Minor Ecdysteroid Components of Leuzea carthamoides

Abstract

Fourteen minor ecdysteroid components were isolated and identified from the roots of Leuzea carthamoides (Willd.) DC. Two of them are new phytoecdysteroids: leuzeasterone (1) a six-member side-chain lactone, and (24Z)-29-hydroxy-24(28)-dehydromakisterone C (4) a structurally related sitostane type analogue and assumed biogenetic precursor of 1. The next one, 5α-20-hydroxyecdysone (6), is a rare A/B-ring trans-annelated epimer of the most common phytoecdysteroid 20-hydroxyecdysone. Further compounds: makisterone C (3), 3-epi-20-hydroxyecdysone (5), integristerone A (7), integristerone B (8), 22-oxo-20-hydroxyecdysone (10), taxisterone (11), rubrosterone (12), dihydrorubrosterone (13) and poststerone (14), are new constituents of L. carthamoides, though already reported as compounds isolated from other natural sources. Two earlier reported minor Leuzea ecdysteroids: the five-membered side-chain lactone carthamosterone (2) and the 11-hydroxy-substituted analogue isovitexirone (9), are also included because they are now better characterised. Certain previously described Leuzea ecdysteroids were not found in our material, which may indicate geographic, seasonal or cultivar variations.