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5. John Kerr (1998) “Essential Oil Profile: Ho leaf/Rosewood” Aromatherapy Today Sept 1998 p7.

“The linalool found in Ho leaf is l-linalol…..the linalool found in Rosewood is d-linalool, about which very little is known.”

Comment. I have seen this error on the chiral nature of Rosewood oil repeated before by Martin Watt and others, so it is worth putting right. In fact, the linalool from genuine Rosewood oil from Aniba rosaeodora is a mixture of laevo (-) or dextro (+) forms, and individual trees should show a dominance of either form, with a corresponding difference in odour. Those oils that are laevo- isomer dominant (>50% according to S. Ohashi et al 1997) are more woody lavendery in odour, those which are dextro-isomer dominant are towards a more sweet petitgrain character. Commercial oils can therefore show a range of values for optical rotation, according to the dominance of the isomer distribution from the trees chosen as oil source.

(Reference S. Ohashi et al. (1997) Perfumer & Flavourist Vol 22 March/April p1-5).

In fact, in spite of J. Kerr’s statement above, we do know a great deal about d-linalool, the old name for it being coriandrol, since it also occurs as a major constituent of Coriander seed oil from Coriandrum sativum.

Finally, as an aside, John mentions thalidomide as an example of optical isomerism where one isomer may be harmful and the other relatively safe, and this is nicely illustrated at http://www.tlchm.bris.ac.uk/motm/thalidomide/optical2iso.html

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