METHODS: Graphite furnace atomic absorption spectrometry (GF-AAS) was used to evaluate six digestion methods, (1) nitric acid, (2) nitric acid overnight, (3) nitric acid-hydrogen peroxide, (4) nitric-perchloric acid, (5) sulfuric acid, and (6) dry ashing, to determine the most suitable digestion method for the determination of heavy metals in the samples.
RESULTS: The concentration ranges of Cd, Pb, As and Se in fresh tea leaves were from 0.03-0.13, 0.19-2.06 and 0.47-1.31 µg/g, respectively while processed tea contained heavy metals at different concentrations: Cd (0.04-0.16 µg/g), Cr (0.45-10.73 µg/g), Pb (0.07-1.03 µg/g), As (0.89-1.90 µg/g) and Se (0.21-10.79 µg/g). Moreover, the soil samples of tea plantations also showed a wide range of concentrations: Cd (0.11-0.45 µg/g), Pb (2.80-66.54 µg/g), As (0.78-4.49 µg/g), and Se content (0.03-0.99 µg/g). Method no. 2 provided sufficient time to digest the tea matrix and was the most efficient method for recovering Cd, Cr, Pb, As and Se. Methods 1 and 3 were also acceptable and can be relatively inexpensive, easy and fast. The heavy metal transfer factors in the investigated soil/tea samples decreased as follows: Cd > As > Se > Pb.
CONCLUSION: Overall, the present study gives current insights into the heavy metal levels both in soils and teas commonly consumed in Bangladesh.
AIM OF THE STUDY: To develop a natural biodegradable macromolecule i.e. Chitosan (CS)-coated-DAUN-PLGA-poly(lactic-co-glycolic acid)-Nanoparticles (NPs) with an aim to improve oral-DAUN bioavailability and to develop as well as validate UHPLC-MS/MS (ESI/Q-TOF) method for plasma quantification and pharmacokinetic analysis (PK) of DAUN.
RESULTS: A particle size (198.3 ± 9.21 nm), drug content (47.06 ± 1.16 mg/mg) and zeta potential (11.3 ± 0.98 mV), consisting of smooth and spherical shape was observed for developed formulation. Cytotoxicity studies for CS-DAUN-PLGA-NPs revealed; a comparative superiority over free DAUN-S (i.v.) in human breast adenocarcinoma cell lines (MCF-7) and a higher permeability i.e. 3.89 folds across rat ileum, as compared to DAUN-PLGA-NPs (p
METHODS: Liquid-liquid partition chromatography was used to separate methanolic extract to get hexane, ethyl acetate, butanol and residual aqueous fractions. The total antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazy (DPPH) radical scavenging and ferric reducing antioxidant power assay (FRAP). The antidiabetic activity of methanol extract and its consequent fractions were examined by α-glucosidase inhibitory bioassay. The chemical profiling was carried out by gas chromatography coupled with quadrupole time-of-flight mass spectrometry (GC Q-TOF MS).
RESULTS: The total yield for methanol extraction was (12.63 ± 0.98) % (w/w) and highest fractionated value found for residual aqueous (52.25 ± 1.01) % (w/w) as compared to the other fractions. Significant DPPH free radical scavenging activity was found for methanolic extract (63.07 ± 0.11) % and (79.98 ± 0.31) % for ethyl acetate fraction among all the fractions evaluated. Methanol extract was the most prominent in case of FRAP (141.89 ± 0.87 μg AAE/g) whereas most effective reducing power observed in ethyl acetate fraction (133.6 ± 0.2987 μg AAE/g). The results also indicated a substantial α-glucosidase inhibitory activity for butanol fraction (72.16 ± 1.0) % and ethyl acetate fraction (70.76 ± 0.49) %. The statistical analysis revealed that total phenolic and total flavonoid content of the samples had the significant (p