Centrifugal partition chromatography in the isolation of minor ecdysteroids from Cyanotis arachnoidea

Phytoecdysteroids are known for their various beneficial bioactivities in mammals including a non-hormonal anabolic and adaptogenic effect. Cyanotis arachnoidea extracts are extensively utilized worldwide as ecdysteroid-rich materials for various purposes, e.g. food supplementation, use in agriculture and aquaculture, etc. Preparative chromatography of ecdysteroids requires extensive use of methods of different selectivity, and only a very limited number of papers are available on related application of modern liquid-liquid chromatographic techniques. In this work, a centrifugal partition chromatography (CPC) method was developed for the isolation of two minor ecdysteroids, dacryhainansterone and calonysterone, from a pre-purified commercial extract of Cyanotis arachnoidea. The biphasic solvent system was optimized by HPLC, and was composed of n-hexane - ethyl acetate - methanol - water (1:5:1:5, v/v/v/v). The isolated dacryhainansterone and calonysterone represented 99.1% and 99.7% purity, respectively. Calonysterone exerts a stronger effect on the protein kinase B (Akt) phosphorylation in mammalian skeletal muscle cells than the abundant 20-hydroxyecdysone, while no related data are available on dacryhainansterone. Despite their presence in food supplements, neither compound has appropriately been assessed for safety and efficacy. The reported method allows the gram scale isolation of these compounds, opening ways to their in-depth pharmacological investigation.