In vitro procuction of scopolamine and hyoscyamine: influence of different elicitors on hairy root cultures of Brugmansia candida

RESUMO

The tropane alkaloids scopolamine and hyoscyamine arestill extracted from plants that belong to several species of Solanaceae because their chemical syntesis is difficult and expensive. These anticholinergic agents are employed in medicine as antispasmodics, preoperative medication and for the treatment of motion sickness. In our laboratory, hairy roots of Brugmansia candida, a South American plant which both alkaloids, were obtained through transformation with Agrobacterium rhizogenes and cultured in vitro. To increase the productivity of the cultures, these were exposed to different elicitors: CaCl2, salicylic acid and autoclaved roots of B. candida. The effects on growth, alkaloid accumulation and release into the medium were evaluated. CaCl2 at 50.00 and 100.00 mM, increased the accumulation of scopolamine and hyoscyamine after 24 hours ( 30-60per cent), while after 48 hour levels of 50.00 mM decreased their accumulation ( 50per cent). No effect was observed on release of alkaloids into the medium. Salicylic acid, a compound involved in plant defense, at 0.01 and 1.00 mM increased accumulation of booth alkaloids (ranging from 30 to 170 per cent), particularly after 24 and 48 hours. There was also increase in the release of scopolamine and hyoscyamine into the medium. The homogenized roots had a positive effect on alkaloid accumulation in the roots throughout the experiment (ranging from 100 to 500 per cent). This was most noticeable for hyoscyamine, particulary after 24 and 72 hours of exposition. The results seen with homogenized roots are probably due to endogenous elicitors which are liberated in the subsequent steps of autoclaving and sonication.