Chemical and biochemical mechanisms underlying the cardioprotective roles of dietary organopolysulfides

Health Benefits and Future Research of Phytochemicals: A Literature Review

Phytochemicals are nonnutritive substances found in plant foods that contribute significantly to the flavor and color of foods. These substances are usually classified as polyphenols, terpenes, sulfur-containing compounds, nitrogen-containing compounds, and others. Numerous studies over the last decades have demonstrated these substances play an immeasurable role in physiological regulation, health care, and disease prevention through their actions in antioxidation, anti-inflammation, antiaging, antivirus, anticancer, antithrombosis, lipid profile regulation, cardiovascular protection, neuroprotection, immunity regulation, and improvement of metabolic functions. This article reviews the chemistry and biochemistry of phytochemicals, their classification and chemical structure, occurrence and biosynthesis in plants, and biological activities and implications for human health and various diseases. The discussions are focused on the most recent important advances in these phytochemical researches. In addition, some future research directions of phytochemicals are set forth regarding dose-response, their mechanism and targets, interactions with gut microbiota, and impact on human health and different stages of chronic diseases.

Harnessing the nutraceutical and therapeutic potential of Allium spp.: current insights and future directions

Apart from the culinary usage, Alliums are known for their therapeutic potential since antiquity. Alliums contain diverse bioactive compounds such as, sulfur-containing compounds (allicin, diallyl sulfides), flavonoids, and saponins. These compounds have demonstrated a wide range of pharmacological actions, including antioxidant, anticancer, anti-inflammatory, antimicrobial, neuroprotective, cardioprotective activities and treatment of metabolic disorders such as diabetes and hyperlipidemia. Despite encouraging preclinical results, translating these findings into clinical practice remains difficult, necessitating more rigorous human trials and molecular research. One of the major constrain in enhancing the therapeutic efficacy of these bioactive compound is to develop large-scale extraction techniques besides improving their stability, solubility, and bioavailability. The current scenario urges to focus research on optimizing the bioavailability of these compounds, evaluate their synergistic effects with existing therapies, as well as their long-term safety. This perspective article provides a comprehensive overview of the therapeutic potential of Allium spp. and suggests the key avenues for future research aiming at realising their full clinical potential.

Garlic bioactive substances and their therapeutic applications for improving human health: a comprehensive review

Garlic (Allium sativum L.) is a widely abundant spice, known for its aroma and pungent flavor. It contains several bioactive compounds and offers a wide range of health benefits to humans, including those pertaining to nutrition, physiology, and medicine. Therefore, garlic is considered as one of the most effective disease-preventive diets. Many in vitro and in vivo studies have reported the sulfur-containing compounds, allicin and ajoene, for their effective anticancer, anti-diabetic, anti-inflammatory, antioxidant, antimicrobial, immune-boosting, and cardioprotective properties. As a rich natural source of bioactive compounds, including polysaccharides, saponins, tannins, linalool, geraniol, phellandrene, β-phellandrene, ajoene, alliin, S-allyl-mercapto cysteine, and β-phellandrene, garlic has many therapeutic applications and may play a role in drug development against various human diseases. In the current review, garlic and its major bioactive components along with their biological function and mechanisms of action for their role in disease prevention and therapy are discussed.

Dental restorative materials and halitosis: a preliminaryin-vitrostudy

Despite the widespread use of dental restorative materials, little information exists in the literature regarding their potential impact on bad breath. This in vitro study aims to fill this gap by investigating the influence of different restorative materials on the release of hydrogen sulfide (H2S). Thirteen diverse dental restorative materials, including composites, flowable composites, glass ionomer restorative materials, high-copper amalgam, and CAD-CAM blocks, were examined. Cellulose Sponge models were used as negative and positive control. All samples were prepared with a diameter of 5 mm and a height of 2 mm. Except for the negative control group, all samples were embedded into Allium cepa L., and the emitted H2S was measured using the Wintact W8802 hydrogen sulfide monitor. Surface roughness's effect on emission was explored by roughening the surfaces of CAD-CAM material samples, and gas emission was measured again. The data were statistically analyzed using the Kruskal-Wallis test and DSCF pairwise comparison tests. Fiber-reinforced flowable composite (EverX Flow), amalgam (Nova 70-caps), and certain composite materials (IPS Empress Direct, Tetric Evoceram, Admira Fusion X-tra) released higher H2S concentrations compared to the negative control. The H2S release period lasted longer in the same materials mentioned above, along with G-aenial Universal Injectable. Indirectly used materials, such as GC Cerasmart, Vita Enamic, and Vita YZ HT, demonstrated significantly lower emissions compared to other direct restoratives. Importantly, the surface roughness of indirect materials did not significantly affect peak H2S concentrations or release times. The study reveals variations in H2S release among restorative materials, suggesting potential advantages of indirect restorative materials in reducing H2S-induced halitosis. This comprehensive understanding of the relationship between restorative materials and halitosis can empower both dental professionals and patients to make well-informed treatment choices. Notably, there is evidence supporting the enhanced performance of indirect restorative materials for individuals affected by halitosis.

Nutrient Combinations Sensed by L-Cell Receptors Potentiate GLP-1 Secretion

Obesity is a risk factor for cardiometabolic diseases. Nutrients stimulate GLP-1 release; however, GLP-1 has a short half-life (<2 min), and only <10-15% reaches the systemic circulation. Human L-cells are localized in the distal ileum and colon, while most nutrients are absorbed in the proximal intestine. We hypothesized that combinations of amino acids and fatty acids potentiate GLP-1 release via different L-cell receptors. GLP-1 secretion was studied in the mouse enteroendocrine STC-1 cells. Cells were pre-incubated with buffer for 1 h and treated with nutrients: alpha-linolenic acid (αLA), phenylalanine (Phe), tryptophan (Trp), and their combinations αLA+Phe and αLA+Trp with dipeptidyl peptidase-4 (DPP4) inhibitor. After 1 h GLP-1 in supernatants was measured and cell lysates taken for qPCR. αLA (12.5 µM) significantly stimulated GLP-1 secretion compared with the control. Phe (6.25-25 mM) and Trp (2.5-10 mM) showed a clear dose response for GLP-1 secretion. The combination of αLA (6.25 µM) and either Phe (12.5 mM) or Trp (5 mM) significantly increased GLP-1 secretion compared with αLA, Phe, or Trp individually. The combination of αLA and Trp upregulated GPR120 expression and potentiated GLP-1 secretion. These nutrient combinations could be used in sustained-delivery formulations to the colon to prolong GLP-1 release for diminishing appetite and preventing obesity.

Untargeted polysulfide omics analysis of alternations in polysulfide production during the germination of broccoli sprouts

Higher consumption of broccoli (Brassica oleracea var. italica) is associated with a reduced risk of cardiometabolic diseases, neurological disorders, diabetes, and cancer. Broccoli is rich in various phytochemicals, including glucosinolates, and isothiocyanates. Moreover, it has recently reported the endogenous production of polysulfides, such as cysteine hydropersulfide (CysS2H) and glutathione hydropersulfide (GS2H), in mammals including humans, and that these bioactive substances function as potent antioxidants and important regulators of redox signaling in vivo. However, few studies have focused on the endogenous polysulfide content of broccoli and the impact of germination on the polysulfide content and composition in broccoli. In this study, we investigated the alternations in polysulfide biosynthesis in broccoli during germination by performing untargeted polysulfide omics analysis and quantitative targeted polysulfide metabolomics through liquid chromatography-electrospray ionization-tandem mass spectrometry. We also performed 2,2-diphenyl-1-picrylhydrazyl radical-scavenging assay to determine the antioxidant properties of the polysulfides. The results revealed that the total polysulfide content of broccoli sprouts significantly increased during germination and growth; CysS2H and cysteine hydrotrisulfide were the predominant organic polysulfide metabolites. Furthermore, we determined that novel sulforaphane (SFN) derivatives conjugated with CysS2H and GS2H were endogenously produced in the broccoli sprouts, and the novel SFN conjugated with CysS2H exhibited a greater radical scavenging capacity than SFN and cysteine. These results suggest that the abundance of polysulfides in broccoli sprouts contribute to their health-promoting properties. Our findings have important biological implications for the development of novel pharmacological targets for the health-promoting effects of broccoli sprouts in humans.

Functional Perspective of Leeks: Active Components, Health Benefits and Action Mechanisms

Leek (Allium fistulosum L.), a common and widely used food ingredient, is a traditional medicine used in Asia to treat a variety of diseases. Leeks contain a variety of bioactive substances, including sulfur compounds, dietary fiber, steroid compounds and flavonoid compounds. Many studies have shown that these active ingredients produce the following effects: promotion of blood circulation, lowering of cholesterol, relief of fatigue, anti-inflammation, anti-bacteria, regulation of cell metabolism, anti-cancer, anti-oxidation, and the lowering of fat and blood sugar levels. In this paper, the main bioactive components and biological functions of leeks were systemically reviewed, and the action mechanisms of bioactive components were discussed. As a common food, the health benefits of leeks are not well known, and there is no systematic summary of leek investigations. In light of this, it is valuable to review the recent progress and provide reference to investigators in the field, which will promote future applications and investigations of leeks.

Anti-Leishmania amazonensis Activity, Cytotoxic Features, and Chemical Profile of Allium sativum (Garlic) Essential Oil

Human tegumentary leishmaniasis (HTL) is a serious tropical disease caused by Leishmania amazonensis. Developing new leishmanicidal agents can help overcome current treatment challenges, such as drug resistance and toxicity. Essential oils are a source of lipophilic substances with diverse therapeutic properties. This study aimed to determine the anti-L. amazonensis activity, cytotoxicity, and chemical profile of Allium sativum essential oil (ASEO). The effect of ASEO on parasite and mammalian cells viability was evaluated using resazurin and MTT assays, respectively. The oil's effect against intracellular amastigotes was also determined. Transmission electron microscopy was used to assess the ultrastructural changes induced by ASEO. In addition, the chemical constituents of ASEO were identified by gas chromatography-mass spectrometry (GC-MS). The cytotoxic potential was evaluated in vitro and in silico. The oil displayed IC₅₀ of 1.76, 3.46, and 3.77 µg/mL against promastigotes, axenic, and intracellular amastigotes, respectively. Photomicrographs of treated parasites showed plasma membrane disruption, increased lipid bodies, and autophagic-like structures. ASEO chemical profiling revealed 1,2,4,6-tetrathiepane (24.84%) and diallyl disulfide (16.75%) as major components. Computational pharmacokinetics and toxicological analysis of ASEO's major components demonstrated good oral bioavailability and better toxicological endpoints than the reference drugs. Altogether, the results suggest that ASEO could be an alternative drug candidate against HTL.

Development of methods for quantitative determination of the total and reactive polysulfides: Reactive polysulfide profiling in vegetables

Alliaceous and cruciferous vegetables are rich in bioactive organosulfur compounds, including polysulfides, which exhibit a broad spectrum of potential health benefits. Here, we developed novel, accurate, and reproducible methods to quantify the total polysulfide content (TPsC) and the reactive polysulfide content (RPsC) using liquid chromatography-electrospray ionization-tandem mass spectrometry, and analyzed the reactive polysulfide profiles of 22 types of fresh vegetables, including onions, garlic, and broccoli. Quantitative analyses revealed that onions contained the largest amounts of polysulfides, followed by broccoli, Chinese chive, and garlic. A strong positive correlation was observed between the TPsC and RPsC, whereas only a moderate positive correlation was found between the total sulfur content and TPsC. These results suggest that reactive polysulfide profiling can be a novel criterion for evaluating the beneficial functions of vegetables and their derivatives, which may lead to an understanding of the detailed mechanisms underlying their bioactivities.

Application of Direct Thermal Desorption-Gas Chromatography-Mass Spectrometry for Determination of Volatile and Semi-Volatile Organosulfur Compounds in Onions: A Novel Analytical Approach

The population is now more aware of their diets due to the connection between food and general health. Onions (Allium cepa L.), common vegetables that are minimally processed and grown locally, are known for their health-promoting properties. The organosulfur compounds present in onions have powerful antioxidant properties and may decrease the likelihood of developing certain disorders. It is vital to employ an optimum approach with the best qualities for studying the target compounds to undertake a thorough analysis of these compounds. In this study, the use of a direct thermal desorption-gas chromatography-mass spectrometry method with a Box-Behnken design and multi-response optimization is proposed. Direct thermal desorption is an environmentally friendly technique that eliminates the use of solvents and requires no prior preparation of the sample. To the author's knowledge, this methodology has not been previously used to study the organosulfur compounds in onions. Likewise, the optimal conditions for pre-extraction and post-analysis of organosulfur compounds were as follows: 46 mg of onion in the tube, a desorption heat of 205 °C for 960 s, and a trap heat of 267 °C for 180 s. The repeatability and intermediate precision of the method were evaluated by conducting 27 tests over three consecutive days. The results obtained for all compounds studied revealed CV values ranging from 1.8% to 9.9%. The major compound reported in onions was 2,4-dimethyl-thiophene, representing 19.4% of the total area of sulfur compounds. The propanethial S-oxide, the principal compound responsible for the tear factor, accounted for 4.5% of the total area.

Beneficial Effect of H2S-Releasing Molecules in an In Vitro Model of Sarcopenia: Relevance of Glucoraphanin

Sarcopenia is a gradual and generalized skeletal muscle (SKM) syndrome, characterized by the impairment of muscle components and functionality. Hydrogen sulfide (H₂S), endogenously formed within the body from the activity of cystathionine-γ-lyase (CSE), cystathionine- β-synthase (CBS), and mercaptopyruvate sulfurtransferase, is involved in SKM function. Here, in an in vitro model of sarcopenia based on damage induced by dexamethasone (DEX, 1 μM, 48 h treatment) in C2C12-derived myotubes, we investigated the protective potential of exogenous and endogenous sources of H₂S, i.e., glucoraphanin (30 μM), L-cysteine (150 μM), and 3-mercaptopyruvate (150 μM). DEX impaired the H₂S signalling in terms of a reduction in CBS and CSE expression and H₂S biosynthesis. Glucoraphanin and 3-mercaptopyruvate but not L-cysteine prevented the apoptotic process induced by DEX. In parallel, the H₂S-releasing molecules reduced the oxidative unbalance evoked by DEX, reducing catalase activity, O₂⁻ levels, and protein carbonylation. Glucoraphanin, 3-mercaptopyruvate, and L-cysteine avoided the changes in myotubes morphology and morphometrics after DEX treatment. In conclusion, in an in vitro model of sarcopenia, an impairment in CBS/CSE/H₂S signalling occurs, whereas glucoraphanin, a natural H₂S-releasing molecule, appears more effective for preventing the SKM damage. Therefore, glucoraphanin supplementation could be an innovative therapeutic approach in the management of sarcopenia.

Dietary Organosulfur-Containing Compounds and Their Health-Promotion Mechanisms

Dietary organosulfur-containing compounds (DOSCs) in fruits, vegetables, and edible mushrooms may hold the key to the health-promotion benefits of these foods. Yet their action mechanisms are not clear, partially due to their high reactivity, which leads to the formation of complex compounds during postharvest processing. Among postharvest processing methods, thermal treatment is the most common way to process these edible plants rich in DOSCs, which undergo complex degradation pathways with the generation of numerous derivatives over a short time. At low temperatures, DOSCs are biotransformed slowly during fermentation to different metabolites (e.g., thiols, sulfides, peptides), whose distinctive biological activity remains largely unexplored. In this review, we discuss the bioavailability of DOSCs in human digestion before illustrating their potential mechanisms for health promotion related to cardiovascular health, cancer chemoprevention, and anti-inflammatory and antimicrobial activities. In particular, it is interesting that different DOSCs react with glutathione or cysteine, leading to the slow release of hydrogen sulfide (H2S), which has broad bioactivity in chronic disease prevention. In addition, DOSCs may interact with protein thiol groups of different protein targets of importance related to inflammation and phase II enzyme upregulation, among other action pathways critical for health promotion.

Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The aroma profile and aroma-active compounds of Brassica oleracea (kale) tea

This study was to understand characteristic aroma properties of kale tea made by roasting kale leaves by profiling its aroma composition and screening its aroma-active compounds. Secondary metabolites of glucosinolates such as ally isothiocyanate, 3-butenyl isothiocyanate, 3-methylthiopropyl isothiocyanate, and 5-methylthiazole were the primary aroma compounds of raw kale but were less abundant in kale tea. Dimethyl trisulfide, cyclohex-2-en-1-ol, benzeneacetaldehyde, and 4-vinylguaiacol were quantitatively major aroma compounds in kale tea. Pyrazines, aldehydes, sulfides, and 4-vinylguaiacol were newly produced only in kale tea. In particular, 2-ethyl-6-methylpyrazine exhibiting the highest flavor dilution factor was the most potent aroma-active compound of kale tea, followed by methional, 2-ethyl-5-methylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, two unknown compounds, dimethyl disulfide, furfural, benzaldehyde, and dimethyl trisulfide. These compounds contributed to roasted, sulfur-like/pungent, and sweet aroma characteristics, which were main aroma properties of kale tea. In addition, (E)-hex-2-enal and (Z)-hex-3-en-1-ol contributed to the green and grassy aromas of kale tea.

Diet and Hydrogen Sulfide Production in Mammals

Significance: In recent times, it has emerged that some dietary sulfur compounds can act on mammalian cell signaling systems via their propensity to release hydrogen sulfide (H₂S). H₂S plays important biochemical and physiological roles in the heart, gastrointestinal tract, brain, kidney, and immune systems of mammals. Reduced levels of H₂S in cells and tissues correlate with a spectrum of pathophysiological conditions, including heart disease, diabetes, obesity, and altered immune function. Recent Advances: In the last decade, researchers have now begun to explore the mechanisms by which dietary-derived sulfur compounds, in addition to cysteine, can act as sources of H₂S. This research has led to the identified several compounds, organic sulfides, isothiocyanates, and inorganic sulfur species including sulfate that can act as potential sources of H₂S in mammalian cells and tissues. Critical Issues: We have summarised progress made in the identification of dietary factors that can impact on endogenous H₂S levels in mammals. We also describe current research focused on how some sulfur molecules present in dietary plants, and associated chemical analogues, act as sources of H₂S, and discuss the biological properties of these molecules as studied in a range of in vitro and in vivo systems. Future Directions: The identification of sulfur compounds in edible plants that can act as novel H₂S releasing molecules is intriguing. Research in this area could inform future studies exploring the impact of diet on H₂S levels in mammalian systems. Despite recent progress, additional work is needed to determine the mechanisms by which H₂S is released from these molecules following ingestions of dietary plants in humans, whether the amounts of H₂S produced is of physiological significance following the metabolism of these compounds in vivo, and if diet could be used to manipulated H₂S levels in humans. Importantly, this will lead to a better understanding of the biological significance of H₂S generated from dietary sources, and this information could be used in the development of plant breeding initiatives to increase the levels of H₂S releasing sulfur compounds in crops, or inform dietary intervention strategies that could be used to alter the levels of H₂S in humans.

Supercritical Carbon Dioxide Extraction of Allium ursinum: Impact of Temperature and Pressure on the Extracts Chemical Profile

The aim of this study was to extract Allium ursinum L. for the first time by supercritical carbon dioxide (SC-CO₂ ) as green sustainable method. The impact of temperature in the range from 40 to 60 °C and pressure between 150 and 400 bar on the quality of the obtained extracts and efficiency of the extraction was investigated. The highest extraction yield (3.43 %) was achieved by applying the extraction conditions of 400 bar and 60 °C. The analysis of the extracts was performed by gas chromatography and mass spectrometry (GC/MS). The most dominant sulfur-containing constituent of the extracts was allyl methyl trisulfide with the highest abundance at 350 bar and 50 °C. In addition, the presence of other pharmacologically potent sulfur compounds was recorded including S-methyl methanethiosulfinate, diallyl trisulfide, S-methyl methylthiosulfonate, and dimethyl trisulfide. Multivariate data analysis tool was utilized to investigate distributions of the identified compounds among the extracts obtained under various extraction conditions and yields. It was determined that the SC-CO₂ extraction can by efficiently used for A. ursinum.

Herbal Medicine from Single Clove Garlic Oil Extract Ameliorates Hepatic Steatosis and Oxidative Status in High Fat Diet Mice

Introduction

High fat diet (HFD) can cause lipid accumulation and contribute to various metabolic disorders. Single clove garlic oil (SCGO) has advantages over regular garlic due to its higher amounts of organosulfide compounds in particular. This study aimed to determine the ability of SCGO extract to ameliorate hepatic steatosis and improve oxidative status by modulating expression of tumour necrosis factor α and superoxide dismutase in mice fed a HFD.

Methods

Twenty-four adult male Balb/C mice were divided into six groups: i) normal diet; ii) positive control diet; iii) negative control diet; and iv) HFD with SCGO at 12.5 mg/kg body weight (mg/kg BW); v) HFD with SCGO at 25 mg/kg BW, vi) HFD with SCGO at 50 mg/kg BW. Liver weight and morphology, spleen weight, serum levels of superoxide dismutase (SOD) and tumour necrosis factor α (TNF-α), TNF-α expression in the aorta and lipid profiles were assessed at the end of the experimental period.

Results

SCGO treatment was associated with significant decreases in liver and spleen weight as well as amelioration of hepatic steatosis. SCGO treatment also decreased TNF-α levels and expression. Serum levels of SOD in the SCGO groups were significantly increased compared with the negative control group. Lipid profiles were improved in the SCGO treatment groups compared with the negative control group.

Conclusion

SCGO as an herbal medicine could be an effective treatment for degenerative disorders caused by HFD.

An Appraisal of Developments in Allium Sulfur Chemistry: Expanding the Pharmacopeia of Garlic

Alliums and allied plant species are rich sources of sulfur compounds that have effects on vascular homeostasis and the control of metabolic systems linked to nutrient metabolism in mammals. In view of the multiple biological effects ascribed to these sulfur molecules, researchers are now using these compounds as inspiration for the synthesis and development of novel sulfur-based therapeutics. This research has led to the chemical synthesis and biological assessment of a diverse array of sulfur compounds representative of derivatives of S-alkenyl-l-cysteine sulfoxides, thiosulfinates, ajoene molecules, sulfides, and S-allylcysteine. Many of these synthetic derivatives have potent antimicrobial and anticancer properties when tested in preclinical models of disease. Therefore, the current review provides an overview of advances in the development and biological assessment of synthetic analogs of allium-derived sulfur compounds.

Effects of heat and shallot (Allium ascalonicum L.) supplementation on nutritional quality and enzymatic browning of apple juice

This study investigated the effects of shallot (Allium ascalonicum L.) supplementation on improved nutritional quality and browning index of apple juice, specifically by comparing between heated (96 °C, 30 min) and unheated apple juice. The results showed that total soluble solid, phenolic content, flavonoid content, as well as antioxidant activities of heated and unheated apple juice, significantly (p < 0.05) increased with the increase in shallot supplementation (0.5%, 1.0%, 1.5%, and 2.0%). The outcomes indicated that the nutritional parameters values for heated apple juice supplemented with shallot were greater than those of unheated apple juice. The unheated and heated apple juice supplemented with shallot showed inhibition of browning, while shallot supplementation exhibited higher functionality upon being heated. The heated apple juice appeared to be an efficient way to reduce browning and to increase antioxidant activities, irrespective of shallot supplementation. Shallot supplementation inhibited browning and improved the nutritional quality of unheated apple juice. These results proved that heated apple juice supplemented with shallot exhibited maximum inhibition of browning and increased nutritional quality. Therefore, heating and shallot supplementation can massively improve the quality of apple juice.

Nutraceutical Insight into Vegetables and their Potential for Nutrition Mediated Healthcare

Background:

The connection between food and good health is not a new concept. Vegetables are being used as a source of nutrition since long. Dietary active components are essential for the normal functioning of the human body.

Methods:

The study basically involves all the three categories of research methodologies, including analytic, descriptive and historical. It involves secondary data from scientific reports, books, and journals.

Results:

Vegetables can be considered as nutraceuticals since they supply bioactive compounds effective in decreasing the risk of many diseases. Vegetables are considered to be protective foods since they contain low calories and higher vitamins and minerals. Vegetables are potentially suitable against civilization diseases, which are caused by the lack of nutrients such as omega-3 fatty acids, antioxidants (vitamin E, vitamin C, β-carotene, selenium, zinc, cryptoxanthin, lycopene etc), and other micronutrients.

Conclusion:

The presence of bioactive compounds like phytochemicals offers nutraceutical values to vegetables. Nutraceutical rich vegetables have been established to have a role in gastrointestinal disorders, cardiovascular diseases, cancer, diabetes and other diseases. Vegetables and fruits not only have the potential to stop the growth of disease but also can cure many diseases and boost the immune system.

Therapeutic Role of Functional Components in Alliums for Preventive Chronic Disease in Human Being

Objectives. Functional components in alliums have long been maintained to play a key role in modifying the major risk factors for chronic disease. To obtain a better understanding of alliums for chronic disease prevention, we conducted a systematic review for risk factors and prevention strategies for chronic disease of functional components in alliums, based on a comprehensive English literature search that was conducted using various electronic search databases, especially the PubMed, ISI Web of Science, and CNKI for the period 2007-2016. Allium genus especially garlic, onion, and Chinese chive is rich in organosulfur compounds, quercetin, flavonoids, saponins, and others, which have anticancer, preventive cardiovascular and heart diseases, anti-inflammation, antiobesity, antidiabetes, antioxidants, antimicrobial activity, neuroprotective and immunological effects, and so on. These results support Allium genus; garlic and onion especially may be the promising dietotherapeutic vegetables and organopolysulfides as well as quercetin mechanism in the treatment of chronic diseases. This review may be used as scientific basis for the development of functional food, nutraceuticals, and alternative drugs to improve the chronic diseases.

H2S biosynthesis and catabolism: new insights from molecular studies

Hydrogen sulfide (H₂S) has profound biological effects within living organisms and is now increasingly being considered alongside other gaseous signalling molecules, such as nitric oxide (NO) and carbon monoxide (CO). Conventional use of pharmacological and molecular approaches has spawned a rapidly growing research field that has identified H₂S as playing a functional role in cell-signalling and post-translational modifications. Recently, a number of laboratories have reported the use of siRNA methodologies and genetic mouse models to mimic the loss of function of genes involved in the biosynthesis and degradation of H₂S within tissues. Studies utilising these systems are revealing new insights into the biology of H₂S within the cardiovascular system, inflammatory disease, and in cell signalling. In light of this work, the current review will describe recent advances in H₂S research made possible by the use of molecular approaches and genetic mouse models with perturbed capacities to generate or detoxify physiological levels of H₂S gas within tissues.

Garlic oil polysulfides: H2S- and O2-independent prooxidants in buffer and antioxidants in cells

The health benefits of garlic and other organosulfur-containing foods are well recognized and have been attributed to both prooxidant and antioxidant activities. The effects of garlic are surprisingly similar to those of hydrogen sulfide (H2S), which is also known to be released from garlic under certain conditions. However, recent evidence suggests that polysulfides, not H2S, may be the actual mediator of physiological signaling. In this study, we monitored formation of H2S and polysulfides from garlic oil in buffer and in human embryonic kidney (HEK) 293 cells with fluorescent dyes, 7-azido-4-methylcoumarin and SSP4, respectively and redox activity with two redox indicators redox-sensitive green fluorescent protein (roGFP) and DCF. Our results show that H2S release from garlic oil in buffer requires other low-molecular-weight thiols, such as cysteine (Cys) or glutathione (GSH), whereas polysulfides are readily detected in garlic oil alone. Administration of garlic oil to cells rapidly increases intracellular polysulfide but has minimal effects on H2S unless Cys or GSH are also present in the extracellular medium. We also observed that garlic oil and diallyltrisulfide (DATS) potently oxidized roGFP in buffer but did not affect DCF. This appears to be a direct polysulfide-mediated oxidation that does not require a reactive oxygen species intermediate. Conversely, when applied to cells, garlic oil became a significant intracellular reductant independent of extracellular Cys or GSH. This suggests that intracellular metabolism and further processing of the sulfur moieties are necessary to confer antioxidant properties to garlic oil in vivo.

Enamel surface changes caused by hydrogen sulfide

BACKGROUND

Volatile sulfur compounds (VSCs) produced inside the mouth are a well-known cause of halitosis. Recent studies have suggested that VSCs modify the pathology of periodontitis by encouraging the migration of bacterial toxins associated with increased permeability of gingival epithelia, and enhancing the production of matrix metalloproteinases in gingival connective tissue. Nonetheless, the effects on the enamel of direct exposure to VSCs within the oral cavity remain unclear. In the present study, we observed the effects of VSCs in the form of hydrogen sulfide (H2S) on enamel surfaces and determined their effects on restorations.

MATERIALS AND METHODS

Extracted human tooth and bovine tooth samples were divided into the H2S experimental side and the control side. We observed the effects of H2S on enamel surfaces using electron microscopy and conducted a shear test.

RESULTS

We found that exposure to H2S obscured the enamel surface's crystal structure. The surface also exhibited coarseness and reticular changes. Shear testing did not reveal any differences in bond strength.

CONCLUSIONS

Our findings suggested that H2S occurring inside the mouth causes changes to the crystal structure of the enamel surface that can lead to tooth wear, but that it does not diminish the effects of dental bonding in adhesive restorations.