New phytoecdysteroids from cultured plants of Ajuga nipponensis Makino

An extract from aerial parts of Ajuga nipponensis Makino was examined by high performance liquid chromatography for minor ecdysteroids. Along with the compounds already reported, namely cyasterone, ajugasterone C, cyasterone 22-acetate and 22-dehydrocyasterone, the presence of three additional bands with the expected ecdysteroid-like UV absorption was observed. The structures of the isolates were unambiguously elucidated based on extensive NMR spectral studies (one and two-dimensional experiments) and pointed out three new phytoecdysteroids. One of the new compounds, 22-dehydrocyasterone 2-glucoside is just the second example of a C-2 glucosyl derivative. The other two compounds displayed hemiacetal functions in the side chain, one unprecedented, and were named ajugacetalsterone A and B.