ABSTRACT
BACKGROUND: Garlic polysaccharides (GPs) constitute over 75% of the dry weight of garlic. They are characterized by fructan with a 2,1-ß-d-Fruf backbone and 2,6-ß-d-Fruf branches. Studies have suggested a role for GPs in regulating gut microbiota but whether they possess a comprehensive function in maintaining intestinal well-being and can serve as effective prebiotics remains unknown. To explore this, varied doses of GPs (1.25-5.0 g kg-1 body weight) and inulin (as a positive control) were administered to Kunming mice via gavage, and their effects on the intestinal epithelial, chemical, and biological barriers were assessed. A constipation model was also established using loperamide to investigate the potential effects of GPs on the relief of constipation. RESULTS: Administration of GPs significantly upregulated expression of tight-junction proteins and mucins in Kunming mouse small-intestine tissue. Garlic polysaccharides elevated cecal butyric acid content, reduced the abundance of Desulfobacterota, and decreased the ratio of Firmicutes to Bacteroidetes (the F/B ratio). Garlic polysaccharides also promoted the growth of Bacteroides acidifaciens and Clostridium saccharogumia. Tax4Fun functional predictions suggested the potential of GPs to prevent human diseases, reducing the risk of insulin resistance, infectious diseases, and drug resistance. Garlic polysaccharides also exhibited a beneficial effect in alleviating loperamide-induced constipation symptoms by enhancing small intestinal transit, softening stool consistency, accelerating bowel movements, and promoting the release of excitatory neurotransmitters. CONCLUSIONS: These findings highlight the important role of GPs in maintaining gut fitness by enhancing intestinal barrier function and peristalsis. Garlic polysaccharides are promising prebiotics, potentially contributing to overall intestinal well-being and health. © 2024 Society of Chemical Industry.
ABSTRACT
Black rice was fermented with Neurospora crassa, after which the dietary fiber (DF) extracted from it was characterized and evaluated for its cholesterol-lowering effect in mice. The findings demonstrated that fermentation increased the level of soluble DF from 17.27% ± 0.12 to 29.69% ± 0.26 and increased the adsorption capacity of DF for water, oil, cholesterol, glucose and sodium cholate. The fermented DF had a more loose and porous structure than that extracted from unfermented rice. Additionally, feeding with DF from the fermented black rice significantly reduced body weight, lowered total cholesterol levels and improved the lipid profile in mice gavaged with a high dose (5 g per kg bw) or a low dose (2.5 g per kg·bw). ELISA showed that the hepatic expression of typical proteins and enzymes that are involved in cholesterol metabolism was regulated by the fermented rice DF, leading to reduced cholesterol production and increased cholesterol clearance. The fermented DF also modified the gut microbiota composition (e.g. Firmicutes reduced and Akkermansia increased), which promoted the production of short-chain fatty acids. In conclusion, fermentation can modify the structure and function of DF in black rice and the fermented dietary fiber has excellent cholesterol lowering effects possibly by cholesterol adsorption, cholesterol metabolism modulation, and intestinal microflora regulation.
Subject(s)
Oryza , Mice , Animals , Oryza/metabolism , Cholesterol/metabolism , Dietary Fiber/analysis , Liver/metabolism , FermentationABSTRACT
Theoretical studies on the binuclear (cycloheptatrienyl)molybdenum carbonyl complexes [(C(7)H(7))(2)Mo(2)(CO)(n)] (n=6, 5, 4, 3, 2, 1, 0) indicate structures with fully bonded heptahapto eta(7)-C(7)H(7) rings and four or fewer carbonyl groups to be energetically competitive. This is in striking contrast to the corresponding chromium derivatives. The lowest energy of such a structure for [(eta(7)-C(7)H(7))(2)Mo(2)(CO)(4)] is a singlet unbridged structure with a formal Mo--Mo single bond with a length of approximately 3.2 A. A higher-energy pentahapto structure [(eta(5)-C(7)H(7))(2)Mo(2)(CO)(4)] is also predicted with a formal Mo [triple bond]Mo triple bond with a length of approximately 2.56 A. Low-energy structures are predicted for [(C(7)H(7))(2)Mo(2)(CO)(3)] with two heptahapto eta(7)-C(7)H(7) rings, either one or two bridging carbonyl groups, and formal Mo=Mo double bonds with a length of approximately 2.8 A. However, the global minimum for [(C(7)H(7))(2)Mo(2)(CO)(3)] is a [(eta(7)-C(7)H(7))(eta(5)-C(7)H(7))Mo(2)(CO)(3)] structure with a formal Mo[triple bond]Mo triple bond with a length of approximately 2.53 A. The lowest-energy structures for [(C(7)H(7))(2)Mo(2)(CO)(2)] and [(C(7)H(7))(2)Mo(2)(CO)] have heptahapto eta(7)-C(7)H(7) rings and predicted metal-metal bond lengths of approximately 2.54 and 2.31 A, respectively, consistent with the formal triple and quadruple bonds, respectively, needed to give both metal atoms the favored 18-electron configuration. The lowest-energy structures for the carbonyl-richer systems [(C(7)H(7))(2)Mo(2)(CO)(n)] (n=6, 5) contain one trihapto eta(3)-C(7)H(7) ring and one pentahapto eta(5)-C(7)H(7) ring.
ABSTRACT
The binuclear homoleptic rhodium carbonyls Rh2(CO)n (n = 8, 7, 6, 5) have been examined theoretically. Three energetically low-lying equilibrium structures of Rh2(CO)8 were found, i.e., one doubly bridged C2v singlet structure and two unbridged singlet structures with D(3d) and D(2d) symmetry. The doubly bridged structure is the global minimum predicted to lie 3.4 kcal/mol below the D(2d) structure and 6.4 kcal/mol below the D(3d) structure. For Rh2(CO)7 the global minimum is either a singlet C2v unbridged structure or a singlet doubly bridged C(s) structure within 1.8 kcal/mol depending upon the theoretical method. For Rh2(CO)6, the global minimum is either a singlet doubly bridged D(2) structure or a singlet unbridged D(2d) structure depending upon the method. Triplet structures for Rh2(CO)7 and Rh2(CO)6 are predicted to be of high energies relative to the low energy singlet structures. For Rh2(CO)5 the C2v singlet singly bridged structure lies below the C2 or C2v triplet structures.
