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Anabolic effect of plant brassinosteroid
Debora Esposito1, Slavko Komarnytsky, Sue Shapses
1Biotech Center, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, USA.
Summary
28-Homobrassinolide (HB), a plant steroid, promotes muscle growth and physical fitness in rats by stimulating protein synthesis. This plant-derived compound shows anabolic effects with minimal androgenic side-effects, suggesting potential therapeutic applications.
Area of Science:
- Plant science
- Endocrinology
- Muscle physiology
Background:
- Brassinosteroids are plant-derived steroids structurally similar to animal steroid hormones.
- 28-Homobrassinolide (HB) is a brassinosteroid with known plant growth-promoting properties.
- The function of brassinosteroids in mammals is largely unknown.
Purpose of the Study:
- To investigate the effects of 28-Homobrassinolide (HB) on mammalian skeletal muscle.
- To determine the anabolic and androgenic potential of HB in vivo and in vitro.
- To explore the signaling pathways involved in HB's action on muscle cells.
Main Methods:
- In vitro studies on L6 rat skeletal muscle cells to assess protein synthesis and degradation.
- In vivo studies involving oral administration of HB to healthy rats on different diets.
- Hershberger assay and in vitro androgen receptor binding assays to evaluate androgenic activity.
- Grip strength tests and muscle fiber analysis in castrated rats.
Main Results:
- HB (4 μM) stimulated protein synthesis and inhibited degradation in L6 cells, partly via the PI3K/Akt pathway.
- Oral HB administration increased food intake, body weight, lean body mass, and gastrocnemius muscle mass in rats.
- HB administration showed low androgenic activity and no direct androgen receptor binding.
- HB improved physical fitness and muscle fiber characteristics (type IIa, IIb, and cross-sectional areas) in rats.
Conclusions:
- Oral 28-Homobrassinolide (HB) elicits a selective anabolic response in mammalian skeletal muscle.
- HB demonstrates potential as a therapeutic agent with minimal androgenic side-effects.
- These findings suggest conserved cellular targets for plant brassinosteroids in mammals.
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