Metabolites

Background: Rosa chinensis, commonly known as the Chinese rose, is one of the most economically significant ornamental plants worldwide. The Rosa chinensis cultivar ‘Rainbow’s End’ notably transitions in color from yellow to red throughout its blooming phase; however, the chemical and molecular foundations underlying this floral color transformation remain inadequately understood. Methods: This study used the petals of the Rosa ‘Rainbow’s End’ cultivar at four developmental stages (R1, R2, R3, and R4) for targeted metabolomic and transcriptomic analyses. Results: Targeted metabolomic analyses revealed that the majority of anthocyanidin metabolites were highest at stages R2 and R3 and lowest at R1 and R4. In contrast, most carotenoid metabolites reached their highest levels at R1 and declined continuously from R2 to R4. These results were consistent with the color phenotype of Rosa ‘Rainbow’s End’ petals and suggested that both anthocyanins and carotenoids play critical roles in flower color variation. Specifically, an upregulation of CHS, ANS, and UGT genes in the anthocyanin biosynthesis pathway was observed in R2 and R3, coinciding with the expression of two MYB transcription factors (MYB14 and MYB54). Conversely, consistent downregulation of PSY, PDS, Z-ISO, ZDS, CHYB, and NCED genes in the carotenoid biosynthesis pathway was detected in R2 to R4 and was associated with four MYB transcription factors (MYB20, MYB43, MYB44, and MYB86). Conclusions: Rosa ‘Rainbow’s End’ is an excellent model for studying variations in flower color. The expression patterns of the identified structural genes involved in anthocyanin and carotenoid biosynthesis pathways, along with the related MYB transcription factors, were aligned with the levels of metabolite changes in the petals of four flowering stages. These genes and transcription factors are likely responsible for the color shifts in Rosa ‘Rainbow’s End’. This study clarifies the mechanisms underlying color changes in Rosa ‘Rainbow’s End’ and provides a theoretical basis for future flower breeding efforts.

Background: Metabolic-associated fatty liver disease (MAFLD) is prevalent in individuals with liver disease; however, it lacks effective therapeutic approaches. Smilax china L., a traditional Chinese medicinal herb, possesses excellent anti-inflammatory and antioxidant activity. This research aimed to explore the therapeutic effects of Smilax china L. extract (SCE) on MAFLD and to elucidate the pharmacological mechanisms. Methods: A rat model of MAFLD was induced through a high-fat diet (HFD), and the model rats subsequently received SCE as a therapeutic intervention for six weeks. The analysis involved 16S rDNA sequencing, untargeted fecal metabolomics, and targeted bile acid metabolomics to investigate the effects of SCE on the gut microbiota and bile acid metabolism. Results: Hepatic steatosis and lipid accumulation were significantly alleviated by the SCE treatment. SCE treatment modulated the gut microbiota disorder, by enhancing the relative abundance of the beneficial gut microbiota, including Clostridium, Oscillospira, and Romboutsia. Untargeted fecal metabolomics revealed a significant enrichment of the metabolites in secondary bile acid biosynthesis. Targeted bile acid metabolomics revealed that SCE reversed the abnormal fecal bile acid metabolic profile, such as HDCA, LCA, and T-β-MCA. These changes activated FXR and PPARα receptors to improve the lipid metabolism by regulating bile acid synthesis. Conclusions: Our study provides evidence that SCE alleviates MAFLD through regulation of the gut microbiota, bile acid metabolism, and activation of the FXR/PPARα pathway, illustrating the mechanism of action of SCE in MAFLD from a novel perspective, and further highlights its therapeutic potential.

Background/Objectives: Salmonid species are globally popular and widely consumed in Japan, especially when grilled. Understanding their flavor characteristics from sensory and compositional perspectives is essential to improve the quality of processed salmonid products. However, scientific knowledge in this area remains limited. This study aimed to explore compounds contributing delicious flavor of grilled salmon by performing correlation analysis between sensory evaluation and volatile profiles of five grilled salmonid species. Methods: To characterize each sample, sensory evaluation using paired comparisons and comprehensive analysis of volatile compounds by gas chromatography/mass spectrometry (GC/MS) were conducted. To select compounds strongly associated with the “delicious flavor of grilled salmon”, orthogonal partial least squares regression (OPLSR) and gas chromatography/olfactometry (GC/O) were performed. A subset of the selected candidate compounds was quantified, and additive tests on the samples were carried out based on their concentrations. Results: Sensory evaluation revealed clear differences in flavor profiles among the five salmonid species. A total of 344 peaks were detected in all samples, and principal component analysis (PCA) of these data showed grouping trends consistent with those obtained from sensory evaluation. OPLSR using sensory and volatile data as variables, and GC/O analysis identified 23 compounds, including trimethylamine, dimethyl sulfide, and 1-heptanol, as candidates contributing to the characteristic flavor of grilled salmonid species. Sensory evaluation of samples supplemented with a subset of these candidates showed that, particularly at the higher addition level, aroma and flavor tended to approach those of the highly preferred samples. Conclusions: These findings suggest that some of the selected candidate compounds contribute to the formation of delicious flavor of grilled salmon and may be useful for flavor design and quality improvement of processed products made from salmonid species.