On-line identification of minor flavones from sugarcane juice by LC/UV/MS and post-column derivatization

Abstract

Este trabalho apresenta a identificação "on line" de flavonas minoritárias do suco da cana-deaçúcar (Saccharum officinarum), por cromatografia líquida de alta eficiência com detector UV acoplada à espectrometria de massas (CL/UV/EM) com ionização química à pressão atmosférica, dissociação induzida por colisão (IQPA-DIC-EM/EM) e derivatização pós-coluna utilizando reagentes de deslocamento de UV. As análises CLAE-UV com reagentes de deslocamento forneceram informações sobre a posição da substituição no esqueleto dos flavonóides e, em combinação com dados de EM, estas técnicas permitiram a identificação "on-line" de cinco flavonas da garapa: luteolina-8-C-glucosil-7-O-glucuronídeo; tricina-7-O-neoesperosideo-4'-O-ramnosídeo; tricina-7-O-metilglucuronato-4'-O-ramnosídeo; tricina-7-O-metilglucuronídeo; swertisina; e outras quatro substâncias foram parcialmente identificadas como flavonas glicosiladas. Somente a swertisina (7-O-metilapigenina-6-C-glicosídeo) foi anteriormente descrita no bagaço da cana-de-açúcar.This work describes the on-line characterization of minor flavones from sugarcane (Saccharum officinarum) juice by high-performance liquid chromatography coupled to diode array UV detection and mass spectrometry (LC/UV/MS) using atmospheric pressure chemical ionizationcollision-induced dissociation (APCI-CID-MS/MS) and post-column derivatization using UV shift reagents. HPLC-UV analysis with shift reagents provided information about the substitution pattern in the flavonoid skeleton and, combined with MS data, these techniques allowed for the on-line identification of five "garapa" flavones: luteolin-8-C-glucosyl-7-O-glucuronide; tricin-7-O-neohesperoside-4'-O-rhamnoside; tricin-7-O-methylglucuronate-4'-O-rhamnoside; tricin-7-O-methylglucuronide; swertisin, while four other compounds were partially identified as glycosylflavones. Only swertisin (7-O-methylapigenin-6-C-glucoside) was reported previously in sugarcane molasses.Keywords: sugarcane juice, Saccharum officinarum L. (Poaceae), flavones, LC/UV/MS, UV shift reagents IntroductionHyphenated techniques such as liquid chromatography with UV photodiode array detection (HPLC-UV) and on-line liquid chromatography-ultraviolet detection-mass spectrometry (HPLC-UV-MS) are powerful techniques for the structural identification of compounds found in extracts prepared from very small amounts of plant material. In the case of plant polyphenolic compounds such as flavonoids and xanthones, the possibility of obtaining on-line UV data by a combination with the post-column addition of UV shift reagents is a very important step to validate the structure assignments proposed for the position of oxygenated groups on the polyphenolic skeleton.1 Recently, HPLC-UV-MS and post-column UV-derivatization were employed in the study of Trifolium extracts containing clovamides, flavonoids and isoflavonoids and their UV data were discussed in detail.2 Hyphenated techniques may be the technique of choice in studies requiring analyses of several plant samples, as in metabolomic studies....

A Small Molecule Swertisin fromEnicostemma littoraleDifferentiates NIH3T3 Cells into Islet-Like Clusters and Restores Normoglycemia upon Transplantation in Diabetic Balb/c Mice

“…These results indicated the presence of swertisin compound as reported earlier by Patel and Mishra and Colombo et al [18, 20]. Mass fragmentation pattern of this compound was also compared with earlier references and found to be identical to swertisin [20]. Our results showed a base peak of m/z 447 [M + H] which corresponded to molecular weight of swertisin in positive ionization mode.…”

“…Structural identification was further performed by ESI MS/MS spectroscopy. Mass fragmentation pattern of a base peak of m/z 447 [M + H] corresponded to swertisin structure, similar to earlier reports by Colombo et al and Sawant et al [38, 39]. Therefore, we confirmed that the compound we isolated is indeed swertisin which has enormous islet neogenic potential.…”

“…Colombo et al have previously reported UV spectrum and HPTLC plots for various compounds from E. littorale [38]. We examined and compared our results with another report by Sawant et al and found that our compound of interest shows identical Rf and absorption maxima values with swertisin as reported by these two groups [39].…”

“…Our results showed a base peak of m/z 447 [M + H] which corresponded to molecular weight of swertisin in positive ionization mode. Further more, a peak of M + H − 120 was also obtained which indicated a loss of 120 u a characteristic peak of C-glycosyl flavonoids as mentioned by Colombo et al (Figure 3(b)) [20]. The compound was found to be soluble in solvents like DMSO and dioxane, while sparingly soluble in methanol and insoluble in water.…”

Nutritional and antimicrobial evaluation of Saccharum officinarum consumed in Calabar, Nigeria

“…It is plausible that S. officinarum owes its reported medicinal properties at least in part to the presence of these alkaloids. The presence of flavonoids in this study agrees with the findings from other studies (Vila et al, 2008;Colombo et al, 2009;Silvia et al, 2009) that have reported the occurrence of several flavonoids in sugarcane. Flavonoids are commonly known for their strong antioxidant activity and have been referred to as "nature's biological response modifiers" because of strong experimental evidence of their inherent ability to modify the body's reaction to allergens, viruses, carcinogens, and inflammatory agents (D'Mello et al, 2010;Tiwari and Rao, 2002).…”