Structure and radical scavenging activity relationships of pyrolytic lignins.

This work deals with antioxidant properties of pyrolytic lignins against two free radicals, 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid). Pyrolytic lignins produced by the thermal pyrolysis of the Etek lignin were extracted from the liquid pyrolysis product and fractionated using solvents of different polarities. The main functional groups linked to the lignin skeleton have been characterized by (1)H NMR and (19)F NMR upon acetylation and trifluoromethylation, respectively.

Ecdysteroids act as inhibitors of calf skin collagenase and oxidative stress.

Three new phytoecdysteroids have been isolated from the seeds of Chenopodium quinoa and structurally identified as 20,26-dihydroxy, 28-methyl ecdysone, 20,26-dihydroxy, 24(28)-dehydro ecdysone, and 20-hydroxyecdysone 22-glycolate using serial chromatographic and spectroscopic methods. Both previously reported compounds and newly identified phytoecdysteroids were evaluated for their inhibitory effect on calf skin collagenase, as this enzyme is involved in aging skin diseases. Their effectiveness on scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals, as well as in chelating the iron metal ions was also investigated.