Determination of Curcuminoids by Liquid Chromatography with Diode Array Detection: Application to the Characterization of Turmeric and Curry Samples

Abstract

Background: A simple, rapid and efficient method for the determination of curcumin and other polyphenols in turmeric and curry samples was here developed. The method relied on sample extraction with methanol and extract analysis by liquid chromatography with diode array detection (HPLC-DAD). Methods: The separation of components was carried out in reversed-phase mode using an elution gradient based on 0.1% (v/v) formic acid aqueous solution and acetonitrile as the components of the mobile phase. Chromatograms were recorded at 420 nm for specific monitoring of curcumin and related compounds. Results: Extraction and separation conditions were optimized by experimental design and multicriteria response functions. Figures of merit were established under the selected experimental conditions. In general, repeatability of peak areas were better than 0.4%, detection limits were below 0.006 mg L-1 and quantitative recoveries expressed as a percentage were about 100 ± 2. The method was applied to quantify curcuminoids in commercial samples. It was found that apart from curcumin, demethoxycurcumin and bisdemethoxycurcumin, other related molecules also occurred in the samples. In this regard, a tentative elucidation of possible unknown curcuminoids was attempted by liquid chromatography coupled to mass spectrometry. Conclusion: Differences in the compositional profiles among samples were encountered to be relevant, so that the resulting HPLC-DAD data was exploited for chemometric characterization of turmeric and curry samples. Samples were successfully discriminated according to matrix types, species varieties and origins.

Characterization of Turmeric and Curry Samples by Liquid Chromatography with Spectroscopic Detection Based on Polyphenolic and Curcuminoid Contents

“…Strategies for the characterization, classification and authentication of turmeric samples typically rely on chemometric methods for a more comprehensive assessment of relevant descriptors, patterns, and relationships. Some researchers have recently explored the possibilities of curcuminoids as a source of analytical information using concentrations of some curcuminoids to discriminate among turmeric products using principal component analysis (PCA) [35]. Ni and coworkers exploited chromatographic fingerprints of extracts from various Chinese provinces by PCA and K-nearest neighbor (KNN) [36].…”

Characterization, Classification and Authentication of Turmeric and Curry Samples by Targeted LC-HRMS Polyphenolic and Curcuminoid Profiling and Chemometrics

“…It is well known that polyphenolic and phenolic acid substances are typically analyzed by reversed-phase chromatography, using water and methanol or acetonitrile (acidified with 0.1% formic acid) as the mobile phase components [ 42 ]. Similar approaches have also been described for the chromatographic determination of curcumin and related compounds [ 8 , 15 , 39 , 40 ]. Therefore, turmeric and curry LC-HRMS polyphenolic and curcuminoid profiles were obtained by C18 reversed-phase column and using a gradient elution program with 0.1% formic acid aqueous solution and acetonitrile with 0.1% formic acid as the mobile phase components.…”

“…Gas chromatography coupled to mass spectrometry (GC–MS) has also been used for the characterization of powdered turmeric [ 32 ] and turmeric oil [ 33 ] samples. Nevertheless, liquid chromatography (LC) with UV detection (LC-UV) [ 34 , 35 , 36 , 37 , 38 , 39 , 40 ] and coupled to mass spectrometry (LC–MS) [ 32 , 41 ] are currently the techniques of choice. Besides, the great chemical diversity among bioactive substances, including polyphenolic and curcuminoid compounds, and the wide range of concentrations in which these phytochemicals can be found in turmeric and related products make liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) the most appropriate strategy for characterization, identification and authentication purposes [ 42 ].…”

“…Apart from quantitative methods, instrumental signals such as chromatographic peak areas of known selected compounds are a good alternative for food characterization and classification, also providing chemical information related to bioactive substances [ 22 , 23 , 24 ]. In this regard, polyphenolic and curcuminoid profiling by HPLC-UV has been reported for the characterization of turmeric and curry samples [ 39 , 40 ]. Finally, the use of DNA barcoding by polymerase chain reaction (PCR) amplification was also proposed for the detection of plant-based adulterants (cassava starch, wheat, barley and rye) in turmeric powder samples [ 52 ].…”

Non-Targeted Ultra-High Performance Liquid Chromatography-High-Resolution Mass Spectrometry (UHPLC-HRMS) Fingerprints for the Chemometric Characterization and Classification of Turmeric and Curry Samples

“…Few critical reviews addressing the characterization and determination of curcumin and curcumin derivatives in turmeric samples have been reported [1,2,13,14]. Analytical methodologies involved spectroscopy such as ultraviolet [15], fluorescence [16], infrared [17,18], and nuclear magnetic resonance (NMR) [19], as well as separation techniques such as capillary electrophoresis (CE) [20][21][22], liquid chromatography (LC) [23][24][25][26], and gas chromatography (GC) [27,28].…”