Antiviral compounds phospholipids

About seven hundred polyacetylenes have been isolated so far mainly from plants belonging to the family of Asteraceae, Umbelliferae and Campanulaceae [11]. Polyacetylenes occur principally as straight chain polyines, allenes, phenyl, thiophenyl, thioether and spiroketal-enoether derivatives in a quite high yield. Thiophenes and related sulfur compounds are usually grouped together with die polyacetylenes because of their common biosynthetic pathways [11]. Few plant-derived lactones, butenolides and phospholipids show antiviral activity. The antiviral activities of thiophenes, polyacetylenes, lactones, butenolides and phospholipids from plant origin are reported in table 8. 

When R = NH2 or COOH the compounds were completely inactive and very nearly so when R = OH, but R = Br and Me were equiactive with R = H. The same pattern was evident in the in vivo tests in mice. It was suggested that the adamantane moiety of (II, R = H) is absorbed by the phospholipid layer of the cell to be protected leaving the polar grouping protruding. The presence of another, presumably hydrated, polar grouping in the molecule prevents this absorption and produces the unfavourable effect on antiviral activity. 

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