Composition and antimicrobial activity of the essential oils from invasive species of the Azores,Hedychium gardnerianum and Pittosporum undulatum

The compositions of the essential oils from the leaves and flowers of Hedychium gardnerianum and from the leaves of Pittosporum undulatum growing on San Miguel Island (Azores) were investigated, and the compounds were identified by GC-MS analyses. The oils in the leaves and flowers of H. gardnerianum were rich in alpha-pinene, beta-pinene and alpha-cadinol, whereas that from P. undulatum was found to contain monoterpenes, sesquiterpenes, diterpenes and alkanes, of which the sesquiterpenes, calamenene (41.4%), farnesol (10.9%), spathulenol (5.6%) and beta-selinene (5.2%) and the diterpene (8beta,13beta)-kaur-16-ene (10.7%) were the major components. Their potential antimicrobial activities were tested against Staphylococcus aureus, S. epidermis and Pseudomonas aeruginosa, and those with the highest activities against S. aureus and S. epidermis were from H. gardnerianum; none had activity against P. aeruginosa. Additionally, the essential oils from Pittosporum undulatum had good antithrombin activity whereas that from H. gardnerianum did not.     

Bioactive Sesquiterpenoids and Diterpenoids from the Liverwort Bazzania albifolia

One undescribed 6,7‐secofusicoccane‐type diterpene, albifolione ( 1 ), and one new aromadendrane‐type sesquiterpenoid ketone, methyl 2‐oxoaromadendra‐1(10),3‐dien‐12‐oate ( 2 ), along with four known compounds, δ‐cuparenol ( 3 ), fusicoauritone ( 4 ), chiloscyphenols A and B ( 5 and 6 , resp.), were isolated from the liverwort Bazzania albifolia Horik. The structures and relative configurations of 1 and 2 were established unequivocally on the basis of spectroscopic data analysis. Preliminary bioassay revealed that compound 5 showed quite strong cytotoxicity against the human tumor cell line MCF‐7, with an IC₅₀ value of 5.6 μM .     

Phytotoxicity of constituents of glandular trichomes and the leaf surface of camphorweed, Heterotheca subaxillaris

Camphorweed, Heterotheca subaxillaris (Lam.) Britt. & Rusby, has a camphor-like odor, and its leaf surfaces contain glandular trichomes of the type shown to contain high levels of isoprenoids in other species. Borneol (1), the phytotoxic calamenene-type sesquiterpenes (2-5, 9-11), and methylated flavones (12-15) were isolated from the dichloromethane rinsate of camphorweed aerial tissues. The strongest plant growth inhibitor against Agrostis stolonifera and Lactuca sativa seedlings, as well as duckweed (Lemna pausicostata), was 2-methoxy-calamenene-14-carboxylic acid (2). Esterification of calamenene carboxylic acids decreased their biological activity.