Optical purity of (3S,3'S)-astaxanthin from Haematococcus pluvialis

Haematococcus pluvialis cultivated in a N-deficient medium produced astaxanthin (1 % of total carotenoids), the monoester (76 %) and diester (7 %) of astaxanthin, β,β-carotene (1 %), an adonirubin ester (3 %), (3R,3′R,6′R)-lutein (7 %), violaxanthin (2 %) and neoxanthin (1 %). The CD values of the mono- and diesters of astaxanthin, the HPLC properties of astaxanthin monoester further esterified with (?)-camphanic acid and the optical purity of astaxanthin determined by HPLC analysis of the diester of(?)-camphanic acid] produced by saponification of the natural mono- and diesters of astaxanthin in the absence of oxygen showed that this green alga synthesizes pure (3S,3′S)-astaxanthin esters.