Contributions to the Chemistry of the Collemataceae. I Lichen Substances in Some Species of Leptogium

Abstract

Gas-liquid chromatography indicates the presence of a number of volatile components in some species of Leptogium, and, while there are variations from one species to the next, the overall chromatographic picture shows a con- siderable degree of similarity in their chemica:l composition. Crystallization of lichen substances is reported for the first time in the genus Leptogium. No record of the occurrence of lichen substances in the Collemataceae has so far been reported (Culberson, 1969). In this communication we provide definite evidence for the presence of such substances in eight species of Leptogium. Material of L. brebissonii was available in some quantity and we have, therefore, concerned ourselves principally with this species. MATERIALS AND METHODS hydrogen chloride to esterify any free carboxyl groups. The solution was neutralized with silver carbonate, centrifuged, and the solution carefully concentrated. The products, in chloro- form, were examined by gas-liquid chromatography. In the case of L. brebissonii, crystallization of the extract was carried out as follows: the air-dried lichen (930 mg) was extracted with ether at room temperature, the extract was concentrated and again treated with ether. The ether-soluble portion was shaken with 5% sodium carbonate and, on acidification, a precipitate was obtained. The precipitate Was centrifuged, washed with water and dried, giving a yield of 38 mg; 3 mg of this residue were crystallized in GE. Standard methods of microchemical extraction were applied to portions of the thallus of L. brebissonii and L. saturninum. The former was extracted with ether and crystallized in GE; L. saturninum was extracted with benzene and crystallized in GAAn. Infra-red spectra were recorded in chloroform on a Perkin-Elmer 135 Sodium Chloride Spectrophotometer.