Evaluation of foliar-applied salicylic acid effect on phytochemical traits of the alcoholic extract from different parts of Verbascum songaricum Schrenk.

Verbascum songaricum Schrenk. as a perennial herb belonging to the Scrophulariaceae family has good therapeutic properties. The application of bio-elicitors increases secondary metabolites in sustainable agricultural systems and the improvement of the quality of active ingredients of medicinal plants. In order to evaluate the foliar-applied salicylic acid on phytochemical properties of the leaf and flower of mulch, the present study was done in a randomized complete block design (RCBD) at the field of research center for medicinal plants of Shahrekord during 2016 and 2017. Foliar application of salicylic acid at three levels (control, 0.5 and 1 mM /L) was applied on the flower in three replications in three growth stages of plant. Total phenol content (TPC) in the leaves and flowers was determined by spectrophotometric method and the phenolic acid amount was determined based on gallic acid and flavonoids (flavonol quercetin) in the extracts by HPLC. According to the results, the effect of salicylic acid on the TPC, phenolic acid and flavonoids in the flower (as the main part of plant) extract of the plant was significant. In conclusion, the foliar application of salicylic acid promotes of polyphenolic compounds by 26% in the amount of flavonoids (flavonol quercetin) in flowers and 20% in the amount of phenolic acids (gallic acid) in flowers of Verbascum songaricum.