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In this work the enantiomeric distribution of chiral coumarins (meranzin and epoxyaurapten), and furocoumarins (oxypeucedanin, byakangelicol, and epoxybergamottin) in different Citrus essential oils (lemon, lime, grapefruit, and bitter orange) was determined by means of a heart-cutting multidimensional-liquid chromatography (MD-LC) system, equipped with a microsilica column in the first dimension in a combination to a cellulosic-based chiral column used in the second dimension. The normal phase-liquid chromatography-liquid chromatography (NP-LC-LC) instrumentation was equipped with a photodiode array detector and a multiport valve as interface. For method optimization and the determination of absolute configuration, natural compounds were isolated and racemic mixture was synthesized. The NP-LC-LC/PDA (where PDA is photodiode array) method provided a good baseline separation of chiral coumarins (meranzin and epoxyaurapten) and furocoumarins (epoxybergamottin and byakangelicol) present in cold-pressed Citrus essential oils without any sample pretreatment. Results obtained showed that for all the chiral compounds present in Citrus essential oils analyzed, there is always a clear prevalence of one of the two enantiomers, and do not appear influenced by the different geographical origin of the oils., (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Citrus essential oils, thanks to their pleasant aroma, are certainly the most used ingredients in the formulation of hydroalcoholic fragrances. The non-volatile fraction of Citrus essential oil is composed for 10–20% of coumarins, furocoumarins and polymethoxyflavones. It is well known that furocoumarins induce photosensitization and have potential carcinogenic and mutagenic effects. It follows that furocoumarins levels in cosmetics product are constantly monitored by opinions and regulations issued by the International Fragrance Association. The aim of this research article was to quantify coumarins, furocoumarins and polymethoxyflavones in thirty commercial hydroalcoholic fragrances using supercritical fluid chromatography in combination with triple quadrupole mass spectrometry technique (SFC-QqQ-MS). According to author's knowledge, this is the first report on the determination of oxygen heterocyclic compounds in hydroalcoholic fragrances by means of SFC-QqQ-MS technique. [ABSTRACT FROM AUTHOR]

Oxygen heterocyclic compounds are secondary metabolites mainly present in the non-volatile fraction of cold-pressed Citrus essential oils. Under this denomination are included coumarins, furocoumarins, and polymethoxyflavones. These compounds possess numerous beneficial properties for human health, but the ingestion of large amounts of coumarins is often related to toxic effects, whereas the phototoxicity caused by furocoumarins and UVA exposure has been well known for a long time. This research has been aimed at the validation of an analytical approach, based on supercritical fluid chromatography coupled to tandem mass spectrometry, for the analysis of OHCs in Citrus essential oils. Among eight columns tested, packed with different stationary phases, the pentafluorophenyl allowed the best baseline separation in 8 min and by using less than 10% of methanol. Calibration curves of twenty-eight standards (coumarins, furocoumarins, polymethoxyflavones) were constructed on spiked lemon distilled essential oil and the method was validated according to the EURACHEM guidelines, by calculating linearity, limit of detection (LoD), limit of quantification (LoQ), accuracy, intra-day, and inter-day precision. Specifically, recoveries were in the 80.0–118.6% range, regression coefficients were between 0.9904 and 0.9998, the LoDs were in the 0.0004–0.0470 mg kg−1 range, the LoQs were in the 0.0014–0.1536 mg kg−1 range, and coefficients of variation were between 0.3 and 2.6% (intra-day) and 1.1 and 7.4% (inter-day). The quantitative profiles of thirteen cold-pressed Citrus essential oils were determined. [ABSTRACT FROM AUTHOR]

Cold-pressed citrus essential oils contain variable amounts of oxygen heterocyclic compounds highly characteristic of each species. Their distribution has been defined by high-performance liquid chromatography (HPLC) analysis with an average time of about 45 minutes. Here are two methods proposed, applying the latest generation HPLC columns based on the fused-core technology. The first method allows the complete resolution of thirty-eight components for a rugged and validated quantitative determination of the oxygen heterocyclic compounds in cold pressed lemon, lime, bergamot grapefruit, sweet orange, bitter orange and mandarin oils, in 10 minutes of total analysis time. The second method is a compromise between chromatographic resolution and analysis time and allows a fingerprinting of each of the abovementioned oils to be obtained, useful for unveiling possible contaminations and frauds in about 3 minutes. This last method can be applied in routine analysis to save time and solvent. The components are sufficiently separated in all the citrus cold pressed oils, permitting detailed profiles of each oil to be acquired and possible contaminations and frauds to be detected. [ABSTRACT FROM PUBLISHER]

Reversed-phase-HPLC analysis by means of superficially porous silica particle columns (fused-core) was applied to the investigation of flavonoids, coumarins, and psoralens in lime juice samples. Hesperidin (367.0 ± 16.0 ppm) and eriocitrin (148.0 ± 7.9 ppm) were the most abundant flavonoids. Fifteen coumarins and furocoumarins were determined, including bergamottin (29.6 ± 1.1 ppm), 5-geranyloxy-7-methoxycoumarin (16.5 ± 0.6 ppm), and oxypeucedanin hydrate (9.9 ± 0.5 ppm) as predominant compounds. These molecules are today well known for their beneficial effects on human health. As a consequence, the present study, beyond investigating for the first time the chemical composition of lime juice, highlights also its health-promoting qualities, due to its content of flavonoids and coumarins. [ABSTRACT FROM AUTHOR]

ABSTRACT A new investigation on manually extracted samples of bergamot ( Citrus bergamia) essential oil was performed by high-performance liquid chromatography coupled with an ion trap-time- of-flight mass spectrometer. The study aimed to define new quality parameters for the evaluation of bergamot essential oils based on the composition of bioflavonoid. Polymethoxylated flavones were identified in manually cold-pressed bergamot ( C. bergamia) essential oil from fruits of three different cultivars ('Femminello', 'Castagnaro' and 'Fantastico') harvested in southern Italy. The separation of the oxygen heterocyclic compounds was optimized by reversed-phase liquid chromatography on a partially porous C18 column under gradient elution. Afterwards, calibration curves were obtained for the quantitative assay using photodiode array detection, while a hybrid ion trap-time-of-flight mass spectrometer was used for structure elucidation, by tandem mass experiments. The methods applied for the identification and the quantitative determination were validated. The results obtained on samples of secure origin prove that the profile of the non-volatile fraction of bergamot peel oil is characterized, in addition to the well known coumarines and psoralens, also by four polymethoxylated flavones, namely sinensetin, nobiletin, tetra- O-methyl-scutellarein, and tangeretin. In particular, the identification and quantitative determination of nobiletin and tangeretin are hereby reported, for the first time, in cold-pressed bergamot essential oil. All the essential oil manually extracted from fruits of the three most common cultivars of C. bergamia contain variable amounts of the four polymethoxyflavones, with the cv. 'Femminello' being the one with the highest total content. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In 2009, a temporary crisis in the world production of acetonitrile caused the abnormal increase of the price of this substance, commonly used as a solvent and in high-pressure liquid chromatography (HPLC) separation as a mobile phase. For this reason, a new HPLC method was developed to analyze the oxygen heterocyclic components of Citrus oils, substituting acetoniuile with methanol. The new method described in this article was validated, new components were isolated and characterized by nuclear magnetic resonance (NMR), and others were synthesized, to obtain pure standards, not commercially available. The results are evaluated in comparison with methods previously developed. Seven genuine cold-pressed Citrus essential oils lemon (C. limon (L.) Burm.), Key lime (C. aurantifolia (Christm.) Swing.) type B, bergamot (C. bergamia), grapefruit (C. paradisi Macf.), bitter orange (C. aurantium L.), sweet orange (C. sinensis (L.) Osbeck) and mandarin (C. deliciosa Ten.) -- were analyzed under identical conditions. In conclusion, it was observed that the replacement of aeetonitrile with methanol in the mobile phase and the increase of the column temperature (from 30 to 40°C) led to a better separation in terms of resolution and total analysis time. Limit of detection (LOD) and limit of quantification (LOQ) were comparable with methods previously developed with acetonitrile in the mobile phase. [ABSTRACT FROM AUTHOR]

Official regulations concerning the maximum number of substances in food are introduced as a consequence of possible adverse effects, after oral administration. In this regard, analytical methods are necessary in order to determine specific targets. Among oxygen heterocyclic compounds (OHCs, that are furocoumarins, coumarins and polymethoxyflavones), only coumarin is subject to restriction by the Regulation (EC) No 1334/2008 of the European Parliament. Furocoumarins are known for their phototoxicity and other side effects due to their dietary intake; however, an official limit about the maximum content of these compounds in food is still missing. The lack of information about the real amount of these compounds in food is responsible for the conflicting opinions about the introduction of an official limit. The HPLC-MS/MS method here proposed, in combination with the linear retention index system, represents an innovative analytical strategy for the characterization of OHCs in citrus beverages. Several types of drinks were analysed in order to quantify 35 OHCs in total. This method is suitable for the quality control of OHCs in food and the obtained results may be considered as informative data useful for the regulatory authorities in the emission of new opinions and for a potential new regulation in this field. [ABSTRACT FROM AUTHOR]