PdRuO2/PVP nanomaterial as a highly selective, stable, and applicable potentiometric sensor for the detection of Cr3.

PdRuO2/PVP nanomaterial was synthesized using a straightforward method and characterized using advanced analytical methods such as TEM, XRD, XPS, elemental mapping and SEM. The synthesized PdRuO2/PVP nanomaterial was used as an ionophore in potentiometric sensor electrodes and successfully adapted to Cr3+ ion detection in a large number of aqueous samples. Several experimental parameters of the PdRuO2/PVP sensor such as potentiometric behavior, selectivity, repeatability, response time, pH, titration, and recovery in real samples were investigated. Potentiometric behavioral characteristics were performed in the concentration range 1 × 10-6-1.0 × 10-1 M. The repeated experiments performed six times showed that there was no deviation in the measurements. The limit of detection of the PdRuO2/PVP potentiometric sensor was very low with a value of 8.6 × 10-8 M. The potentiometric measurements showed that the synthesized PdRuO2/PVP ionophore was highly effective in detecting Cr3+ in a wide pH range of 2.0-8.0 and was found to have a shelf life of over 1 year. As a result, the synthesized PdRuO2/PVP electrode material was found to be highly selective, stable, and applicable for Cr3+ detection.

New potentiometric PVC membrane electrode for Ferric Reduction Antioxidant Power assay.

In this study, a fast, reproducible and simple-to-apply a new potentiometric determination method was developed for the evaluation of iron (III) reducing power (FRAP), one of the antioxidant capacity tests. For this purpose, an all-solid-state contact iron (III)-selective poly vinyl chloride (PVC) membrane electrode (FRAP-PME) has been developed. In the structure of the developed polymeric membrane electrode (PME), Fe(II)-quercetin compound was used as the active ingredient. It was obtained that PME exhibits a linear potentiometric behavior against the concentration change of Fe(III) ion between 1.0 × 10-1-1.0 × 10-5 mol L-1 and the detection limit is 8.0 × 10-6 molL-1. PME showed a very rapid potential response (40-45 s) and was found to have a very high selectivity towards Fe(III) ion in the presence of other species that might interfere. The proposed potentiometric method has been successfully applied to evaluate the iron (III) reducing power of plant extracts.

Antiproliferative and cytotoxic effects of bioactive compounds isolated from Onosma bourgaei.

Onosma species have been used commonly for traditional medicine for years due to their bioactive compounds content. Onosma bourgaei aerial part was extracted with hexane and methanol successively. The methanol extract was subjected to chromatographic techniques to isolate allantoin (1), 3,4-dihydroxybenzaldehyde (2), luteolin-7-O-glucoside (3), apigenin-7-O-ß-glucoside (4), diosmetin-7-O-ß-glucoside (5), rosmarinic acid (6), and globoidnan A (7). The structure of isolated compounds were identified by spectroscopic techniques such as 1D-NMR, 2D-NMR, FTIR, and LC-TOF/MS/MS. Antiproliferative activity of extract and natural compounds were carried out using HeLa (human epithelial cervix adenocarcinoma, ATCC® CCL-2™), HT29 (human colorectal adenocarcinoma, ATCC® HTB38™), MCF7 (human mammary gland adenocarcinoma, ATCC® HTB22™), and A549 (human lung carcinoma, ATCC® CCL185™) cancerous cells and normal cells, FL (human epithelial amnion cell, ATCC® CCL62™). Lactate dehydrogenase (LDH) was performed for cytotoxicity. The compounds, 4, 6, and 7 displayed the strong antiproliferative activity against corresponding cell lines. Apigenin-7-O-ß-glucoside (4) revealed the excellent activity on HeLa, HT29, A549, and MCF6 cancer cell lines with the values of (IC50, µM) 167.3, 196.8 181.1, and 203.5, respectively, compared standard compound, cisplatin.

A new potentiometric PVC membrane sensor for the determination of DPPH radical scavenging activity of plant extracts.

In this study, a simple, fast, stable and low-cost potentiometric determination method is recommended for the evaluation of 1,1-diphenyl-1-picrylhydrazil radical (DPPH•) scavenging activity, which is one of the antioxidant activity tests. For this purpose, a new type of solid-state-contact potentiometric polyvinyl chloride (PVC) membrane sensor was developed. Gallic acid compound, which is sensitive to the DPPH•, was used as the active ingredient in the membrane structure of the sensor. The potentiometric behavior of the developed DPPH•-selective PVC membrane sensor was characterized. The detection limit of the developed sensor was obtained as 2.3 µg/mL. The sensor can measure at low volumes with its high selectivity. The measurement results obtained were in accordance with the results of the spectroscopic method in the literature. The developed DPPH•-selective PVC membrane sensor was quickly dipped directly into the plant extracts and successfully used in test measurements of DPPH• scavenging activity.

Chemical composition, antioxidant, and antimicrobial activities of two essential oils from Algerian propolis.

This study aims to investigate the chemical composition, antioxidant, and antimicrobial activity of two essential oils (EOs) from Algerian propolis. The volatile constituents were analyzed by gas chromatography-mass spectrometry. Fifty components were identified from the oils. The major components were found to be: cedrol (17.0%), ß-eudesmol (7.7%), and α-eudesmol (6.7%) in EO of propolis from Oum El Bouaghi (EOPO) whilst α-pinene (56.1%), cis-verbenol (6.0%), and cyclohexene,3-acetoxy-4-(1-hydroxy-1-methylethyl)-1-methyl (4.4%) in EO of propolis from Batna (EOPB). The antioxidant properties of EOPO and EOPB were determined using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS•+) and cupric reducing antioxidant capacity (CUPRAC assays), respectively. Both EOs had more cupric ion reducing ability than scavenging ABTS•+ radicals. The antimicrobial potential of the two EOs against eight pathogens was assayed by the agar diffusion method and the mode of action was determined by microdilution assay. The results revealed that EOPB was bactericidal for all tested pathogenic bacteria and fungicidal for Candida albicans ATCC 10231, whereas, EOPO showed bacteriostatic effect against Escherichia coli O157:H7 and Pseudomonas aeruginosa ATCC27853 and fungistatic effect against C. albicans ATCC 10231. Thus, the obtained results suggest the important use of propolis EOs as preservative agents.

Bioactivity-guided isolation of flavonoids from Cynanchum acutum L. subsp. sibiricum (willd.) Rech. f. and investigation of their antiproliferative activity.

Cynanchum acutum L. subsp. sibiricum (Willd.) Rech. f. was extracted with hexane, acetone, methanol and water individually. A sample was heated in water then extracted with ethyl acetate. Among the extracts, the ethyl acetate extract exhibited the most antiproliferative activity, so isolation of bioactive compounds was carried out from this extract. A new compound, kaempferol-3-O-ß-xylopyranosyl-(1-2)-ß-rhamnopyranoside (1) along with five known compounds, quercetin-3-O-ß-xyloside (2), kaempferol-3-O-ß-glucoside (3), quercetin-3-O-ß-glucoside (4), kaempferol-3-O-ß-rhamnopyranoside (5), and kaempferol-3-O-ß-d-neohesperidoside (6) were isolated from ethyl acetate extract. The structures were elucidated by spectroscopic techniques, basically 1D NMR, 2D NMR and LC-TOF/MS. Antiproliferative effects of isolated compounds were determined by xCELLigence using the HeLa (human uterus carcinoma) cell lines. Compound 2 and compound 5 revealed the good antiproliferative activity against HeLa cell lines.