Hp agilent 8453 spectrophotometer

An HP Agilent 8453 spectrophotometer (Agilent Technologies, Santa Clara, CA, USA) was used to determine of the model drug (TH or SA) concentration in the dissolution samples [44 (link),45 (link),46 (link),47 (link)] The absorbance values of the samples withdrawn at the predetermined times were measured against the corresponding blank sample using the fixed-wavelength method. A wavelength of 272 nm for TH and 298 nm for SA together with three-point background correction were applied. The used wavelengths corresponded to the absorption maximum of the model drugs. The validity of the Lambert–Beer law was verified in the expected range of the drug concentrations. To transform the absorbance values into the concentrations and percentages, the calibration-curve method was used.

LP was determined by MDA or thiobarbituric acid-reactive-substances (TBARS) assay as described by Hodges et al. [21 (link)] with some modifications. Briefly, 0.2g of fern fronds were homogenized in 5 mL of 80% ethanol and then centrifuged at 12,000× g for 20 min (Thermo Scientific Heraeus Biofuge Stratos, Heraeus Holding GmbH, Hanau, Germany). A 1-mL aliquot of sample extract was mixed with 1 mL of either (i)−TBA solution comprised of 20% (w/v) trichloroacetic acid and 0.01% butylated hydroxytoluene or (ii)+TBA solution containing the above plus 0.65% TBA. Samples were then mixed vigorously, heated at 95 °C in water bath for 25 min, and then quickly cooled on ice. After centrifugation at 12,000× g for 20 min, the absorbance of the supernatant was recorded at 440 nm, 532 nm and 660 nm (HP Agilent 8453 spectrophotometer, Agilent Technologies, Waldbronn, Germany). MDA equivalents were calculated by using the following equations.



Results were expressed as MDA equivalents per g of dry weight (nmolg⁻¹ DW). Three biological replicates of each treatment were used for evaluation.