ニホンハッカ（Ｍｅｎｔｈａ ａｒｖｅｎｓｉｓ）の成分的変種（その２）

Abstract

We report the chemotypes of the S2 clones derived from self-pollination of two S1 clones (S2-2 and S1-10) of wild Mentha arvensis (Tosa hakka). The essential oil was studied. The 27 S2 clones derived from the S1-2 clone (chemotype 2), which all contained much limonene, piperitenone oxide, and piperitone oxide, were divided into the following three chemotypes. i) Chemotype 1 was of the same type as the parent with much piperitenone oxide and piperitone oxide. Twenty-six percent (7/27) of the S2 clones were of this type. ii) Chemotype 2 was the same as that of the S1-2 clone. Some 70% (19/27) of the 27 S2 clones were of this type. iii) Chemotype 3 was of the pulegone-menthol type. Four percent (1/27) of the S2 clones were of this type. The 24 S2 clones derived from the S1-10 clone of chemotype 3 were grouped into two chemotypes. Seventy-one percent (17/24) of these S2 clones had chemotype 3 and 29% (7/24) of the clones had chemotype 1. The ratio of the pulegone content to the menthol content in the 17 S2 clones of chemotype 3 and derived from the S1-10 clone was about 2:1. Clones with a low menthol content were more frequently obtained than those with a high menthol content.