H1NMR data of Chemical structure of compounds
Both compounds were tested for purity using RP-HPLC with acetonitrile–water (1:5 v/v). Compound 1 showed a signal at a retention time of 15.87 min with some minor signals. Compound 2 showed a signal at a retention time of 21.06 min with some minor signals. Compounds were identified by their H1NMR data comparing with those recorded in the literature. The structure corresponding to compound 1 is presented in Figure 5 and agrees with the chemical structure of a catechin. Optical rotation of compound 1 was [α]20 = -53,4; which allows us to conclude that compound 1 is (-)-epicatechin. The structure corresponding to compound 2, from extract of Hypnea musciformis, is presented in Figure 6 and agrees with the chemical structure of a dihydrochalcone known as phloretin.
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Structure elucidation of compounds responsible for LDL oxidation protection (obtained from Hypnea musciformis ) Following the separation and purification of compounds responsible for LDL oxidation protection, structural elucidation was performed using Nuclear Magnetic Resonance H1NMR. The NMR spectra were captured in a Bruker Advance 400 (400.13 MHz) spectrometer using as solvents methanol-d4 (Merck, Darmstadt, Germany), with a deuteration grade of 99.8%. The solvent residual signals were used as an internal standard, (δH 7.26; δC 77.0) for chloroform and (δH 3.31 and 4.87, δC 49.1) for methanol. In order to differentiate isomers present in the samples previously separated, purified and identified, optical rotations were measured on a Polartronic E, Schmidt+Haensch polarimeter using a cell of 1 mL x 5 cm of length at 20 °C. All samples used for optical rotations were resuspended in a 1% acetone water mix at 1:1 proportion (50%v/v).