Screening of plant extracts for antimicrobial activity against
bacteria and yeasts with dermatological relevance.

* Weckesser S,
* Engel K,
* Simon-Haarhaus B,
* Wittmer A,
* Pelz K,
* Schempp CM.

Department of Dermatology, University of Freiburg, Hauptstrasse 7,
79104 Freiburg, Germany.

There is cumulative resistance against antibiotics of many
bacteria. Therefore, the development of new antiseptics and
antimicrobial agents for the treatment of skin infections is of
increasing interest. We have screened six plant extracts and isolated
compounds for antimicrobial effects on bacteria and yeasts with
dermatological relevance. The following plant extracts have been
tested: Gentiana lutea, Harpagophytum procumbens, Boswellia serrata
(dry extracts), Usnea barbata, Rosmarinus officinalis and Salvia
officinalis (supercritical carbon dioxide [CO(2)] extracts).
Additionally, the following characteristic plant substances were
tested: usnic acid, carnosol, carnosic acid, ursolic acid, oleanolic
acid, harpagoside, boswellic acid and gentiopicroside. The extracts
and compounds were tested against 29 aerobic and anaerobic bacteria
and yeasts in the agar dilution test. U. barbata-extract and usnic
acid were the most active compounds, especially in anaerobic bacteria.
Usnea CO(2)-extract effectively inhibited the growth of several
Gram-positive bacteria like Staphylococcus aureus (including
methicillin-resistant strains - MRSA), Propionibacterium acnes and
Corynebacterium species. Growth of the dimorphic yeast Malassezia
furfur was also inhibited by Usnea-extract. Besides the Usnea-extract,
Rosmarinus-, Salvia-, Boswellia- and Harpagophytum-extracts proved to
be effective against a panel of bacteria. It is concluded that due to
their antimicrobial effects some of the plant extracts may be used for
the topical treatment of skin disorders like acne vulgaris and
seborrhoic eczema.

PMID: 17291738 [PubMed - as supplied by publisher]