Cytotoxicity of flavonoid glycosides , flavonoid aglycones and phenolic acids from Inula oculus-christi L . on mammalian cell lines

Center of research interest in modern pharmacological therapy is increasingly shifting on drugs of plant origin. This statement largely relates to anti-tumor therapy. Natural bioactive molecules or their derivatives could serve as prototypes of final formulations for anticancer drugs (Rocha et al., 2001, Gordaliza, 2007). Multidrug resistance (MDR) is a critical problem in cancer chemotherapy. Cancer cells can develop resistance not only to a single cytotoxic drug, but also to entire classes of structurally and functionally unrelated compounds. Certain natural products obtained from medicinal plants may serve as potent drugs for reversing multidrug resistance in cancer cells due to their ability to inhibit ATP-dependent protein transporters, metabolic enzymes, and to induce apoptosis (Eid et al., 2015). It is essential to extend the investigations on medicinal plants, used in traditional medicine in order to reveal the natural remedies’ potential. Plants of the genus Inula are widely used in folk medicine as expectorants, antitussives, bactericides as well as for the treatment of lung inflammation and have shown to possess anti-inflammatory and secretolytic activity (Seca et al., 2014). Experimental research findings indicate anti-tumor, antimicrobial and antidiabetic activity for some of them (Tripathi & Chaturvedi, 1995, Lokhande et al., 2007, Lee et al., 2016). It is difficult to assess which compounds of the extracts are accountable for the beneficial impact. We have directed our efforts on investigating the effects of different extracts from I. oculus-christi, enriched with certain groups of biologically active substances – flavonoids, flavonoid glycosides, phenolic acids. It is shown that certain flavonoids from I. britannica protect primary cultured neurons against oxidative stress (Kim et al., 2002), and reduce the levels of histamine and bronchoconstriction in cases of asthma (Das et al., 2003). Other reported biological activities of flavonoids are: anti-inflammatory, antibacterial, antiviral, anticancer, hepatoprotective. They are capable to inhibit lipid-peroxidation, platelet aggregation, capillary permeability (Cushnie & Lamb, 2005). Epidemiological studies show an inverse correlation between dietary flavonoid intake and mortality from coronary heart disease (Cook & Samman, 1996). Ralitsa K. Veleva 1 Veselina S. MoskovaDoumanova 1 Milka N. Todorova 2 Antoaneta B. Trendafilova 2 Jordan A. Doumanov 1 Tanya I. TopouzovaHristova 1 Cytotoxicity of flavonoid glycosides, flavonoid aglycones and phenolic acids from Inula oculus-christi L. on mammalian cell lines