Leonurus cardiaca L. (Lamiaceae) is a valuable medicinal plant species widely applied in folk medicine as a cardiotonic, sedative and antiarhythmic agent. With the aim to assess suitability for cultivation of this species some biological and phytochemical characteristics were studied.

In 1997-1998 plants of 4 localities in Lyulin and Vitosha mountains (Sofia floral region) were observed for determination of phenological stages and biological productivity of herbage (60 g in average per plant).

Experiments on seed germination under laboratory conditions indicated that fresh seeds required about 4-month storage period to ripen fully which increased the germination to 62%. Germination of 6-month storage seeds could be improved by 10% using cool stratification for minimum 6 weeks.

Content of different bioactive substances of Herba Leonuri cardiacae was determined: flavonoids 0.61%; total alkaloids 0.03%, tannins 2.54%, essential oil 0.35-0.50%. Seven alkaloids were detected by thin-layer chromatography.

Wide range of bioactive substances as well as their variability is a good prerequisite for breeding of L. cardiaca with the purpose to obtain standardised plant material. Species could be suitable for reclamation of terrains polluted with household and farm wastes.