Changes in affinin contents in Heliopsis longipes (chilcuague) after a controlled elicitation strategy under greenhouse conditions

Abstract Heliopsis longipes (H. longipes) is an endemic plant of the Sierra Gorda, Mexico, whose root crude extract is used as an analgesic, anti-inflammatory and anti-ulcerative. Affinin is the main substance that provides these properties. Affinin concentrations have been seen to vary depending on the time of the year in which it is collected. Controlled cultivation of H. longipes may reduce the synthesis of affinin but using elicitation technique it might be possible to increase and standardize the biosynthesis of this specialized metabolite. The aim of this research was to determine the changes in the affinin contents in H. longipes roots after controlled elicitation using salicylic acid and hydrogen peroxide as elicitors under greenhouse conditions. After a period of acclimation of 150 days for chilcuague plants, both elicitors were foliarly sprayed for two weeks. Besides affinin contents, changes on the biomass production, catalase, superoxide dismutase, phenylalanine ammonia-lyase and valine decarboxylase enzymatic activities in H. longipes were evaluated. The results showed that low doses of both elicitors significantly increased affinin contents in roots in comparison with controls without affecting morphological variables. This increase in affinin was correlated with concomitant increases in enzymatic activities related to stress responses as catalase (CAT), superoxide dismutase (SOD), phenylalanine ammonia-lyase (PAL), as well as the increase in valine decarboxylase activity (VDC), an enzyme related with biosynthesis of aliphatic alkamides as affinin. Thus, controlled elicitation might be an interesting strategy to increase affinin contents in chilcuague cultivated under greenhouse conditions.