Coluria Geoides

Coluria geoides (family Rosaceae) is a perennial (), and has the following synonyms: Coluria potentilloides R. Br., Coluria laxmanni Aschers. et Gr., Caryophyllata potentilloides Lam., Geum laxmanni Gartn., Geum potentilloides Ait., Laxmannia geoides Fisch., Laxmannia potentilloides Fisch., Siversia geoides Spreng., Dryas geoides Pall.

Coluria R.Br. genus comprises of six species which are distributed in China; only Coluria geoides is native to South Siberia and Mongolia, and its morphology is described in The Flora of the Union of Soviet Socialist Republics (). The fruit anatomy of 30 species belonging to the subsection Geinae was studied by Korotaeva (). The findings of this study proposed to move genus Coluria R. Br. and Waldsteinia Willd. to the independent subsection Coluriinae. The only information available on the chemical composition of C. geoides is on the essential oil, which can be obtained from the roots by steam distillation (). The yield of essential oil is 1-1.8% of the dry weight. Eugenol () is the main component of the oil and constitutes 96% of it. In fresh roots eugenol occurs in the form of a glycoside which is assumed to be gein (geosid) ().

Coluria geoides was cultivated in the Soviet Union as a source of eugenol (). The best conditions for its culture were present in the Ukraine. The roots of the plants developed very well and resembled a beard. Cultivation experiments in this species were also undertaken in Poland (); 0.8% essential oil was obtained from the roots. The Polish investigations showed that the roots, used as the raw material for volatile oil distillation, should be gathered after 2-3 years of cultivation in the field. The weight of rhizomes with roots from one plant was ca. 30 g. After 3 years 2-41 of dry rhizomes and roots can be obtained from 1 ha. In Poland’s climate, the plants start blooming in the second year of vegetation. The weight of 1000 fruits is ca. 0.8 g. The germination capacity estimated in the first year after gathering, in the laboratory on Petri dishes at 18-25 °C, was 80%. The seeds, when sown during the spring in the field, germinated within 3 weeks.

Fresh roots are light brown and have a pleasant aroma resembling that of cloves. This aroma is more active when the roots are withered, an intensification of aroma caused by the fermentation process of eugenol glycoside. In the Soviet Union, instead of cinnamon, roots of Coluria geoides were used as spices for cakes, brandy, and tea. Sometimes they were also used to aromatize tobacco.

Coluria geoides can be propagated in vitro by axillary shoots, and after 8 months (six passages), about 1300 plantlets can be obtained from one explant. As the plants differ in dry weight of roots, micropropagation could contribute to fast multiplication of valuable strains, being a source of raw material for eugenol production.

The amount of essential oil obtained from roots cultured in vitro was not comparable to that from plants growing in the field. Eugenol was the main oil component. The results suggest that root culture cannot be a good source of eugenol occurring in the form of glycosides.

Selections from the book: “Medicinal and Aromatic Plants V”, 1993.