STUDY OF FLAVONOIDS PRESENT IN POMELO (Citrus Maxima) BY DSC, UV-VIS, IR, 1H AND 13C NMR AND MS

Abstract

Flavonoids are among the most important plant metabolites. Due to their potential benefits, there is a considerable interest in this natural product. In genus Citrus, some plants have not yet been much exploited in Brazil, as in the case of grapefruit (Citrus maxima), whose main flavonoids are naringin and their aglycone naringenin. The physico-chemical characteristics are important pre-requisites of reference chemical in future studies. In this context, the objective of this study was to determine the characterization of naringin and naringenin by melting point, DSC, UV-VIS, 1H and 13C NMR, IR and MS. Results revealed that, naringin and naringenin after characterization, can be used as a chemical of reference in future studies and contribute to seeking possible technological applications.

Polyphenol Liquid–Liquid Extraction Process Development Using NRTL-SAC

“… 28 For the case of naringin, however, one was confronted with a particular problem: some literature mentions that it is able to crystallize 30 (e.g., in water, as an octahydrate and with a melting temperature of 83 °C); another study suggests that it does not solidify in a crystalline structure and does not have a defined melting point. 31 In both cases, the approximations contained in eq 2 may no longer be valid (either the water of hydration is not taken into account or there is no defined melting point). Owing to that, two approaches were followed in this case: in one of them, an equation with the same structure as eq 2 was used, but leaving the melting temperature and enthalpy as regressing parameters; in the other one, the relation between the liquid–liquid partition coefficient and the activity coefficient of the molecule in the aqueous and organic phases was used instead: 19 where P is the volume-based partition coefficient, V̅ org the molar volume of the organic phase, and V̅ aq is the molar volume of the aqueous phase.…”

Flow Injection Spectrophotometric Determination of Naringenin in Supplements Using Solid-Phase Reactor Containing Immobilized Manganese Dioxide

“…To assess the quality and validity of the determination method of NAR, a comparison was made between the proposed analytical method and [21]. NAR was analyzed using UV-vis 260 Shimadzu double-beam spectrophotometer, the spectrum of 15 µg/ml of NAR in ethanol was traced between 200 and 600 nm against reagent blank of ethanol, and it was found that maximum absorption was at a wavelength of 292 nm (Fig.…”

“…Three concentrations were analyzed using previous optimal conditions. The results are compared statistically with those obtained using UV method [21] using t-test and F test at 95% confidence level [22]. In terms of accuracy and precision, the results indicate that there was no significant difference between the proposed method and the comparative method (Table 4).…”

<p>Colon Targeting of Naringin for Enhanced Cytoprotection Against Indomethacin-Induced Colitis in Rabbits</p>

“…53 The band of -OH axial deformation at 1042 cm −1 appeared in the FT-IR spectrum of naringin. 54 The spectrum of EUD-L 100-55 showed a broad band of hydroxyl groups (-OH stretch vibration) in the range of 3000-3600 cm −1 , methyl and methylene C-H stretch vibration at 2990 and 2939 cm −1 , a strong stretching C=O band at 1740 cm −1 , and two bands of ester C-O stretching vibration at 1268 and 1178 cm −1 (Figure 1A). 55 FT-IR spectrum of naringin-EUD-L 1:1 PM appeared to be an overlap of that of drug and polymer.…”

“…According to this figure, naringin showed two endothermic peaks at 95.51°C and 162.93°C corresponding to the successive loss of two water molecules. 54 A sharp endothermic peak at 245.57°C is related to naringin melting. 53,59 EUD-L exhibited an endotherm at 202.28°C corresponding to its glass transition temperature.…”