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Joe-Ann McCoy, Jeanine M. Davis, N. Dwight Camper, Ikhlas Khan and Avula Bharathi

Black cohosh [Actaea racemosa L. syn. Cimicifuga racemosa (L.) Nuttal] is a native North American medicinal plant traditionally harvested for its rhizomes and roots. Black cohosh products were listed in the top 10 selling herbal supplements from 2002 to 2005. As a result of increasing commercial demand, there is a need to develop propagation protocols suitable for production purposes to replace current methods of harvesting from wild populations. The objectives of this study were to 1) determine optimal rhizome propagule division size for successful regeneration, 2) analyze triterpene glycoside concentrations, 3) quantify survival rates after 3 years of production, and 4) evaluate net yield results. Experimental sites included a shade cloth structure in an agricultural research field, a shaded forest interior, and a shaded, disturbed forest edge. Plant emergence, growth, and survival were assessed at each site over a 3-year period. Optimal rhizome division size for propagation was a 10 to 30-g section originating from terminal rhizome portions. Rhizome survival averaged 97% among all treatments tested by year 3 at three sites. No differences in mean triterpene glycoside concentrations were detected between rhizome size classes or sites tested. Mean cimiracemoside concentrations ranged from 0.80 to 1.39 mg·g–1 d/w tissue, deoxyactein 0.47 to 0.92 mg·g–1, and actein 10.41 to 13.69 mg·g–1. No differences in triterpene levels were detected between flowering and nonflowering plants, nor were yields reduced. Net yields from a shade cloth production site were 9 and 17 times higher than a disturbed forest edge and forest site respectively. Black cohosh is a strong candidate for commercial propagation under adequate site selection.

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Valtcho D. Zheljazkov, Andrew M. Jones, Bharathi Avula, Victor Maddox and Dennis E. Rowe

Podophyllotoxin is an anticancer compound found in Indian mayapple (Podophyllum emodii Wall.), American mayapple (Podophyllum peltatum L.), and other species. Podophyllotoxin and its derivatives are used in several commercially available pharmaceutical products such as the anticancer drugs etoposide, teniposide, and etopophos. Currently, the commercial production of podophyllotoxin is based on Indian mayapple. The objective of this study was to estimate podophyllotoxin concentration in American mayapple across its natural habitats in the eastern United States and to identify high podophyllotoxin types that could be used for further selection and cultivar development. Analyses of American mayapple leaves collected from 37 mayapple colonies across 18 states indicated a significant variation in podophyllotoxin, α-peltatin, and β-peltatin content and the presence of chemotypes. Overall, the concentrations of podophyllotoxin, α-peltatin, and β-peltatin in the collected accessions ranged from below detectable levels to 45.1, 47.3, and 7.0 mg·g−1 dry weight, respectively. We classified American mayapple accessions into seven groups: 1) with very high concentration of podophyllotoxin (greater than 20 mg·g−1) and no α- or β-peltatin; 2) high podophyllotoxin (greater than 10 mg·g−1) and no α-peltatin but trace amounts of β−peltatin; 3) medium podophyllotoxin (1 to 10 mg·g−1) and no α- or β-peltatin; 4) low podophyllotoxin (0.05 to 1 mg·g−1) and high α-peltatin; 5) trace amounts of podophyllotoxin and high concentration of α-peltatin and α-peltatin; 6) high α-peltatin and trace amounts of podophyllotoxin or β−peltatin; and 7) high α−peltatin and no podophyllotoxin or β-peltatin. American mayapple was found to grow on various soil types with a range of pH (4.6 to 7.6) and dissimilar concentrations of phytoavailable soil nutrients. Tissue zinc concentration was positively correlated to podophyllotoxin, whereas soil and tissue phosphorus was positively correlated to the concentration of α-peltatin. The results from this study may contribute toward the development of high podophyllotoxin-containing varieties of American mayapple and the development of a new cash crop for American farmers.