Natural product P57 induces hypothermia through targeting pyridoxal kinase.

Induction of hypothermia during hibernation/torpor enables certain mammals to survive under extreme environmental conditions. However, pharmacological induction of hypothermia in most mammals remains a huge challenge. Here we show that a natural product P57 promptly induces hypothermia and decreases energy expenditure in mice. Mechanistically, P57 inhibits the kinase activity of pyridoxal kinase (PDXK), a key metabolic enzyme of vitamin B6 catalyzing phosphorylation of pyridoxal (PL), resulting in the accumulation of PL in hypothalamus to cause hypothermia. The hypothermia induced by P57 is significantly blunted in the mice with knockout of PDXK in the preoptic area (POA) of hypothalamus. We further found that P57 and PL have consistent effects on gene expression regulation in hypothalamus, and they may activate medial preoptic area (MPA) neurons in POA to induce hypothermia. Taken together, our findings demonstrate that P57 has a potential application in therapeutic hypothermia through regulation of vitamin B6 metabolism and PDXK serves as a previously unknown target of P57 in thermoregulation. In addition, P57 may serve as a chemical probe for exploring the neuron circuitry related to hypothermia state in mice.

Highly enantioselective transfer hydrogenation of racemic α-substituted ß-keto sulfonamides via dynamic kinetic resolution.

Highly enantioselective transfer hydrogenation of ß-keto sulfonamides was developed via dynamic kinetic resolution using a chiral Ru(ii) catalyst with an azeotropic solution of HCO2H/Et3N as a hydrogen donor, affording α-substituted ß-hydroxyl sulfonamides in good yields with excellent diastereo- and enantioselectivities. This method is featured with mild conditions, easy operation, and a broad substrate scope, which make it possible to find wide applications in the synthesis of natural products and biologically active compounds containing the α-substituted ß-hydroxyl sulfonamide core.