Uv vis spectrophotometer 200v

Free radical scavenging activity of the aqueous and ethanolic extracts of L. vulgaris was evaluated spectrophotometrically by monitoring the disappearance of 2,2-diphenyl-1-picrylhydrazil (DPPH·, Sigma-Aldrich Chemie, Steinheim, Germany) at 517 nm, according to the method described by Brand-Williams et al. (1995). 1 ml of 0.15 mM solution of DPPH in ethanol was mixed with 3 mL of the extracts (NLW, NLE, NFW, NFE, NAW, NAE, IVW and IVE) at different concentrations (25, 50, 100 and 200 μg/ml), vortexed and then kept in the dark for 30 min. Decrease in the absorbance of these solutions was measured at 517 nm with Hitachi U-1900, UV-VIS Spectrophotometer 200V against blank samples. All analyses were made in triplicate. % inhibition was determined with a formula “DPPH· Scavenging Effect (% inhibition) = [(A₀-A!/A₀) x 100]” (Gülçin et al., 2004), where A₀ is the absorbance of the control and A! is the absorbance of tested extracts.

The amount of total phenolic content was determined in 80% methanol extracts of calli obtained from B. perennis using the Folin-Ciocalteu assay (Slinkard and Singleton, 1977), with some modifications. Therefore, 20 μL of each calibration solution or sample or blank, 100 μL Folin-Ciocalteu reagent (Sigma^®) and 1.58 mL of deionized water were transferred in a 10 mL test tube and mixed thoroughly. After 2 minutes, 300 μL of 20% Na2CO3 solution was added in the test tube. The solutions were incubated at 20 ± 2 °C for 2 hours and measured the absorbance of each solutions at 765 nm against the blank (the “0 mL” solution) using the spectrophotometer (Hitachi U-1900, UV-VIS Spectrophotometer 200V, JAPAN). Gallic acid was used as a standard (0-500 mg/L). The total phenol content of 80% methanolic extracts from callus was expressed as mg gallic acid equivalents (GAE)/ g dried weight (dw). Three measurements of one sample were performed at same time.