ABSTRACT
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.
Subject(s)
Allergens/adverse effects , Dermatitis, Allergic Contact/diagnosis , Facial Dermatoses/diagnosis , Wood/adverse effects , Adult , Dermatitis, Allergic Contact/etiology , Dermatitis, Allergic Contact/pathology , Diagnosis, Differential , Facial Dermatoses/etiology , Facial Dermatoses/pathology , Female , Humans , Male , Middle Aged , Music , Patch TestsSubject(s)
Allergens/adverse effects , Caproates/adverse effects , Dermatitis, Allergic Contact/diagnosis , Lactones/adverse effects , Naphthalenesulfonates/adverse effects , Organometallic Compounds/adverse effects , Sutures/adverse effects , Dermatitis, Allergic Contact/etiology , Diagnosis, Differential , Female , Humans , Middle Aged , Patch Tests , Wounds and Injuries/pathologyABSTRACT
BACKGROUND: Nonterpenoid and diterpenoid phenanthrenequinones (PACs) have been found in the plant kingdom. Some of them occur in plants used in traditional Chinese medicine like Tan-Shen whereas others are constituents of orchids that are popular as ornamental plants. OBJECTIVE: Case reports and our own observations in orchid nurseries suggest that some or even all of these PACs possess a distinct sensitizing potency. Occasional exposure (particularly of botanists) to field-grown orchids, as well as occupational contact with sawdust of PAC-containing tropical timbers, caused allergic contact dermatitis. However, experimental studies in guinea pigs to determine the sensitizing capacity of PACs have not been performed so far. METHODS: Guinea pigs were sensitizied by a modified Freund's complete adjuvant method with four naturally occurring and 22 synthetic PACs in order to find out which and how many substituents at the carbons of the three rings of the PAC will influence the sensitizing power of the molecule. Subsequently, the lowest unoccupied molecular orbital (LUMO) coefficients were calculated to show whether a correlation exists between chemical reactivity and sensitizing capacity. RESULTS: Sensitizing capacity was found to be strong in two PACs, moderate in eight PACs, and weak in ten PACs. Five PACs were extremely weak in sensitizing capacity, and one PAC was completely negative. Two substituents on the left-hand carbons C-7 and C-8 of ring C were shown to be responsible for a strong sensitizing capacity. One methoxy group alone or three of them, especially when localized at C-5, decreased the sensitizing capacity to moderate. Substitution with a methoxy group at C-3 and/or at C-2 of the quinonoid ring itself (ring A) led to a weak sensitizing capacity. The ortho-quinones 1,2-PAC and 9,10-PAC were also weakly sensitizing. In fact, LUMO coefficient calculations corroborated a good correlation between chemical reactivity and sensitizing capacity. CONCLUSION: Substitution with methoxy groups at C-7 and/or at C-8 of ring C of 1,4-phenanthrenequinone increases the LUMO coefficients at the 2,3 double bond of ring A and thus facilitates nucleophilic substitution of protein nitrogen or sulfur nucleophiles at this electron-deficient double bond. The four naturally occurring PACs that were investigated--cypripedin, denbinobin, annoquinone-A, and latinone--do not fulfill these criteria and are thus only weak sensitizers. However, as-yet-unstudied phenanthrenequinones occurring in plants or trees and having no substituents at C-2 or C-3 of the quinonoid ring must be considered potentially strong allergens.
