Identification of Antioxidative Flavonols and Anthocyanins in Sicana odorifera Fruit Peel

Abstract

Ten flavonols and three anthocyanins were identified in the fruit peel of melón de olor (Sicana odorifera), and their structures were established by spectrometric and spectroscopic (ESI-MS and NMR) techniques. One of the identified flavonols, quercetin 3-O-(6''-O-malonyl)-β-D-glucopyranoside 4'-O-β-D-glucopyranoside, has not been reported before in the plant kingdom. Although quercetin-3-O-α-L-rhamnopyranosyl-(1→6)-β-d-glucopyranoside-4'-O-β-D-glucopyranoside had been reported before in literature and structure elucidation was done by comparison of NMR data with published data, to the best of our knowledge complete 1D and 2D NMR data have not been not delineated so far. Moreover, the antioxidant activity of pure compounds was measured by ABTS assay. It was established that quercetin 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside, quercetin-3-O-(6''-malonyl)-glucopyranoside, quercetin-3-O-β-D-glucopyranoside, and quercetin-3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside-4'-O-β-D-glucopyranoside contribute significantly to the antioxidant activity exhibited by the fruit peel methanolic extract.

Evaluation of anticandidal and antioxidant activities of phenolic compounds from Pyrostegia venusta (Ker Gawl.) Miers

“…The 13 C NMR shifts of the aglycone moiety corresponded to the shifts described for quercetin [26]. HSQC analysis furnished all the signals.…”

Isolation of flavonoids from Anemopaegma arvense (Vell) Stellf. ex de Souza and their antifungal activity against Trichophyton rubrum

“…The identity of the flavonoids was confirmed based on 1 H and 13 C NMR spectral data and by comparison with the literature (Jaramillo et al, 2011). The position of the interglycosidic linkage was provided by 13 C NMR and was confirmed by HMBC and HMQC experiments.…”

New α-glucosides of caffeoyl quinic acid from the leaves of Moringa oleifera Lam.

“…In contrast, repeated chromatography of the n-BuOHsoluble fraction yielded five known flavonoid glucosides (6)(7)(8)(9)(10). Compounds 3-10 were identified as chlorogenic acid (3) [12], 4-O-caffeoyl quinic acid (4) [12], 5-O-caffeoyl quinic acid (5) [12], isoquercitrin (6) [13], quercetin 3-O-b-D-(6 00 -O-malonyl)-glucoside (7) [14], astragalin (8) [13], kaempferol 3-O-b-D-(6 00 -O-malonyl)-glucoside (9) [14], and quercetin 3-O-b-D-(6 00 -O-3-hydroxy-3-methylglutaryl)-glucoside (10) [15], by comparison of their spectral data with those described in the literature (Fig. 1 , including an ester carbonyl signal.…”

“…H-and13 C NMR spectra were measured on a JEOL JNM-ECA500 spectrometer with TMS as an internal standard. Mass spectra were determined on a JEOL HX-110 spectrometer.…”