Frullania tamarisci Frullanolide

Frullanolide, a sesquiterpene lactone, is contained in Frullania tamarisci (l) Dum. (L-Frullanolide) and Frullania dilatata (l) Dum. (o-frullanolide). Sensitivity causes mainly airborne contact dermatitis in forest rangers, lumbermen, sawyers, carpenters, and merchants in rough timber. 

Incubation of (-)-frullanolide (226), obtained from the European liverwort Frullania tamarisci subsp. tamarisci that causes a potent allergenic contact dermatitis, was incubated by A. niger to give dihydrofrullanolide (227), nonallergenic compound in 31.8% yield. In this case, C11-C13 dihydro derivative was not obtained (Hashimoto et al., 2005). 

Frullanolide (338), with a d s-lactone ring, has been isolated from the epiphytic liverwort, Frullania tamarisci. The structure was deduced from its spectral properties (775,255, 287) and confirmed by conversion to l,2-dihydro-6-epi-P-santonin (366) also obtained from 6-epi-P-santonin (367) (775, 287) (Scheme 40). The enantiomer (339) of (338) was isolated from European F, dilatata (30, 175, 287). 

In North America and Europe, it has long been known that some occupational allergies are associated with handling of wood on which epiphitic liverworts grow. The hapten of this allergy is a sesquiterpene lactone, (—)-frullanolide (338), isolated from Frullania tamarisci ssp. tamarisci, or ( + )-frullanolide (339) from F. dilatata 14,18, 30, 32,37,175, 255, 287). The isolation of these compounds represented the first discovery in bryophytes of compounds with biological activity in humans. The eudesmanolides (349) and (352) and the eremophilanolide (322) also caused intense allergies. Patients sensitive to Frullania species are all sensitive to at least one of the lactones isolated from F. dilatata 30). 

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