Structure of Herbarin

Abstract

Herbarin and dehydroherbarin, isolated from the fungus Torula herbarum (Pers.), belong to the class of pigments in which a naphthaquinone moiety is fused to an oxacyclohexene ring at the 1, 2-positions. Their structures are discussed. 25O THE JOURNAL OF ANTIBIOTICS APR. 1971

Secondary metabolites of fungi from marine habitats

“…A strain of Trichoderma longibrachiatum was isolated from blue mussel, Mytilus edulis, collected in France. Using various mass spectrometric techniques, eight new short peptaibols were identified, each of them comprising 11 amino acids, trichobrachins A I-IV (436)(437)(438)(439) and trichobrachins B I-IV (440)(441)(442)(443). 303 Reinvestigation of the same strain led to the partial characterisation by mass spectrometry of a further microheterogenous mixture of 30 peptaibols, out of which 21 were new.…”

“…198 The biosynthesis of the 2-azaanthraquinone, scorpinone (648), originally described from the marine sediment-derived fungus Amorosia littoralis, 439 has been demonstrated to proceed via a regular polyketide pathway with a linear heptaketide as biosynthetic intermediate, 440 which would also account for the presence of the known cyclic hemiketal herbarin, originally isolated from a terrestrial Torula herbarum. 441 Thus, it seems clear that at some point late in the biosynthesis of 648, an exchange of an oxygen for a nitrogen atom has to occur, however, it is not possible to decide whether this nitrogen is derived from inorganic nitrogen or a nitrogen-containing organic precursor.…”

Pyranonaphthoquinone antibiotics—isolation, structure and biological activity

“…compounds in the arrangement and type of oxygenated substituents around the naphthoquinone nucleus. 41,42 The methoxy groups were assigned to positions 7 and 9 (versus 6 and 8) on biogenic grounds. Herbarin methyl acetal 28 was also obtained 43 from T. herbarum, and, like 26 and 27, its structure determined by spectroscopic means.…”

Three New Naphthoquinone Pigments Isolated from the Freshwater Fungus,Astrosphaeriella papuana

“…Astropaquinones differ from naturally occurring precedents in the identity of the substituents and their substitution patterns. These compounds, however, bear close biogenetic resemblance to a variety of fungal metabolites, and can be classified as heptaketides [27,28]. The core structures of astropaquinones B and C are closely related to two known fungal metabolites, thysanone isolated from the fungus Thysanonophora penicilloides as an effective inhibitor of human rhinovirus 3C-protease [18], and 1-hydroxydehydroherbarin from Corynespora sp.…”