Organ-specific and environmental control of accumulation of psychollatine,a major indole alkaloid glucoside from Psychotria umbellata

Psychollatine is an unusual indole alkaloid produced by Psychotria umbellata Vell, an Atlantic Forest understorey tree. Leaves, young inflorescences and fruit pulp displayed high amounts of psychollatine (from 2.5 to 4.5% dry wt). Seeds accumulated lower quantities (0.2% dry wt), and roots, trace amounts (0.06% dry wt). Alkaloid accumulation was not seasonally affected and leaf content was not significantly enhanced by wounding, exposure to salicylic acid, hydrogen peroxide, or UV. The alkaloid content in leaves decreased upon cutting exposure to auxin. Under strong UV, the amount of chlorophylls did not decrease compared to control contents at 48 and 72 h. Post-harvest psychollatine content in leaves was stable in different temperatures, except at 65 °C. Psychollatine was an effective singlet oxygen, superoxide, and peroxide quencher. These antioxidant properties and the constitutively high amount of psychollatine indicate a role for the alkaloid in oxidative stress responses.