Hydrosoluble Complexes of Sterols, Sterol Esters and Their Precursors from <em>Zea mays</em> L.

The study undertaken shows the existence of water-soluble complexes of sterols, sterol esters and their precursors (triterpenes and 4α-methylsterols) in a higher plant, Zea mays L. The leaves, roots and culture medium were treated separately in order to investigate the role and nature of these complexes. The sterols found in the water-soluble form represent 0.1-1% by weight of the total sterols in the plant. The composition of the hydrosoluble fraction of the sterols and their precursors is different from that of the lipid-soluble fraction, cholesterol, sitosterol and isofucosterol being preferentially complexed compared to campesterol and stigmasterol. This complex was found in the microsomal supernatant after homogenisation and also in the culture medium. The sterols are released from the complex by a treatment with pyrogallol under basic conditions or after repeated extraction with petroleum ether. The complex is precipitated with ethanol but not with trichloroacetic acid. The behaviour of several sterols on treatment with a solution of starch was investigated. Starch was able to complex with a large number of phytosterols unspecifically. The implication of this complex for the transport of sterols, for the biosynthesis of steroids and the ecological impact is discussed. [ABSTRACT FROM AUTHOR]