Bioactivity of brassinolide methyl ethers

Luo, Weide; Janzen, Loeke; Pharis, Richard P.; Back, Thomas G.

doi:10.1016/s0031-9422(97)00881-9

Cited by 17 publications

(18 citation statements)

References 14 publications

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“…This kind of conjugation is considered to be a mechanism for brassinosteroids deactivation. Luo et al (1998) prepared a series of methyl ethers of brassinolide (1) to prevent such conjugation and, employing the rice lamina inclination assay, verified that, while brassinolide 23-methyl ether (182) showed weak or low activity even at high dosage (1,000 ng per plant), the 22-methyl ether 183 showed an activity comparable to 24epibrassinolide (6) at dosages up to 100 ng per plant and the 22,23-dimethyl ether 184 even at dosages up to 1,000 ng per plant (see structures of compounds 179-184 in figure 25). Another way of deactivation was the recently shown enzymatic sulfonation of several brassinosteroids, including 24-epibrassinolide (6), with a steroid sulfotransferase from Brassica napus.…”

Section: Biological Activity and Structure-activity Relationshipsmentioning

confidence: 99%

Brassinosteroid phytohormones: structure, bioactivity and applications

Zullo

Adam²

2002

Braz. J. Plant Physiol.

113

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Section: Biological Activity and Structure-activity Relationshipsmentioning

confidence: 99%

Brassinosteroid phytohormones: structure, bioactivity and applications

Zullo

Adam²

2002

Braz. J. Plant Physiol.

113

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“…In fact, inactive 23-OMe BL becomes active upon methylation of the 22-OH group corresponding to a similar increase in the molecular hydrophobicity. 35) Considering these results, we concluded that the oxygen of the 22-OH group works as a hydrogen bond acceptor similar to carbonyl oxygen.…”

Section: Structure-activity Relationship Studymentioning

confidence: 80%

“…Methylation of the 23-OH, which is presumed to be the -OH group of our ester compounds (7)(8)(9)(10)(11)(12)(13), was detrimental to activity. 35) This observation is not consistent with the fact that the activity was maintained by the methylation of the -OH group of the ester side chain. These contradictory results may be due to different physicochemical properties such as hydrophobicity and steric effect differences between compounds containing an ester versus an alkyl moiety.…”

Section: Structure-activity Relationship Studymentioning

confidence: 86%

Synthesis of Brassinosteroids of Varying Acyl Side Chains and Evaluation of Their Brassinolide-like Activity

Uesusuki

Watanabe

Yamamoto

et al. 2004

Bioscience, Biotechnology, and Biochemistry

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Brassinosteroids containing various side chain moieties were synthesized and their activity was determined as the reciprocal logarithm of the ED(50) (50% effective dose per plant in moles) in the rice lamina inclination assay using synergist indole-3-acetic acid (IAA). The introduction of a hydroxyl group in the alpha-position to the carbonyl group of the ester structure significantly enhanced the activity. 2alpha,3alpha-Dihydroxy-17beta-[(2R,3S)-2-hydroxy-3-methylpentanoyl]oxy-B-homo-7-oxa-5alpha-androstan-6-one showed the highest activity, for which the pED(50) was determined to be 10.5 under synergistic conditions with IAA. Under identical conditions, the pED(50) values of brassinolide and castasterone were determined to be 13.6 and 12.3 respectively. With respect to the alpha-carbon of the acyl moiety, the R-form was 10 times more potent than the corresponding S-form. Substituting the terminal structure (Et) of the side chain to that of the most potent compound, brassinolide (i-Pr), did not increase the activity.

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“…Consequently, different research groups have tried to improve the biological activity of the brassinosteroids by blocking some of the metabolic pathways. However, methylation of either of the OH groups of the side chain reduced the biological activity of brassinolide even though the MeO–C(22) brassinolide was more potent than MeO–C(23) brassinolide . Takatsuto et al .…”

Section: Relative Biological Potency Of Brassinosteroid Derivativesmentioning

confidence: 99%

Biological Activity of Brassinosteroids – Direct Comparison of Known and New Analogs in planta

Wendeborn

Lachia

Jung

et al. 2017

Helvetica Chimica Acta

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A systematic investigation of structural modifications of brassinosteroids is presented. We describe in detail their synthetic preparation, which includes significant improvements of previously reported protocols as well as access to new analogs with functional modifications of the steroid skeleton and of the C(17)‐attached side chain. We report the biological potency of the prepared brassinosteroid analogs as plant hormones, which were carefully established in the French bean second internode elongation assay and discuss our observations in light of the recently reported structural data detailing the molecular interactions between brassinolide in the trimeric complex with the protein receptors kinases BRASSINOSTEROID INSENSITIVE 1 (BRI1) and SOMATIC EMBRYOGENESIS RECEPTOR KINASE 1 (SERK1). In a further part of this work we describe the preparation of H2O‐soluble pro‐forms of 24‐epicastasterone and we discuss their physical properties, hydrolytic stabilities and biological activity.

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Bioactivity of brassinolide methyl ethers

Cited by 17 publications

References 14 publications

Brassinosteroid phytohormones: structure, bioactivity and applications

Brassinosteroid phytohormones: structure, bioactivity and applications

Synthesis of Brassinosteroids of Varying Acyl Side Chains and Evaluation of Their Brassinolide-like Activity

Biological Activity of Brassinosteroids – Direct Comparison of Known and New Analogs in planta

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