Activation of oxidative burst induces antioxidant response and indole alkaloid production in Uncaria Tomentosa root cultures

• Published in: Planta Medica
• Main Authors: Huerta-Heredia, AA, Vera-Reyes, I, Ponce-Noyola, T, Cerda-García-Rojas, CM, Trejo-Tapia, G, Ramos-Valdivia, AC
• Format: Conference Proceeding
• Language: English
• Published: 19.07.2012
• ISSN: 0032-0943; 1439-0221
• DOI: 10.1055/s-0032-1320344

Uncaria tomentosa (cat's claw), an indigenous plant from the Amazon rainforest, is the source of monoterpenoid oxindole alkaloids (MOA) with immunomodulatory and antitumor activities. In cell cultures, production of these alkaloids has been stimulated by hydrodynamic stress via oxidative burst, while in root cultures, the role of reactive oxygen species in alkaloid production has not been fully examined. Roots were grown in 200 mL airlift bioreactors using a 4% (w/v) inoculum, reaching a total biomass of 21.1±0.8g dry wt L -1 after 65 days. Within the first hour of culture, a H 2 O 2 peak (0.34µmol g -1 dry wt) was observed, indicating that oxidative burst occurred. In order to register the root redox state, activity of antioxidant enzymes was monitored. SOD and POD showed activity peaks of 340±5 U mg prot -1 and 546±8µM min -1 mg prot -1 5 days after inoculation, while GR and GPx activities remain constant. The oxidative burst and enzyme response were associated with 14 and 6-fold increase of MOA and 3α-dihydrocadambine (DHC) at day five (1.4±0.1 and 6.2±0.7mg L -1 ), also preceded by a two-fold increase of strictosidine synthase and strictosidine glucosidase activities. Enhancement of both activities showed correlation with mRNA transcript level. MOA and DHC production was 12 and 14-fold higher than those found in roots grown in Erlenmeyer flasks.