Production of iridoids and phenolics by transformed Harpagophytum procumbens root cultures

Harpagophytum procumbens (Devil's claw) is an important medicinal plant, which tubers are used for the treatment of different inflammatory diseases. In this study, the time courses of growth of Devil's claw hairy roots and accumulation of intracellular total iridoids and phenolics were investigated during cultivation under submerged conditions. After 21 days of growth in liquid hormone-free MS medium, a growth index of 81.3 was achieved and the accumulated biomass reached 0.58 g/flask. It was found that the time courses of total iridoids and phenolics production showed almost the same patterns with a maximum on day 21 from the beginning of cultivation (15.93 mg harpagoside equivalents/L and 261 mg gallic acid equivalents/L, respectively). The methanolic extracts possessed relatively high DPPH-radical scavenging properties (IC₅₀ 4.08 mg/mL), while for the culture media no antiradical activity was detected. According to our best knowledge, the present report is the first one dealing with the investigation of transformed root cultures from Harpagophytum procumbens plants.