Separation of lycopene and itscis isomers by liquid chromatography

Abstract

SummaryLycopene is an important biological compound that is widely distributed in fruits and vegetables. Epidemiological study has shown that the dietary intake of lycopene may reduce the risk of certain types of cancers such as prostate cancer. However, the formation of c/s-isomers of lycopene during food processing and storage may decrease its biological activity Thus, it is important to learn about the content of lycopene and its cis isomers in foods. In this studywe compared I',,vo types of columns (C18 and C30) and various solvent systems for the separation of lycopene and its cis isomers by HPLC. Results showed that all-trans-lycopene and its nine cis isomers could be resolved by employing a C30 column with a mobile phase of n-butanol-acetonitrile-methylene chloride (30:70:10, v/v/v) and detection at 476 nm within 35 min. A C30 column was found to provide more powerful resolution of lycopene and its cis isomers, but the retention time was drastically increased compared to that of a C18 column. The c/s-isomers of lycopene were tentatively identified as 5-cis, 9-cis, 13-cis, 15-cis-lycopene, and possibly as four lycopene di-cis isomers, based on spectral characteristics and Q ratios as reported in the literature. The method developed in this study could be applied to determine the lycopene content in tomatoes.

New Developments in Lycopene Analysis by Spectroscopic and Chromatographic Techniques, Accompanied With Mathematical Modelling

“…For the last few decades, HPLC has been the preferred method to separate, identify, and quantify carotenoids in food and biological samples, allowing us to distinguish between the geometrical structures of carotenoids, including some mono-and di-cis-isomers [211,212].…”

“…Yeum et al [217] separated five isomers of lycopene by using a C30 column and a gradient solvent system of methanol/methyl-ter-butyl-ether (MTBE)/water. Lee and Chen [211] compared two types of columns (C18 and C30) and various solvent systems for separation. All-trans-lycopene and 9-cis isomers (5-cis, 9-cis, 13-cis, 15-cis, and 4-di-cis-lycopene) were resolved by employing a C30 column with a mobile phase of n-butanol-ACN-dichloromethane (30:70:10, v/v/v) within 35 min [211].…”

“…Lee and Chen [211] compared two types of columns (C18 and C30) and various solvent systems for separation. All-trans-lycopene and 9-cis isomers (5-cis, 9-cis, 13-cis, 15-cis, and 4-di-cis-lycopene) were resolved by employing a C30 column with a mobile phase of n-butanol-ACN-dichloromethane (30:70:10, v/v/v) within 35 min [211]. Fröhlich et al [218] also used a C30 column to distinguish between lycopene isomers.…”

“…The mono-cis isomers result in a hypsochromic shift of about 4 nm when compared to the all-trans form. The central cisisomers have a strong peak at about 340 nm and the di-cis isomers may be shifted to shorter wavelengths than the mono-cis isomers [211,[226][227][228].…”

Obtenção de cristais de licopeno a partir de descarte de tomate

“…A Tabela 7 mostra a identidade dos picos presentes nestas figuras. Os isômeros 15-cis-(pico 14), 13-cis-(pico 16), 9-cis-(pico 17) e 5-cis-licopeno (pico 20) foram identificados por comparação da ordem de eluição em coluna C 30 com a literatura [10,21,25], e dos λ max e forma do espectro com dados previamente relatados [19,23,27]. A identidade destes isômeros foi confirmada com padrões.…”