This study was undertaken in order to evaluate possible antioxidative and antiproliferative activities of three Helleborus taxa. The dry leaves and roots of three Helleborus taxa were extracted with ethanol and water. A phytochemical evaluation of the selected extracts was performed using spectrophotometric methods and a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity assay was used for measuring the antioxidative activity of extracts. The antiproliferative activity of the three Helleborus taxa was studied using Burkitt's lymphoma B cells (BJAB) cell lines. The phytochemical evaluation showed that the leaves contain high levels of total phenolic and flavonoid content. Results from the DPPH assay indicated that the activity of the ethanol and water extracts of the leaves was higher than that of positive control (thymol). Extracts from the roots of H. odorus also displayed higher antioxidant activity than the positive probe, while H. mulifidus and H. hercegovinus root extracts were less effective. A statistically significant correlation between total phenolic content and antioxidative properties indicates that these compounds contribute to the antioxidant activity. The highest percentage of cell growth inhibition was observed when testing the water root extracts of H. multifidus (50.14%) and H. hercegovinus (49.04%). In contrast, the water leaf extract of H. hercegovinus exhibited the lowest inhibition of cell growth (8.59%), although it showed strong antioxidant activity.

Karalija, E., Paric, A.: The effect of BA and IBA on the secondary metabolite production by shoot cultureof Thymus vulgaris L.. Biologica Nyssana, 2 (1), September 2011: 29-35. In vitro shoots of the common thyme ( Thymus vulgaris L.) were established, and the effects of differentconcentrations of the cytokinin BA and the auxin IBA on secondary metabolite production were investigated.The highest number of shoots was obtained through cultivation on the MS medium containing 2 mg/L BAand 0.1 mg/L IBA and 4 mg/L BA and 0.1 mg/L IBA (14.3 and 13.3 respectively). Quantitative changes inchlorophyll a, chlorophyll b and carotenoid content were recorded in response to the effect of varyingconcentrations of growth regulators in the medium. Furthermore, after addition of plant growth regulators(0.5 mg/L BA + 0.1 mg/L IBA) to the medium, elicitation of phenolic compounds was recorded in plantlets.The concentration range of BA from 2 to 4 mg/L improved the production of flavonoids (0.61 and 0.64 mg/gFW). In contrast, plantlets cultivated on the same treatment, showed a decrease in monomeric anthocyanins. Key words : common thyme, in vitro, micropropagation, secondary metabolite production

Karalija, E., Trbojevic, S., Paric, A.: Somatic embryogenesis and in vitro plantlet regeneration of Lilium martagon L. var. cattaniae Vis.. Biologica Nyssana, 1 (1-2), December 2010: 57-60. In this study organogenic capacity of two different explants type (leaves and whole bulbs) of Lilium martagon L. var. cattaniae Vis. was examined. For induction of in vitro somatic embryogenesis and adventitive regeneration different concentrations of 2,4-dichlorophenoxyacetic acid and 6-benzilaminopurine (from 0,25 mg/l to 8,00 mg/l) added to MS basal medium were used. Our results indicate that concentration of 0,5 mg/l 2,4-dichlorophenoxyacetic acid and 4 mg/l 6- benzilaminopurine promoted somatic embryogenesis from leaves of Lilium martagon var. cattaniae, while all other concentrations promoted direct shoot regeneration from bulb explants. Root formation was induced on MS basal medium with 0,2 mg/l indole butyric acid. These plantlets were acclimatized well in a greenhouse conditions.