Samples of the lichen Stereocaulon glabrum (135 grams) were collected on January 25, 2007 from Highlander Point at Cierva Cove on the Antarctic Peninsula. Lichens were ground and subjected to soxhlet extraction using hexane, acetone, methanol and 70% ethanol/water. TLC plates from the acetone extracts indicated an ethyl acetate:hexane mixture as best suited for separation. Samples were further purified using HPLC. Chromatography studies revealed the presence of lobaric acid, �-sitosterol, and an unreported compound 4-methoxycarbonyl-2,6-dihydroxy-benzaldehyde. Lobaric acid, which was thought not to be produced by S. glabrum, was structurally identified using a 600 MHz NMR and estimated to be over 1.85% of the lichen fresh weight. Thus far, 2.5 grams of lobaric acid have been isolated. Antioxidant studies using DPPH revealed extremely high antioxidant properties with 4-methoxycarbonyl-2,6-dihydroxy-benzaldehyde. Further research is needed to confirm structure analysis of the new compound. Additional chemical investigations of S. glabrum will include study of the remaining extracts and elucidation of unknown compounds.

Determination of allelopathic secondary metabolites of the lichen <i>Stereocaulon glabrum</i>

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Determination of allelopathic secondary metabolites of the lichen Stereocaulon glabrum