Uv 3100pc spectrophotometer

The total phenolic content (TPC) of the Mauritia flexuosa oil was determined using the Folin-Ciocalteu method [44 (link),45 (link)]. Briefly, 20.0 μL of a dilute solution of oil in ethanol (10.0 μL/mL and 2.5 μL/mL) was mixed with 100.0 μL of Folin-Ciocalteu reagent. The solution was stirred for 1 min and kept at rest for 4 min. After, 75.0 μL of Na₂CO₃ (10% w/v) was added and stirred for 1 min. After incubation in the dark for 2 h, at room temperature, the absorbance of the solution and the blank were determined by UV-vis at 750 nm (VWR UV-3100 PC Spectrophotometer). The total phenolic content was calculated from a calibration curve, using gallic acid as standard. The result was expressed as milligrams of gallic acid equivalents per gram of Mauritia flexuosa oil.
To determine the total content of flavonoids in Mauritia flexuosa oil, the aluminum chloride method was used [45 (link),46 (link)]. Briefly, 20.0 μL of a diluted solution of oil in ethanol (10.0 μL/mL and 2.5 μL/mL) was mixed with 210.0 μL of methanol (80%) and 20.0 μL of 2% AlCl₃ was added. The solution was mixed and kept in the dark at room temperature for 30 min, and the absorbance of the mixture was monitored by UV-Vis at 427 nm (VWR UV-3100 PC Spectrophotometer). The total flavonoid content was expressed as milligrams of quercetin equivalents per gram of Mauritia flexuosa oil.

Column chromatography was carried out on silica gel (0.06–0.2 mm, Merck, Darmstadt, Germany). Gel filtration was performed on Sephadex LH-20 (GE Healthcare, Uppsala, Sweden). Analytical TLC was performed on Merck pre-coated silica gel 60 F₂₅₄ plates (Merck, Darmstadt, Germany). Preparative HPLC, LaChrom System (Merck Hitachi) equipped with a Phenomenex Jupiter column (10 mm, C18, 300 Å, 250 × 21.1 mm) was used for purification of the compounds. Melting points were measured on B-540 melting point apparatus (Büchi, Flawil, Switzerland). UV spectra were recorded on a UV-3100PC spectrophotometer (VWR International GmbH, Darmstadt, Germany). IR spectra were recorded on a Nicolet 380 FT-IR spectrometer (Thermo Electron Corporation, Madison, WI, USA). High Resolution ESI-MS was done on a Micromass AC-TOFmicro mass spectrometer (Micromass, Agilent Technologies 1200 series, Tokyo, Japan). CD spectra were measured on a JASCO J-810 CD spectrometer (JASCO, Tokyo, Japan). Optical rotations were measured on a P-1020 polarimeter (JASCO, Tokyo, Japan). 1D (¹H, ¹³C) NMR and 2D (COSY, HSQC, HMBC, NOESY) NMR spectra were recorded on an Avance 500 MHz spectrometer (Bruker, Billerica, MA, USA, at 500 MHz (¹H) and 125 MHz (¹³C) at 298 K, using the residual solvent peaks (acetone: δ_H 2.05, δ_C 29.84; CDCl₃: δ_H 7.26, δ_C 77.16) as a reference.