Increased level of tetrahydro-beta-carboline derivatives in short-term fermented garlic

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.

The effect of single clove Black garlic on the hemostasis status and lipid profile in male Sprague Dawley rats with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) patients have alteration in hemostasis components. Thus, including excess expression of plasminogen activator inhibitor-1 (PAI-1), causing fibrinolysis disorders; the majority of these patients are hypercoagulable state prone to thrombosis. Some evidence suggests that garlic and garlic supplements have antithrombotic and anti-inflammatory properties. Besides, garlic stimulates fibrinolytic activity and normalizes plasma lipid imbalances. Black garlic is processed garlic that is produced through natural aging at a controlled temperature (70 °C) and high humidity (90%) for several days, without other additives. This study aimed to prove the effect of single clove black garlic (SCBG) (Allium sativum Linn) on PAI-1 levels and lipid profiles of NAFLD rats induced by a high-fat fructose diet (HFFD) containing 1.25% cholesterol and 0.5% cholic acid.The rats were then divided into healthy control group (K1+); NAFLD control group without treatment (K2+); 0.9 mg simvastatin treatment group (K1-); 45 mg metformin treatment group (K2-); SCBG 450 mg per 200g BW (X1); 900 mg per 200 g BW (X2); and 1350 mg per 200 g BW (X3). All treatments were administered for 4 weeks via oral gavage. As a result, significant differences in PAI-1 levels and lipid profiles between groups after the administration (p = 0.001) were noted and also by simvastatin and metformin, respectively. There was a correlation between PAI-1 and lipid profile of SCBG treatment. In conclusion, the administration of SCBG (1350 mg per 200 g BB per day) for 4 weeks had a significant effect on PAI-1 levels, and the lipid profiles in Sprague Dawley rats modeled NAFLD (p = 0.001). SCBG has provided benefits that can be useful in the management of NAFLD but it’s not equivalent to medicine.

Formation, nutritional value, and enhancement of characteristic components in black garlic: A review for maximizing the goodness to humans

Black garlic (BG) is essentially a processed food and obtained through the transformation of fresh garlic (FG) (Allium sativum L.) via a range of chemical reactions (including the Maillard reaction) and microbial fermentation. This review provides the up-to-date knowledge of the dynamic and complicated changes in major components during the conversion of FG to BG, including moisture, lipids, carbohydrates (such as sugars), proteins, organic acids, organic sulfur compounds, alkaloids, polyphenols, melanoidins, 5-hydroxymethylfurfural, vitamins, minerals, enzymes, and garlic endophytes. The obtained evidence confirms that BG has several advantages over FG in certain product attributes and biological properties (especially antioxidant activity), and the factors affecting the quality of BG include the type and characteristics of FG and processing technologies and methods (especially pretreatments, and processing temperature and humidity). The interactions among garlic components, and between garlic nutrients and microbes, as well as the interplay between pretreatment and main manufacturing process, all determine the sensory and nutritional qualities of BG. Before BG is marketed as a novel snack or functional food, more research is required to fill the knowledge gaps related to quantitative monitoring of the changes in metabolites (especially those taste-active and/or biological-active substances) during BG manufacturing to maximize BG's antioxidant, anticancer, antiobesity, anti-inflammatory, immunostimulatory, anti-allergic, hepatoprotective, cardioprotective and oxidative stress-/hangover syndrome-reducing functions, and beneficial effects on memory/nervous systems. Assessments of the quality, efficacy, and safety of BG should be performed considering the impacts of BG production conditions, postproduction handling, and intake methods.

Metabolomics for Biomarker Discovery in Fermented Black Garlic and Potential Bioprotective Responses against Cardiovascular Diseases

Fermented black garlic has multiple beneficial biological activities, including cardiovascular protection, anticancer, hepatoprotective, and antibacterial properties. In this study, metabolic differences in the properties of black and fresh garlic were investigated via liquid chromatography quadrupole/time-of-flight-based metabolomics, leading to the identification of characteristic components. Fermented black garlic samples and their Amadori products (AC) promoted angiogenesis, prevented thrombus formation by rescuing chemical-induced vascular lesions in zebrafish, and inhibited H₂O₂-induced injury of endothelial cells, thus reducing the risk of cardiovascular disease. AC suppressed activation of the mitogen-activated protein kinase pathway through inhibition of p38 and ERK1/2 phosphorylation, in turn, increasing the availability of c-Fos/c-Jun or c-Jun/c-Jun complexes for apoptotic resistance. Clarification of the associated signaling pathways should therefore provide a solid foundation for optimization of black garlic-based therapies.

Extracts of black garlic exhibits gastrointestinal motility effect

In this studied, extracts of black garlic on the improvement of gastrointestinal function, antioxidant activity, total polyphenols, total flavonoids and total polysaccharides were evaluated. Results showed that the black garlic n-butanol fraction extract (BA) had significantly increased effect within small intestine in vitro, while the ethyl acetate fractions had no significant effect on small intestine in vitro. Increase of 5-HT₄ content effectively stimulated the gastrointestinal peristalsis, which enhanced its gastrointestinal tract emptying, and promoted defecation. As for antioxidant activity test, the water extract was more effective in SOD activity test, DPPH radical scavenging rates, ferric reducing antioxidant power and reducing power. In addition, the water fraction was simulated by gastric acid digestion and hydrolysis, and the small intestine was isolated after acid hydrolysis (AW). It was found that the water fraction extract after acid hydrolysis did significantly improve the intestinal contraction rate. In short, extract of black garlic could effectively promote gastrointestinal motility and promote defecation. The active compounds were highly polar ingredients since water extract of black garlic exhibits most significant effect on improving gastrointestinal function.

Characterization of garlic endophytes isolated from the black garlic processing

The objectives of this study were to isolate and identify garlic endophytes, and explore the characteristics of dominant strains. Garlic endophytes were studied through phenotypical characterization and comparative sequence analysis of 16S rDNA based on culture‐dependent approaches. Representative strains inferred from 16S rDNA sequencing were selected for further identification by gyrA and rpoB gene loci and phylogenetic analysis based on concateneted house‐keeping sequences. Seven kinds of Bacillus were found from garlic and black garlic, respectively. Further studies demonstrated that the total bacteria and endophytes showed a sharp decrease firstly, followed by a rapid rise, then maintained at a certain level, and finally slowed down during the black garlic processing. B. subtilis, B. methylotrophicus, and B. amyloliquefaciens were the dominant strains. The selected strains were capable of fermenting glucose, lactose, sucrose, and garlic polysaccharide to produce acid but no gas, with a strong ability of heat resistance. The results indicated that there were a certain number of garlic endophytes during the black garlic processing, and Bacillus was the dominant strains under the conventional culture‐dependent methods. This report provided useful information for the presence and type of garlic endophytes during the black garlic processing, which were of great significance to study the formation mechanism and quality improvement of black garlic in the future, as well as the security of garlic powder.

Physicochemical Properties, Biological Activity, Health Benefits, and General Limitations of Aged Black Garlic: A Review

Garlic (Allium sativum) has been used as a medicinal food since ancient times. However, some people are reluctant to ingest raw garlic due to its unpleasant odor and taste. Therefore, many types of garlic preparations have been developed to reduce these attributes without losing biological functions. Aged black garlic (ABG) is a garlic preparation with a sweet and sour taste and no strong odor. It has recently been introduced to Asian markets as a functional food. Extensive in vitro and in vivo studies have demonstrated that ABG has a variety of biological functions such as antioxidant, anti-inflammatory, anti-cancer, anti-obesity, anti-diabetic, anti-allergic, cardioprotective, and hepatoprotective effects. Recent studies have compared the biological activity and function of ABG to those of raw garlic. ABG shows lower anti-inflammatory, anti-coagulation, immunomodulatory, and anti-allergic effects compared to raw garlic. This paper reviews the physicochemical properties, biological activity, health benefits, adverse effects, and general limitations of ABG.

Composition analysis and antioxidant properties of black garlic extract

Black garlic produced from fresh garlic under controlled high temperature and humidity has strong antioxidant properties. To determine these compounds, five fractions (from F1 to F5) were separated and purified by elution with chloroform:methanol at different ratios (8:1, 6:1, 4:1, 2:1, and 0:1; v/v). The antioxidant activity of each fraction was analyzed. The results showed that F3 and F4 had higher phenolic contents and stronger 2,2-diphenyl-2-picrylhydrazyl radical scavenging activity than the others. Seven purified individual components were further separated using semipreparation high-performance liquid chromatography from these two intensely antioxidant fractions (F3 and F4), their structures were elucidated by high-performance liquid chromatography coupled to diode array detection, electrospray ionization, mass spectrometry, ¹H nuclear magnetic resonance, and ¹³C nuclear magnetic resonance spectrometry. Three compounds including adenosine, uridine, and 2-acetylpyrrole were first identified in black garlic, except for 5-hydroxymethylfurfural, (1S, 3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid, and (1R, 3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid. The cellular antioxidant activities of uridine, adenosine, carboline alkaloids, 5-hydroxymethylfurfural, and ethyl acetate extracts were consistent with the results of in vitro experimental anti-oxidant properties. The results provide useful information for understanding the health benefits of black garlic products.

Black garlic: A critical review of its production, bioactivity, and application

Black garlic is obtained from fresh garlic (Allium sativum L.) that has been fermented for a period of time at a controlled high temperature (60–90°C) under controlled high humidity (80–90%). When compared with fresh garlic, black garlic does not release a strong offensive flavor owing to the reduced content of allicin. Enhanced bioactivity of black garlic compared with that of fresh garlic is attributed to its changes in physicochemical properties. Studies concerning the fundamental findings of black garlic, such as its production, bioactivity, and applications, have thus been conducted. Several types of black garlic products are also available in the market with a fair selling volume. In this article, we summarize the current knowledge of changes in the components, bioactivity, production, and applications of black garlic, as well as the proposed future prospects on their possible applications as a functional food product.

Comprehensive NMR analysis of compositional changes of black garlic during thermal processing

Black garlic is a processed food product obtained by subjecting whole raw garlic to thermal processing that causes chemical reactions, such as the Maillard reaction, which change the composition of the garlic. In this paper, we report a nuclear magnetic resonance (NMR)-based comprehensive analysis of raw garlic and black garlic extracts to determine the compositional changes resulting from thermal processing. (1)H NMR spectra with a detailed signal assignment showed that 38 components were altered by thermal processing of raw garlic. For example, the contents of 11 l-amino acids increased during the first step of thermal processing over 5 days and then decreased. Multivariate data analysis revealed changes in the contents of fructose, glucose, acetic acid, formic acid, pyroglutamic acid, cycloalliin, and 5-(hydroxymethyl)furfural (5-HMF). Our results provide comprehensive information on changes in NMR-detectable components during thermal processing of whole garlic.

Physicochemical and antioxidant properties of black garlic

Black garlic (BG) is a processed garlic product prepared by heat treatment of whole garlic bulbs (Allium sativum L.) at high temperature under high humidity for several days, resulting in black cloves with a sweet taste. BG has recently been introduced to the Korean market as a product beneficial to health. To clarify how BG changes during the 35 day aging period, the physicochemical characteristics, antioxidant contents, and antioxidant activities were evaluated under controlled conditions of 70 °C and 90% relative humidity. Reducing sugar and total acidity of BG increased during the aging period, whereas pH decreased from pH 6.33 to 3.74. Lightness and yellowness values of BG radically decreased during the aging period, whereas redness values increased significantly. Antioxidant components, including the total polyphenol and total flavonoids contents of BG, increased significantly until the 21st day of aging (p < 0.05) and correspondingly, the antioxidant activities of BG, measured by DPPH, ABTS, FRAP, and reducing power assays, were highest on the 21st day of aging. These results indicate that BG can be considered to not only possess antioxidant properties during the aging period, but also to reach its optimal antioxidant properties at the 21st day of aging.

Inhibition of ENNG-induced pyloric stomach and small intestinal carcinogenesis in mice by high temperature- and pressure-treated garlic

High temperature- and pressure-treated garlic (HTPG) has been shown to have enhanced antioxidative activity and polyphenol contents. Previously, we reported that HTPG inhibited 1,2-dimethylhydrazine-induced mucin depleted foci (premalignant lesions) and O6-methylguanine DNA adduct formation in the rat colorectum. In the present study, we investigated the modifying effects of HTPG on N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG)- induced pyloric stomach and small intestinal carcinogenesis in mice. Male C57BL/6 mice were given ENNG (100 mg/l) in drinking water for the first 4 weeks, then a basal diet or diet containing 2% or 5% HTPG for 30 weeks. The incidence and multiplicity of pyloric stomach and small intestinal (duodenal and jejunal) tumors in the 2% HTPG group (but not in the 5% HTPG group) were significantly lower than those in the control group. Cell proliferation of normal-appearing duodenal mucosa was assessed by MIB-5 immunohistochemistry and shown to be significantly lower with 2% HTPG (but again not 5% HTPG) than in controls. These results in dicate that HTPG, at 2% in the diet, inhibited ENNG-induced pyloric stomach and small intestinal (especially duodenal) tumorigenesis in mice, associated with suppression of cell proliferation.

Physical stability, antioxidative properties, and photoprotective effects of a functionalized formulation containing black garlic extract

When garlic is fermented, certain aspects of its bioactivity are changed. Black garlic is a type of fermented garlic used as a food ingredient in Asian cuisine. Black garlic's popularity has spread around the world as it has become a sought-after ingredient used in high-end cuisine. The formulations containing 10% black garlic extract or 10% normal garlic extract showed stable pH, color, precipitation, and organoleptic features, although these characteristics changed slightly. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities of the black garlic formulation were significantly (p<0.05) higher compared to those of the base formulation and normal garlic formulation. Mice treated with the black garlic formulation (119.63 μM/g) had significant (p<0.05) decreases in thiobarbituric acid reactive substance (TBARS) levels by lipid peroxidation compared to ultraviolet B (UVB)-control mice (142.37 μM/g). Moreover, significant (p<0.05) prevention of glutathione reduced form (GSH) depletion was observed in the black garlic formulation treated mice (vehicle: 3.46 mM/g vs. black garlic: 5.60mM/g). The formulation containing 10% black garlic extract retained physical stability and had high anti-radical efficiencies. Furthermore, it is possible to suggest that this formulation may be effective in protecting skin from UVB photodamage.

Ethnobiology and Ethnopharmacology of Lepidium meyenii (Maca), a Plant from the Peruvian Highlands

Lepidium meyenii (maca) is a Peruvian plant of the Brassicaceae family cultivated for more than 2000 years, which grows exclusively in the central Andes between 4000 and 4500 m altitude. Maca is used as a food supplement and also for its medicinal properties described traditionally. Since the 90s of the XX century, an increasing interest in products from maca has been observed in many parts of the world. In the last decade, exportation of maca from Peru has increased from 1,415,000 USD in 2001 to USD 6,170,000 USD in 2010. Experimental scientific evidence showed that maca has nutritional, energizer, and fertility-enhancer properties, and it acts on sexual dysfunctions, osteoporosis, benign prostatic hyperplasia, memory and learning, and protects skin against ultraviolet radiation. Clinical trials showed efficacy of maca on sexual dysfunctions as well as increasing sperm count and motility. Maca is a plant with great potential as an adaptogen and appears to be promising as a nutraceutical in the prevention of several diseases.

Kinetic analysis of reactive oxygen species generated by the in vitro reconstituted NADPH oxidase and xanthine oxidase systems

The nicotinamide adenine dinucleotide (NADH)/nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and the xanthine oxidase (XOD) systems generate reactive oxygen species (ROS). In the present study, to characterize the difference between the two systems, the kinetics of ROS generated by both the NADH oxidase and XOD systems were analysed by an electron spin resonance (ESR) spin trapping method using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), 5-(diethoxyphosphoryl)-5-methyl-pyrroline N-oxide (DEPMPO) and 5-(2,2-dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO). As a result, two major differences in ROS kinetics were found between the two systems: (i) the kinetics of (•)OH and (ii) the kinetics of hydrogen peroxide. In the NADH oxidase system, the interaction of hydrogen peroxide with each component of the enzyme system (NADPH, NADH oxidase and FAD) was found to generate (•)OH. In contrast, (•)OH generation was found to be independent of hydrogen peroxide in the XOD system. In addition, the hydrogen peroxide level in the NADPH-NADH oxidase system was much lower than measured in the XOD system. This lower level of free hydrogen peroxide is most likely due to the interaction between hydrogen peroxide and NADPH, because the hydrogen peroxide level was reduced by ~90% in the presence of NADPH.

The Methyltetrahydro-{beta}-Carbolines in Maca (Lepidium meyenii)

Maca, a plant native to the Peruvian highlands, contains (1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA). The family of the tetrahydro-β-carbolines has been associated with both biologically helpful and harmful compounds. We present evidence that MTCA is a natural constituent of Maca, and on consumption no toxicity is found. This suggests that, when consumed as multi-component, MTCA may loose its adversity as drug action.