I turn small drinking bowls called quaiches out of laburnum (because thats what they were traditionaly made from) and wanted the facts on toxicity. kew gardens is the UK source of all info on toxic plants and offer a free advice service...copied below is their not entirely conclusive reply. I read it as lots of toxin in seeds and bark..less if any in the wood. Personally I would still be cautious if turning it green or sanding it always safest to wear a mask.
I have not found much information that refers to the toxicity of the wood of Laburnum. It is not listed in Hausen (1981) a book we have here on our reference shelves.
The main toxin in laburnum is cytisine, a quinolizidine alkaloid. This toxic constituent occurs mainly in Laburnum seeds and bark, but also in all parts of the plant according to Dauncey ed. 2000 from which the following information has been extracted:
Latin name: LABURNUM spp.
Common names: GOLDEN CHAIN, GOLDEN RAIN, LABURNUM
Category in HTA Code (1994) and (2000): B, CAUTION toxic if eaten
This taxon includes common laburnum (Laburnum anagyroides Medik.), Scotch laburnum (L. aplinum (Mill.) Bercht. and Presl.), and the hybrid between these two species, L. x watereri (Kirchn..) Dipp.
Circumstances of exposure: Common trees of gardens and parks. The fruits (pods) and seeds may be eaten in mistake for edible peas, particularly by children, and the flowers for false acacia (Robinia pseudoacacia).
Poisonous parts: All parts, particularly the bark and seeds.
Main toxins: Cytisine, a quinolizidine alkaloid.
Summary: Ingestion of Laburnum usually causes only gastrointestinal upset. Severe intoxication, which is rare, may result in neurological symptoms.
Author: Marie Pickford
[see Quinolizidine Alkaloids entry]
In Laburnum species, the cytisine content of the seeds is 1.5-3.0%, leaves 0.35%, and fruits 0.2% (Bruneton, 1996). It has been stated that the leaves become less toxic and the flowers and fruits more so as the season progresses (Cooper, 1974 cited in Cooper and Johnson, 1998).
Ingestion: [see Quinolizidine Alkaloids entry].
Two 10-year-old girls ate 5 and 10 fruits of Laburnum anagyroides. Both developed nausea and vomiting and were pale and tachycardic. Both were given activated charcoal and were discharged well the next day. The plant was identified by a botanist (NPIS (London) case report 98/112974).
Nine people (7 adults; 2 children aged 12 and 13) who had eaten fritters containing Laburnum anagyroides flowers developed symptoms 2-3 hours later including nausea, vomiting, abdominal pain, muscle tremors, dilated pupils and dizziness. They all underwent a gastric lavage and recovered fully within 48 hours. The flowers had been used in mistake for false acacia (Robinia pseudoacacia) to flavour the fritters. Cytisine was detected in the urine of two of the patients (Furet et al., 1986).
A 50-year-old paranoid schizophrenic died with no witnessed clinical symptoms following ingestion of Laburnum anagyroides fruits. He had also taken his normal therapeutic dose of chlorpromazine. He was found collapsed and deeply cyanosed. There was no evidence of vomiting. Ten minutes previously he was reported by a nurse to have been asleep in bed. At post-mortem examination 23 fruits closely resembling Laburnum anagyroides were found in the stomach. Toxicological analysis showed that 35-50 mg cytisine had been absorbed. The time to death following ingestion of a large quantity of a cytisine-containing plant material is unknown, but is thought to be rapid, perhaps within minutes (Richards and Stephens, 1970).
Toxin group: QUINOLIZIDINE ALKALOIDS
Cytisine (also known as baptitoxine, citisine, sophorine, and ulexine (Harborne et al., 1996)) is potentially very toxic and acts in the same way as nicotine, first stimulating and then depressing the central nervous system; death may occur from respiratory paralysis (Dale and Laidlaw, 1912). Serious symptoms are rare, possibly because of the emetic effect of cytisine. The lethal dose is estimated to be 0.5 mg/kg body weight (Bramley and Goulding, 1981). In Laburnum species, the cytisine content of the seeds is 1.5-3.0%, leaves 0.35%, and fruits 0.2% (Bruneton, 1996).
Other quinolizidine alkaloids (lupanine, lupinine, anagyrine and sparteine) are present in Lupinus species. Their toxic effects are similar to those of cytisine, but not so severe. In a case of Lupinus poisoning, where lupanine was detected in the urine, increased heart rate and extrasystoles occurred (Luque Marquez et al., 1991).
Sparteine produces a dose-dependent reduction in heart rate and blood pressure in animal experiments. It possesses sodium and potassium channel blocking properties in the rat, which may account for its antiarrhythmic action (Pugsley et al., 1995). Autonomic ganglia are stimulated by small amounts and paralysed by large doses. Sparteine has little effect on the CNS, but peripherally paralyses motor nerve terminals and sympathetic ganglia as a result of a curare-like action (Reynolds, 1996).
Ingestion: These alkaloids are absorbed rapidly through all mucous membranes. Initial symptoms usually appear within 1 hour (Fuller and McClintock, 1986), and include a burning sensation in the oropharynx, nausea, vomiting, abdominal pain and occasionally diarrhoea. This can progress to headache, dizziness, confusion, dilated pupils, clammy skin, tachycardia, pyrexia, dyspnoea and drowsiness. In most cases recovery is complete in 12-24 hours.
After a large ingestion (of Laburnum) the more serious effects include hallucinations, convulsions, respiratory failure, coma and rarely death (Cooper and Johnson, 1998).
Author: Marie Pickford, Marion Cooper, Tony Johnson
Bruneton (1999) also includes a detailed review of the effects of poisoning from the seeds of Laburnum.
Cytisine itself is highly toxic (LD50-- is 18 mg/kg intraperatoneally in mice) (Harbourne and Baxter 1993). Harborne and Baxter (1996) gives the LD50 (mus, ivn) 1.3 mg/kg and LD50 (mice, orally) 101 mg/kg.
The Combined chemical dictionary list the following properties for cytisine(-)-, apparently it is soluble in water.
Chapman & Hall Number CFX24
CAS Registry Number 485-35-8
Type of Compound Code VX0920
Molecular Formula C11H14N2O
Molecular Weight 190.244
Accurate Mass 190.110613
Percentage Composition C 69.45%; H 7.42%; N 14.72%; O 8.41%
Hazard and Toxicity Highly toxic. LD50 (mus, orl) 101 mg/kg ; BERDY HAZD : LD50 (mus, ivn) 1.3 mg/kg
Other Data Pharmacol. active isomer
Solubility BERDY SOL: Sol. H2O, EtOH, C6H6; poorly sol. Et2O, hexane
Biological Source Alkaloid from Cytisus laburnum, many other Cytisus spp., Baptisia, Genista, Laburnum, Sophora, Thermopsis, Ammodendron, Anagyris and Euchresta spp. (Leguminosae)
Biological Use / Importance Shows nicotine-like CNS activity. Antiinflammatory agent. Shows psychoactive props. Has been used as respiratory stimulant in the former USSR. Common cause of poisoning of humans and animals by Cytisus laburnum
Melting Point Mp 155° subl.
Optical Rotation [_]17D -119 ( H2O )
Bisby, et al (1994) list the original academic papers that cite that cytisine is present in the stem bark, stem or the whole plant. They are largely in obscure scientific journals so I could not follow these up to see if quantities in these plant parts are mentioned.
1. Dauncey, E.D (ed.) 2000. Revision of the Horticultural Trades Association Code of Practice for the labelling of potentially harmful plants. Medical toxicology Unit Guy’s & St Thomas’ Hospital Trust and Royal Botanic Gardens, Kew. (11 February 2000, updated 14 March 2003 to include labelling requirements of the ‘2000 code,’ includes A, B, C taxa and D (label not required), and taxa not previously considered). [Toxicity Authors: Marion Cooper and Tony Johnson, and Nicola Bates, and other Information Officers and staff of the National Poisons Information Service (London): Peter Barber, Jennifer Butler, Mark Colbridge, Grainne Cullen, Digby Green, Robie Kamanyire, Frances Northall, Marie Pickford, Elizabeth Schofield, Nicola Scott, Brian Widdop.]
2. Hausen, Bjorn (1981). Woods injurious to human health: a manual. Berlin: Walter de Gruyter
3. Harbourne and Baxter (1993). Phytochemical Dictionary. Taylor & Francis
4. Harbourne and Baxter (1996). Dictionary of Plant Toxins. Chichester: John Wiley and Sons .
5. Bruneton, J. 1999, Toxic plants dangerous to humans and animal. Lavoisier, Paris, 545pp includes a detailed review of the effects of poisoning from the seeds of Laburnum
6. Bisby, F.A., Buckingham, J. & Harbourne, J.B. (Eds) 1994. Phytochemical dictionary of the Leguminosae Vol 1. Plants and their constituents, Cambridge: Chapman & Hall
7. Combined Chemical Dictionary Taylor & Francis Group 2006. http://ccd.chemnetbase.com/dictionar...&struct=&disp=