Sterol composition and accumulation in maturing borage (Borago officinalis L.) seeds

In the present work, we describe a simple and validated method for the extraction of total sterols from maturing seeds of wild borage (Borago officinalis L.) and their analysis by GUMS. In the other hand, we have analyzed and identified the sterols contained in the free fraction by HPLC. The obtained results showed that campesterol is the major component in total sterols of borage; nevertheless, the free fraction is characterized by the predomination of beta-sitosterol as main sterol. The survey of the kinetic of total sterol accumulation during seed formation and ripening, showed an increase in sterol contents during the first stages of seed replenishment followed by a sharp decrease in these contents in fully ripened seeds. These results showed that reducing sterol content in mature seeds seems to be an adaptive strategy permitting to reduce fluidity of bio-membranes in order to limit water and ion exchanges.