24-Epicastasterone  (Synonyms: 24-epi-Castasterone)

24-Epicastasterone (24-epi-Castasterone) is a bioactive brassinosteroid and a ligand of ABCB1 and ABCB19 in Arabidopsis thaliana. 24-Epicastasterone stimulates the ATPase activity of ABCB19 and the ATP hydrolysis activity of ABCB1, which drive the efflux of substances from plant cells. 24-Epicastasterone increases the activities of catalase and guaiacol peroxidase in the roots of wheat seedlings. 24-Epicastasterone alleviates heat-induced lipid peroxidation through a ROS-dependent mechanism and enhances the heat tolerance of common wheat seedlings^[1][2][3].

24-epicastasterone (20 min pre-incubation on ice, 10 min reaction at 37°C) potently stimulates the ATPase activity of purified Arabidopsis ABCB19 protein in a dose-dependent manner^[1].
24-epicastasterone (0.05 mM) binds directly to purified Arabidopsis ABCB19 protein reconstituted in amphipols with a dissociation constant of 0.36 μM^[1].
24-Epicastasterone (1 μM; foliar spray; once daily; 11 consecutive days) rescues growth in brassinosteroid-deficient Arabidopsis biosynthetic mutants but not in ABCB19 transporter-deficient mutants, confirming ABCB19 is required for functional 24-epicastasterone signaling^[1].
24-epicastasterone (5-200 nM; 24 h) increases the heat resistance of Triticum aestivum cv. Doskonala wheat seedlings, with the most significant effect observed at a 50 nM concentration applied for 24 h, and a significant effect also seen at 20 nM^[2].
24-epicastasterone (50 nM; 2 h, 4 h, 24 h) modulates the activity of superoxide dismutase, catalase, and guaiacol peroxidase in roots of Triticum aestivum cv. Doskonala wheat seedlings, with superoxide dismutase activity elevated at 4 h, catalase activity elevated at 24 h, and guaiacol peroxidase activity elevated at 4 h but not significantly different from control at 24 h^[2].
24-epicastasterone (50 nM; 24 h before heat stress) reduces heat-induced lipid peroxidation in roots of Triticum aestivum cv. Doskonala wheat seedlings, an effect dependent on NADPH oxidase-mediated hydrogen peroxide production^[2].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

464.68

C₂₈H₄₈O₅

72050-71-6

Solid

Off-white to light brown

C[C@@]12[C@]3([H])[C@](CC([C@@]1([H])C[C@@H]([C@@H](C2)O)O)=O)([H])[C@@]4([H])[C@](CC3)([C@@](CC4)([H])[C@H](C)[C@@H](O)[C@H](O)[C@H](C)C(C)C)C

Room temperature in continental US; may vary elsewhere.

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month. When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

• [1]. Ying W, et al. Structure and function of the Arabidopsis ABC transporter ABCB19 in brassinosteroid export. Science. 2024 Mar 22;383(6689):eadj4591.  [Content Brief]

  [2]. Litvinovskaya, R.P., et al. ROS-Dependent Stress-Protective Effect of 24-Epicastasterone and Its Monosalicylate on Wheat Seedlings in Hyperthermia. Appl Biochem Microbiol 57, 770–777 (2021).

  [3]. Wei H, et al. Structural insights into brassinosteroid export mediated by the Arabidopsis ABC transporter ABCB1. Plant Commun. 2025;6(1):101181.  [Content Brief]