I wonder if anyone out there has any info which would help an inquirer.
What little we know is listed and any further information would be greatly
Thanks in advance
Maff Fisheries Lab
Burnham on Crouch. Essex. UK
E-MAIL r.waldock at dfr.maff.gov.uk
Chap enquiring is a charcoal-maker wanting to use Rhododendron.
He has already found out from Kew poisonous plants info. that these are the
toxins involved (spelling may be a bit dodgy):
Toxic Diterpenoid resins which have Andromadane skeletons. The class is
called Grayanotoxins and sub-groups of this are Asebotoxins, Rodojaponins,
lyoniatoxins. The original name for these when they were first discovered
was Acetylandromadol. These toxins are present in the plant in the form of
a highly toxic oil found in the stems and leaves of the plant.
The chemicals are listed in the Merck index and the given melting point is
258-260 C. The Bpt is not given but it is suggested that the toxins start
to break down at around about 450 C. The charcoaling process involves the
timber being seasoned for at least 12 months prior to use so this may allow
enough time for the toxins to disperse. It also said that heat would almost
certainly speed the process and the charcoaling process involves
temperatures of at least 450 C.
What the chap really wants to know is the chemical properties of the toxins,
ie a more definate answer to the question of if/when they break down and if
so what they break down to and would these also toxic. Would the chemicals
end up in the food if it were BBQ'd over the wood?