Ginsenoside Rb1, Compound K and 20(S)-Protopanaxadiol Attenuate High-Fat Diet-Induced Hyperlipidemia in Rats via Modulation of Gut Microbiota and Bile Acid Metabolism.

Hyperlipidemia, characterized by elevated serum lipid concentrations resulting from lipid metabolism dysfunction, represents a prevalent global health concern. Ginsenoside Rb1, compound K (CK), and 20(S)-protopanaxadiol (PPD), bioactive constituents derived from Panax ginseng, have shown promise in mitigating lipid metabolism disorders. However, the comparative efficacy and underlying mechanisms of these compounds in hyperlipidemia prevention remain inadequately explored. This study investigates the impact of ginsenoside Rb1, CK, and PPD supplementation on hyperlipidemia in rats induced by a high-fat diet. Our findings demonstrate that ginsenoside Rb1 significantly decreased body weight and body weight gain, ameliorated hepatic steatosis, and improved dyslipidemia in HFD-fed rats, outperforming CK and PPD. Moreover, ginsenoside Rb1, CK, and PPD distinctly modified gut microbiota composition and function. Ginsenoside Rb1 increased the relative abundance of Blautia and Eubacterium, while PPD elevated Akkermansia levels. Both CK and PPD increased Prevotella and Bacteroides, whereas Clostridium-sensu-stricto and Lactobacillus were reduced following treatment with all three compounds. Notably, only ginsenoside Rb1 enhanced lipid metabolism by modulating the PPARγ/ACC/FAS signaling pathway and promoting fatty acid ß-oxidation. Additionally, all three ginsenosides markedly improved bile acid enterohepatic circulation via the FXR/CYP7A1 pathway, reducing hepatic and serum total bile acids and modulating bile acid pool composition by decreasing primary/unconjugated bile acids (CA, CDCA, and ß-MCA) and increasing conjugated bile acids (TCDCA, GCDCA, GDCA, and TUDCA), correlated with gut microbiota changes. In conclusion, our results suggest that ginsenoside Rb1, CK, and PPD supplementation offer promising prebiotic interventions for managing HFD-induced hyperlipidemia in rats, with ginsenoside Rb1 demonstrating superior efficacy.

Mucilaginibacter Phenanthrenivorans sp. nov., a Novel Phenanthrene Degradation Bacterium Isolated from Wetland Soil.

BJC16-A38T, a Gram-negative, aerobic and non-motile rod-shaped strain was isolated from a permafrost wetland soil sample. BJC16-A38T was oxidase- and catalase-positive, and produced pale yellow colonies on modified R2A agar plates. The 16S rRNA gene sequence of BJC16-A38T shared the highest sequence similarity with those of Mucilaginibacter xinganensis BJC16-A31T (97.44%), Mucilaginibacter gotjawali SA3-7T (96.79%) and Mucilaginibacter frigoritolerans FT22T (96.14%). Phylogenetic analysis revealed that BJC16-A38T formed a separate lineage together with strain M. xinganensis BJC16-A31T in the genus Mucilaginibacter. BJC16-A38T contained menaquinone-7 (MK-7) as the predominant isoprenoid quinine. Major fatty acids in cells were iso-C15:0, summed feature 3 (16:1ω7c/16:1ω6c) and iso-C17:03-OH. BJC16-A38T contained phosphatidylethanolamine, two unknown polar lipids, six unidentified phospholipids and an unidentified aminolipid. The Genome of BJC16-A38T was sequenced using the Genome Analyzer IIx sequence platform and 38 contigs were produced in total with an average G + C percentage of 44.00%. The average nucleotide identity (ANI) of BJC16-A38T with respect to those of M. xinganensis BJC16-A31T, M. gotjawali SA3-7T and M. frigoritolerans FT22T were 79.60%, 77.24% and 77.58%, respectively. Digital DNA-DNA hybridization (DDH) values between BJC16-A38T and the tree reference strains were 21.30%, 19.60% and 19.70%, respectively. BJC16-A38T exhibited phenanthrene biodegradation activity that can degrade 88.02% phenanthrene in the MM medium after 7 days cultivation. Phenotypic, chemotaxonomic, phylogenetic and genomic characteristics concluded that strain BJC16-A38T represents a novel species of the genus Mucilaginibacter. Hence, the name Mucilaginibacter phenanthrenivorans sp. nov. is proposed. The type strain is BJC16-A38T (= CGMCC 1.12693T = NBRC 110383T).