Isolation and identification of 26‐hydroxyecdysone 2‐phosphate: An ecdysteroid conjugate of eggs and ovaries of the tobacco hornworm, Manduca sexta

Abstract Maturing eggs (48 to 64 h old) of the tobacco hornworm, Manduca sexta, contain at least three ecdysteroid conjugates, two of which have been previously identified as 26‐hydroxyecdysone 26‐phosphate (the major conjugate) and 26‐hydroxyecdysone 22‐glucoside. In this study we have isolated and identified the third conjugate as 26‐hydroxyecdysone 2‐phosphate by XAD‐2 chromatography, C18 SEP‐PAK separation, ion suppression reversed‐phase high‐performance liquid chromatography, nuclear magnetic resonance, and fast atom bombardment mass spectrometry. This compound is the second most abundant conjugate of ovaries from 4‐day‐old adult females. The possible role for this ecdysteroid conjugate is discussed.