Farnesane-Type Sesquiterpenoids with Antibiotic Activity from Chiliadenus lopadusanus

Chiliadenus lopadusanus Brullo is an Asteraceae plant species endemic to Lampedusa island, the largest island of the Pelage archipelago, Italy. The organic extract of its whole aerial parts, showing antibiotic activity against Staphylococcus aureus and Acinetobacter baumannii, wasfractionated employing bioguided purification procedures affording three main farnesane-type sesquiterpenoids. They were identified by spectroscopic methods (NMR and ESIMS data) as the (E)-3,7,11-trimethyldodeca-1,6,10-triene-3,9-diol, (E)-10-hydroxy-2,6,10-trimethyldodeca-2,6,11- trien-4-one and (E)-10-hydroxy-2,6,10-trimethyl-dodeca-6,11-dien-4-one, commonly named 9-hydroxynerolidol, 9-oxonerolidol, and chiliadenol B, respectively. These three sesquiterpenes, isolated for the first time from C. lopadusanus, were tested on methicillin-resistant S. aureus and A. baumannii showing antibacterial and antibiofilm activities. This plant could be used as a source to isolate secondary metabolites as potential new antibiotics.

Compositional Variability and Toxic Activity of Mugwort (Artemisia vulgaris) Essential Oils

The compositional variability of the essential oils of aerial parts of mugwort ( Artemisia vulgaris L.), collected from fifteen wild populations in Lithuania is detailed. The most predominant components were davanones (13.8-45.5%, six oils), germacrene D (9.1-30.5%, four oils), 1,8-cineole (16.4%, one oil), camphor (18.9%, one oil), trans-thujone (8.9 and 10.9%, two oils) and cis-chrysanthenyl acetate (10.4%, one oil). To the best of our knowledge, the davanone chemotype for A. vulgaris oils is described for the first time. The toxicity of the mugwort essential oils was determined using brine shrimp ( Artemia sp.) assay. LC50 values (10.3-23.1 μg/mL) obtained for the oils after 24 h of exposure revealed that the oils containing appreciable amounts of germacrene D, 1,8-cineole, camphor and davanone were notably toxic.

Essential Oils of Chiliadenus Lopadusanus (Asteraceae)

The essential oils from the leaves and flowers of Chiliadenus lopadusanus growing on Lampedusa Island were obtained by hydrodistillation and analyzed by GC-MS. The major component was camphor (39.4% in the leaves and 24.0% in the flowers), followed in the leaves by torreyol (6.7%), t-cadinol (5.2%) and 1,8-cineole (3.8%), while in the flowers by t-cadinol (15.2%), t-muurolol (5.1%) and torreyol (4.5%). Among the compounds identified, several seem to play a role in antibacterial, antifungal, allelopathic and spasmolytic activity. In addition, several compounds identified in this study seem to influence the attraction of Megachile ( Eutricharaea) apicalis (Megachilidae) and Halictus ( Seladonia) gemmeus (Halictidae), two hymenopteran here identified as pollinators of Chiliadenus lopadusanus.