The aerial parts of flowering Mentha pulegium plants (cut at ground level) and individual M. pulegium plants were collected in the summer (July, 2003) from three wild populations located in the Municipality of Laganas, Zakynthos, W. Greece. Location 1 (N 37° 41′ 29″, E 20° 50′ 25″; map datum WGS 84; altitude 3 m; 14/07/03) was close to Keri Beach (Limni Keriou), Location 2 (N 37° 43′ 34″, E 20° 50′ 41″; altitude 3 m; 13/07/03) was near the village of Kalamaki and Location 3 (N 37° 39′ 39″, E 20° 48′ 44″; altitude 160 m; 17/07/03) was near the village of Vasilikos. The three locations are within the mainland limits of the protected area of the National Marine Park of Zakynthos (NATURA 2000 Network, site GR 2210002; 14).

The composition of the inflorescence (I), leaf (L) and stem (S) essential oils of wild Mentha pulegium plants from three populations (1-3) on the island of Zakynthos were examined. Pulegone (32.8 %, S1 to 75.8 %, I3) was the major constituent of all of the oils. The other main constituents were piperitenone (5.1 %, L3 to 35 %, I2), isomenthone (4.3 %, I2 to 28.6 %, L3) and piperitone (0.5 %, I3 to 5.2 %, L2). In total, C-3-oxygenated p-menthane compounds constituted from 73.0 % (S1) to 96.2 % (I2) of the oils. The piperitenone content of the inforescence oils was up to 2.4 (Loc 3) times higher than that of the leaf oils. Correspondingly, the isomenthone content of the leaf oils was up to 4.2 (Loc 2) times higher than that of the inforescence oils. The ratio of the isomenthone:piperitenone content of the oils (n=3) was markedly different for the inforescence (mean 0.31), leaf (mean 2.91) and stem (mean 1.12) oils.