In this paper, the effect of isosteviol on the physiological metabolism of Brassica napus seedlings under salt stress is explored. Brassica napus seeds (Qinyou 2) were used as materials, and the seeds were soaked in different concentrations of isosteviol under salt stress. The fresh weight, dry weight, osmotic substance, absorption and distribution of Na⁺, K⁺, Cl⁻, and the content of reactive oxygen species (ROS) were measured, and these results were combined with the changes shown by Fourier transform infrared spectroscopy (FTIR). The results showed that isosteviol at an appropriate concentration could effectively increase the biomass and soluble protein content of Brassica napus seedlings and reduce the contents of proline, glycine betaine, and ROS in the seedlings. Isosteviol reduces the oxidative damage to Brassica napus seedlings caused by salt stress by regulating the production of osmotic substances and ROS. In addition, after seed soaking in isosteviol, the Na⁺ content in the shoots of the Brassica napus seedlings was always lower than that in the roots, while the opposite was true for the K⁺ content. This indicated that under salt stress the Na⁺ absorbed by the Brassica napus seedlings was mainly accumulated in the roots and that less Na⁺ was transported to the shoots, while more of the K⁺ absorbed by the Brassica napus seedlings was retained in the leaves. It is speculated that this may be an important mechanism for Brassica napus seedlings to relieve Na⁺ toxicity. The spectroscopy analysis showed that, compared with the control group (T1), salt stress increased the absorbance values of carbohydrates, proteins, lipids, nucleic acids, etc., indicating structural damage to the plasma membrane and cell wall. The spectra of the isosteviol seed soaking treatment group were nearly the same as those of the control group (T1). The correlation analysis shows that under salt stress the Brassica napus seedling tissues could absorb large amounts of Na⁺ and Cl⁻ to induce oxidative stress and inhibit the growth of the plants. After the seed soaking treatment, isosteviol could significantly reduce the absorption of Na⁺ by the seedling tissues, increase the K⁺ content, and reduce the salt stress damage to the plant seedlings. Therefore, under salt stress, seed soaking with isosteviol at an appropriate concentration (10⁻⁹~10⁻⁸ M) can increase the salt resistance of Brassica napus seedlings by regulating their physiological and metabolic functions.

Melt blending is an effective way to prepare new composite materials, but most polymers are incompatible. In order to reduce the interfacial tension and obtain fine and stable morphology with internal symmetric micro-textures, suitable compatibilizers should be added to the blend. The two immiscible polymers, low-density polyethylene (LDPE) and polystyrene (PS), were compatibilized by styrene/ethylene/butylene/styrene block copolymers grafted with maleic anhydride (SEBS-g-MAH) and organomontmorillonite (OMMT). The scanning electron microscope results indicated that the size of the PS phase decreased with increasing the content of SEBS-g-MAH. By introducing OMMT into LDPE/PS/SEBS-g-MAH composites, the compatibility of composites was further improved. The rheological analysis and Cole–Cole plot analysis indicated that the addition of SEBS-g-MAH and OMMT increased the interaction between the two phases. The tensile strength, elongation at break, and impact strength of the LDPE/PS/SEBS-g-MAH (70/30/7, wt%) composite increased by 64%, 255%, and 380%, respectively, compared with the LDPE/PS (70/30, wt%) composite. A small amount of OMMT could synergistically compatibilize the LDPE/PS composite with SEBS-g-MAH. After adding 0.3% OMMT into the LDPE/PS/SEBS-g-MAH system, the tensile strength, elongation at break, and impact strength of the composite were further increased to 18.57 MPa, 71.87%, and 33.28 kJ/m², respectively.

(-)-Epigallocatechin gallate (EGCG) possesses potent bioactivities but its applications in functional cosmetics is severely limited by its poor water solubility and chemical instability. To overcome these challenges, this study engineered a recombinant levansucrase from Vibrio natriegens to catalyze the transfructosylation of EGCG. The conversion rate of EGCG to fructoside reached 65.59%. The purified product was unequivocally identified as EGCG-1F, with a fructosyl group linked to the 3′-hydroxyl group. Compared to pristine EGCG, EGCG-1F exhibited remarkably enhanced water solubility (96.6-fold that of EGCG) and aqueous stability under acidic and thermal conditions. Biological evaluation revealed that EGCG-1F significantly enhanced HaCaT cell migration, upregulated the expression of basement membrane-associated collagens in ultraviolet B-damaged HaCaT cells, and modulated ultraviolet A-induced senescence in human dermal fibroblasts by type I collagen, type III collagen and matrix metalloproteinase-1 balance. This study demonstrates that enzymatic fructosylation is an effective approach to generate a stable and safe EGCG derivative with potential applications in skin barrier repair and anti-aging functional cosmetics.

Epigallocatechin gallate (EGCG), the predominant catechin in green tea, has limited application due to its poor water solubility and instability. To addres