Planta Med 2012; 78 - PI461
DOI: 10.1055/s-0032-1321148

Antimicrobial activity of Cladonia incrassata acetone extract

A Dieu 1, M Millot 1, Y Champavier 2, JA Chulia 1, J Vergnaud 1, V Chaleix 1, P Bressollier 1, V Sol 1, V Gloaguen 1
  • 1Laboratoire de Chimie des Substances Naturelles EA 1069
  • 2Service Commun de Recherche et d'Analyse des Biomolécules de Limoges, Faculté de Pharmacie, 2 rue du Docteur Marcland, 87025 Limoges cedex, France

Lichens of the genera Cladonia and Usnea biosynthesize usnic acid, a widely spread dibenzofuran derivative endowed with antimicrobial activity. Usnic acid contents of Cladonia incrassata and Usnea florida acetone extracts were assessed by HPLC. Evaluation of antimicrobial activities against Staphylococcus aureus and Candida albicans showed that C. incrassata extract is more effective than usnic acid. Phytochemical study of this extract was initiated using a bioautographic protocol for tracking down active compounds. Two dibenzofurans isolated by preparative TLC and semi-preparative HPLC were further identified by NMR and MS as didymic acid and condidymic acid respectively. The strong antimicrobial activity of C. incrassata extract can be attributed to these two molecules, whose potential use as preservatives is currently under study.

Activity of 0.1% solutions of C. incrassata acetone extract (CiA), U. florida acetone extract (UfA) and usnic acid (AU) against S. aureus (a) and C. albicans (b)

R=C3H7: didymic acid; R=C5H11: condidymic acid