Five methanolic extracts obtained from different parts of birch, Betula pendula, Roth. (external and internal bark, flowers, leaves and buds), were evaluated for their antibacterial activity in this study. Triterpene compounds, betulin, betulinic acid, oleanolic acid and lupeol, were isolated from the external parts of birch bark using the method of dry column chromatography (DCC) as well as preparative thin layer chromatography (TLC). These compounds were also investigated for their antibacterial activity. Taking into account that decoction is the most commonly used pharmaceutical form of herbal drug, decoctions made from external bark, leaf, flower and bud were investigated for their antibacterial activity. Antibacterial screening, against selected Gram-positive bacteria, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538P and Gram-negative bacteria, Escherichia coli ATCC 8739 and Pseudomonas aeruginosa ATCC 9027 was carried out. The methods of diffusion and dilution were used for this investigation according to European Pharmacopoea, 1996. The most prominent antibacterial activity showed oleanolic acid against bacterial species Staphylococcus aureus, expressed as minimal inhibitory concentration (MIC): 1.25% and Bacillus subtilis MIC: 0.625%. Escherichia coli showed resistance on all investigated samples.

1Institute of Physiology and Biochemistry, Faculty of Medicine, University of Sarajevo, Čekaluša 90, 71000 Sarajevo, Bosnia and Herzegovina 2Institute of Nuclear Medicine, University of Sarajevo Clinical Center, Bolnicka 25, 71000 Sarajevo, Bosnia and Herzegovina 3Clinic of Nephrology, University of Sarajevo Clinical Center, Bolnicka 25, 71000 Sarajevo, Bosnia and Herzegovina 4Policlinic of Internal Medicine “Al Tawil,” Koste Hermana 1, 71000 Sarajevo, Bosnia and Herzegovina 5Faculty of Science, University of Sarajevo, Bosnia and Herzegovina

Aim: Cardiovascular changes that accompany thyroid disorders could be stimulus for the release of BNP from heart ventricles. Different factors, including stress environment conditions, have important role in pathogenesis of thyroid disorders and could possibly affect this response. The aim of this study was to assess the relationship between NT-proBNP and thyroid hormones levels in females with different thyroid functional states. Materials and methods: The study included 104 female patients, age 18-55 years, divided into three groups: hyperthyroid, hypothyroid and euthyroid (control). Serum NT-proBNP, FT3, FT4 and TSH levels were determined in all groups, but in hyper- and hypothyroid group before and after the adequate therapy aimed to the regulation of thyroid status. NT-proBNP concentration was determined by Electrochemiluminescent Immunoassay “ECLIA” method on Roche Elecsys 2010 system. Results: Mean serum NT-proBNP level in hyperthyroid group, before the therapy was 99.35 pg/mL and was significantly higher compared to serum NT-proBNP levels in control (65.90 pg/mL) and hypothyroid group (56.82 pg/mL, p<0.05). After therapy, serum NT-proBNP levels significantly decreased in hyperthyroid (53.64 pg/ml, p<0.01) and significantly increased in hypothyroid group (69.95pg/mL, p<0.04). A significant correlation between serum thyroid hormones, TSH and NT-proBNP levels were observed in hyperthyroid patients, but in hypothyroid patients only between NT-proBNP and FT3 levels. Multiple regression analyses demonstrated that FT3 level was independently associated with serum NT-proBNP levels in hyperthyroid group, after normalization of thyroid status. Conclusion: Thyroid hormones possibly effect BNP secretion and therefore affect the serum