies for this disease as it also deals with the clinical trials in the stated field.

Evaluation of the Effect of Garlic Tablet as a Complementary Treatment for Patients with Diabetic Retinopathy

PURPOSE

The aim of this study was to investigate the effectiveness of garlic (Allium sativum L.) tablets as a complimentary herbal medication in diabetic macular edema.

METHODS

A total of 91 diabetic participants (117 eyes) with central involved macular edema underwent a double-blind randomized trial. The patients used garlic tablets (500 mg) (2 tab/day) or placebo for 4 weeks and subsequently were examined by an expert ophthalmologist. Clinical manifestations including the best-corrected visual acuity (BCVA, logMAR), central macular thickness (CMT, μm), and intraocular pressure (IOP) were measured as the main outcomes.

RESULTS

BCVA was significantly improved by a 0.18 decrease in mean logMAR value in the garlic-treated patients in comparison with 0.06 in the control ones (P value = 0.027). CMT was decreased in both groups by a 102.99 μm decrease in the garlic group compared to 52.67 μm in the placebo group, albeit in a nonsignificant manner (P value: 0.094). IOP was decreased in the garlic group by 1.03 mmHg (P value: 0.024) and increased by 0.3 mmHg (P value: 0.468) in the placebo group.

CONCLUSION

Our trial suggests that garlic supplements can improve visual acuity, decrease the CMT and lower the IOP, and can be considered as an adjuvant treatment in patients with diabetic macular edema. Garlic was satisfactorily tolerated in diabetic patients, and no significant adverse effect interrupting the safety profile was observed.

Antitumor Effects of Natural Compounds Derived from Allium sativum on Neuroblastoma: An Overview

Garlic (Allium sativum) has been used in alternative medicine to treat several diseases, such as cardiovascular and neurodegenerative diseases, cancer, and hepatic diseases. Several publications have highlighted other features of garlic, including its antibacterial, antioxidative, antihypertensive, and antithrombotic properties. The properties of garlic result from the combination of natural compounds that act synergistically and cause different effects. Some garlic-derived compounds have been studied for the treatment of several types of cancer; however, reports on the effects of garlic on neuroblastoma are scarce. Neuroblastoma is a prevalent childhood tumor for which the search for therapeutic alternatives to improve treatment without affecting the patients’ quality of life continues. Garlic-derived compounds hold potential for the treatment of this type of cancer. A review of articles published to date on some garlic compounds and their effect on neuroblastoma was undertaken to comprehend the possible therapeutic role of these compounds. This review aimed to analyze the impact of some garlic compounds on cells derived from neuroblastoma.

Immunomodulatory effects of Allium Sativum L. and its constituents against viral infections and metabolic diseases

BACKGROUND

Allium sativum L., or garlic, is one of the most studied plants worldwide within the field of traditional medicine. Current interests lie in the potential use of garlic as a preventive measure and adjuvant treatment for viral infections, e.g., SARS-CoV-2. Even though it cannot be presented as a single treatment, its beneficial effects are beyond doubt. The World Health Organization has deemed it an essential part of any balanced diet with immunomodulatory properties.

OBJECTIVE

The aim of the study was to review the literature on the effects of garlic compounds and preparations on immunomodulation and viral infection management, with emphasis on SARS-CoV-2.

METHOD

Exhaustive literature search has been carried out on electronic databases.

CONCLUSION

Garlic is a fundamental part of a well-balanced diet which helps maintain general good health. The reported information regarding garlic's ability to beneficially modulate inflammation and the immune system is encouraging. Nonetheless, more efforts must be made to understand the actual medicinal properties and mechanisms of action of the compounds found in this plant to inhibit or diminish viral infections, particularly SARS-CoV-2. Based on our findings, we propose a series of innovative strategies to achieve such a challenge in the near future.

Black Garlic and Its Bioactive Compounds on Human Health Diseases: A Review

Black garlic (BG) is a form of aged garlic obtained from raw garlic (Allium sativum) via Millard reaction under high temperature (60-90 °C) and humidity (70-90%) for a period of time. Several studies reported higher contents of water-soluble antioxidants compounds (S-allyl cysteine, S-allyl-mercapto cysteine), 5-hydroxymethylfurfural, organosulfur compounds, polyphenol, volatile compounds, and products of other Millard reactions compared to fresh garlic after the thermal processing. Recent studies have demonstrated that BG and its bioactive compounds possess a wide range of biological activities and pharmacological properties that preserve and show better efficacy in preventing different types of diseases. Most of these benefits can be attributed to its anti-oxidation, anti-inflammation, anti-obesity, hepatoprotection, hypolipidemia, anti-cancer, anti-allergy, immunomodulation, nephroprotection, cardiovascular protection, and neuroprotection. Substantial studies have been conducted on BG and its components against different common human diseases in the last few decades. Still, a lot of research is ongoing to find out the therapeutic effects of BG. Thus, in this review, we summarized the pre-clinical and clinical studies of BG and its bioactive compounds on human health along with diverse bioactivity, a related mode of action, and also future challenges.

Cardioprotective properties of natural medicine in isoproterenol induced myocardial damage in the male Albino rats

The main aim of this study is to investigate cardioprotective properties of natural medicine inmyocardial damage induced male Albino rats. The aqueous extractof Allium sativumwas used for the determination of phenolic compounds and flavonoids. The amount of phenol (1.39 ± 0.37 GAE/g dry weight) and flavonoids (49.1 ± 2.79 QE/g dry weight) were high in aqueous extract. A. sativumextract and showed 68.39 ± 3.6% DPPHscavenging activity. Isoproterenol was used to induce myocardial injury in Albino rats in vivo by subcutaneous injection (100 mg/kg body weight). To achieve this, experimental animals were categorized into six groups (n = 4), namely, positive, negative control, only isoproterenol administered groups, and garlic extract administered group at 100-300 mg extract/kg body weight. Oxidative stress marker and cardiac markers were assayed to analyze the cardioprotective properties of garlic extract. At 300 mg/kg doseof garlic extract, rat was recovered from various altered factors such as, aspartate aminotransferase, alkaline transminase and alkaline phosphatase. The rats treated with 300 mggarlic extract/kg body weight decreased the level of asparate aminotransferase (126 ± 6.4 IU/L) than other lower doses (100 mg extract/kg and 200 mg extract/kg). Alkaline transaminase level of rat serum level was 81 ± 4.34 IU/L. In the isoproterenol treated rats elevated level was observed (152 ± 4.42 IU/L enzyme activity). Pre-treatment of Albino rat with A. sativum extract reduced cardiac damage. Isoproterenol exposed animal showed 207.6 ± 1.2 mg/dL triglyceride and the garlic administered rat (300 mgextract/kg) reduced LDL-cholesterol level (61.3 ± 1.3 mg/dL) significantly (p < 0.05). Creatinine kinase -MB level was 269.5 ± 12.5 IU/L in the control animal and stress induced animal showed elevated level (572.3 ± 19.4 IU/L). Garlic treated experimental animal (300 µg/kg bw) decreased CK-MB level. To conclude, the aqueous extract of A. sativumshowed cardio protective properties against myocardial injury.

Neuroprotective Natural Products for Alzheimer's Disease

Alzheimer's disease (AD) is the number one neurovegetative disease, but its treatment options are relatively few and ineffective. In efforts to discover new strategies for AD therapy, natural products have aroused interest in the research community and in the pharmaceutical industry for their neuroprotective activity, targeting different pathological mechanisms associated with AD. A wide variety of natural products from different origins have been evaluated preclinically and clinically for their neuroprotective mechanisms in preventing and attenuating the multifactorial pathologies of AD. This review mainly focuses on the possible neuroprotective mechanisms from natural products that may be beneficial in AD treatment and the natural product mixtures or extracts from different sources that have demonstrated neuroprotective activity in preclinical and/or clinical studies. It is believed that natural product mixtures or extracts containing multiple bioactive compounds that can work additively or synergistically to exhibit multiple neuroprotective mechanisms might be an effective approach in AD drug discovery.

Effects of Thai Local Ingredient Odorants, Litsea cubeba and Garlic Essential Oils, on Brainwaves and Moods

The functional food market is growing with a compound annual growth rate of 7.9%. Thai food recipes use several kinds of herbs. Lemongrass, garlic, and turmeric are ingredients used in Thai curry paste. Essential oils released in the preparation step create the flavor and fragrance of the famous tom yum and massaman dishes. While the biological activities of these ingredients have been investigated, including the antioxidant, anti-inflammatory, and antimicrobial activities, there is still a lack of understanding regarding the responses to the essential oils of these plants. To investigate the effects of essential oil inhalation on the brain and mood responses, electroencephalography was carried out during the non-task resting state, and self-assessment of the mood state was performed. The essential oils were prepared in several dilutions in the range of the supra-threshold level. The results show that Litsea cubeba oil inhalation showed a sedative effect, observed from alpha and beta wave power reductions. The frontal and temporal regions of the brain were involved in the wave alterations. Garlic oil increased the alpha wave power at lower concentrations; however, a sedative effect was also observed at higher concentrations. Lower dilution oil induced changes in the fast alpha activity in the frontal region. The alpha and beta wave powers were decreased with higher dilution oils, particularly in the temporal, parietal, and occipital regions. Both Litsea cubeba and turmeric oils resulted in better positive moods than garlic oil. Garlic oil caused more negative moods than the others. The psychophysiological activities and the related brain functions require further investigation. The knowledge obtained from this study may be used to design functional food products.

Therapeutic potential of Allium Sativum against the Aβ(1-40)-induced oxidative stress and mitochondrial dysfunction in the Wistar rats

From the early stages of any neurodegenerative-disease mitochondrial functionality has been mortally extricated, though the exact timeline of these events is still unclear, it is likely to represent a progressive neurons-decline and cognitive-functions. Hence strategies suggested by herbal extract to restore mitochondrial functions may be a remedial approach to chronic neurodegenerative disorder like Alzheimer's disease (AD). This research was designed to evaluate if Aβ1-40 induced oxidative stress and mitochondrial dysfunction could be inhibited by Allium Sativum (AS) supplementation. AD was induced by a single intra-hippocampal injection of Aβ1-40 (5 μg/4 μl), while herbal supplementation was given orally (100, 250, 500 mg/kg body weight, daily) for 3 weeks. Morris water maze was used to assess cognitive function shows deficits in Aβ1-40 treated animals, there is no significant alteration in locomotor function as examined by actophotometer. This was accompanied by enhancement in oxidative stress indicating by accentuated ROS and protein carbonyl levels. Concomitantly, decrease in activity of antioxidant enzymes was observed in diseased animals; as expressed by reduced superoxide-dismutase and catalase activity, as well as reduction in GSH levels and impaired mitochondrial functions. Medium dose of AS has been found effective in restoring the memory impairment along with antioxidant levels but high dose is more efficient as observed in the Aβ1-40 treated rats. High dose of AS, on the other hand significantly ameliorates the mitochondrial-dysfunction in comparison to medium dose. Taken together, the findings reveal that AS reverses Aβ1-40 induced brain alteration, it could be an efficient clinical mitigation action against AD growth.

Wasef L, Elewa YHA, A. Al-Sagan A, Abd El-Hack ME, Taha AE, M. Abd-Elhakim Y, Prasad Devkota H. Chemical Constituents and Pharmacological Activities of Garlic (Allium sativum L.): A Review

Medicinal plants have been used from ancient times for human healthcare as in the form of traditional medicines, spices, and other food components. Garlic (Allium sativum L.) is an aromatic herbaceous plant that is consumed worldwide as food and traditional remedy for various diseases. It has been reported to possess several biological properties including anticarcinogenic, antioxidant, antidiabetic, renoprotective, anti-atherosclerotic, antibacterial, antifungal, and antihypertensive activities in traditional medicines. A. sativum is rich in several sulfur-containing phytoconstituents such as alliin, allicin, ajoenes, vinyldithiins, and flavonoids such as quercetin. Extracts and isolated compounds of A. sativum have been evaluated for various biological activities including antibacterial, antiviral, antifungal, antiprotozoal, antioxidant, anti-inflammatory, and anticancer activities among others. This review examines the phytochemical composition, pharmacokinetics, and pharmacological activities of A. sativum extracts as well as its main active constituent, allicin.

Bioactive components from garlic on brain resiliency against neuroinflammation and neurodegeneration

Garlic (Allium sativum) has been widely used for culinary and medicinal purposes. Aged garlic extract (AGE) and sulfur-containing compounds, including S-allylcysteine (SAC) are well documented botanical active components of garlic. AGE is prepared by the prolonged extraction of fresh garlic with aqueous ethanol and is considered a nutritional supplement with potential to promote human health. SAC is a water-soluble organosulfur compound and the most abundant component of AGE. Studies have demonstrated that both AGE and SAC can exert neuroprotective effects against neuroinflammation and neurodegeneration. Another bioactive component in AGE is N-α-(1-deoxy-D-fructos-1-yl)-L-arginine (FruArg) although less is known about the metabolic activity of this compound. The main aim of this review was to provide an undated overview of the neuroprotective perspectives of these active garlic components (AGE, SAC and FruArg). Of interest, our studies and those of others indicate that both AGE and FruArg are involved in the regulation of gene transcription and protein expression. AGE has been shown to reverse 67% of the transcriptome alteration induced by endotoxins-lipopolysaccharide (LPS), and FruArg has been shown to account for the protective effects by reversing 55% of genes altered in a cell-based neuroinflammation paradigm stimulated by LPS in murine BV-2 microglial cells. AGE and FruArg can alleviate neuroinflammatory responses through a variety of signaling pathways, such as Toll-like receptor and interleukin (IL)-6 signaling, as well as by upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated oxidative stress pathways known to promote microglial resiliency against neuroinflammation and neurodegeneration. The capability of FruArg to pass through the blood-brain barrier further supports its potential as a therapeutic compound. In summary, these experimental results provide new insight into the understanding of the neuroprotective effects of garlic components in promoting brain resiliency for health benefits.

Effect of garlic powder on hippocampal long-term potentiation in rats fed high fat diet: an in vivo study

The objective of this study was to determine the relation between the chronic consumption of garlic powder in combination with high-fat diet (HFD) on long term potentiation (LTP) in the dentate gyrus (DG) of rat hippocampus. Male rats were divided to 4 groups, control with the standard diet, control with a standard diet plus garlic, high-fat diet (HFD) group and high-fat diet with garlic. Following 6 months of controlled dietary in each experimental group, the rats were anesthetized with i.p. injection of ketamine and xylazin (100 and 2.5 mg/kg, respectively), and placed into a stereotaxic apparatus for surgery, electrode implantation and field potential recording. The population spike (PS) amplitude and slope of excitatory post synaptic potentials (EPSP) were measured in the DG area of adult rats in response to stimulation applied to the perforant path (PP) (by 400 Hz tetanization). The results showed that garlic increased EPSP slope and PS amplitude respect to HFD group. It was suggested that the garlic powder administration could attenuate the deteriorating effect of HFD on in vivo hippocampal LTP in the granular cells of the DG.

A New Hope for a Devastating Disease: Hydrogen Sulfide in Parkinson's Disease

Hydrogen sulfide (H₂S) has been regarded as the third gaseous transmitter alongside nitric oxide (NO) and carbon monoxide (CO). In mammalian brain, H₂S is produced redundantly by four enzymatic pathways, implying its abundance in the organ. In physiological conditions, H₂S has been found to induce the formation of long-term potential in neuronal cells by augmenting the activity of N-methyl-D-aspartate (NMDA) receptor. Likewise, it also actively takes part in the regulation of intracellular Ca²⁺ and pH homeostasis in both neuronal cells and glia cells. Intriguingly, emerging evidence indicates a connection of H₂S with Parkinson's disease. Specifically, the endogenous H₂S level in the substantia nigra (SN) is significantly reduced along with 6-hydroxydopamine (6-OHDA) treatment in rats, while supplementation of H₂S not only reverses 6-OHDA-induced neuronal loss but also attenuates the following disorders of movement, suggesting a protective effect of H₂S in Parkinson's disease (PD). Remarkably, the protective effect has been extensively demonstrated with various in vitro and in vivo PD models. These suggest that H₂S may be a new hope for the treatment of PD. Further studies have shown that the protective effects can be ascribed to H₂S-mediated anti-oxidation, anti-inflammation, anti-apoptosis, and pro-survival activity, which are also summarized in the review. Moreover, the progresses on the development of H₂S donors are also conveyed with an emphasis on the treatment of PD. Nevertheless, one should bear in mind that the precise role of H₂S in the pathogenesis of PD remains largely elusive. Therefore, more studies are warranted before turning the hope into a real therapy for PD.

Antioxidants and Dementia Risk: Consideration through a Cerebrovascular Perspective

A number of natural and chemical compounds that exert anti-oxidative properties are demonstrated to be beneficial for brain and cognitive function, and some are reported to reduce the risk of dementia. However, the detailed mechanisms by which those anti-oxidative compounds show positive effects on cognition and dementia are still unclear. An emerging body of evidence suggests that the integrity of the cerebrovascular blood-brain barrier (BBB) is centrally involved in the onset and progression of cognitive impairment and dementia. While recent studies revealed that some anti-oxidative agents appear to be protective against the disruption of BBB integrity and structure, few studies considered the neuroprotective effects of antioxidants in the context of cerebrovascular integrity. Therefore, in this review, we examine the mechanistic insights of antioxidants as a pleiotropic agent for cognitive impairment and dementia through a cerebrovascular axis by primarily focusing on the current available data from physiological studies. Conclusively, there is a compelling body of evidence that suggest antioxidants may prevent cognitive decline and dementia by protecting the integrity and function of BBB and, indeed, further studies are needed to directly examine these effects in addition to underlying molecular mechanisms.

Anti-hypertensive Herbs and their Mechanisms of Action: Part I

The use of herbal therapies for treatment and management of cardiovascular diseases (CVDs) is increasing. Plants contain a bounty of phytochemicals that have proven to be protective by reducing the risk of various ailments and diseases. Indeed, accumulating literature provides the scientific evidence and hence reason d'etre for the application of herbal therapy in relation to CVDs. Slowly, but absolutely, herbal remedies are being entrenched into evidence-based medical practice. This is partly due to the supporting clinical trials and epidemiological studies. The rationale for this expanding interest and use of plant based treatments being that a significant proportion of hypertensive patients do not respond to Modern therapeutic medication. Other elements to this equation are the cost of medication, side-effects, accessibility, and availability of drugs. Therefore, we believe it is pertinent to review the literature on the beneficial effects of herbs and their isolated compounds as medication for treatment of hypertension, a prevalent risk factor for CVDs. Our search utilized the PubMed and ScienceDirect databases, and the criterion for inclusion was based on the following keywords and phrases: hypertension, high blood pressure, herbal medicine, complementary and alternative medicine (CAM), nitric oxide, vascular smooth muscle cell (VSMC) proliferation, hydrogen sulfide, nuclear factor kappa-B, oxidative stress, and epigenetics/epigenomics. Each of the aforementioned keywords was co-joined with herb in question, and where possible with its constituent molecule(s). In this first of a two-part review, we provide a brief introduction of hypertension, followed by a discussion of the molecular and cellular mechanisms. We then present and discuss the plants that are most commonly used in the treatment and management of hypertension.

Allium sativum L. Improves Visual Memory and Attention in Healthy Human Volunteers

Studies have shown that Allium sativum L. (AS) protects amyloid-beta peptide-induced apoptosis, prevents oxidative insults to neurons and synapses, and thus prevent Alzheimer's disease progression in experimental animals. However, there is no experimental evidence in human regarding its putative role in memory and cognition. We have studied the effect of AS consumption by healthy human volunteers on visual memory, verbal memory, attention, and executive function in comparison to control subjects taking placebo. The study was conducted over five weeks and twenty volunteers of both genders were recruited and divided randomly into two groups: A (AS) and B (placebo). Both groups participated in the 6 computerized neuropsychological tests of the Cambridge Neuropsychological Test Automated Battery (CANTAB) twice: at the beginning and after five weeks of the study. We found statistically significant difference (p < 0.05) in several parameters of visual memory and attention due to AS ingestion. We also found statistically nonsignificant (p > 0.05) beneficial effects on verbal memory and executive function within a short period of time among the volunteers. Study for a longer period of time with patients suffering from neurodegenerative diseases might yield more relevant results regarding the potential therapeutic role of AS.

Diallyl trisufide protects against oxygen glucose deprivation -induced apoptosis by scavenging free radicals via the PI3K/Akt -mediated Nrf2/HO-1 signaling pathway in B35 neural cells

Oxidative stress contributes to development of ischemic brain damage. Many antioxidants have been proven effective in ameliorating cerebral ischemia injury by inhibiting oxidative stress. DATS, an organosulfuric component of garlic oil, exhibits antioxidative effects. In present study, we used OGD model to investigate the neuroprotective effects of DATS and the mechanisms related to these effects. B35 neural cells exposed to OGD caused a decrease in cell viability and increases in the percentage of apoptotic cells and the level of intracellular cleaved caspase-3, all of which were markedly attenuated by DATS. Further, DATS treatment significantly increased Nrf2 expression and nuclear translocation, upregulated downstream gene HO-1 and inhibited intracellular ROS and MDA generation, all of which were markedly attenuated in cells transfected with Nrf2-specific siRNA. In addition, inhibition of PI3K/Akt signaling by PI3K-specific siRNA not only decreased the expression level of Nrf2 and HO-1 proteins, but also diminished the antioxidative and neuroprotective effect of DATS. Taken together, these results indicate that DATS protects B35 neural cells against OGD-induced cell injury by inhibiting ROS production via upregulating the PI3K/Akt-mediated Nrf2 pathway, which further activates HO-1. Based on our results, DATS may be a potential candidate for intervention in hypoxic-ischemic brain injuries such as stroke.

The antitrichomonal efficacy of garlic and metronidazole against Trichomonas gallinae infecting domestic pigeons

Trichomonas gallinae is the causative agent of canker in pigeon. This work was carried out to investigate in the vitro and in vivo efficacy of aqueous water extract of garlic (AGE) on the growth of T. gallinae infecting pigeons compared to those of metronidazole (MTZ). MTZ and AGE were added, at different concentrations, to glucose-serum broth medium containing 1 × 10(4) trophozoites/ml. In the in vivo experiment, 48 squabs were grouped into four groups. The first group (gr. I) was not infected and not treated. Each squab of the other group was infected with 1 × 10(4) trophozoites. The second group (gr. II) was infected and not treated. On day 0, the third group (gr. III) was treated with MTZ (50 mg/kg BW) and the fourth group (gr. IV) was treated with AGE (200 mg/kg BW) for seven successive days in drinking water. In vitro study revealed that the MLC, 24, 48, and 72 h post treatment were 50, 25, and 12.5 μg/ml, respectively, for MTZ and 75, 50, and 50 mg/ml, respectively, for AGE. Garlic (200 mg/kg BW) had the highest antitrichomonal effect and shortened course of treatment of pigeons from 7 days in gr. III to 5 days. Squabs in gr. II suffered from macrocytic hypochromic anemia, whereas squabs in grs. III and IV showed normal blood pictures. Serum total protein, albumin, and globulin were increased, whereas AST, ALT, and the total cholesterol were decreased in grs. III and IV when compared to those of gr. II. Pigeons protected with AGE showed increased body weight and reduced mortality percentage than the other groups. Our results indicated that garlic may be a promising phytotherapeutic agent for protection against trichomoniasis in pigeons.

Therapeutic uses and pharmacological properties of garlic, shallot, and their biologically active compounds

OBJECTIVE(S)

Garlic (Allium sativum L. family Liliaceae) is well known in Iran and its leaves, flowers, and cloves have been used in traditional medicine for a long time. Research in recent decades has shown widespread pharmacological effects of A. sativum and its organosulfur compounds especially Allicin. Studies carried out on the chemical composition of the plant show that the most important constituents of this plant are organosulfur compounds such as allicin, diallyl disulphide, S-allylcysteine, and diallyl trisulfide. Allicin represents one of the most studied among these naturally occurring compounds. In addition to A. sativum, these compounds are also present in A. hirtifolium (shallot) and have been used to treat various diseases. This article reviews the pharmacological effects and traditional uses of A. sativum, A. hirtifolium, and their active constituents to show whether or not they can be further used as potential natural sources for the development of novel drugs.

MATERIALS AND METHODS

For this purpose, the authors went through a vast number of sources and articles and all needed data was gathered. The findings were reviewed and classified on the basis of relevance to the topic and a summary of all effects were reported as tables.

CONCLUSION

Garlic and shallots are safe and rich sources of biologically active compounds with low toxicity. Further studies are needed to confirm the safety and quality of the plants to be used by clinicians as therapeutic agents.

Garlic and hepatic coccidiosis: prophylaxis or treatment?

A study was conducted to investigate the protective and therapeutic effects of crude garlic (Allium sativum) against experimental infection with Eimeria stiedae in rabbits. Forty rabbits were divided into four groups of ten rabbits each: a healthy control group (HC); a challenged-garlic-protected group (CGP) which received a daily dose of 0.5 g/kg body weight (bwt) crude garlic for five successive days before challenge with E. stiedae; a challenged-garlic-treated group (CGT) which was treated with a daily dose of 0.5 g/kg bwt crude garlic for five successive days post-challenge; and an infected control group (IC). The challenge dose was 5 x 10(4) sporulated E. stiedae oocysts per rabbit. Mortality rate, body weight gain, feed conversion ratio and faecal oocyst count were evaluated throughout the experiment. At the end of the experiment, all rabbits were killed and histopathological examination was performed. No mortalities were recorded in the HC and CGP groups, whilst mortality was found to be 20% and 40% in the CGT and IC groups, respectively. CGP rabbits had better body weight gain and lower numbers of oocysts than those in the CGT and IC groups. Hepatic lesions were less severe in the CGP group than in the CGT and IC groups. These results showed that oral administration of crude garlic ameliorated the adverse impacts of hepatic coccidiosis on rabbits when used as a prophylactic, but garlic was less effective as a therapeutic.