Elsevier

Steroids

Volume 39, Issue 1, January 1982, Pages 89-105
Steroids

Synthesis of brassinosteroids and relationship of structure to plant growth-promoting effects

https://doi.org/10.1016/0039-128X(82)90129-5Get rights and content

Abstract

A number of brassinosteroids with and without hydroxyl groups or an alkyl stubstituent in their side chain were synthesized. The alkyl substituent at C-24 highly influenced the oxidation of the C-22 double bond with osmium tetroxide and, hence the ratio of the 22β, 23β- and 22α, 23α-glycolic isomers obtained. Two different bean bioassays used to compare the plant growth-promoting capabilities of these compounds and of brassinolide and its three side chain 22,23-cis-glycolic isomers showed that brassinolide was the most active. The next most active brassinosteroids were generally those with 22α-OH, 23a-OH orientation and a β-methyl or α-ethyl substituent at C-24. Similarly, of the synthetic precursor tetrahydroxy ketones of the brassinosteroids, those with 22α-OH, 23α-OH orientation (like brassinolide) and an alkyl group at C-24 were also the most active in both bioassays. The results indicate stringent structural features are required for a steroid to induce brassin activity. The structural requirements are: a trans A/B ring system (5α-hydrogen), a 6-ketone or a 7-oxa-6-ketone system in ring B, cis α-oriented hydroxyl groups at C-2 and C-3, cis hydroxy groups at C-22 and C-23 as well as a methyl or ethyl substituent at C-24.

References (19)

  • M.J. Thompson et al.

    Steroids

    (1981)
  • R.F.N. Hutchins et al.

    Steroids

    (1970)
  • M.J. Thompson et al.

    Steroids

    (1970)
  • W.R. Nes

    Adv. Lipid Res.

    (1977)
  • J.W. Mitchell et al.

    Nature (London)

    (1970)
  • J.F. Worley et al.

    J. Am. Hortic. Soc.

    (1970)
  • J.F. Worley et al.

    Hortic Sci.

    (1972)
  • J.W. Mitchell et al.

    Nature (London) New Biol.

    (1972)
  • M.D. Grove et al.

    Nature (London)

    (1979)
There are more references available in the full text version of this article.

Cited by (144)

  • An introduction to brassinosteroids

    2022, Brassinosteroids in Plant Developmental Biology and Stress Tolerance
  • Effects of Brassinosteroid Associated with Auxin and Gibberellin on Apple Tree Growth and Gene Expression Patterns

    2019, Horticultural Plant Journal
    Citation Excerpt :

    Plant hormones are important for growth, metabolism, and responses to environmental stimuli (Lee et al., 1981; Chiang et al., 1995; Cohen et al., 2003; Nambara and Marion-Poll, 2005). Brassinosteroid (BR), auxin (IAA), and gibberellin (GA) are the main plant growth promoting hormones (Thompson et al., 1982; Wu et al., 1996). BR helps in regulating many biological processes (Li et al., 2006; Lu et al., 2013; Feng et al., 2017).

  • Brassinolide-like activity of castasterone analogs with varied side chains against rice lamina inclination

    2017, Bioorganic and Medicinal Chemistry
    Citation Excerpt :

    Mp 240–242 °C (MeOH/H2O; lit.25 mp 242–244 °C; lit.26 mp 221–222 °C). [

View all citing articles on Scopus
View full text