Huw H. Rees

Publications (3)4.71 Total impact

• Article: Phytoecdysteroids in seeds and plants of Rhagodia baccata (Labill.) Moq. (Chenopodiaceae)

  Laurence Dinan, Satyajit D. Sarker, Pauline Bourne, Pensri Whiting, Vladimir Šik, Huw H. Rees
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  ABSTRACT: Seeds of Rhagodia baccata afforded, in addition to 20-hydroxyecdysone and polypodine B, a novel phytoecdysteroid, (20R)-22-deoxy-20,21-dihydroxyecdysone, the structure of which was elucidated unequivocally by UV, LSIMS and NMR techniques. This compound possessed agonistic activity in the Drosophila melanogaster BII cell bioassay, with an ED50 value of 2.0 × 10–7M (ED50 value for 20-hydroxyecdysone = 7.5 × 10–9M). The distribution of ecdysteroids in plants of R. baccata has been determined. Highest levels are associated with the youngest aerial tissues and with the roots. Ecdysteroid profiles are qualitatively very similar throughout the plant, with 20-hydroxyecdysone and polypodine B predominating in all plant parts tested. Arch. Insect Biochem. Physiol. 41:18–23, 1999. © 1999 Wiley-Liss, Inc.
  Archives of Insect Biochemistry and Physiology 05/1999; 41(1):18 - 23. · 1.36 Impact Factor
• Article: 20-Hydroxyecdysone 2-β-d-glucopyranoside from the seeds of Xerophyllum tenax

  Brenda Alison, Pensri Whiting, Satyajit D. Sarker, Laurence Dinan, Eric Underwood, Vladimir Šik, Huw H. Rees
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  ABSTRACT: Bioassay/RIA-directed HPLC purification of a MeOH extract of the seeds of Xerophyllum tenax yielded 20-hydroxyecdysone and 20-hydroxyecdysone 2-β-d-glucopyranoside, the latter being a novel natural product. The structures were elucidated primarily on the basis of 1D and 2D NMR spectroscopic evidence. The ecdysteroid agonist activity of these isolates was determined on the BII tumorous blood cell line of Drosophila melanogaster. ED50 values for 20-hydroxyecdysone and 20-hydroxyecdysone 2-β-d-glucopyra-noside were found to be 8.0 × 10−9M and 1.3 × 10−4M, respectively. The significance of the presence of ecdysteroid conjugates in plants is discussed.
  Biochemical Systematics and Ecology.
• Article: Moschatine: an unusual steroidal glycoside from centaurea moschata

  Satyajit D Sarker, Laurence Dinan, Vladimir Šik, Huw H Rees
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  ABSTRACT: High-performance liquid chromatographic analysis of the seeds of Centaurea moschata has afforded a novel steroidal glycoside: moschatine [(20S)-20-{6-O-(3-methoxy-4-α-l-rhamnopyranosyloxybenzoyl)-β-d-glucopyranosyloxy}-15α-hydroxy-8β,9α,14α,17α-pregn-4-en-3-one]. The structure of this compound was elucidated by a combination of UV, LSIMS, and a series of 1D and 2D NMR spectral analyses.
  Phytochemistry 48(6):1039-1043. · 3.35 Impact Factor