|McCoy, Joe Ann|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2006
Publication Date: 12/20/2006
Citation: Mccoy, J.H., Davis, J.M., Camper, N.D., Kahn, I., Bharathi, A. 2006. Influence of rhizome propagule size on yields and triterpene glycoside concentrations of black cohosh (Actaea Racemosa L.). HortScience. 42(1):61-64.
Interpretive Summary: Actaea racemosa L. (black cohosh) is a native North American plant whose medicinal use predates European settlement and continues to be widely used today. Rhizomes have been harvested and used for medicinal purposes by native North American Indians, early American and European physicians, and also served as a primary ingredient in the famous Lydia Pinkham patented medicine of the early 1900’s (Foster, 1999; Upton, 2002). The German government’s safety regulatory board, the Commission E, has approved the use of black cohosh for specific symptoms associated with menopause which is the primary focus for current demand (Blumenthal et al., 1998). Black cohosh based products have consistently been listed in the top ten selling herbal supplements from 2002-2005 (Blumenthal, 2003). The majority of commercial black cohosh material is wildharvested exclusively from Eastern North American hardwood forests where it grows as an understory, shade-tolerant, hardy perennial. Due to increasing harvest pressures, black cohosh is listed among the top species of concern on both The Nature Conservancy and The United Plant Saver’s lists of medicinal species at risk due to wild-collection (Nielsen, 2002; United Plant Savers, 1997). Both rhizomes and roots are harvested and standardized to various concentrations of three triterpene glycosides, actein, deoxyactein, and cimiracemoside A. Large variations in triterpene glycoside constituents among various commercial products have been reported (Ganzera et al., 2000) Influence of production environment or methods on consituent concentrations is not well documented or understood. The overall objective of this study was to experimentally determine if a successful rhizome propagation protocol could be established for future field and/or forest production purposes in the Southeastern Appalachian Mountains within the native range of black cohosh. Specific objectives were to: 1.) determine optimal rhizome propagule division size for successful regeneration; 2.) analyze triterpene glycoside concentrations between rhizome propagule size classes tested; 3.) quantify survival rates after three years of production; and, 4.) evaluate net yield results. Robust rhizome propagation was observed without soil amendments or fertilizer addition at all sites. Of three sites tested, a site using agricultural Shadecloth produced net rhizome yields 9-17 times higher and net seed yields 53 times higher than two forest sites tested. Yields at the Disturbed Forest site were 1.8 times higher than those of the Forest site. All rhizome section size classes tested had excellent survival rates but propagules originating from terminal meristematic portions of the rhizome produced higher net rhizome and seed yields. Future spacing and soil amendment studies are necessary to optimize yields. Selection studies are also necessary to establish superior genotypes. When rhizomes were analyzed for variation in triterpene glycoside concentrations, there were no differences between sites or treatments tested although there was variability between individuals. In conclusion, Actaea racemosa is a strong candidate for commercial propagation under adequate site selection.
Technical Abstract: 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 ten selling herbal supplements from 2002-2005. Due to increasing commercial demand there is a need to develop propagation protocols suitable for production purposes to replace current methods of harvesting from wild populations. Objectives of this study were to: 1.) determine optimal rhizome propagule division size for successful regeneration; 2.) analyze triterpene glycoside concentrations between rhizome propagule size classes tested; 3.) quantify survival rates after three years of production; and 4.) evaluate net yield results. Experimental sites included a shadecloth 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 three-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 three 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 d/w tissue, deoxyactein 0.47 to 0.92 mg/g and actein 10.41 to 13.69 mg/g. No differences in triterpene levels were detected between flowering and non-flowering plants nor were yields reduced. Net yields from a shadecloth 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.