Regio- and diastereoselective construction of α-hydroxy-δ-amino ester derivatives via 1,4-conjugate addition of ß,γ-unsaturated N-sulfonylimines.

A first example of 1,4-conjugate addition of ß,γ-unsaturated N-sulfonylimines via the oxonium ylides trapping process was developed. This method afforded a novel and efficient access for the high regio- and diastereoselective construction of α-hydroxyl-δ-amino esters derivatives, which exhibit inhibitory activity on PTP1B and SIRT1 enzymes in vitro. The synthetic potentials and the biological activity of the resulting products were well demonstrated to be promising for drug discovery.

Ethanol fumigation combined with modified atmosphere packaging delays potato greening under light.

Potato greening under light causes post-harvest loss and compromises progress being made in the potato industry. In this study, we investigated the inhibiting effects of ethanol fumigation treatment on potato greening and water loss under light. This paper also examined the different treatments on the relationship between starch granule size and potato greening. Our results suggested that ethanol fumigation combined with modified atmosphere packaging have an effective in improving the overall visual quality and maintained a higher a* value and lower chlorophyll concentration. Ethanol fumigation combined with modified atmosphere packaging treatment deterred greening and water loss compared to the alone treatment. This was due to the larger starch granule size and fewer grana lamellae around the amyloplasts. Our results provide an effectively strategy that treating potatoes with 600 µL L-1 ethanol combined with modified atmosphere packaging to delay potato greening and explain the underlying mechanism of ethanol inhibition of potato greening.

Abscisic acid alleviates chilling injury in cold-stored peach fruit by regulating ethylene and hydrogen peroxide metabolism.

Peach (Prunus persica (L.) Batsch) is susceptible to chilling injury under improper low-temperature storage (2°C-5°C). Previous research has shown that abscisic acid (ABA) alleviates chilling injury in fruits and vegetables, but the potential mechanism is still unclear. To explore its effectiveness and potential mechanism in alleviating chilling injury during cold storage, exogenous ABA was applied to peach fruit by immersion in 100 µmol L-1 solutions for 10 min. In our experiment, ABA alleviated chilling injury by reducing hydrogen peroxide (H2O2) content and ethylene production. In addition, ABA inhibited the expression of the ethylene synthesis-related genes PpACO1 and PpEIN2. At the same time, ABA activated the antioxidant enzymatic pathway and the ascorbate-glutathione (AsA-GSH) cycle, the transcript abundance encoding genes related to antioxidant enzyme activities also changed correspondingly. The results suggested that ABA alleviated chilling injury by scavenging excessive H2O2 by promoting antioxidant enzymes and the AsA-GSH pathway.

Nitric oxide alleviates chilling injury by regulating the metabolism of lipid and cell wall in cold-storage peach fruit.

Peach fruit are prone to development of chilling injury during cold storage at around 0-7 °C. Nitric oxide (NO) has been proven to alleviate chilling injury, but the mechanism was still unclear. In this study, peach fruit were immersed in a NO donor (sodium nitroprusside, SNP) solution for 10 min, then stored at 0 °C. The SNP alleviated chilling injury, including decreasing the internal browning index, malondialdehyde content, electrolyte leakage, and lipoxygenase activity, and maintaining firmness. Furthermore, SNP maintenance of fruit firmness was associated with reduction of xyloglucan endotransglycosylase/hydrolase family member gene expression and decrease of cell wall hydrolase activity, especially the activities of polygalacturonase, xyloglucan endoglycosyl transferase, cellulase, and ß-galactosidase. Meanwhile, SNP regulated the lipid metabolism by up-regulating the expression of genes encoding glycerol-3-phosphate acyltransferase, ketoacy-ACP synthase, phosphatidylinositol bisphosphate and long-chain acyl-CoA. Thus, the results of this study indicate that SNP alleviates chilling injury of post-harvest peach fruit by regulating cell wall and lipid metabolism.