Phenolic compounds and antioxidant activity of sunflower hybrids inoculated with broomrape

Abstract

Phenolic compounds such as polyphenols, tannins and flavonoids as well as antioxidant activity, play an important role in the plant defense mechanisms. The above mentioned parameters were measured in four sunflower hybrids (NORH-34, HOB-2, IMI-3-911 and NS-H-111) inoculated with broomrape (sunflower root parasitic plant). The synthesis and accumulation of these compounds depended on genotype and broomrape inoculation. Total phenolic content in healthy sunflower root tissue ranged from 2.87 up to 10.53 mg, while in infected root tissue this parameter ranged from 6.06 to 12.66 mg gallic acid equivalents/g dry root weight. Total tannins content in healthy root ranged from 2.01 to 6.74 and in infected root from 4.30 to 8.17 mg gallic acid equivalents/g dry root weight. Total flavonoids in healthy root tissue were within the range 3.36-44.94 and in infected root tissue 35.35-83.89 mg of rutin equivalents/g dry root weight. Antioxidant activity in sunflower roots correlated with the total phenolic and total tannins and flavonoids content.