Phenolic lipids biological properties

ABSTRACT This review is concerned with non-isoprenoid phenolic lipids typified by compounds biosynthesised by the polyketide pathway. Botanical, biological and entomological sources of such phenolic lipids are described which contain monohydric phenols, notably cardanol and relatives, dihydric phenols such as cardols, alk(en)ylresorcinols,urushiols and phenolic acids, particularly anacardic acids. Some recently investigated mixed types of dihydric phenolic lipids are included. Separatory methods are briefly reviewed. Synthetic methods for the saturated and unsaturated members of the three main classes of interest in structure/activity studies are summarised. Biological properties of members of the three main classes are given and discussed. 

Synthesis has often followed structural elucidation of a phenolic lipid to complete the characterisation process. However it may also become of greater significance in the study of biological properties, particularly in the involvement of structure/activity relationships. 

The properties of phenolic lipids have tended to be dominated by technological aspects and it is only comparatively recently that potential biological usefulness has come to the fore. For example, products derived from the Anacardiacae occidentale, notably cardanol obtained by semisynthesis through thermal decarboxylation were all directed to polymeric and technical applications and the vast industrial literature [246] contains only two references to insecticidal uses of chlorinated cardanol [247]. 

These results and those now discussed which show the ability of resorcinolic lipids to incorporate and modulate phospholipid bilayer properties, suggest a possible similar role in biological membrane-related enzymatic activities. It has been demonstrated that at a concentration of 10 5 M, long-chain resorcinolic lipids, caused a decrease of apparent acetylocholinesterase activity in the erythrocyte membrane while simultaneously stimulating the activity of Ca2+-dependent ATPase [348]. The inhibition of erythrocyte acetylcholinesterase has been also observed for other phenolic lipids (Stasiuk and Kozubek - unpublished work) and a similar effect of one of the homologues, namely tridecylresorcinol shown towards Na+-K+ ATPase [157]. a-Glucosidase and aldolase were also inhibited by resorcinolic lipids isolated from cashew [283]. 

---