In vitro Prebiotic Properties of Garlic Polysaccharides and Its Oligosaccharide Mixtures Obtained by Acid Hydrolysis

Evaluation of Prebiotic and Health-Promoting Functions of Honeybee Brood Biopeptides and Their Maillard Reaction Conjugates

This study addresses the growing interest in natural functional ingredients by evaluating the prebiotic and health-promoting functions of honeybee brood biopeptides (HBb-Bps) and their conjugates. The purpose was to investigate their antioxidant activities, enzyme inhibition properties, and effects on probiotic growth and short-chain fatty acid (SCFA) production. The HBb-Bps were conjugated with honey, glucose, and fructose via the Maillard reaction. Antioxidant activities were assessed using DPPH and ABTS assays. The inhibitory effects on amylase, pancreatic lipase, and the angiotensin-converting enzyme (ACE) were measured. Probiotic growth and SCFA production were evaluated using L. plantarum TISTR846, and L. lactis TISTR1464. The HBb-Bps and their conjugates exhibited enhanced antioxidant activities post-Maillard reaction. They showed moderate enzyme inhibition, which decreased after conjugation. However, ACE inhibition increased with conjugation. The HBb-Bps significantly promoted probiotic growth and SCFA production, with further enhancement by the Maillard reaction. Overall, the HBb-Bps and their conjugates demonstrate significant prebiotic and health-promoting functions, suggesting their potential as natural ingredients in functional foods and nutraceuticals. Further research should focus on the in vivo effects and, given their solubility and stability these biopeptides could be incorporated into functional food formulations, such as health beverages, protein bars, and other fortified foods designed to deliver specific health benefits.

Neokestose suppresses the increase in plasma glucose caused by oral administration of sucrose in a streptozotocin‑induced diabetic rat

Neokestose is considered to have a prebiotic function. However, the physiological activity of neokestose remains unknown. Neokestose has a blastose, a sucrose analog, in its structure. We previously demonstrated that oral administration of blastose to diabetic rats suppressed the increase in plasma glucose (PG) concentration after sucrose administration. Therefore, neokestose might have a similar effect. In this study, we investigated the effects of neokestose on PG concentrations and the mechanism of its action. We first administered neokestose orally to streptozotocin-induced diabetic rats and observed that the expected consequent increase in PG concentration was significantly suppressed. Next, we examined the inhibitory effect of neokestose on glycosidase activity, but observed only a slight inhibitory effect. Therefore, we hypothesized that neokestose might be hydrolyzed by gastric acid to produce blastose. We performed an acid hydrolysis of neokestose using artificial gastric juice. After acid hydrolysis, peaks corresponding to neokestose and its decomposition products including blastose were observed. Therefore, we suggest that neokestose and blastose, a decomposition product, synergistically inhibit glycosidase activity. These findings support the potential use of neokestose as a useful functional oligosaccharide that can help manage plasma glucose concentrations in patients with diabetes mellitus.

Preparation, structural characterization, biological activity, and nutritional applications of oligosaccharides

Oligosaccharides are low-molecular-weight carbohydrates between monosaccharides and polysaccharides. They can be extracted directly from natural products by physicochemical methods or obtained by chemical synthesis or enzymatic reaction. Oligosaccharides have important physicochemical and physiological properties. Their research and production involve many disciplines such as medicine, chemical industry, and biology. Functional oligosaccharides, as an excellent functional food base, can be used as dietary fibrer and prebiotics to enrich the diet; improve the microecology of the gut; exert antitumour, anti-inflammatory, antioxidant, and lipid-lowering properties. Therefore, the industrial applications of oligosaccharides have increased rapidly in the past few years. It has great prospects in the field of food and medicinal chemistry. This review summarized the preparation, structural features and biological activities of oligosaccharides, with particular emphasis on the application of functional oligosaccharides in the food industry and human nutritional health. It aims to inform further research and development of oligosaccharides and food chemistry.

In-vitro screening of compatible synbiotics and (introducing) "prophybiotics" as a tool to improve gut health

Synbiotics have been intensively studied recently to improve gut health of humans and animals. The success of synergistic synbiotics depends on the compatibility of the prebiotic and probiotic components. Certain plant extracts possess both antimicrobial and prebiotic properties representing a potential use in combination with probiotics to improve the gut health. Here, we coined the term "prophybiotics" to describe this combined bioactivity. The current study aimed to select prebiotics that are preferred as an energy source and antimicrobial plant extracts which do not inhibit the growth, of six strains of lactic acid bacteria (LAB namely; Lactiplantibacillus plantarum, Lacticaseibacillus casei, Limosilactobacillus reuteri, Lacticaseibacillus rhamnosus, Leuconostoc mesenteroides, and Pediococcus pentosaceus) in-vitro to identify compatible combinations for potential synbiotic/prophybiotic use, respectively. Their growth kinetics were profiled in the presence of prebiotics: Inulin, Raffinose, and Saccharicterpenin with glucose, as the control, using carbohydrate free MRS broth media. Similarly, their growth kinetics in MRS broth supplemented with turmeric, green tea, and garlic extracts at varying concentrations were profiled. The results revealed the most compatible pairs of prebiotics and LAB. Turmeric and garlic had very little inhibitory effect on the growth of the LAB while green tea inhibited the growth of all LAB in a dose-dependent manner. Therefore, we conclude that turmeric and garlic have broad potential for use in prophybiotics, while the prebiotics studied here have limited use in synbiotics, with these LAB.

Extraction, purification, structural features, modifications, bioactivities, structure-activity relationships, and applications of polysaccharides from garlic: A review

Garlic is a common vegetable and spice in people's daily diets, in which garlic polysaccharide (GP) is one of the most important active components with a variety of benefits, such as antioxidant, immune-enhancing, anti-inflammatory, liver-protective and bowel-regulating properties. >20 types of GPs, mainly crude polysaccharides, have been identified. However, the exact chemical composition of GPs or the mechanism underlying their pharmacological activity is still not fully understood. The extraction and purification methods of GPs are compared in this review while providing detailed information on their structural features, identification methods, major biological activities, mechanisms of actions, structural modifications, structure-activity relationships as well as potential applications. Finally, the limitations of GP research and future issues that need to be addressed are discussed in this review. GPs are widely recognized as substances with great potential in the pharmaceutical and food industries. Therefore, this review aims to provide a comprehensive summary of the latest research progresses in the field of GPs, together with scientific insights and a theoretical support for the development of GPs in research and industrialization.

Prophybiotics for in-ovo stimulation; validation of effects on gut health and production of broiler chickens

Probiotics and phytobiotics have demonstrated effective improvement of gut health in broiler chickens when individually administered in-ovo. However, their combined use in-ovo, has not been studied to date. We coined the term "prophybiotic" (probiotic + phytobiotic) for such a combination. The current study therefore, aimed to elucidate the effects of combined use of a selected probiotic and a phytobiotic in-ovo, on broiler gut health and production parameters, as opposed to use of probiotics alone. ROSS 308 hatching eggs were injected with either Leuconostoc mesenteroides (probiotic: PB) or L. mesenteroides with garlic aqueous extract (prophyiotic: PPB) on the 12th day of incubation. Relative abundances of bacteria in feces and cecal content (qPCR), immune related gene expression in cecal mucosa (qPCR) and histomorphology of cecal tissue (PAS staining) were analyzed along with production parameters (hatch quality, body weight, feed efficiency and slaughter and meat quality). PPB treatment increased the abundance of faecalibacteria and bifidobacteria in feces (d 7) and Akkermansia sp. in cecal content. Moreover, it decreased Escherichia coli abundance in both feces (d 34) and cecal content. PB treatment only increased the faecalibacteria in feces (d 7) and Akkermansia sp. in the cecal content. Moreover, PPB treatment resulted in up-regulation of immune related genes (Avian beta defensing 1, Free fatty acid receptor 2 and Mucin 6) and increased the crypt depth in ceca whereas PB treatment demonstrated a higher crypt depth and a tendency to increase Mucin 6 gene expression. Both treatments did not impair the production parameters studied. In conclusion, our results suggest that in-ovo PPB treatment may have enhanced potential in boosting the immune system without compromising broiler production and efficiency, as compared to the use of probiotic alone. Our study, highlights the potential of carefully selected PPB combinations for better results in improving gut health of broiler chickens.

Integrated Transcriptomics and Metabolomics Analysis of the Fructan Metabolism Response to Low-Temperature Stress in Garlic

As the main reserve carbohydrate in garlic, fructan contributes to garlic's yield and quality formation. Numerous studies have shown that plant fructan metabolism induces a stress response to adverse environments. However, the transcriptional regulation mechanism of garlic fructan in low-temperature environments is still unknown. In this study, the fructan metabolism of garlic seedlings under low-temperature stress was revealed by transcriptome and metabolome approaches. With the extension of stress time, the number of differentially expressed genes and metabolites increased. Using weighted gene co-expression network analysis (WGCNA), three key enzyme genes related to fructan metabolism were screened (a total of 12 transcripts): sucrose: sucrose 1-fructosyltransferase (1-SST) gene; fructan: fructan 6G fructosyltransferase (6G-FFT) gene; and fructan 1-exohydrolase (1-FEH) gene. Finally, two hub genes were obtained, namely Cluster-4573.161559 (6G-FFT) and Cluster-4573.153574 (1-FEH). The correlation network and metabolic heat map analysis between fructan genes and carbohydrate metabolites indicate that the expression of key enzyme genes in fructan metabolism plays a positive promoting role in the fructan response to low temperatures in garlic. The number of genes associated with the key enzyme of fructan metabolism in trehalose 6-phosphate was the highest, and the accumulation of trehalose 6-phosphate content may mainly depend on the key enzyme genes of fructan metabolism rather than the enzyme genes in its own synthesis pathway. This study not only obtained the key genes of fructan metabolism in garlic seedlings responding to low temperatures but also preliminarily analyzed its regulatory mechanism, providing an important theoretical basis for further elucidating the cold resistance mechanism of garlic fructan metabolism.

Simultaneous microwave-assisted extraction of bioactive compounds from aged garlic

In this work, the simultaneous extraction of bioactives (organosulfur compounds, such as S-allyl-L-cysteine (SAC), carbohydrates, such as neokestose and neonystose, and total phenolic compounds) from aged garlic has been optimized for the first time to obtain multifunctional extracts for further application as food ingredients. Analytical methods using liquid chromatography coupled to mass spectrometry (HPLC-MS) and by hydrophilic interaction liquid chromatography with evaporative light scattering detection (HILIC-ELSD) were also previously optimized. High sensitivity (limits of detection between 0.013 and 0.77 µg mL^-1) and appropriate repeatability (< 12%) and accuracy (> 92%) for the analysis of bioactives were achieved. After selecting water as the extraction solvent and microwave-assisted extraction (MAE) as the most efficient technique, operation conditions were optimized using a Box-Behnken experimental design (60 min; 120 °C; 0.05 g mL^-1; 1 cycle) to maximize the content of bioactives from different aged garlic samples. Regarding organosulfur compounds, only SAC (traces-2.32 mg g^-1 dry sample) and cycloalliin (1.23-3.01 mg g^-1 dry sample) were detected in all samples, while amino acids such as arginine (0.24-3.45 mg g^-1 dry sample) and proline (0.43-3.91 mg g^-1 dry sample) were, in general, the most abundant. Bioactive carbohydrates (from trisaccharides to nonasaccharides) were only detected in fresh garlic and aged garlic processed under mild conditions, whereas all garlic extracts showed antioxidant activity. The developed MAE methodology is shown as a successful alternative to other procedures for the simultaneous extraction of aged garlic bioactives intended by the food and nutraceutical industries, among others.

Garlic consumption in relation to colorectal cancer risk and to alterations of blood bacterial DNA

PURPOSE

Garlic consumption has been inversely associated to intestinal adenoma (IA) and colorectal cancer (CRC) risk, although evidence is not consistent. Gut microbiota has been implied in CRC pathogenesis and is also influenced by garlic consumption. We analyzed whether dietary garlic influence CRC risk and bacterial DNA in blood.

METHODS

We conducted a case-control study in Italy involving 100 incident CRC cases, 100 IA and 100 healthy controls matched by center, sex and age. We used a validated food frequency questionnaire to assess dietary habits and garlic consumption. Blood bacterial DNA profile was estimated using qPCR and16S rRNA gene profiling. We derived odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) of IA and CRC according to garlic consumption from multiple conditional logistic regression. We used Mann-Whitney and chi-square tests to evaluate taxa differences in abundance and prevalence.

RESULTS

The OR of CRC for medium/high versus low/null garlic consumption was 0.27 (95% CI = 0.11-0.66). Differences in garlic consumption were found for selected blood bacterial taxa. Medium/high garlic consumption was associated to an increase of Corynebacteriales order, Nocardiaceae family and Rhodococcus genus, and to a decrease of Family XI and Finegoldia genus.

CONCLUSIONS

The study adds data on the protective effect of dietary garlic on CRC risk. Moreover, it supports evidence of a translocation of bacterial material to bloodstream and corroborates the hypothesis of a diet-microbiota axis as a mechanism behind the role of garlic in CRC prevention.

A Review on Garlic as a Supplement for Alzheimer’s Disease: A Mechanistic Insight into its Direct and Indirect Effects

Alzheimer’s disease (AD) is one of the most complicated neurodegenerative diseases causing dementia in human beings. Aside from that, the incidence of AD is increasing and its treatment is very complicated. There are several known hypotheses regarding the pathology of Alzheimer’s disease, including the amyloid beta hypothesis, tau hypothesis, inflammation hypothesis, and cholinergic hypothesis, which are investigated in different researches to completely elucidate the pathology of AD. Besides, some new mechanisms, such as immune, endocrine, and vagus pathways, as well as bacteria metabolite secretions, are being explained as other causes to be somehow related to AD pathogenesis. There is still no definite treatment for Alzheimer’s disease that can completely cure and eradicate AD. Garlic (Allium sativum) is a traditional herb used as a spice in different cultures, and due to the organosulfur compounds, like allicin, it possesses highly anti-oxidant properties; the benefits of garlic in cardiovascular diseases, like hypertension and atherosclerosis, have been examined and reviewed, although its beneficiary effects in neurodegenerative diseases, such as AD, are not completely understood. In this review, we discuss the effects of garlic based on its components, such as allicin and S-allyl cysteine, on Alzheimer’s disease and the mechanisms of garlic components that can be beneficiary for AD patients, including its effects on amyloid beta, oxidative stress, tau protein, gene expression, and cholinesterase enzymes. Based on the literature review, garlic has been revealed to have beneficiary effects on Alzheimer’s disease, especially in animal studies; however, more studies should be done on humans to find the exact mechanisms of garlic’s effects on AD patients.

Anti-Inflammatory and Antioxidant Effects Induced by Allium sativum L. Extracts on an Ex Vivo Experimental Model of Ulcerative Colitis

Inflammatory bowel diseases (IBDs) are chronic and multifactorial inflammatory conditions of the colonic mucosa (ulcerative colitis), characterized by increased and unbalanced immune response to external stimuli. Garlic and its bioactive constituents were reported to exert various biological effects, including anti-inflammatory, antioxidant and immunomodulatory activities. We aimed to evaluate the protective effects of a hydroalcoholic (GHE) and a water (GWE) extract from a Sicilian variety of garlic, known as Nubia red garlic, on an ex vivo experimental model of ulcerative colitis, involving isolated LPS-treated mouse colon specimens. Both extracts were able to counteract LPS-induced cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-α, nuclear factor-kB (NF-kB), and interleukin (IL)-6 gene expression in mouse colon. Moreover, the same extracts inhibited prostaglandin (PG)E₂, 8-iso-PGF_2α, and increased the 5-hydroxyindoleacetic acid/serotonin ratio following treatment with LPS. In particular, GHE showed a better anti-inflammatory profile. The anti-inflammatory and antioxidant effects induced by both extracts could be related, at least partially, to their polyphenolic composition, with particular regards to catechin. Concluding, our results showed that GHE and GWE exhibited protective effects in colon, thus suggesting their potential use in the prevention and management of ulcerative colitis.

Digestive properties and prebiotic activity of garlic saccharides with different-molecular-weight obtained by acidolysis

Garlic saccharides have prebiotic activity, but the association between their function and structure is still poorly known. In present study, four different garlic saccharides were obtained from garlic polysaccharides (GPs) after acidolysis by ultrafiltration. Obtained GPs were constituted by different monosaccharides, among which fructose and glucose were the main components, while galactose was a major component of GPs-U6. All four saccharides were partly degraded by the simulated digestive system, and most could reach the large intestine to be utilized by the gut microbiota. Except for GPs-U6, the other three garlic saccharide fractions had good prebiotic activity in vitro and in vivo. Furthermore, GPs-U0.3 with lower molecular weight (Mw) showed better prebiotic activity, including promoting the production of short-chain fatty acids (SCFAs), increasing the abundance of beneficial bacteria such as Bifidobacterium, Lachnospiraceae NK4A136 group and Phoscolarctobacterium, and inhibiting the growth of potentially harmful bacteria. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway enrichment analysis showed that GPs-U0.3 could reduce the risk of cancer and cardiovascular diseases. Overall, this findings of the present study revealed the digestive properties of GPs, as well as the potential association between their chemical structures and fermentation characteristics by gut microbiota. Thus, it can be stated that GPs-U0.3 can be used as potential prebiotics in functional foods, which provides a theoretical basis for the targeted preparation of functionalized garlic saccharides.

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Four garlic saccharides of different Mw could pass through the digestive system and reach the large intestine safely.

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GPs-U2, GPs-U1 and GPs-U0.3 significantly modulate the composition and abundance of gut microbiota.

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GPs-U2, GPs-U1 and GPs-U0.3 significantly enhance the production of SCFAs.

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GPs-U0.3 exhibit better probiotic activity in vitro and in vivo.

Onion and garlic polysaccharides: A review on extraction, characterization, bioactivity, and modifications

Allium cepa (onion) and Allium sativum (garlic) are important members of the Amaryllidaceae (Alliaceae) family and are being used both as food and medicine for centuries in different parts of the world. Polysaccharides have been extracted from different parts of onion and garlic such as bulb, straw and cell wall. The current literature portrays several studies on the extraction of polysaccharides from onion and garlic, their modification and determination of their structural (molecular weight, monosaccharide unit and their arrangement, type and position of glycosidic bond or linkage, degree of polymerization, chain conformation) and functional properties (emulsifying property, moisture retention, hygroscopicity, thermal stability, foaming ability, fat-binding capacity). In this line, this review, summarizes the various extraction techniques used for polysaccharides from onion and garlic, involving methods like solvent extraction method. Furthermore, the antioxidant, antitumor, anticancer, immunomodulatory, antimicrobial, anti-inflammatory, and antidiabetic properties of onion and garlic polysaccharides as reported in in vivo and in vitro studies is also critically assessed in this review. Different studies have proved onion and garlic polysaccharides as potential antioxidant and immunomodulatory agent. Studies have implemented to improve the functionality of onion and garlic polysaccharides through various modification approaches. Further studies are warranted for utilizing onion and garlic polysaccharides in the food, nutraceutical, pharmaceutical and cosmetic industries.