Summary.

The Balkan endemite Haberlea rhodopensis Friv. (Gesneriaceae) is a very rare, relict plant species, which grows in restricted humid and shady areas in Bulgaria. The species is among the few plants known as resurrection plants for their vegetative desiccation tolerance. After successful establishment of a protocol for in vitro multiplication earlier, here we report that the in vitro produced plants possess the same resurrection capability as the plants from the nature. Leaf extracts of the plants contain three groups of biologically active substances: flavonoids, tannins and polysaccharides. Leaves of in vitro multiplicated plants produced about 30% more flavonoids than the plants from natural habitats. Total content of flavonoids showed a better correlation than total tannins with the free radical scavenging effect of the extracts measured by means of the DPPH discoloration assay. The extracts of Haberlea rhodopensis leaves display strong antioxidative activity, which could be exploited as potential pharmaceuticals.