Pear is one of the most popular fruits in the world. With the fruit ripening, a series of physiological changes have taken place in fragrant pear, but up to now, the research on the metabolism and biological activity of phenolic compounds in different growth stages of fragrant pear is still lacking. In this study, four kinds of Xinjiang pears were selected as research objects, and the changes of phenolic content, antioxidant capacity, cell protection and whitening activity during fruit development were analyzed. The results showed that the phenolic content and antioxidant capacity of four pear varieties presented a decreasing trend throughout the developmental stages. The phenolic content and antioxidant activity of the four pears in the young fruit stage were the highest, and the active ingredients of the Nanguo pear were higher than the other three pear fruits. Pear extract could protect cells by eliminating excessive ROS in cells, especially in young fruit stage. The western blot results showed that the extract of fragrant pear in the young fruit stage could inhibit the expression of TYR, TYR1 and MITF in B16 cells, and it was speculated that the extract of fragrant pear in the young fruit stage might have good whitening activity. Therefore, the findings suggest that young pear display a good antioxidant potential and could have a good application prospect in food preservation and health product industry.

Hyaluronic acid (HA) is an acidic mucopolysaccharide of animal origin composed of repeating disaccharide units of N-acetylglucosamine and glucuronic acid. Due to its excellent biocompatibility, biodegradability, and selective affinity for CD44 receptors on cell surfaces, HA is widely employed as a drug carrier. In our study, we aimed to target subcellular bacteria by grafting cystamine onto HA scaffolds through an amide reaction, producing a linker responsive to H₂S and pH changes. Subsequently, hydrophobic dodecylamine was attached to HA, forming amphiphilic molecules. These amphiphilic entities can self-assemble into nanomicelles in an aqueous solution, thereby encapsulating the antibacterial agent triclosan (TCS). The resulting HA-based system (HASS-TCS) can be internalized via CD44-mediated endocytosis, releasing substantial amounts of streptomycin and TCS in H₂S-rich and acidic environments. Additionally, HASS-TCS has demonstrated effectiveness in eradicating biofilms and addressing intracellular infections caused by Salmonella. This study underscores a novel pH-sensitive hyaluronic acid-based drug delivery system with significant potential for the effective treatment of intracellular infections.

In order to discover more promising anti-fungal agents, a series of benzoxazole family was synthesized by PPA-catalyzed condensation and a Raney nickel/hydrazine reduction. Altogether 45 compounds were obtained in good to excellent yields and characterized by FT-IR, NMR, MS, and X-ray crystal diffraction. Moreover, the biological activity against eight phytopathogenic fungi was investigated. All in all, most of these compounds bear moderate antifungal activities. Among them, three candidates show the strongest activities, compound 4ac, 4bc provided over 50% inhibition rate against five fungi. Especially, the inhibitory rate of compound 4ah on Mycosphaerella melonis reached 76.4%.

A 2,2,2-trifluroenthanol (TFE) promoted synthesis of unsymmetric ureas was described. This approach enabled the construction of a variety of ureas from the readily prepared and easy-to-handle dioxazolones and amines via tandem Lossen rearrangement/condensation process. The reaction featured mild conditions for the urea synthesis under metal-free conditions, which was successively applied in the scale-up synthesis of herbicides Monuro and Isoproturon. Graphical Abstract

An asymmetric synthesis of (8Z,21R)-21-methylpentatriacont-8-ene, the sex pheromone of the yellow-spotted longicorn beetle Psacothea hilaris, has been achieved using Evan’s induction as the key step. Based on the asymmetric methylation product of chiral (R)-4-benzyl-1,3-oxazolidin-2-one, the carbon chain of the target molecule was assembled through a C₅+C₁₂+C₁₁+C₈ sequence. (2R)-4-(Benzyloxy)-2-methylbutan-1-ol, which can be obtained from γ-lactone following Evan’s protocol, was connected to a C₁₂ alkyl group. The chiral methyl group remained the key moiety (97% ee). After another Wittig reaction and catalytic hydrogenation step, the designed key intermediate (13R)-13-methylheptacosan-1-ol was obtained. Finally, after oxidation and Wittig reaction, the synthesis of the target molecule was completed in 10 linear steps with an ultra-high overall yield of 36.2%.

Bioinformatics studies of fruit responses to postharvest mechanical damage provide crucial insights for cultivar improvement, logistics optimization, and q