Elsevier

Food Chemistry

Volume 124, Issue 2, 15 January 2011, Pages 576-582
Food Chemistry

Distribution of C- and O-glycosyl flavonoids, (3-hydroxy-3-methylglutaryl)glycosyl flavanones and furocoumarins in Citrus aurantium L. juice

https://doi.org/10.1016/j.foodchem.2010.06.076Get rights and content

Abstract

The qualitative and quantitative flavonoid and furocoumarin composition of crude sour orange (Citrus aurantium L.) juice was determined via reverse-phase LC–DAD–ESI–MS–MS analysis. In a single course, a comprehensive chromatographic profile of 14 compounds (furocoumarins, C- and O-glycosyl flavonoids) was obtained. Seven flavonoids and a furocoumarin were identified for the first time in sour orange juice: three C-glucosides (lucenin-2, vicenin-2 and lucenin-2, 4′-methyl ether), two O-glycosides (rhoifolin 4′-glucoside and narirutin 4′-glucoside), two 3-hydroxy-3-methylglutaryl flavanone glycosides (melitidin and brutieridin) and a furocoumarin (epoxybergamottin). Furthermore, the antioxidant activity of sour orange juice was assessed by means of ABTSradical dot+ and DPPHradical dot radical scavenging assays.

Introduction

The positive effects of citrus fruit consumption on human health was of common knowledge centuries before researchers begun to unravel the complexity of such food matrices. Over the past decades, a large number of studies have been carried out with the aim of identifying the bioactive components present in different parts of citrus fruits, in an attempt to gain a deeper understanding of the correlation between diet, health benefits and reduced risk of diseases.

Nowadays, a great amount of data has been collected on the biomedical properties of many relevant nutraceuticals (Patil, Jayaprakasha, Murthy, & Vikram, 2009). In this context, several epidemiological studies have associated the consumption of phenolic compounds, and more specifically flavonoids, with lower risks of different types of cancer (Nichenametla, Taruscio, Barney, & Exon, 2006) and cardiovascular diseases (Kris-Etherton et al., 2002), and have shown that they possess antioxidant, anti-inflammatory and anti-ageing activity (Benavente-García & Castillo, 2008). Citrus fruits are among the richest dietary sources of flavonoids (Berhow et al., 1998, Tripoli et al., 2007) and, in their juices, flavonoids usually occur as O-glycosyl and C-glycosyl derivatives (Gattuso, Barreca, Gargiulli, Leuzzi, & Caristi, 2007).

Citrus aurantium L. (commonly known as sour or bitter orange) has long been used in food industry as an ingredient of liqueurs and marmalades, and its extracts have also been employed in traditional Chinese medicine to activate vital energy and circulation, eliminate phlegm, and disperse stagnation (Ou, 1989). Recently, products containing sour orange have been exploited for the production of ephedrine-free dietary supplements for weight loss and appetite control.

However, the growing interest in sour orange products is due to the fact that they are rich in different classes of bioactive compounds such as synephrine alkaloids (Santana, Sharpless, & Nelson, 2008), which showed controversial effects on blood pressure and heart rate, limonoids and phytosterols (Jayaprakasha, Jadegoud, Gowda, & Patil, 2010) and flavonoids (Barreca et al., 2009, Bellocco et al., 2009), which are associated with anticancer activity and apoptotic activation. As for the latter, previous studies (Kawaii et al., 1999, Nogata et al., 2006) reported the chromatographic separation of the main flavonoid components of C. aurantium. The main components of C. aurantium juice were identified as neoeriocitrin, naringin, and neohesperidin, similarly to what we recently reported on two closely related taxons, C. myrtifolia Raf. (Barreca, Bellocco, Caristi, Leuzzi, & Gattuso, 2010), which is a mutation of sour orange, and C. bergamia Risso (Gattuso et al., 2007, Gattuso et al., 2006), which is a hybrid between sour orange and citron. In the present paper, by applying a methodology based on a single chromatographic course by reverse-phase LC–DAD–ESI–MS–MS, we are reporting the identification and quantification of 14 compounds (five flavones, eight flavanones and a furocoumarin), eight of which were found in sour orange juice for the first time. Our study on the antioxidant activity of crude sour orange juice is also reported.

Section snippets

Samples

The fruits of Citrus aurantium L. (sour orange) were orange-coloured, oblate spheroids, with a diameter of about 10–12 cm, and they were harvested in Calabria, Italy. The fruits were harvested in December, about 5 months after the flowering period. The specimens were identified by Prof. G. Tripodi, Università di Messina, Italy. The investigation was carried out on 10 samples from the 2009–2010 fruit season.

Reagents and standard solutions

HPLC-grade acetonitrile and methanol were supplied by Sigma–Aldrich (St. Louis, MO, USA),

Identification of flavonoids and furocoumaris

The DAD chromatograms recorded at 278, 325 and 310 nm (Fig. 1) and the UV spectra obtained in correspondence of each chromatographic peak, revealed that C. aurantium juice contains both flavonoids and furocoumarins. In fact, the comparison of the relative absorbances at 278 and 325 nm (Fig. 1A and B) made the discrimination of flavanones and flavones possible. On this basis, compounds 14 and 9 were assigned a flavone skeleton, whereas derivatives 58 and 1013 were found to belong to the

Conclusions

In this paper, a comprehensive profile of the flavonoids and furocoumarin components of C. aurantium juice has been presented. The HPLC–DAD–ESI–MS–MS procedure we have developed over the past few years allowed us to identify and simultaneously quantify 14 different components in a single chromatographic course, even at very low concentrations. Among these, two statin-like flavanones (melitidin and brutieridin), a furocoumarin (epoxybergamottin), three C-glucosyl flavones (lucenin-2, vicenin-2

Acknowledgments

The Authors are grateful to Prof. G. Tripodi (Dipartimento di Scienze della Vita “M. Malpighi”, Università di Messina) for his valuable advice.

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