Development of a vortex-assisted switchable-hydrophilicity solvent-based liquid phase microextraction for fast and reliable extraction of Zn (II), Fe (II), Pb (II), and Cd (II) from various baby food products.

This manuscript describes the development of a novel liquid phase microextraction (LPME) method for the extraction and determination of Zn (II), Fe (II), Pb (II), and Cd (II) in various infant/baby food and supplements products. The method is based on vortex-assisted extraction combined with a switchable-hydrophilicity solvent (SHS) sample preparation. The SHS, which undergoes reversible phase changes triggered by pH change, enables selective extraction and easy phase separation. A flame atomic absorption spectroscopy was used in the final determination step. Optimization studies revealed, that the optimal pH of the sample solution (after digestion) during analytes extraction is 5.5. A l-proline is added to the sample (375 mM) to ensure the complexation of the target metal cations. After the complexation step, 750 µL of SHS - a N, N-Dimethylcyclohexylamine along with 0.9 mL of 2 M of acetic acid solution is added (hydrophilicity switch-on stage) and mixed manually to obtain a homogeneous solution. In the last stage, 0.45 mL of 10 M NaOH solution (hydrophilicity switch-off stage) is added to the sample solution and a vortex for 100 s is applied to ensure the effective extraction and separation of the complex containing the analytes. At this stage, a cloudy solution is immediately obtained. Finally, the effective phase separation is obtained at the centrifugation step (4000 rpm for 2 mins). The method limit of detection was as 0.03, 0.009, 0.6, and 0.2 ng/L for Zn (II), Fe (II), Cd (II), and Pb (II) respectively with RSD% below 2.0 %. The analysis of certified reference materials and real samples proved the full applicability of the method for routine analysis, contributing to the field of heavy metal analysis and ensuring the safety of baby products. According to the AGREE methodology, this method can be named as green analytical chemistry method with a score of 0.77.

Determination of in vitro antioxidative and antimicrobial properties and total phenolic contents of Ziziphora clinopodioides, Cyclotrichium niveum, and Mentha longifolia ssp. typhoides var. typhoides.

The aerial parts of Ziziphora clinopodioides, Cyclotrichium niveum, and Mentha longifolia ssp. typhoides var. typhoides were screened for their possible antioxidant and antimicrobial activities in addition to their penolic contents. Antioxidant activity was employed by two complementary test systems: 2,2'-diphenyl-1-picrylhydrazyl free radical scavenging and beta-carotene/linoleic acid. In the first case, Z. clinopodioides was superior to the other species with a 50% inhibitory concentration value of 37.73 +/- 1.18 microg/mg. Similar results were obtained from the beta-carotene/linoleic acid system. Inhibition capacity of the linoleic acid of Z. clinopodioides was 83.56 +/- 1.19%. Additionally, antioxidant activities of butylated hydroxytoluene, curcumin, and ascorbic acid were determined in parallel experiments. Methanol extracts obtained from the plants studied were found to have moderate antimicrobial activity against all microorganisms tested. In general, Z. clinopodioides extract exhibited stronger activity than the other extracts. On the other hand, Acinetobacter lwoffii and Candida krusei were the most sensitive microorganisms for the all extracts. The amount of the total phenolics was highest in Z. clinopodioides extract (129.55 +/- 2.26 microg/mg), followed by M. longifolia ssp. typhoides var. typhoides (93.47 +/-1.84 microg/mg). It is extremely important to note that there is a positive correlation between antioxidant activity potential and amount of phenolic compounds.

Antioxidant activities, metal contents, total phenolics and flavonoids of seven Morchella species.

Seven Morchella species were analyzed for their antioxidant activities in different test systems namely beta-carotene/linoleic acid, DPPH, reducing power, chelating effect and scavenging effect (%) on the stable ABTS*(+), in addition to their heavy metals, total phenolic and flavonoid contents. In beta-carotene/linoleic acid system, the most active mushrooms were M. esculenta var. umbrina and M.angusticeps. In the case of DPPH, methanol extract of M. conica showed high antioxidant activity. The reducing power of the methanol extracts of mushrooms increased with concentration. Chelating capacity of the extracts was also increased with the concentration. On the other hand, in 40 microg ml(-1) concentration, methanol extract of M. conica, exhibited the highest radical scavenging activity (78.66+/-2.07%) when reacted with the ABTS*(+) radical. Amounts of seven elements (Cu, Mn, Co, Zn, Fe, Ca, and Mg) and five heavy metals (Ni, Pb, Cd, Cr, and Al) were also determined in all species. M. conica was found to have the highest phenolic content among the samples. Flavonoid content of M. rotunda was also found superior (0.59+/-0.01 microg QEs/mg extract).

Determination of the antimicrobial and antioxidative properties and total phenolics of two "endemic" Lamiaceae species from Turkey: Ballota rotundifolia L. and Teucrium chamaedrys C. Koch.

This study was designed to examine the in vitro antimicrobial and antioxidant activities and the amount of total phenolics of the methanol extracts of Ballota rotundifolia L. and Teucrium chamaedrys C. Koch. In the case of antimicrobial activity tests, polar sub-fractions of the methanol extracts of plant species exhibited weakest antimicrobial activity when compared with the non-polar ones. While, non-polar sub-fraction of B. rotundifolia showed moderate activity against A. lwoffii, C. perfringens and the yeasts, T. chamaedrys performed excellent activity pattern against all of the tested microorganisms. The sub-fractions were also screened for their possible antioxidant activities by two complementary tests, namely DPPH free radical-scavenging and beta-carotene/linoleic acid assays. Non-polar extracts of the plant species remained inactive in both test systems. On the other hand polar extracts showed remarkable antioxidant activities. In DPPH system, free radical scavenging effect of T. chamaedrys was measured as 18.00 +/- 1.42 microg.mg(-1). It is extremely important to point out that, polar sub-fraction of T. chamaedrys is found as effective as the positive control BHT. Non-polar sub-fraction of T. chamaedrys found to have the highest total phenolic amount (97.12 +/- 1.28 microg/mg). Results obtained from this experiment confirm the relationship between the amount of phenolics and biological activities.