Penicillium oxalicum alkaloid

Oxaline (143) was isolated in 1974 by Nagel et al. (183,184) from cultures of the toxicogenic fungus Penicillium oxalicum. The compound may be classified as an indole alkaloid, but it is one of the three indole alkaloids known at present that also contains an imidazole substituent the other indole alkaloids being roquefortine (144) and neoxaline (145). The structure of oxaline was deduced from physicochemical data and confirmed by single-crystal X-ray analysis. It has been suggested that in the biosynthesis of oxaline, nature makes use of the amino acids tryptophan and histidine (184). 

The structure of oxaline (36), the principal alkaloid of a toxigenic strain of Penicillium oxalicum, represents a departure from those hitherto encountered in this area. The molecule possesses several unusual features, viz. the N—OMe group, the dehydrohistidine unit, the reversed isopentenyl group at C-3 (the only other example known to date is metabolite LL-S490j8), and the presence of three nitrogen functionalities attached to a single carbon atom (C-2). 

Oxaline was first isolated as a new alkaloid from a toxigenic strain of Penicillium oxalicum M-555. No bioactivity was reported for this compound which was originally characterized by x ray crystallography [64, 65]. 

Vinokurova NG, Reshetilova TA, Adanin VM, Kozlovskii AG (1991) Alkaloid composition of Penicillium palitans and Penicillium oxalicum. Appl Biochem Microbiol 27 644—648... 

Vinokurova, N.G., Reshetilova, T.A., Adanin, VM. and Kozlovsky, A.G. (1991) Study of the alkaloid composition of Penicillium palitans and Penicillium oxalicum. Prikl. Biokhim. Microbiol, (in Russian), 27, 850-855. 

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