Detection of secondary metabolites in dried cultures of Penicillium preserved in herbaria

Abstract

In order to ascertain whether secondary metabolites used in the chemotaxonomy of Penicillium could be detected in dried cultures preserved in herbaria, the metabolic products of both dried and living cultures of nine representative isolates (including the nomenclatural types of four species) were compared by thin-layer chromatography (tlc) in a range of systems. Most of the metabolites seen in the living cultures were detected in the dried cultures, which ranged from 22 to 35 years in age. This demonstrates that chemical data can be obtained from dried material of microfungi preserved in herbaria in a manner comparable to that already documented for lichen-forming fungi. It also provides another reason for depositing dried cultures of microfungi which do not have structures that dry well in herbaria. The technique will be of value in checking the products of dried type cultures, surveys of the products of the numerous microfungi present in major herbaria, and searches for alternative producers of particular economically important compounds or toxins.