Planta Med 2004; 70(2): 166-170
DOI: 10.1055/s-2004-815495
Original Paper
Analytical Methods
© Georg Thieme Verlag Stuttgart · New York

Sesquiterpene Lactones in Arnica montana: a Rapid Analytical Method and the Effects of Flower Maturity and Simulated Mechanical Harvesting on Quality and Yield

James A. Douglas1 , Bruce M. Smallfield2 , Elaine J. Burgess3 , Nigel B. Perry3 , Rosemary E. Anderson2 , Malcolm H. Douglas2 , V. leAnne Glennie3
  • 1New Zealand Institute for Crop & Food Research Ltd., Ruakura Research Centre, Hamilton, New Zealand
  • 2New Zealand Institute for Crop & Food Research Ltd., Invermay Agricultural Research Centre, Mosgiel, New Zealand
  • 3Plant Extracts Research Unit, New Zealand Institute for Crop & Food Research Ltd., University of Otago, Dunedin, New Zealand
This research was supported by the New Zealand Foundation for Research, Science and Technology contract C02X0211.
Further Information

Publication History

Received: July 30, 2003

Accepted: November 8, 2003

Publication Date:
02 March 2004 (online)

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Abstract

A rapid extraction, clean-up and RPLC procedure suitable for routine quantitative analyses of sesquiterpene lactones (SLs) in Arnica montana is described. Seven SLs were isolated of which tigloyl and methacryloyl esters of helenalin made up over 50 % of the total. This method was applied to analyses of replicated samples of different flower parts, different stages of flower maturity, and herb from different harvest methods. The mean total SL levels were higher in the disk flowers (0.872 % w/w) than the ray flowers (0.712 %), lower in the flower receptacles (0.354 %) and lowest in stems (0.028 %). Relative levels of individual SLs varied significantly between flower parts, especially acetyldihydrohelenalin which had its highest concentration in stems. The total SL contents increased progressively as the flowers matured, from 0.512 % in buds to 0.943 % in withered flowers. Harvesting a range of flower maturities at one time in a simulated mechanical harvest, followed by mechanical separation of low quality stem material gave the same quality as hand harvested A. montana flowers (over 0.8 % total SLs) and the flower yields from the two processes were similar when adjusted for harvesting technique (320 kg dry matter/ha by hand, 295 kg/ha mechanical). Delaying flower harvest until the flower petals had withered greatly improved the SL concentration of the drug.