Anti-aging cosmetics are often sought after in order to slow down the aging process. Free radicals are one of the main causes of skin aging, and therefore antioxidants are used in anti-aging cosmetics. The aim of this study was to investigate which method is the most suitable for determining the antioxidant capacity of these products. Having samples extracted, the antioxidant capacity of the extracts obtained was determined by the following spectrophotometric methods: DPPH, Folin-Ciocalteu, FRAP, the ABTS method and the ferroion chelation method with ferrosine. The antioxidant capacity of the samples varied depending on the extract type and the method used. DPPH and ferroion chelation measurements with ferrosine were carried out in the part of the spectrum where plant pigments absorb. These pigments are often found in anti-aging products affecting these methods measurement results. The Folin-Ciocalteu method is suitable for researching the antioxidant capacity of hydrophilic extracts, but not lipophilic ones, where turbidity and the formation of a gelled ring occur. The FRAP method revealed similar results for all the samples and proved to be less sensitive than the others. The ABTS method for both types of extracts has proven to be the most suitable and sensitive method for determining the antioxidant capacity of anti-aging products.

In this study, the preservation of As(III) in model solutions and natural groundwater samples from four locations in Croatia was conducted. Model laboratory samples were spiked with As(III) and As(V), and different complexing agents. Solutions were analysed in intervals of 24, 48 h and during ten days after preparation. Model samples containing citric acid, sodium citrate, sodium oxalate and potassium sodium tartrate in combination with acetic acid, spiked with As(III)and As(V), showed good species preservation. As(III), in model samples, was preserved for 7 days with citric acid, and citric acid in combination with acetic acid, as well as with tartrate. As(III), in natural samples, was preserved for 6 to 12 days with potassium sodium tartrate, citric acid, and citric acid in combination with acetic acid and showed improvement, compared with unpreserved samples (oxidation in 3 days). The results showed that acetic acid alone was not successful in preserving As speciation. Good resolution of inorganic arsenic species was achieved using differential pulse anodic stripping voltammetry technique (DPASV). Since this technique is comparatively cheaper and more convenient to use than other available techniques it could become a method of choice for arsenic speciation in water.

Sloe (Prunus spinosa L.) extracts are a good source of natural bioactive compounds, including phytosterols. Phytosterols are known to be applied in the treatment of various prostate diseases. The in vitro antiproliferative activity of sloe ethanolic extracts (flower, leaf, and fruit), collected from three areas in Bosnia and Herzegovina, were investigated against human prostate cancer cell lines PC-3 and DU145 using MTT assay. β-sitosterol, campesterol and stigmasterol were quantified by HPLC-PDA analysis using Symmetry C18 chromatographic column. The results of the analysis proved the presence of phytosterols, mostly β-sitosterol in all extracts. All extracts possess antiproliferative activity. The highest activity against PC-3 and DU145 was gathered from leaf extracts obtained by different extraction methods (microwave-assisted extraction and ultrasound-assisted extraction). To the best of our knowledge, no other studies have presented results on antiproliferative activity of ethanol sloe extracts. Based on these results, further investigation should be recommended on other cancer cell lines as well.

Magnesium is an essential element and the intracellular divalent cation involved in many biochemical functions. People with magnesium deficiency must increase their intake of magnesium, usually in the form of various supplements. A common form of magnesium supplement widely available in pharmacies is magnesium oxide (MgO). In this work, the content of MgO was determined in pharmaceutical supplementations using spectrophotometry, based on the reaction between magnesium ions and eriochrome black T at a wavelength of 535 nm. The analysed content of MgO ranged from 360.5 to 386.5 mg MgO, which corresponds to the daily Mg recommended values (300 to 400 mg).

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