On the genuineness of citrus essential oils. Part XL. The composition of the coumarins and psoralens of Calabrian bergamot essential oil (Citrus bergamia Risso)

The content of bergamottin, 5‐geranyloxy‐7‐methoxycoumarin, citropten and bergapten in Calabrian bergamot essential oil was determined by HPLC. 128 genuine bergamot essential oils, cold‐pressed during the year 1992, were analysed; for each sample the date and area of production of the fruits is known. The percentage of bergamottin ranges between 1.02% and 2.75%. 5‐geranyloxy‐7‐methoxycoumarin between 0.08 and 0.22%, citropten between 0.14% and 0.35%, bergapten between 0.11 and 0.32%. The mean content of bergamottin and 5‐geranyloxy‐7‐methoxycoumarin did not vary during the production period, while that of citropten and bergapten decreased considerably from January to March. There does not seem to be any evident correlation between the production areas of the fruits and the coumarin composition. The presence of some peaks absent in genuine bergamot essential oils, has been detected in three bergamot oils, available on the market, probably because of lime oil addition.