Geraniol, Linalool, Thymol and Carvacrol-rich Essential Oils from Monarda Hybrids

Monarda fistulosa L., var. menthaefolia, native to southern Manitoba, was crossed with M. didyma, and through a series of open pollination and selection cycles, winter-hardy disease-resistant hybrids were generated. The volatile constituents of essential oil from these hybrids were analyzed by GC and GC/MS. The volatile concentrates obtained by nitrogen extraction contained high levels of cyclic terpenes including α-pinene and camphene. The volatile composition of oil extracted by hydrodistillation varied significantly among different hybrids. The oil of one hybrid contained geraniol(>92%), oil of a second hybrid contained carvacrol (73.5%), oil of a third hybrid contained linalool (67%), oil of a fourth hybrid contained thymol (31%) and oil of a fifth hybrid contained 1, 8-cineole (22%). The corresponding oil yields obtained by hydrodistillation were 1.17, 1.08, 1.0, 0.62 and 0.68 g/100 g of fresh plant tissue, respectively.