Post-harvest and scale-up extraction of American mayapple leaves for podophyllotoxin production

Leaves of American mayapple (Podophyllum peltatum L.) are of interest to the pharmaceutical industry as an alternative source of podophyllotoxin, an aryltetralin lignan that is the precursor of widely used anticancer drugs etoposide, teniposide, and etopophos. In this study, the effects of post-harvest handling were evaluated by inflicting physical damage to leaves of mayapple to simulate rough handling. The effects of storage conditions before and after being dried were also evaluated. In addition, techniques for conducting large-scale extractions of podophyllotoxin from bulk samples were investigated. Crushing injury, damaging the leaves in more than 70% of its area, has improved podophyllotoxin content of leaves when dried at 40 ◦C within 24 h of harvest. In contrast, podophyllotoxin content was greatly reduced when the leaves were dried at room temperature at 15% relative humidity and 24 ◦C. Podophyllotoxin was stable with no significant changes over time when the leaves were dried, ground, and stored under different conditions for up to 60 days. Based on these findings, mayapple leaves do not require careful handling at harvest. In fact, leaves can be handled in a manner consistent with mechanical injury as long as leaves are dried at 40 ◦C within 24 h. Leaves can then be stored for up to 60 days, and probably much longer, when dry. If leaves cannot be dried in a timely manner, they can be stored at 4 ◦C for up to 4 weeks without significant loss of podophyllotoxin. © 2005 Elsevier B.V. All rights reserved.