Isolation and Characterization of Novel Ecdysteroids

Ajugasterone C (1) was isolated during our previous phytochemical work [30 (link)]. Calonysterone 2-acetate (15) was isolated from a fraction of a commercial extract of Cyanotis arachnoidea C.B. Clarke (Shaanxi KingSci Biotechnology Co., Ltd., Xi’an, People’s Republic of China) during the current study and is reported here as a new ecdysteroid. We have recently reported the purification process in detail. Briefly, calonysterone 2-acetate was obtained after the following fractionation steps: percolation with methanol, column chromatography on silica (Merck KGaA, Darmstadt, Germany; eluent: dichloromethane—methanol/95:5, v/v), column chromatography on Lichroprep RP C18 (Merck KGaA, Darmstadt, Germany; eluent: 20% aqueous acetonitrile), and column chromatography on silica 60 GF₂₅₄ (Merck KGaA, Darmstadt, Germany; eluent: n-hexane—ethyl acetate 6:5, v/v). For ¹H and ¹³C NMR chemical shifts of compound 15 see Table 2.
Poststerone was previously prepared by semi-synthesis from 20-hydroxyecdysone isolated from the same extract of C. arachnoidea [11 (link)].