Transcriptomic and metabolomic analysis reveals the difference between large and small flower taxa of Herba Epimedii during flavonoid accumulation

Exploring regulatory network of icariin synthesis in Herba Epimedii through integrated omics analysis

Herba Epimedii's leaves are highly valued in traditional Chinese medicine for their substantial concentration of flavonoids, which play a crucial role in manifesting the plant's therapeutic properties. This study investigated the metabolomic, transcriptomic and proteomic profiles of leaves from two Herba Epimedii cultivars, Epipremnum sagittatum (J) and Epipremnum pubescens (R), at three different developmental stages. Metabolite identification and analysis revealed a total of 1,412 and 1,421 metabolites with known structures were found. Flavonoids made up of 33%, including 10 significant accumulated icariin analogues. Transcriptomic analysis unveiled totally 41,644 differentially expressed genes (DEGs) containing five encoded genes participated in icariin biosynthesis pathways. Totally, 9,745 differentially expressed proteins (DEPs) were found, including Cluster-47248.2.p1 (UDP-glucuronosy/UDP-glucosyltransferase), Cluster-30441.2.p1 (O-glucosyltransferase), and Cluster-28344.9.p1 (anthocyanidin 3-O-glucoside 2 "-O-glucosyltransferase-like) through proteomics analysis which are involved to icariin biosynthesis. Protein-protein interaction (PPI) assay exhibited, totally 12 proteins showing a strong relationship of false discovery rate (FDR) <0.05 with these three proteins containing 2 leucine-rich repeat receptor kinase-like protein SRF7, and 5 methyl jasmonate esterase 1. Multi-omics connection networks uncovered 237 DEGs and 72 DEPs exhibited significant associations with the 10 icariin analogues. Overall, our integrated omics approach provides comprehensive insights into the regulatory network underlying icariin synthesis in Herba Epimedii, offering valuable resources for further research and development in medicinal plant cultivation and pharmaceutical applications.

New insights of flavonoid glycosidases and their application in food industry

Flavonoids are significant natural nutraceuticals and a key component of dietary supplements. Given that flavonoid glycosides are more plentiful in nature and less beneficial to human health than their aglycone counterparts, they serve as potential precursors for flavonoid production. Glycosidases have shown substantial potential within the food industry, particularly in enhancing the organoleptic properties of juice, wine, and tea. When applied to food resources, glycosidases can amplify their biological activities, thereby improving the performance of functional foods. This review provides up-to-date information on flavonoid glycosidases, including their catalytic mechanisms, biochemical properties, and natural sources, as well as their applications within the food industry. The use of flavonoid glycosidases in improving food quality is also reviewed.

New 8-prenylated quercetin glycosides from the flowers of Epimedium acuminatum and their testosterone production-promoting activities

Phytochemical investigation was carried out for the flowers of Epimedium acuminatum Franchet. by first conducting LC-MS analysis, leading to the identification of 32 compounds. Furthermore, guided by LC-MS profiling, three new 8-prenylated quercetin glycosides (3′-hydroxylikarisoside C, 3′-hydroxylepimedoside E, 3′-hydroxyldiphylloside B), one new anthocyanin (delphinidin-3-O-p-coumaroyl-sophoroside) and six known compounds were isolated from the flowers of E. acuminatum for the first time, and their structures were characterized based on spectroscopic methods including 1D and 2D NMR, and HRESIMS. Combining our discoveries and literature survey, a revised classification of Epimedium flavonols was proposed as Type A (8-prenylated kaempferol based), which was further subdivided into subtype icaritin and subtype demethylicaritin, and Type B (8-prenylated quercetin based), which was further subdivided into subtype 3′-hydroxylicaritin and subtype 3′-hydroxyldemethylicaritin. The structure-activity relationship (SAR) study was carried out by comparing testosterone production-promoting activities of all the new compounds along with nine related Epimedium flavonols, revealing that the new 8-prenylated quercetin glycosides (subtype 3′-hydroxyldemethylicaritin in Type B) exhibited lower testosterone production-promoting activities in rat primary Leydig cells than Epimedium flavonols of subtype demethylicaritin in Type A, but possessed higher activities than the Epimedium flavonols of subtype icaritin in Type A. These results suggested that either methylation at C-4′ position or hydroxylation at C-3′ position of ring B could significantly reduce the testosterone production-promoting activities of Epimedium flavonols.