A1-Phytoprostane-I is a cyclopentenone isoprostane produced by the action of reactive oxygen species on α-linolenic acid in plants. There are two A1-phytoprostanes, both having the single ketone group on the ring structure. This isoform results from cyclization between carbons 9 and 13 of linolenic acid, as opposed to carbons 3 and 7 in A1-phytoprostane-II. A1-Phytoprostanes induce the expression of glutathione-S-transferase, increase phytoalexin biosynthesis, and trigger the expression of several genes involved in primary and secondary metabolism in plants.
