Biotransformation of α-Terpineol by the Larvae of Common Cutworm (Spodoptera litura)

Biotransformation of α-terpineol by the common cutworm (Spodoptera litura) larvae was investigated. α-Terpineol was mixed in an artificial diet, and the diet was fed to the larvae (fourth−fifth instar) of S. litura. Metabolites were isolated from the frass and analyzed spectroscopically. Main metabolites were 7-hydroxy-α-terpineol (p-menth-1-ene-7,8-diol) and oleuropeic acid (8-hydroxy-p-menth-1-en-7-oic acid). Intestinal bacteria from the frass of larvae did not participate in the metabolism of α-terpineol. α-Terpineol was preferentially oxidized at the C-7 position (allylic methyl group) by S. litura larvae. Keywords: Common cutworm; Spodoptera litura; biotransformation; α-terpineol; 7-hydroxy-α-terpineol; oleuropeic acid; allylic methyl group; positional specific oxidation