Sweet potato (Ipomoea batatas L.) leaf is a natural source of phenolic compounds with strong antioxidant activity and potential utility as an antioxidant. The aim of this study was to evaluate the polyphenol composition and antioxidant activities of ethanol extracts and their various solvent-partitioned fractions (petroleum ether, ethyl acetate, and aqueous fraction) from sweet potato leaves and petioles. Seven caffeoylquinic acid (CQA) derivatives and four flavonoids were detected in sweet potato leaves by HPLC-ESI-MS. The total phenolic content (TPC) and total flavonoid content (TFC) in leaf (112.98 ± 4.14 mg gallic acid equivalent (GAE)/g of dried extract, 56.87 ± 5.69 mg rutin equivalent (RE)/g of dried extract) was more than ten times higher than in petiole (9.22 ± 2.67 mg GAE/g of dried extract, 3.81 ± 0.52 mg RE/g of dried extract). The antioxidant contents of ethyl acetate fractions increased dramatically relative to those of crude extracts for both leaves and petioles. Purification using solvent partition with ethyl acetate increased TPC and TFC of crude extracts, especially the CQA derivatives including 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, 4,5-dicaffeoylquinic acid, and 3,4,5-tricaffeoylquinic acid. Meanwhile, the ethyl acetate fractions with the highest CQA content were associated with the highest scavenging activities towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) and higher ferric ion reducing antioxidant power (FRAP)-reducing power.

Obesity is a prevalent chronic disease that has significant negative impacts on humans and our companion animals, including dogs and cats. Obesity occurs with multiple comorbidities, such as diabetes, hypertension, heart disease and osteoarthritis in dogs and cats. A direct link between lipid metabolism dysregulation and obesity-associated diseases has been implicated. However, the understanding of such pathophysiology in companion animals is limited. This review aims to address the role of lipid metabolism in various metabolic disorders associated with obesity, emphasizing the involvement of the gut microbiota. Furthermore, we also discuss the management of obesity, including approaches like nutritional interventions, thus providing novel insights into obesity prevention and treatment for canines and felines.

Tryptophan (TRP) metabolites have been identified as potent biomarkers for complications of type 2 diabetes mellitus (T2DM). However, it remains unclear whether the therapeutic effect of metformin in T2DM is related to the modulation of TRP metabolic pathway. This study aims to investigate whether metformin affects TRP metabolism in T2DM mice through the gut microbiota. A liquid chromatography-tandem mass spectrometry method was established to determine 16 TRP metabolites in the serum, colon content, urine, and feces of T2DM mice, and the correlations between metabolites and the T2DM mice gut microbiota were performed. The method demonstrated acceptable linearity ( R ² > 0.996), with the limit of quantification ranging from 0.29 to 69.444 nmol/L for 16 analytes, and the limit of detection ranging from 0.087 to 20.833 nmol/L. In T2DM mice, metformin treatment effectively restored levels of indole-3-lactic acid (ILA), indole-3-propionic acid (IPA), and the ILA/IPA ratio, along with several aryl hydrocarbon receptor ligands in the serum, with a notable impact in the colon but not in the urine. This restoration was accompanied by a shift in the relative abundance of Dubosiella , Turicibacter , RF39 , Clostridia_UCG-014 , and Alistipes . Spearman’s correlation analysis revealed positive correlations between Turicibacter and Alistipes with IPA and indole-3-acetic acid. Conversely, these genera displayed negative correlations with ILA and kynurenine. In addition, our study revealed the presence of endogenous indole pathway in germ-free mice, and the impact of metformin on endogenous TRP metabolism in T2DM mice cannot be disregarded. Further research is needed to investigate the regulation of TRP metabolism by metformin. IMPORTANCE: This study provides valuable insights into the interrelationship between metformin administration, changes in the tryptophan (TRP) metabolome, and gut microbiota in type 2 diabetes mellitus (T2DM) mice. Indole-3-lactic acid (ILA)/indole-3-propionic acid (IPA) emerges as a potential biomarker for the development of T2DM and prediction of therapeutic response. While the indole metabolic pathway has long been associated exclusively with the gut microbiome, recent research has demonstrated the ability of host interleukin-4-induced-1 to metabolize TRP. The detection of indole derivatives in the serum of germ-free mice suggests the existence of inherent endogenous indole metabolic pathways. These findings deepen our understanding of metformin's efficacy in correcting TRP metabolic disorders and provide valuable directions for further investigation. Moreover, this knowledge may pave the way for the development of targeted treatment strategies for T2DM, focusing on the gut microbiome and restoration of associated TRP metabolism.

Phytohormones have garnered considerable interest as potential modulators of the gut-bone axis. Denosumab (Deno), a widely utilized therapeutic agent for postmenopausal osteoporosis, has not been previously investigated for its effects on gut health. The objective of this study was to assess the efficacy of isoflavones (SI), naringin (Nar), and Deno in the management of postmenopausal osteoporosis by targeting the gut-bone axis. The postmenopausal osteoporosis model in mice was established via bilateral oophorectomy. Subsequently, mice in the Deno group received subcutaneous injections of Deno at a dosage of 10 mg/kg, administered twice weekly. In contrast, mice in the SI and Nar groups were subjected to oral gavage with 200 mg/kg/day of SI and Nar, respectively. The treatment period for all groups lasted for 8 weeks. Upon the conclusion of the experiment, a thorough evaluation of the effects of SI, Nar, and Deno on bone and gut health in mice was conducted through immunological, pathological, imaging, and multi-omics methodologies. Deno, SI, and Nar significantly alleviated the physical symptoms in postmenopausal mice. However, only SI and Nar significantly modulated the gut microbiota. Akkermansia was significantly enriched after the gavage of SI and Nar. Akkermansia has the capacity to not only augment bone mass and alleviate strength deterioration via extracellular vesicles, but it also influences bone metabolism by diminishing inflammation and modulating lipid metabolism. Notably, no significant changes in the gut microbiota were observed in the Deno group, which may be attributed to the differences in the method of administration, as Deno was administered via subcutaneous injection rather than gavage. SI and Nar may influence the gut–bone axis through Akkermansia and have the potential of alternative treatment options for postmenopausal osteoporosis. Although the gut microbiota is not significantly affected by the subcutaneous administration of Deno, the long-term management of postmenopausal osteoporosis and the exploration of various management models warrant additional scrutiny. Furthermore, this study has yet to establish a dose–response relationship, indicating that further research is essential to clarify the regulatory effects of varying doses of SI and Nar on postmenopausal osteoporosis especially the modulation of gut microbiota.

Previous studies have found that Astragalus Polysaccharide (APS) and Lactobacillus plantarum PS128 (PS128) have potential antidepressant effects, but their effects on the gut microbiota and metabolites of major depressive disorder (MDD) are still unclear. We examined the effect of APS on gut microbiota and metabolites of first-episode and drug naïve MDD patients using in vitro fermentation, and further explored whether PS128 could enhance the utilization ability of APS. Fresh fecal samples from 15 MDD patients were collected, and analyzed for differences in gas production, gut microbiota, and tryptophan (Trp) related metabolites after 48 h of fermentation. APS fermentation increased the abundance of Bifidobacterium and decreased the abundance of Lachnoclostridium (p < 0.05). APS also increased total gas production and levels of indole lactic acid (ILA), Trp, and 5-hydroxytryptophan (5-HTP) (p < 0.05). Compared with APS, APS with PS128 synbiotics fermentation increased the abundance of Lactobacillus (p < 0.05), reduced total gas production and percentages of CO₂, H₂, and H₂S (p < 0.05), and to some extent increased the levels of ILA, Trp, and 5-HTP, although not statistically significant (p > 0.05). Correlation analysis showed Bifidobacterium was positively correlated with ILA, Trp and 5-HTP; On the contrary, Lachnoclostridium was negatively correlated with ILA, Trp, and 5-HTP. All these results suggest that APS could regulate gut microbiota structure and Trp related metabolites in MDD patients; Compared to APS, APS and PS128 synbiotic fermentation could reduce gas production but shows limited ability to modulate gut microbiota structure or Trp related metabolites in MDD patients.