Hongzao He

Safflower (Carthamus tinctorius L.) is a cash crop grown worldwide. Its seeds and flowers are primarily processed for edible oil and medicinal raw materials, while stems and leaves are discarded as agricultural waste. Recently, plant-derived exosome-like nanoparticles (PELNs) have gained growing research interest in food nutrition owing to their exceptional biocompatibility and relatively low cost for large-scale production. This study aimed to explore the potential functional value of safflower leaf agricultural waste by isolating safflower-derived PELNs. Firstly, a protocol was established for the isolation and purification of safflower (Carthamus tinctorius L.)-derived exosome-like nanoparticles (Ct-ELNs) from safflower leaves using sucrose density gradient ultracentrifugation. NTA analysis revealed that the 30–45% sucrose fraction enriched with Ct-ELNs exhibited the most uniform particle size, highest particle concentration, and optimal purity. Transmission electron microscopy confirmed typical PELNs ultrastructure: disc- or cup-shaped vesicles surrounded by bilayer lipid membranes. FM4-64 fluorescence suggests time-dependent association and likely cellular uptake of labeled Ct-ELNs by IPEC-J2 cells. Cellular assays demonstrated that Ct-ELNs elevated IPEC-J2 cell metabolic activity under matched protein-normalized dosing conditions. The 30–45% sucrose fraction showed the most favorable physicochemical profile and preliminary in vitro protective effects, including improved IPEC-J2 cell metabolic activity and modulation of Enterotoxigenic Escherichia coli (ETEC)-induced inflammation-related gene expression. Overall, this study established an optimized isolation protocol for Ct-ELNs derived from safflower leaves. These data indicate that safflower-derived Ct-ELNs confer preliminary cytoprotective transcriptional regulatory effects on intestinal epithelial cells under in vitro culture conditions.

Laifeng ginger (Zingiber officinale cv. Fengtoujiang) is a famous Geographical Indication (GI) ginger variety, which grows specifically in Laifeng County, Hubei, China. In recent years, it faced a serious food safety issue of lead (Pb) exceedance in the rhizomes even though the Pb content in the soil remains at a safe level. This problem severely hinders the local ginger’s market growth. In the present study, a field study across 37 Laifeng ginger farms revealed a connection between the occurrence of Pb exceedance and the choices of fertilizers. Cultivation experiments demonstrated that with more organic fertilizer (OF) applied, the Pb of rhizome effectively declined, and the branching and longitudinal growth were enhanced. The OF application facilitated Pb translocation from rhizomes to stems and leaves. Furthermore, we showed that OF improved the soil properties by altering the pH and the composition of soil microbial communities at the genus level, which was likely to be associated with reduced the Pb content in the ginger rhizomes. This research tackles the critical industry issue of Pb exceedance in Laifeng ginger, providing a basis for the fertilization of root and tuber plants with excessive heavy metal levels, and establishes a foundation for sustainable GI product development.