Exploitation of the Bulgarian Flora’s Biodiversity as a Source of Immunomodulatory And/or Antineoplastic Agents: Current Challenges and Perspectives

The Balkan Region represents one of the Europe’s major centres of plant diversity, with an substantial number of endemic genera and species having a wide distribution throughout the diverse ecosystems of the region. Plants remain an unequalled source of biochemical diversity and in the last several decades there is an unprecedented interest towards identifying perspective leads of plant origin. The phytochemical and pharmacological investigation of medicinal plants has long history as corroborated by the large number of facilities located in the Bulgarian Academy of Sciences, Faculty of Pharmacy at Medical University, Sofi a or within the Bulgarian pharmaceutical industry. Several examples from our search for new immunomodulatory and/or antineoplastic compounds obtained from Bulgarian plants will be presented to demonstrate the potential and problems of the pharmacological screening of natural products. These include: i) isolation, purifi cation, identifi cation and biological evaluation of saponines with immunomodulatory and anti-cancer effects; ii) phytochemical, biotechnological and pharmacological evaluation of indigenous Linum sp. as sources for cytotoxic podophyllotoxin-like lignans; iii) phytochemical evaluation of the phenolic compounds (acylphloroglucinols, benzophenones, xanthones) from Hypericum sp. and investigation of their antineoplastic, antiangiogenic and myeloprotective effects; iv) investigation of the alkaloid thaliblastin from Thalictrum spp. as modulator of multidrug-resistance in cancer cells.