Essential oil composition of the Balkan endemic Thymus longedentatus (Degen & Urum. ) Ronniger / Composición del aceite esencial de Thymus longedentatus (Degen & Urum. ) Ronniger endemic de los Balcanes

The chemical composition of essential oil obtained from the aerial parts of the Balkan endemic species Thymus longedentatus was studied by GC-MS. Twenty eight compounds, consisting 98.2% of the total components were detected in amounts exceeding 0.1%. The oil was characterized by relatively high concencentration of oxygentated monoterpenes (78.7%), among which citral isomers neral (27.5%) and geranial (30.3%) were the principal ones. In addition, 1,8-cineole (7.8%), trans-ß-ocimene (7.5%), and ß-myrcene (3.7%) were detected in significant ammounts. Germacrene D (4.4%) was found to be the main sesquiterpene in the essential oil.

Se estudió mediante GC-MS la composición química del aceite esencial obtenido de las partes aéreas de Thymus longedentatus, especie endémica de los Balcanes. Se detectaron veintiocho compuestos, que representaban un 98,2% del total de compuestos y que se encontraban en cantidades superiores al 0,1%. El aceite se caracterizó por una concentración relativamente alta de monoterpenos oxigenados (78.7%), entre los cuales los isómeros de citral, neral (27.5%) y geranial (30.3%) eran los principales. Además, se detectó 1,8-cineol (7,8%), trans-ß-ocimeno (7,5%) y ß-mirceno (3,7%) en cantidades significativas. Se encontró que Germacreno D (4.4%) es el principal sesquiterpeno en el aceite esencial.

New cycloartane triterpenes from bioactive extract of propolis from Pitcairn Island.

Dichloromethane extract of propolis (DCME) originating from Pitcairn Island demonstrated potent cytotoxicity against triple-negative MDA-MB-231 human breast carcinoma cells. The results from MTT assay showed that DCME inhibits the growth of the cancer cells in a dose- and time-dependent manner and upon the cell growth inhibition propolis extract provoked apoptotic changes in the cell nuclei. A detailed chemical investigation of DCME led to the isolation of four new cycloartane triterpenes (1-4), along with 17 known compounds (5-21). The structures of the new compounds were elucidated by means of extensive analysis of their spectroscopic data and comparison with those reported for their analogues. In vitro antimicrobial activity of new compounds (1-4) along with the DCME against four human pathogens was evaluated. All tested constituents except compound 2 were highly active against Escherichia coli with MIC 64 µg/ml. Compound 1 exhibited high antifungal activity against Candida albicans with potency close to that of the positive control (amphotericin B). The DCME showed very good antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans. This is the first study on propolis from Pitcairn Island.