Variation in the extract composition of mints of different origin cultivated in Finland

Mentha x piperita L., and five other Mentha species of mint were grown in N orthern Finland at the North Ostrobothnia Research Station of the Agricultu ral Research Center at latitude 64 degrees 40'N and 25 degrees 05'E. To inv estigate the influence of harvest dates on the oil composition, leaves were collected at an early flowering stage (50% of buds) (I) and when 30% were in full bloom (II). Different harvesting times did not greatly affect the p ercentage of the main components for any of the mints. At this stage of pla nt development, young leaves contained more menthone th:tn menthol, and app arently the amount of menthol had only started to increase. Also the relati ve percentages for menthofuran and pulegone were lan in the leaves. The com positional studies were performed by GC/MS on solvent extracts of two leave s.