1.
Phytochemistry
; 67(7): 716-22, 2006 Apr.
Article
in English
| MEDLINE
| ID: mdl-16434071
ABSTRACT
The hexane extract of fresh air-dried leaves of Helichrysum tenax (Asteraceae) afforded ent-beyer-15-en-19-ol (1), its 4-epimer ent-beyer-15-en-18-ol (2), 15beta,16beta-epoxide-ent-beyeran-19-ol (3), as well as (4) consisting of two units of (1) linked as a diester of malonic acid, and (5), a compound. Its constituents are (1) and (3) also linked as a diester of malonic acid. The leaves of the plant are densely covered in fine glandular trichomes. These are extremely sticky and exude a mixture of the above diterpenes. Antimicrobial tests showed that (1), in particular, was highly active (3.1 and 3.6 microg/ml) against Bacillus cereus and Staphylococcus epidermidis, respectively.