Epibrassinolide (BP55) (EBR) is a biologically active compound of the brassinosteroids, is a natural brassinosteroid (BR) derivative, is a plant regulator with a similar structure to mammalian steroids.

Epibrassinolide(EBR)已表明具有潜在的诱导各种癌症细胞凋亡的能力，而不影响非肿瘤细胞的增长[1]。此外，EBR还能保护神经元PC12细胞免受1-甲基-4-苯基吡啶诱导的氧化应激及其导致的多巴胺能神经元凋亡[2]。

Cells were seeded at 1*10^4 density per well in 96-well plates and exposed to various concentrations of EBR for 24 and 48 h. 10 ul 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) dye (5 mg/ml) ?was added to each well and cells were kept at 37 C for 4 h. The resulting formazan crystals were solubilized in 200 ul DMSO.?The density of the solubilized formazan was read at 570 nm spectrophotometrically.