Pergamon PII: S0305-1978(97)00003- 3 Biochemica/Systematics andEcology. Vol.25. No. 3, pp. 255-261,1997 ¢~1997 Elsevier ScienceLtd All rightsreserved.Printedin GreatBritain 0305-1978/97 $17.00+0.00 20-Hydroxyecdysone 2- -D-Glucopyranoside from the Seeds of Xerophyllum tenax BRENDA ALISON,* PENSRI WHITING,* SATYAJIT D. SARKER,* LAURENCE DINAN,*§ ERIC UNDERWOOD, t VLADIMIR SIKT and HUW H. REESt *Department of Biological Sciences, University of Exeter, Washington Singer Laboratories, Perry Road, Exeter, Devon EX4 4QG, U.K.; tDepartment of Chemistry, University of Exeter, Stocker Road, Exeter, Devon EX4 4QD, U.K.; tDepartment of Biochemistry, The University of Liverpool, P.O. Box 147, Liverpool L69 3BX, U.K. Key Word Index--Xerophyllum tenax; Melanthiaceae; Liliaceae; ecdysteroid; steroid; seeds; Drosophila mela- nogaster, bioassay; chemotaxonomy. Abstract--Bioassay/RIA-directed H PLC purification of a MeOH extract of the seeds of Xerophyllum tenax yielded 20-hydroxyecdysone and 20-hydroxyecdysone 2-~-D-glucopyranoside, the latter being a novel natural product. The structures were elucidated primarily on the basis of 1D and 2D NMR spectroscopic evi- dence. The ecdysteroid agonist activity of these isolates was determined on the Bu tumorous blood cell line of Drosophila melanogaster. EDso values for 20-hydroxyecdysone and 20-hydroxyecdysone 2-~-D-glucopyra- 9 4 noside were found to be 8.0x10- M and 1.3x10- M, respectively. The significance of the presence of ecdysteroid conjugates in plants is discussed. © 1997 Elsevier Science Ltd Introduction Ecdysteroids are insect moulting and metamorphosis hormones which play essential roles at all stages of insect development. Ecdysteroids are also present in a wide range of plant species (Lafont and Wilson, 1996). While the functions of these molecules in plants are still to be proven, the most probable explanation for their presence is that phytoecdysteroids might provide some protection against non-adapted phytophagous insects (Bergamasco and Horn, 1983). Since the discovery of ecdysteroids in plants in 1966 (Nakanishi et al., 1966), ca. 150 ecdysteroids of diverse structures have been iso- lated and identified from many plant species (Lafont and Wilson, 1996). However, understanding of the pattern of distribution of ecdysteroids within the plant kingdom is fragmentary and the significance of the vast array of different phytoecdysteroid struc- tures is obscure. It is necessary to search for new plant sources for ecdysteroids and identify new ecdysteroids in order to have a better understanding about the pattern of distribution of phytoecdysteroids in plants, their possible chemotaxonomic and ecolo- gical implications, and to assess the structure/activity relationship of this class of com- pounds. As a part of our bioassay/RIA-based search for ecdysteroids from new plant sources (Sarker et al., 1996a,b,c, 1997), we have examined the seeds of Xerophyllum tenax Nutt. (Family--Melanthiaceae, according to Brummitt (1992), or Liliaceae [Cronquist, 1981 ]) which is an American perennial herb, with a mass of very narrow leaves densely clustered at the base from which arises a stem, 3-5 ft high, bearing a dense, leafy raceme §Corresponding author. (Received 1 October 1996; accepted 10 December 1996) 255