A series of phytoecodysteroids, including alpha-ecdysone, 2-deoxy-alpha-ecdysone, and 2-deoxyecdysterone isolated from Silene praemixta, integristerone A and ecdysterone isolated from Rhaponticum carthamoides and 22-acetylcyasterone and turkesterone isolated from Ajuga turkestanica, exhibit a