Stress-induced biosynthesis of dicaffeoylquinic acids in globe artichoke.
Leaf extracts from globe artichoke ( Cynara cardunculus L. var. scolymus) have been widely used in medicine as hepatoprotectant and choleretic agents. Globe artichoke leaves represent a natural source of phenolic acids with dicaffeoylquinic acids, such as cynarin (1,3-dicaffeoylquinic acid), along with its biosynthetic precursor chlorogenic acid (5-caffeoylquinic acid) as the most abundant molecules. This paper reports the development of an experimental system to induce caffeoylquinic acids. This system may serve to study the regulation of the biosynthesis of (poly)phenolic compounds in globe artichoke and the genetic basis of this metabolic regulation. By means of HPLC-PDA and accurate mass LC-QTOF MS and MS/MS analyses, the major phenolic compounds in globe artichoke leaves were identified: four isomers of dicaffeoylquinic acid, three isomers of caffeoylquinic acid, and the flavone luteolin 7-glucoside. Next, plant material was identified in which the concentration of phenolic compounds was comparable in the absence of particular treatments, with the aim to use this material to test the effect of stress application on the regulation of biosynthesis of caffeoylquinic acids. Using this material, the effect of UV-C, methyl jasmonate, and salicylic acid treatments on (poly)phenolic compounds was tested in different globe artichoke genotypes. UV-C exposure consistently increased the levels of dicaffeoylquinic acids in all genotypes, whereas the effect on compounds from the same biosynthetic pathway, for example, chlorogenic acid and luteolin-7-glucoside, was much less pronounced and was not statistically significant. No effect of methyl jasmonate or salicylic acid was found. Time-response experiments indicated that the level of dicaffeoylquinic acids reached a maximum at 24 h after UV radiation. On the basis of these results a role of dicaffeoylquinic acids in UV protection in globe artichoke is hypothesized.
Moglia
Andrea
A
DiVaPRA, Plant Genetics and Breeding, University of Torino, via L. da Vinci 44, 10095 Grugliasco (TO) Italy.
Lanteri
Sergio
S
Comino
Cinzia
C
Acquadro
Alberto
A
de Vos
Ric
R
Beekwilder
Jules
J
D000085:Acetates / Q000494:pharmacology*; D000975:Antioxidants / Q000032:analysis; D003517:Cyclopentanes / Q000494:pharmacology*; D031943:Cynara scolymus / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D054883:Oxylipins / Q000494:pharmacology*; D010636:Phenols / Q000032:analysis; D018515:Plant Leaves / Q000737:chemistry; D011801:Quinic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D020156:Salicylic Acid / Q000494:pharmacology*; D014466:Ultraviolet Rays
D000085:Acetates; D000975:Antioxidants; D003517:Cyclopentanes; D054883:Oxylipins; D010636:Phenols; C472707:caffeoylquinic acid; D011801:Quinic Acid; C072239:methyl jasmonate; D020156:Salicylic Acid