The free sterols, steryl esters, steryl glycosides and acylated steryl
glycosides were examined from five plant species grown as cell suspen
sion cultures, i.e. Apium graveolens, Morinda citrifolia, Nicotiana ta
bacum, Solanum tuberosum and Tabernaemontana divaricata. The amount an
d composition of the various steryl lipid classes varied between plant
species, but some features previously reported in suspension cultures
of A. graveolens were common to other species. Firstly, stigmasterol,
which represented between 3 and 44% of the free sterols of the cultur
es, was either undetected or contributed very little to the steryl est
er fraction. Secondly, the precursor sterols (cycloartenol, obtusifoli
ol) were esterified in greater proportion to palmitic acid than to the
C-18 fatty acids. There did not appear to be a simple relationship be
tween the amount of free sterol and the extent of esterification in th
e various cultures, as the free sterol:esterified sterol ratio varied
from 0.39 to 79.25. The composition of the steryl lipids of S. tuberos
um differed markedly from that of the other cultures. The steryl glyco
sides of this species contained both pyranosides and furanosides, whic
h were separable under the GC conditions employed. The steryl lipids o
f N. tabacum and S. tuberosum were also at variance with reported lipi
d analyses of the whole plant tissue of these species.