Agnieszka Stobiecka

Hydrolates from lavender (Lavandula angustifolia) - their chemical composition as well as aromatic, antimicrobial and antioxidant properties

It was shown that the method for obtaining hydrolates from lavender (Lavandula angustifolia) influences the content of active compounds and the aromatic, antimicrobial and antioxidant properties of the hydrolates. The content of volatile organic compounds ranged from 9.12 to 97.23 mg/100 mL of hydrolate. Lavender hydrolate variants showed low antimicrobial activity (from 0% to 0.05%). The radical scavenging activity of DPPH was from 3.6 ± 0.5% to 3.8 ± 0.6% and oxygen radical absorbance capacity (ORACFL) results were from 0 to 266 μM Trolox equivalent, depending on the hydrolate variant.

Synthesis and characterisation of Thio-H, a new excitation and emission ratioable fluorescent Ca2+/Mg2+ indicator with high brightness

A new fluorescent ratiometric indicator for Ca2+ and Mg2+, tricaesium salt of {2-[bis(carboxymethyl)amino]-5-(5-phenylthiophen-2-yl)phenoxy}acetic acid, Thio-H, has been synthesised and evaluated for its cation binding properties via fluorimetric titrations. Thio-H has the interesting property of being both excitation and emission ratioable, expanding the range of possible applications. The in vitro dissociation constant, Kd, measured at 20 °C in 100 mM KCl, pH 7.20 for the Ca2+–Thio-H complex is 45 ± 13 μM; for Mg2+–Thio-H a Kd value of 5.6 ± 0.6 mM is found. The free form of Thio-H has a high fluorescence quantum yield (0.74), which decreases to 0.50 and 0.65 upon binding to Ca2+ and Mg2+, respectively. Measurements under physiological conditions show that increasing the temperature from 20 to 37 °C decreases the affinity of Thio-H for Ca2+. Changing the pH from 7.05 to 7.40 does not affect the Kd value of the Mg2+ complex but it increases somewhat the affinity of the probe for Ca2+. In the presence of 1 mM Mg2+, the Ca2+ affinity of Thio-H decreases (Kd = 126 ± 46 μM at 20 °C, pH 7.05). Time-resolved fluorescence measurements confirm that the inflection point in the fluorimetric titration curve can be correctly assigned to Kd. Since the dissociation constant for the Mg2+–indicator complex falls within the intracellular [Mg2+] domain, while the Kd value for Ca2+ is well above the basal Ca2+ levels, Thio-H has potential applications as a Mg2+ indicator. The low affinity for Ca2+ can be exploited for detecting intracellular Ca2+ levels in the micromolar range, on condition that [Mg2+]i remains practically constant during the measurements. Thio-H provides an excellent addition to the commercial ratiometric low-affinity Ca2+ indicators Mag-fura-2, Mag-fura-5, Mag-indo-1, Fura-FF, and BTC.

Chemical composition and biological activity of Abies alba and A. koreana seed and cone essential oils and characterization of their seed hydrolates.

The chemical composition, including the enantiomeric excess of the main terpenes, the antimicrobial and antiradical activities, as well as the cytotoxicity of Abies alba and A. koreana seed and cone essential oils were investigated. Additionally, their seed hydrolates were characterized. In the examined oils and hydrolates, a total of 174 compounds were identified, which comprised 95.6–99.9% of the volatiles. The essential oils were mainly composed of monoterpene hydrocarbons, whereas the composition of the hydrolates, differing from the seed oils of the corresponding fir species, consisted mainly of oxygenated derivatives of sesquiterpenes. The seed and cone essential oils of both firs exhibited DPPH‐radical‐scavenging properties and low antibacterial activity against the bacterial strains tested. Moreover, they evoked only low cytotoxicity towards normal fibroblasts and the two cancer cell lines MCF‐7 and MDA‐MBA‐231. At concentrations up to 50 μg/ml, all essential oils were safe in relation to normal fibroblasts. Although they induced cytotoxicity towards the cancer cells at concentrations slightly lower than those required for the inhibition of fibroblast proliferation, their influence on cancer cells was weak, with IC50 values similar to those observed towards normal fibroblasts.

A comparative study on composition and antioxidant activities of supercritical carbon dioxide, hexane and ethanol extracts from blackberry (Rubus fruticosus) growing in Poland

BACKGROUND Large quantities of blackberry seeds are produced as a pomace during the processing of juice and jam production; this by-product is a very interesting raw material both for oil manufacturing and as a source of bioactive compounds. In this work the composition, yield and antioxidant activity of three types of Rubus fructicosus pomace extracts isolated by liquid extraction using solvents of different polarity, as well with supercritical CO2 fluid extraction have been compared. RESULTS The highest extract yield was reported for Soxhlet extraction using ethanol as a solvent (14.2%). Supercritical carbon dioxide and hexane extracts were characterised by the highest content of phytosterols (1445 and 1583 mg 100 g-1 of extract, respectively) among which β-sitosterol was the main one, while the concentration of tocopherols, with predominant γ-isomer, was the highest for both hexane and ethanol extracts, being 2364 and 2334 mg 100 g-1 , respectively. Using a GC-MS method 95 volatiles, in which non-saturated aldehydes were predominant, were identified in the essential oil of seed pomace and in the volatile oil isolated from supercritical extract. The ethanolic extract which is characterised by the highest phenolic content (9443 mg GAE 100 g-1 ) exhibited the highest antioxidant activity (according to the ABTS•+ and DPPH• assays). CONCLUSION All pomace extracts examined were of high quality, rich in essential omega fatty acids and with a very high content of bioactive compounds, such as phytosterols and tocopherols. The high nutritional value of extracts from berry seed pomace could justify the commercialisation of specific extracts not only as food additives but also as cosmetic components.