Guava polysaccharides attenuate high fat and STZ-induced hyperglycemia by regulating gut microbiota and arachidonic acid metabolism.

This study investigated the hypoglycemic mechanism of guava polysaccharides (GP) through the gut microbiota (GM) and related metabolites. Our findings demonstrated that GP significantly mitigated high-fat diet- and streptozotocin-induced hyperglycemia, insulin resistance, hyperlipidemia, elevated alanine aminotransferase, high hepatic inflammation levels, and prevented pancreatic atrophy and hepatomegaly. Interestingly, the benefits of GP were attributed to alterations in the GM. GP decreased the ratio of Firmicutes to Bacteroidetes, significantly inhibiting deleterious bacteria, including Uncultured_f_Desulfovibrionaceae, Bilophila, and Desulfovibrio, while promoting the proliferation of probiotic Bifidobacterium and Bacteroides. In addition, GP promoted the generation of short-chain fatty acids. Notably, the arachidonic acid (AA) metabolism pathway was enriched in liver metabolites. GP significantly elevated hepatic AA and 15-hydroxyeicosatetraenoic acid, while reducing prostaglandin E2 and 5- and 12-hydroxyeicosatetraenoic acid. This modulation is accompanied by the downregulation of hepatic cyclooxygenase-1, 12-lipoxygenase, P38, and c-Jun N-terminal kinase mRNA expression, and the upregulation of cytochrome P4502J5 and insulin receptor substrate 1/2 mRNA expression. However, GP antibiotic treatment did not induce significant alterations in FBG and AA levels or gene expression. Overall, our findings suggest that the hypoglycemic effect of GP may be intricately linked to alterations in AA metabolism, which depends on the GM.

The composition of phenolic compounds in Chinese olive (Canarium album L.) cultivars and their contribution to the anti-inflammatory properties of the cultivars.

Objective: This study aimed to explore the phenolic compounds (PCs) present in three Chinese olive (Canarium album L.) cultivars and the contribution of these PCs to the anti-inflammatory activities of the cultivars. Methods: Ultra-high performance liquid chromatography coupled with hybrid quadrupole-orbitrap/mass spectrometry (UPLC-Q-Exactive/MS) was used to identify and quantify the PCs present in three Chinese olive cultivars, "Na zhong," "Tan xiang," and "Xiang zhong". 2,2-diphenyl-1-picrylhydrazyl (DPPH); 2,2'-azinobis (3-ethylbenzothiazoline 6-sulfonate) (ABTS); and oxygen radical absorption capacity (ORAC) assays were used to assess the antioxidant activities of the PCs. Furthermore, we analyzed the anti-inflammatory action of these PCs using lipopolysaccharide (LPS)-induced RAW264.7 cells. Results: A total of 44 PCs were identified in the three cultivars. Of these, 17 PCs were previously unidentified in Chinese olive. Among the cultivars, the free phenolics (FPs) of "Tan xiang" showed the strongest antioxidant activity. All cultivars have shown significant inhibition of TNF-α and IL-6 production. Clustering correlation analysis showed galloyl-bis-HHDP-glucose and paeonol have significant anti-inflammatory ability in FPs. Quininic, galloylquinic acid, 4-hydroxycinnamic acid and gallic acid hexoside have shown significant inhibition of IL-6 production in BPs. Furthermore, gallic acid, catechin, syringic acid, and nobiletin exhibit negative correlation in FPs and positive correlation in BPs of cytokine production, while corilagin and methyl ellagic acid pentoside exhibited opposite correlation. Conclusion: In summary, this study contributed to the literature on PCs in Chinese olives and the potential health benefits of FPs and BPs.

Effect of microbial communities on flavor profile of Hakka rice wine throughout production.

Hakka rice wine is produced from grains by co-fermentation with abundant microbes in an open fermentation environment. Indigenous microbiota and enzymes convert the nutrients in grains into flavor compounds through enzymatic biochemical reactions and microbial metabolism. High-throughput sequencing technology revealed that non-Saccharomyces yeasts dominated the traditional fermentation process, with genera such as Kodamaea ohmeri, Candida orthopsilosis, and Trichosporon asteroides forming a dynamic community that highly correlated with the evolution of 80 volatile compounds in Hakka rice wine. Among the 104 volatile compounds detected by GC-MS, 22 aroma-active compounds with relative odor activity values (ROAV) > 1 were quantified, 11 of which made significant contributions (P < 0.05) to the overall aroma and were responsible for the sweet, grainy, and herbal aromas of Hakka rice wine.

Integrated Transcriptomics and Metabolomics Reveal the Mechanism of Alliin in Improving Hyperlipidemia.

This research aims to assess the anti-hyperlipidemia effects of alliin in vivo and its potential mechanisms through transcriptomics and metabolomics analysis. A hyperlipidemia mode was established in C57BL/6 mice fed a high-fat diet, and the related physiological parameters of the animals were recorded. Serum TC and MDA in livers significantly decreased by 12.34% and 29.59%, respectively, and SOD and CAT in livers significantly increased by 40.64% and 39.05%, respectively, after high doses of alliin interventions. In total, 148 significantly different genes, particularly Cel, Sqle, Myc, and Ugt1a2, were revealed for their potential roles in HFD-induced alliin, mainly through steroid biosynthesis, triglyceride metabolism, drug metabolism-cytochrome P450, and the PI3K-Akt signaling pathway, according to transcriptomics analysis. Metabolomics results revealed 18 significantly different metabolites between the alliin group and HFD group, which were classified as carboxylic acids, such as N-undecanoylglycine, adipic acid, D-pantothenic acid, cyprodenate, and pivagabine. We found pantothenic acid played a vital role and was effective through pantothenic acid and CoA biosynthesis metabolism. The "steroid biosynthesis pathway" was identified as the most significant metabolic pathway by integrated transcriptomics and metabolomics analysis. This work offered a theoretical framework for the mechanism of alliin lipid lowering in the future. The development and utilization of alliin will be a viable strategy to improve the health status of people with hyperlipidemia, suggesting prospective market opportunities.

Identification of the proteome of the midgut of silkworm, Bombyx mori L., by multidimensional liquid chromatography (MDLC) LTQ-Orbitrap MS.

The midgut is the digestive apparatus of the silkworm and its proteome was studied by using nano-LC (liquid chromatography) electrospray ionization MS/MS (tandem MS). MS data were analysed by using X!Tandem searching software using different parameters and validated by using the Poisson model. A total of 90 proteins were identified and 79 proteins were described for the first time. Among the new proteins, (i) 22 proteins were closely related to the digestive function of the midgut, including 11 proteins of digestive enzymes secreted by the epithelium, eight proteins of intestine wall muscle and mechanical digestion and three proteins of peritrophic membrane that could prevent the epithelium from being mechanically rubbed; (ii) 44 proteins were involved in metabolism of substance and energy; and (iii) 11 proteins were associated with signal transduction, substance transport and cell skeleton.

Gene analysis of an antiviral protein SP-2 from Chinese wild silkworm, Bombyx mandarina Moore and its bioactivity assay.

The cDNA encoding an antiviral protein SP-2 against BmNPV was cloned from the midgut of Chinese wild silkworm, Bombyx mandarina Moore (GenBank access AY945210) based on the available information of the domesticated silkworm. Its cDNA was 855 bp encoding 284 amino acids with predicted molecular weight of 29.6 kDa. Its full length in genomics was 1376 bp, including 5 exons and 4 introns. The expression analysis indicated that it was only expressed in midgut, and its expression level was higher during feeding stage of larval instars while very lower during the moltism and mature stages. The deduced amino acid sequence of this protein showed eight-amino-acid variation compared with the counterpart of domesticated silkworm. Its antiviral activity was assayed through in vitro test. The results indicated that it showed strong bioactivity against BmNPV, and its activity was 1.6 fold higher that the counterpart of domesticated silkworm.