Development of Chemical Sensor Based on Fatty Hydroxamic Acid for The Determination of Vanadium (V) and Iron (Iii) Ions

Chemical sensor based on the use of uv-visible spectrophotometer and optical fibre reflectance spectrometer (OFRS) for the determination of Fe(II1) and V(V) ions have been developed in this study. Fatty hydroxamic acid (FHA) was used as a reagent for both metals and shows good properties after characterization using manual batch method. FHA immobilized on poly(viny1 chloride) (PVC) and poly(methy1 methacrylate) (PMMA) as sensing membranes were successfully applied for determination of V(V). However, both immobilization processes were not showing any measurable signal in determination of Fe(II1). PMMA membrane immobilized FHA was characterized using uv-visible spectrophotometer. The sensing membrane changed fiom colorless to dark purple in the presence of V(V) with response time of five minutes. The relative standard deviation (RSD) of the reproducibility were found to be 9.29% and\ud 7.09% for V(V) at concentration of 50 ppm and 200 ppm, respectively.Interference fiom foreign ions were studied at 1:l mole ratio of V(V) to interfering ion. The interference faced by Fe(II1) was the greatest when it was compared with other cations, whereas phosphate ion gave the highest anion interferences. The limit of detection of the PMMA membrane immobilized FHA was calculated to be 8.4 ppm. PVC membrane immobilized FHA was characterized using optical fibre reflectance spectrometer. The sensing membrane changed its color from colorless to purple in the presence of V(V) and with response time of five minutes. The RSD of the reproducibility were found to be 3.91% and 3.85% for V(V) at concentration of 1 ppm and 20 ppm, respectively. Interference from foreign ions were studied at 1 : 1 mole ratio of V(V) to interfering ion. Fe(II1) was found to interfere most compared to other cations, whereas citrate gave the highest anion interferences. The limit of detection of the PVC membrane immobilized FHA was calculated to be 0.1 ppm. The results obtained from both instruments which have been developed in this study were compared with the well established method of inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The comparison results show an excellent agreement between the developed method and ICP-AES method. This indicates that the results obtained fiom both methods are comparable

3,5-Dichloro­salicylaldehyde

The title compound (systematic name: 3,5-dichloro-2-hydroxy­benzaldehyde), C7H4Cl2O2, crystallizes as discrete mol­ecules, the conformation of which may be influenced by an intra­molecular hydr­oxy–carbonyl O—H⋯O hydrogen bond

3-Chloro­quinuclidinium chloride

The cation of the title compound, C7H13ClN+·Cl−, forms a linear hydrogen bond to the chloride anion. The cation is disordered about a mirror plane

Low-temperature redetermination of 3,4,5,6-tetra­hydro­pyrimidin-2(1H)-one

The low-temperature structure of the title compound, C4H8N2O, is ordered, whereas the central methyl­ene groups is disordered in the reported room-temperature structure. The molecule lies across a mirror plane; adjacent mol­ecules are linked by an N—H⋯O hydrogen bond into a chain

Optical fibre chemical sensor for trace vanadium(V) determination based on newly synthesized palm based fatty hydroxamic acid immobilized in polyvinyl chloride membrane

Fatty hydroxamic acid (FHA) immobilized in polyvinyl chloride (PVC) has been studied as a sensor element of an optical fibre chemical sensor for V(V). By using this instrument, V(V) in solution has been determined in the log concentration range of 0–2.5 (i.e. 1.0–300 mg/L). The detection limit was 1.0 mg/L. The relative standard deviation (R.S.D.) of the method for the reproducibility study at V(V) concentration of 200 mg/L and 300 mg/L were calculated to be 2.9% and 2.0%, respectively. Interference from foreign ions was also studied at 1:1 mole ratio of V(V):foreign ions. It was found that, Fe(III) ion interfered most in the determination of vanadium(V). Excellent agreement with ICP-AES method was achieved when the proposed method was applied towards determination of V(V)

Antioxidant, antimicrobial and cytotoxic potential of condensed tannins from Leucaena leucocephala hybrid-Rendang

Condensed tannins (CTs) are one of the promising compounds due to their potentially health-promoting qualities. In this study, CTs were extracted from a Leucaena leucocephala hybrid-Rendang and subjected to various biological studies including antioxidant (using Ferric reducing antioxidant power (FRAP), DPPH and ABTS radical scavenging assay), anti-microbial (against different pathogens) and cytotoxic activities (toward human breast adenocarcinoma (MCF-7), human colon carcinoma (HT29), human cervical carcinoma (HeLa) and human liver carcinoma (HepG2) cell lines) in cancer cells through in vitro experiments. The structural characteristics and purity of CTs extract were determined using 13C NMR. The results showed that CTs exhibited higher in vitro antioxidant activities (2257.12 ± 80.55 mg TEAC/g extract, 605.3 ± 1.82 mg TEAC/g extract and 1014.03 ± 1.20 mg TEAC/g extract in FRAP, ABTS and DPPH assay, respectively) and demonstrated anti-microbial activities toward selected Gram's positive and Gram's negative bacteria tested with MIC and MBC value at 6.25–50 mg/mL. Furthermore, among other selected cancer cells, CTs also demonstrated cytotoxic activity toward human breast cancer cells (MCF-7) (IC50 = 38.33 ± 2.08 μg/mL). Characteristic of apoptosis such as cell shrinkage, nuclear condensation and apoptotic bodies were shown in MCF-7. These preliminary investigations have provided scientific rationale to use CTs as an alternative therapy for various oxidative and inflammatory associated diseases

Phytochemical Composition and Biological Activities of Selected Wild Berries (Rubus moluccanus L., R. fraxinifolius Poir., and R. alpestris Blume)

Berries, from the genus Rubus, are among the vital components in a healthy diet. In this study, 80% methanol extracts from the three wild Rubus species (Rubus moluccanus L., Rubus fraxinifolius Poir., and Rubus alpestris Blume) were evaluated for their phytochemical contents (total phenolics, flavonoid, anthocyanin, and carotenoid content), antioxidant (DPPH, FRAP, and ABTS assays), antiacetylcholinesterase, and antibacterial activities. GC-MS was used for quantification of naturally occurring phytochemicals. The results showed that R. alpestris contained the highest total phenolic [24.25±0.1 mg gallic acid equivalent (GAE)/g] and carotenoid content [21.86±0.63 mg β-carotene equivalents (BC)/g], as well as the highest DPPH scavenging and FRAP activities. The highest total flavonoid [18.17±0.20 mg catechin equivalents (CE)/g] and anthocyanin content [36.96±0.39 mg cyanidin-3-glucoside equivalents (c-3-gE)/g] have been shown by R. moluccanus. For antibacterial assays, R. moluccanus and R. alpestris extracts showed mild inhibition towards Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Salmonella enteritidis. Anticholinesterase activity for all extracts was in the range of 23–26%. The GC-MS analysis revealed the presence of at least 12, 21, and 7 different organic compounds in 80% methanol extracts of R. alpestris, R. moluccanus, and R. fraxinifolius, respectively, which might contribute to the bioactivity

Garcinia dulcis Fruit Extract Induced Cytotoxicity and Apoptosis in HepG2 Liver Cancer Cell Line

Garcinia dulcis or locally known in Malaysia as “mundu” belongs to the family of Clusiaceae. The study was conducted to investigate the anticancer potential of different parts of G. dulcis fruit extracts and their possible mechanism of action in HepG2 liver cancer cell line. MTT assay showed that the peel, flesh, and seed extracts of G. dulcis induced cytotoxicity in HepG2 cell line with IC50 values of 46.33 ± 4.51, 38.33 ± 3.51, and 7.5 ± 2.52 µg/mL, respectively. The flesh extract of G. dulcis induced cell cycle arrest at sub-G1 (apoptosis) phase in a time-dependent manner. Staining with Annexin V-FITC and propidium iodide showed that 41.2% of the cell population underwent apoptosis after 72 hours of exposure of the HepG2 cell line to G. dulcis flesh extract. Caspase-3 has been shown to be activated which finally leads to the death of HepG2 cell (apoptosis). GC-MS analysis showed that the highest percentage of compound identified in the extract of G. dulcis flesh was hydroxymethylfurfural and 3-methyl-2,5-furandione, together with xanthones and flavonoids (based on literature), could synergistically contribute to the observed effects. This finding suggested that the flesh extract of G. dulcis has its own potential as cancer chemotherapeutic agent against liver cancer cell