Wood species of the genus Dalbergia have long been known for their sensitizing(contact allergic) properties. Since many trade names have only the character of a fantasy name, a botanical determination of the wood species is essential. Sensitizations are mainly caused by wood dusts in the wood processing industry, but more rarely also by intensive skin contact with the wood species in question (e.g. costume jewelry, musical instruments, wooden shoes). Type IV sensitizations are generally caused by the substances contained in the heartwood. These are alkaloids, gylcosides, saponins, flavonoids, phenol derivatives. Furthermore, benzoquinone, naphthoquinone, furanoquinone, phenanthrenequinone. The following substances have been identified as contact allergens:
- Obtusaquinone (test concentration: 1%)
- 4-methoxydalbergion (test concentration: 1%)
- 4-Hydroxy-4-methoxydalbergione (test concentration: 1%)
- 4,4-Dimethyloxyalbergione (test concentration: 1%)
Ethanol extracts of the respective wood can also be prepared and, depending on the type of wood, 1%-10% dilutions can be tested.