Geranium macrorrhizum

Abstract: The volatile hydrodistilled compounds from aerial parts and rhizomes of the ethnopharmacologically highly valued plant species Geranium macrorrhizum L. were screened for their antimicrobial activity in disc-diffusion and microdilution assays. The assays pointed out to a very high and selective activity of the oils against Bacillus subtilis with minimum inhibitory concentrations (MIC) of 0.4-1.0 μg/ml. This prompted us to perform detailed compositional analyses of the oils. GC and GC/MS analyses allowed the identification of 283 constituents. The oils consisted mainly of sesquiterpenoids, the main ones being germacrone (49.7% in the oil from aerial parts) and δ-guaiene (49.2% in rhizome oil). Significant qualitative and quantitative compositional differences in the oils from the two plant parts were observed. Further antimicrobial testing enabled us to determine that germacrone, the major constituent of the oil from aerial parts, was not the sole agent responsible for the observed activity.

Abstract: Geranium kikianum Kit Tan & G. Vold sp. nov. (Geraniaceae) is illustrated and described as a new species endemic to Greece. It occurs beside streams and other wet places in open Pinus nigra forest at the foothills of Mt Taigetos in the southern Peloponnese. It is closely related to G. macrorrhizum, a species more widely distributed in southern and central Europe, ranging from the southern Alps to the Balkan Peninsula. It differs from the latter by its smaller and narrower deflexed petal limb, slender claw and occurrence in wet habitats. The genome sizes of G. kikianum and of Greek populations of G. macrorrhizum are presented here for the first time. The nuclear DNA content (2C values) of 2.84 pg for G. kikianum and 2.83 and 2.87 pg for two G. macrorrhizum populations from Greece probably corresponds to a 2n92 cytotype while the smaller genome size of 1.45 pg in a population of G. macrorrhizum from Mt Smolikas, Greece may correspond to a 2n46 cytotype. Geranium macrorrhizum L. occurs in the southern Alps, Apennine and Carpathian Mountains, extending to southern Greece in the Balkan Peninsula. In Europe it is increasingly cultivated on account of its ornamental flowers and no petrol station in Austria seems to be without it (pers. comm. M. A. Fischer Sep 2010). Being winter-hardy it naturalizes easily in parts of central Europe. It is also grown, especially in Bulgaria, for its aromatic essential oil and pharmacists know the latter as ‘‘zdravec oil’’, with reference to its Bulgarian name zdravets, meaning ‘health’. As the specific epithet implies, G. macrorrhizum has a stout horizontal rhizome sheathed in old stipules; the branched rhizome, mainly subterranean, is also partly above ground. The basal leaves are large (510 cm in diameter) and palmatifid to 3/44/5, with rhombic, pinnately lobed and incised-dentate segments. The petals are patent, with claw shorter than the limb; the limb is broadly obovate, entire to subemarginate, deep carmine to dull magenta-red. The stamens are conspicuously exserted. In Greece this species inhabits rocky limestone slopes (rarely schist), and is often found amongst boulders and rock-rubble in ravines and gorges but it is not a plant of wet places. It flowers from JunAug at altitudes of 1500 2100 m a.s.l., usually earlier at lower levels, e.g. AprMay. It has been recorded from the northern regions down to the mountains of Sterea Ellas on the mainland. Within the Peloponnese there are two records from the western foothills of Taigetos: ‘‘in faucibus Langada inter Kalamata