(R)-4-Methoxydalbergione

Airborne contact dermatitis in gaitas (flageolets) constructors after exposure to sawdust of caviuna.[Pubmed:17441850]

Contact Dermatitis. 2007 May;56(5):274-7.

Exotic wood species are used in the manufacture of furniture, musical instruments, tool handles, and other wooden items. Exposure to sawdust of the wood can produce dermatitis on exposed areas in woodworkers. We studied 7 patients, gaitas constructors who used caviuna wood to make their instruments. They developed dermatitis on exposed areas hours after they had begun to work with caviuna. We performed patch tests using the European standard series, caviuna sawdust sample, and a series of dalbergiones. 15 controls were performed. Two caviuna samples provided by a patient were analysed by thin-layer chromatography (TLC). Patch test with caviuna sawdust yielded positive reactions in all patients. 5 of the 7 sufferers reacted strongly to obtusaquinine and (R)-4-Methoxydalbergione deriving from Dalbergia retusa, but also to sensitizers present in other rosewoods. Patch tests with R-3,4-dimethoxydalbergione deriving from Machaerium scleroxylum remained negative in the patients, as well as in control subjects. The TLC analysis of the samples showed that the woods could have been M. scleroxylum, D. cearensis or D. frustescens, but not D. retusa. In our patients, airborne contact dermatitis was caused by exposure to caviuna sawdust. The patients must have been in contact with different Dalbergia species and especially with D. retusa.

Contact allergy to a cocobolo bracelet.[Pubmed:16242087]

Dermatitis. 2005 Sep;16(3):139-41.

Tropical woods are highly valued because of their strength, hardness, and resistance to moisture. These characteristics make them easy to work with and extremely durable, and that is why they have been used in the manufacture of wooden jewelry, musical instruments, furniture, and handles of many different objects. We present a case of a 44-year-old man who developed pruritus, erythema, and blistering around his right wrist, corresponding exactly to the area where he had worn a wooden bracelet. Thin-layer chromatography performed with the extract of the shavings revealed (R)-4-Methoxydalbergione and obtusaquinone (the main components of cocobolo wood) and (S)-4'-hydroxy-4-methoxydalbergione (in lower amounts). Patch-testing with sawdust from the bracelet resulted in a very strong reaction. Patch tests with the pure constituents yielded +++ reactions to the main sensitizers of cocobolo, including obtusaquinone, but also to sensitizers present in other rosewoods. This last fact can be explained by cross-reactivity between different dalbergiones. Contact dermatitis from tropical woods is more frequent than thought, owing to their high sensitizing properties. An exhaustive search can identify the allergen responsible in many cases.

Screening in vitro of natural products against blood forms of Trypanosoma cruzi.[Pubmed:1949141]

Trans R Soc Trop Med Hyg. 1991 May-Jun;85(3):372-4.

Transmission of Chagas disease by blood transfusion is a major health problem in Central and South America. The annual incidence of transfusion-transmitted Chagas disease in Brazil is about 20,000 cases. Crystal violet is the only trypanosomicidal agent available at present, but there are some restrictions on its use. In a search for possible new chemoprophylactic agents, several natural products of different structural types were tested in vitro against infective blood trypomastigotes of Trypanosoma cruzi. Four compounds had high activity at a concentration of 5 x 10(-4) M: the diarylpropanoids (3R)-claussequinone, (R)-4-Methoxydalbergione and (S)-4,4'-dimethoxy-dalbergione, and 15-deoxygoyazensolide, a sesquiterpenelactone. Haemoculture and serology of mice inoculated with infected blood treated with these active compounds were negative after 3 and 6 months. The benzoquinone moiety seemed to be important for this activity since lapachol and related naphthoquinones are known to be trypanosomicidal. 15-Deoxygoyazensolide has previously been recognized as a schistosomicide.