Effects of intermittent-direct-electric-current (IDC) on polyphenols and antioxidant activity in radish (<em>Raphanus sativus</em> L.) during growth


  • D. Dannehl
  • S. Huyskens-Keil
  • I. Eichholz
  • C. Ulrichs
  • U. Schmidt


In the present study the effects of intermittent-direct-electric-current (IDC; for one hour per day) on phenolic compounds and antioxidant activity in radish (Raphanus sativus L.) was studied. The radish plants were cultivated in rock wool substrate in combination with drip irrigation. Two stainless steel plates were added on the rock wool substrate and acted as electrodes to supply the currents to the plants. Three different IDC treatments (200 mA, 600 mA, and 1000 mA) were applied during growth period and passed horizontally through the nutrient solution as well as through the tissue of the radish plants. After 16 days of growth the radish plants were randomly harvested, divided into three segments (root, tuber, shoot) and were used for the determination of total phenolic content, anthocyanins, and antioxidative activity.
This new technology increased the health-promoting phytochemical compounds in radish segments with no sign of damage. In radish tubers total phenol content, anthocyanins, and antioxidant activity increased with increasing IDC. The same was observed for the total phenol content in radish roots. However in contrast, the phenolic compounds of radish shoots remained unaffected by IDC. In conclusion IDC can serve as a general mean to stimulate the synthesis of phenolic compounds and associated antioxidant activity in radish tubers.