Evaluating the hypolipidemic effect of garlic essential oil encapsulated in a novel double-layer delivery system.

The limited application of garlic essential oil (GEO) is attributed to its pungent taste, poor water solubility and low bioavailability. Liposomes are nontoxic, biodegradable and biocompatible, and ß-cyclodextrin can inhibit undesirable odors and improve the stability and bioavailability. Thus a promising dual-layer GEO ß-cyclodextrin inclusion compound liposome (GEO-DCL) delivery system with both advantages was designed and prepared in this study. Experimental results indicated that the encapsulation efficiency of GEO-DCLs was 5% higher than that of GEO liposomes (GEO-CLs), reaching more than 88%. In vitro release experiment showed that the release rate of GEO in GEO-DCLs was 40% lower than that of GEO-CLs after incubation in gastric juice for 6-h, indicating that the stability of GEO-DCLs was better than GEO-CLs. Evaluation of the effects of GEO-DCLs on lowering blood lipid levels in hypercholesterolemia mice. GEO-DCLs could reduce the weight and fat deposition in hypercholesterolemia mice. Inhibiting the increase of TC, LDL-C, and decrease of HDL-C in mice. The degree of liver injury was decreased, the number of round lipid droplets in liver cytoplasm was reduced, and the growth of fat cells was inhibited. The lipid-lowering effects of GEO-DCLs were dose-dependent. GEO-DCL can improve the bioavailability of GEO and improve dyslipidemia. Based on GEO's efficacy in lowering blood lipids, this study developed a kind of GEO-DCL compound pomegranate juice beverage with good taste, miscibility and double effect of reducing blood lipids. This study lays a foundation for the application of GEO in the field of functional food.

The antihyperuricemia activity of Astragali Radix through regulating the expression of uric acid transporters via PI3K/Akt signalling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Astragali Radix (AR) is the dry root of the leguminous plants Astragalus membranaceus (Fisch) Beg. var. mongholicus (Beg) Hsiao, and Astragalus membranaceus (Fisch) Bge., being used as a medicinal and edible resource. AR is used in traditional Chinese medicine prescriptions to treat hyperuricemia, but this particular effect is rarely reported, and the associated mechanism of action is still need to be elucidated. AIM OF THE STUDY: To research the uric acid (UA)-lowering activity and mechanism of AR and the representative compounds through the constructed hyperuricemia mouse and cellular models. MATERIALS AND METHODS: In our study, the chemical profile of AR was analysed by UHPLC-QE-MS, as well as the mechanism of action of AR and the representative compounds on hyperuricemia was studied through the constructed hyperuricemia mouse and cellular models. RESULTS: The main compounds in AR were terpenoids, flavonoids and alkaloids. Mice group treated with the highest AR dosage showed significantly lower (p < 0.0001) serum uric acid (208 ± 9 µmol/L) than the control group (317 ± 11 µmol/L). Furthermore, UA increased in a dose-dependence manner in urine and faeces. Serum creatinine and blood urea nitrogen standards, as well as xanthine oxidase in mice liver, decreased (p < 0.05) in all cases, indicating that AR could relieve acute hyperuricemia. UA reabsorption protein (URAT1 and GLUT9) was down-regulated in AR administration groups, while the secretory protein (ABCG2) was up-regulated, indicating that AR could promote the excretion of UA by regulating UA transporters via PI3K/Akt signalling pathway. CONCLUSION: This study validated the activity, and revealed the mechanism of AR in reducing UA, which provided experimental and clinical basis for the treatment of hyperuricemia with it.

Improved colonic inflammation by nervonic acid via inhibition of NF-κB signaling pathway of DSS-induced colitis mice.

BACKGROUND: Nervonic acid (C24:1∆15, 24:1 ω-9, cis-tetracos-15-enoic acid; NA), a long-chain monounsaturated fatty acid, plays an essential role in prevention of metabolic diseases, and immune regulation, and has anti-inflammatory properties. As a chronic, immune-mediated inflammatory disease, ulcerative colitis (UC) can affect the large intestine. The influences of NA on UC are largely unknown. PURPOSE: The present study aimed to decipher the anti-UC effect of NA in the mouse colitis model. Specifically, we wanted to explore whether NA can regulate the levels of inflammatory factors in RAW264.7 cells and mouse colitis model. METHODS: To address the above issues, the RAW264.7 cell inflammation model was established by lipopolysaccharide (LPS), then the inflammatory factors tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-1ß (IL-1ß), and Interleukin-10 (IL-10) were detected by Enzyme-linked immunosorbent assay (ELISA). The therapeutic effects of NA for UC were evaluated using C57BL/6 mice gavaged dextran sodium sulfate (DSS). Hematoxylin and eosin (H&E) staining, Myeloperoxidase (MPO) kit assay, ELISA, immunofluorescence assay, and LC-MS/MS were used to assess histological changes, MPO levels, inflammatory factors release, expression and distribution of intestinal tight junction (TJ) protein ZO-1, and metabolic pathways, respectively. The levels of proteins involved in the nuclear factor kappa-B (NF-κB) pathway in the UC were investigated by western blotting and RT-qPCR. RESULTS: In vitro experiments verified that NA could reduce inflammatory response and inhibit the activation of key signal pathways associated with inflammation in LPS-induced RAW264.7 cells. Further, results from the mouse colitis model suggested that NA could restore intestinal barrier function and suppress NF-κB signal pathways to ameliorate DSS-induced colitis. In addition, untargeted metabolomics analysis of NA protection against UC found that NA protected mice from colitis by regulating citrate cycle, amino acid metabolism, pyrimidine and purine metabolism. CONCLUSION: These results suggested that NA could ameliorate the secretion of inflammatory factors, suppress the NF-κB signaling pathway, and protect the integrity of colon tissue, thereby having a novel role in prevention or treatment therapy for UC. This work for the first time indicated that NA might be a potential functional food ingredient for preventing and treating inflammatory bowel disease (IBD).

Genomic insights into the evolutionary history and diversification of bulb traits in garlic.

BACKGROUND: Garlic is an entirely sterile crop with important value as a vegetable, condiment, and medicine. However, the evolutionary history of garlic remains largely unknown. RESULTS: Here we report a comprehensive map of garlic genomic variation, consisting of amazingly 129.4 million variations. Evolutionary analysis indicates that the garlic population diverged at least 100,000 years ago, and the two groups cultivated in China were domesticated from two independent routes. Consequently, 15.0 and 17.5% of genes underwent an expression change in two cultivated groups, causing a reshaping of their transcriptomic architecture. Furthermore, we find independent domestication leads to few overlaps of deleterious substitutions in these two groups due to separate accumulation and selection-based removal. By analysis of selective sweeps, genome-wide trait associations and associated transcriptomic analysis, we uncover differential selections for the bulb traits in these two garlic groups during their domestication. CONCLUSIONS: This study provides valuable resources for garlic genomics-based breeding, and comprehensive insights into the evolutionary history of this clonal-propagated crop.

Enhancing stability and anti-inflammatory properties of curcumin in ulcerative colitis therapy using liposomes mediated colon-specific drug delivery system.

Curcumin liposomes (CUR-LPs) was identified by evaluating morphology, appearance, zeta potential, particle diameter, and drug encapsulation efficiency. The results indicated that particle diameter, surface charge and polydispersity index (PDI) of curcumin (CUR)-loaded anionic liposomes were 167 nm, -34 mV and 0.09, respectively. CUR-LPs is high stable pseudo-pH-sensitive nanoparticles system which has a favorable stability in simulated gastric fluid and slower degradation rate allowing CUR sustained release for prolonged times in simulated intestinal fluid. Within 1 h, the CUR consumption was 21.82% in simulated gastric fluid (SGF) and 27.32% in simulated intestinal fluid (SIF), respectively. CUR-LPs could attenuate clinical symptoms including weight loss, diarrhea and fecal bleeding. Especially, it could also prevent dextran sulfate sodium salt (DSS)-inducedcolon tissue damage and colon shortening, and reduce the production of malondialdehyde (MDA), colonic myeloperoxidase (MPO), Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in animal model. Our study illustrated that liposomes (LPs) was a potential carrier to develop the colon-specific drug delivery system incorporating CUR for treating ulcerative colitis.

Production and excretion of astaxanthin by engineered Yarrowia lipolytica using plant oil as both the carbon source and the biocompatible extractant.

This study aimed to develop a bioprocess using plant oil as the carbon source for lipid-assimilating yeast to produce high-value astaxanthin. Using high-oleic safflower oil as a model, efficient cell growth and astaxanthin production by the engineered Yarrowia lipolytica strain ST7403 was demonstrated, and a considerable portion of astaxanthin was found excreted into the spent oil. Astaxanthin was the predominant carotenoid in the extracellular oil phase that allowed facile in situ recovery of astaxanthin without cell lysis. Autoclaving the safflower oil medium elevated the peroxide level but it declined quickly during fermentation (reduced by 84% by day 3) and did not inhibit cell growth or astaxanthin production. In a 1.5-L fed-batch bioreactor culture with a YnB-based medium containing 20% safflower oil, and with the feeding of casamino acids, astaxanthin production reached 54 mg/L (53% excreted) in 28 days. Further improvement in astaxanthin titer and productivity was achieved by restoring leucine biosynthesis in the host, and running fed-batch fermentation using a high carbon-to-nitrogen ratio yeast extract/peptone medium containing 70% safflower oil, with feeding of additional yeast extract/peptone, to attain 167 mg/L astaxanthin (48% excreted) in 9.5 days of culture. These findings facilitate industrial microbial biorefinery development that utilizes renewable lipids as feedstocks to not only produce high-value products but also effectively extract and recover the products, including non-native ones.Key Points• Yarrowia lipolytica can use plant oil as a C-source for astaxanthin production.• Astaxanthin is excreted and accumulated in the extracellular oil phase.• Astaxanthin is the predominant carotenoid in the extracellular oil phase.• Plant oil serves as a biocompatible solvent for in situ astaxanthin extraction. Graphical abstract.

A Chromosome-Level Genome Assembly of Garlic (Allium sativum) Provides Insights into Genome Evolution and Allicin Biosynthesis.

Garlic, an economically important vegetable, spice, and medicinal crop, produces highly enlarged bulbs and unique organosulfur compounds. Here, we report a chromosome-level genome assembly for garlic, with a total size of approximately 16.24 Gb, as well as the annotation of 57 561 predicted protein-coding genes, making garlic the first Allium species with a sequenced genome. Analysis of this garlic genome assembly reveals a recent burst of transposable elements, explaining the substantial expansion of the garlic genome. We examined the evolution of certain genes associated with the biosynthesis of allicin and inulin neoseries-type fructans, and provided new insights into the biosynthesis of these two compounds. Furthermore, a large-scale transcriptome was produced to characterize the expression patterns of garlic genes in different tissues and at various growth stages of enlarged bulbs. The reference genome and large-scale transcriptome data generated in this study provide valuable new resources for research on garlic biology and breeding.

Effects and mechanism of free amino acids on browning in the processing of black garlic.

BACKGROUND: Black garlic is produced by heating raw garlic at a high temperature for a long time without any additives. The thermal processing induces many chemical reactions, such as the Maillard reaction, which causes the color change from white to dark brown. Garlic contains a variety of amino acids, and the effect of each amino acid on browning is not fully understood. This work investigated the effect and mechanism of free amino acids on the browning of black garlic using model solutions containing garlic neutral polysaccharide, hydrolyzed garlic neutral polysaccharide, fructose, and free amino acids. RESULTS: A significant increase in reducing sugar was detected when garlic neutral polysaccharide was heated with glycine. The browning intensity of garlic neutral polysaccharide-glycine model solution was obviously higher after heating at 80 °C compared with that of garlic neutral polysaccharide solution. The model solution containing histidine had the greatest browning degree. The histidine model has a stable pH value, and almost no 5-hydroxymethylfurfural (5-HMF) was detected. CONCLUSION: Amino acid can promote the breaking of the garlic neutral polysaccharide chain and can react with the fructose generated to form browning. Histidine has the greatest effect on the browning, because histidine could eliminate the inhibiting effect of organic acid on Maillard reaction due to the buffer ability, and histidine had high reactivity in the late stage of Maillard reaction. © 2019 Society of Chemical Industry.

Characterization of microbial community structure and metabolic potential using Illumina MiSeq platform during the black garlic processing.

Black garlic is a distinctive garlic deep-processed product made from fresh garlic at high temperature and controlled humidity. To explore microbial community structure, diversity and metabolic potential during the 12days of the black garlic processing, Illumina MiSeq sequencing technology was performed to sequence the 16S rRNA V3-V4 hypervariable region of bacteria. A total of 677,917 high quality reads were yielded with an average read length of 416bp. Operational taxonomic units (OTU) clustering analysis showed that the number of species OTUs ranged from 148 to 1974, with alpha diversity increasing remarkably, indicating the high microbial community abundance and diversity. Taxonomic analysis indicated that bacterial community was classified into 45 phyla and 1125 distinct genera, and the microbiome of black garlic samples based on phylogenetic analysis was dominated by distinct populations of four genera: Thermus, Corynebacterium, Streptococcus and Brevundimonas. The metabolic pathways were predicted for 16S rRNA marker gene sequences based on Kyoto Encyclopedia of Genes and Genomes (KEGG), indicating that amino acid metabolism, carbohydrate metabolism and membrane transport were important for the black garlic fermentation process. Overall, the study was the first to reveal microbial community structure and speculate the composition of functional genes in black garlic samples. The results contributed to further analysis of the interaction between microbial community and black garlic components at different stages, which was of great significance to study the formation mechanism and quality improvement of black garlic in the future.

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.

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-ß-carboline-3-carboxylic acid, and (1R, 3S)-1-methyl-1,2,3,4-tetrahydro-ß-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 antioxidant properties. The results provide useful information for understanding the health benefits of black garlic products.

Effects of temperature on the quality of black garlic.

BACKGROUND: Black garlic is a type of garlic product that is generally produced by heating raw garlic at high temperature with controlled humidity for more than 30 days. Black garlic has appeared on the market for many years. It is crucial to investigate the characteristics of quality formation of black garlic during processing at various temperatures. RESULTS: In this study, fresh garlic was processed to black garlic at temperatures of 60, 70, 80 and 90 °C. Moisture, amino acid nitrogen and allicin contents decreased gradually during thermal processing of various temperatures. Reducing sugar, 5-hydroxymethylfurfural, total phenols, total acids contents and browning increased. The changing rate of quality indicators and flavour of black garlic varied at different temperatures. Browning intensity reached about 74 when black garlic aged. The sensory score was significantly higher in black garlic aged at 70 °C (39.95 ± 0.31) compared with that at other temperatures, suggesting that 70 °C might facilitate formation of good quality and flavour of black garlic during processing. CONCLUSION: Temperature had a remarkable impact on the quality and flavour of black garlic. © 2015 Society of Chemical Industry.