Abstract The largest mountainous lake in Bosnia and Herzegovina, Lake Blidinje, is located 1,185 meters above sea level. Polymictic lakes are those in which the entire water column is frequently mixed. Shallow lakes function very differently than deep lakes in many ways because of the strong sediment– water interaction and the possibility for significant water impact on vegetation. In the multiple regression analysis, two models were developed with coefficients of multiple determination (R2 = 0.720 and R2 = 0.497) for the independent variable chlorophyll a. The resulting models are compared with water quality monitoring data from 2017 to 2019.

Considering the vast cultural and traditional heritage of the use of aromatic herbs and wildflowers for the treatment of light medical conditions in the Balkans, a comparison of the antioxidant capacity of wildflowers extracts from Herzegovina was studied using both cyclic voltammetry and spectrophotometry. The cyclic voltammograms taken in the potential range between 0 V and 800 mV and scan rate of 100 mV s−1 were used for the quantification of the electrochemical properties of polyphenols present in four aqueous plant extracts. Antioxidant capacity expressed as mmoL of gallic acid equivalents per gram of dried weight of the sample (mmoL GAE g−1 dw) was deduced from the area below the major anodic peaks (Q400 pH 6.0, Q500 pH 4.7, Q600 pH 3.6). The results of electrochemical measurements suggest that the major contributors of antioxidant properties of examined plants are polyphenolic compounds that contain ortho-dihydroxy-phenol or gallate groups. Using Ferric reducing-antioxidant power (FRAP) and 2,2′-azino-bis spectrophotometric methods (3-ethylbenzthiazoline-6-sulphonic acid) radical cation-scavenging activity (ABTS) additionally determined antioxidant capacity. The FRAP results ranged from 2.9702–9.9418 mmoL Fe/g dw, while the results for ABTS assays expressed as Trolox equivalents (TE) ranged from 14.1842–42.6217 mmoL TE/g dw. The Folin–Ciocalteu procedure was applied to determine the total phenolics content (TP). The TP content expressed as Gallic acid equivalents (GAE) ranged from 6.0343–9.472 mmoL GAE/g dw. The measurements of total flavonoid (TF) and total condensed tannin (TT) contents were also performed to obtain a broader polyphenolic profile of tested plant materials. Origanum vulgare L. scored the highest on each test, with the exception of TT content, followed by the Mentha × piperita L., Artemisia annua L., and Artemisia absinthium L., respectively. The highest TT content, expressed as mg of (−)catechin equivalents per gram of dried weight of sample (mg CE/g dw), was achieved with A. absinthium extract (119.230 mg CE/g dw) followed by O. vulgare (90.384 mg CE/g dw), A. annua (86.538 mg CE/g dw) and M. piperita (69.231 mg CE/g dw), respectively. In addition, a very good correlation between electrochemical and spectroscopic methods was achieved.

1 Department of Chemistry, Faculty of Science and Education, University of Mostar, Matice hrvatske bb, 88 000 Mostar, Bosnia and Herzegovina; 2 Faculty of Agronomy and Food Technology, University of Mostar, Biskupa Čule bb, 88 000 Mostar, Bosnia and Herzegovina; 3 Department of Analytical Chemistry, Faculty of Chemistry and Technology, University of Split, Ruđera Boškovića 35, 21 000 Split, Croatia; E-mail: ante.prkic@ktf-split.hr

The chemical composition of essential oils isolated from immortelle (Helicrysum italicum subsp. italicum) collected in Herzegovina during five different periods, was investigated by GC/MS analysis. The main compounds were a-pinene (15.7 %) and γ-curcumene (12.8 %), followed by 4,6,9-trimethyldec-8-en-3,5-dione (8.7 %), neryl acetate (6.9 %), limonene (6.4 %) and β-selinene (5.3 %). In total, 69 components were identified whose share changed over the vegetative cycle. Antioxidant activity of methanolic extracts of immortelle were determined according to DPPH (IC50 = 23–34 μg/mL) and FRAP (29 μg/mL is equivalent to 1.1‒2.2 mM Fe2+) methods. Acetylcholinesterase inhibitory potential, investigated by modified Ellman’s assay and determined as IC50 values, were 340–440 μg/mL for methanol extracts and 135 μg/mL for essential oil. Metanolic extracts showed strong antioxidant activity and potential to inhibit AChE. Essential oil possesses complex chemical composition, inhibition activity of AChE and weak antioxidant capacity.