Podophyllotoxin Content and Yield of American Mayapple Leaves in Sun and Shade

Abstract

<jats:p>Four levels of shade (0%, 30%, 55%, and 80%) were used to determine their effect on growth and lignan content of american mayapple (<jats:italic>Podophyllum peltatum</jats:italic> L.). Mayapple rhizomes were harvested from the wild and transplanted into plant beds on 20 Dec. 2001 using a randomized complete block design with four blocks. Growth and lignan content were recorded during spring of 2002 and 2003. Leaf samples were analyzed for the following lignans: podophyllotoxin, alpha-peltatin, and beta-peltatin. Increasing levels of shade increased shoot longevity, leaf area per plant (cm<jats:sup>2</jats:sup>/plant), and shoot height. Shade did not affect shoot emergence, total leaf area (cm<jats:sup>2</jats:sup>·m<jats:sup>-2</jats:sup>), or leaf dry mass (g·m<jats:sup>-2</jats:sup> or g/plant). Regardless of year, podophyllotoxin and total lignan contents at 0% shade were significantly greater than those at 80% shade, and the overall trend was for decreasing contents with increasing shade. Shade did not affect alpha-peltatin content. Content of beta-peltatin was greatest at 0% shade compared to the other three shade treatments. Year affected alpha-peltatin and beta-peltatin contents, with less content of each in 2003 than in 2002. There were large numerical decreases in podophyllotoxin yield (podophyllotoxin content per unit area, mg·m<jats:sup>-2</jats:sup>) as shade increased from 0% to 80%, but these differences were only marginally significant (<jats:italic>P</jats:italic> = 0.0897). In contrast, podophyllotoxin yield was significantly greater in 2003 than in 2002 as total leaf area and dry mass significantly increased. Increasing levels of shade slightly decreased air and soil temperatures. Our results indicate that american mayapple is not a shade-requiring species. Under full sun (0% shade) shoots did not persist as long as under shade and leaves were smaller and thicker, but total lignan content was significantly greater than under shade. It appears that growers of specialty crops serving the pharmaceutical industry can establish and cultivate american mayapple under full sun, thus providing leaf biomass with high podophyllotoxin content while avoiding the cost of expensive shade structures.</jats:p>

Frequency and Timing of Leaf Removal Affect Growth and Podophyllotoxin Content of American Mayapple in Shade

“…These differences existed during the fi rst year, before leaf removal treatments were applied, and persisted rather consistently throughout the duration of the study. Differences between the two studies are consistent with reports describing a shift in lignan content from relatively higher podophyllotoxin content and lower peltatin content in full sun to lower podophyllotoxin content and higher peltatin content in shade (Cushman et al, 2005b;Moraes et al 2005).…”

“…If domesticated, it is expected that commercial plantings would use only accessions with the highest levels of the compound, thus providing the highest return to growers of specialty crops serving the pharmaceutical industry (Meijer, 1974;Moraes et al, 2000). Recent research showed the species to be relatively easy to manipulate using common horticultural practices (Cushman et al, 2005a(Cushman et al, , 2005bCushman and Maqbool, 2005). In addition, increasing levels of shade were reported to result in decreasing podophyllotoxin content (Cushman et al, 2005b;Moraes et al, 2005).…”

“…Recent research showed the species to be relatively easy to manipulate using common horticultural practices (Cushman et al, 2005a(Cushman et al, , 2005bCushman and Maqbool, 2005). In addition, increasing levels of shade were reported to result in decreasing podophyllotoxin content (Cushman et al, 2005b;Moraes et al, 2005). Other lignans found in mayapple leaves, of secondary interest as pharmaceutical compounds, are α-peltatin, β-peltatin, and epipodophyllotoxin.…”

Propagule Type and Planting Time Affect Subsequent Mayapple Growth

“…Weed control, pest control, fertilization, and irrigation were identical to that described in Cushman et al (2005a). Construction fabric made of 0.9-m-wide woven plastic material and supported by wooden stakes was installed alongside plots in 2003 and 2004 to reduce wind damage to mayapple shoots and leaves.…”

“…Two-node segments performed better than one-node propagules, and segments chilled 60 days or longer performed far better than those chilled for a shorter duration. Two-node segments harvested from the wild were also used successfully to establish fi eld studies, one exploring increasing levels of shade (Cushman et al, 2005a) and the another exploring the use of organic mulches in combination with different rhizome planting depths (Cushman et al, 2005b).…”