The metabolic products of micro-organisms can be classified either as
compounds of primary metabolic concern or else as secondary
metabolites - substances which are apparently non-essential to the
producing or- ganism. Fungi have a remarkable capacity to produce such
secondary metabolites, e. g. mycotoxins with a diverse array of
structural and pharmacological properties (1). The present resurgence of
interest in all aspects of mycotoxin research (2, 3) can be related to
the impact of the hepatotoxins (aflatoxin, sporidesmin, and phomopsin),
nephrotoxins (ochratoxin and citrinin), and dermal toxins
(trichothecenes) on human and animal health. Some of the mycotoxins
appear to act at the level of the central nervous system. Ergotism, the
earliest known mycotoxicosis, that is a disease caused by mycotoxins,
was attributed to the contamination of wheat by the parasitic
neurotoxin-producing fungus, C/aviceps purpurea. These neuro- toxins
elaborated by C. purpurea are collectively called the ergot toxins (4).
The neurotoxin, citreoviridin (1) which causes paralysis in the
extremities of laboratory animals, followed sometimes by convulsions and
respiratory arrest, has been implicated in acute cardiac beri-beri in
Japan (5). Tremoring has not been associated with citreoviridin or the
structurally related aurovertins (2) (6) and asteltoxin (3) (7); these
compounds are therefore excluded from this review. However, verrucosidin
(4) (8), a tremorgenic compound which structurally resembles (1)-(3),
will be described later.