Lumichrome and Phenyllactic Acid as Chemical Markers of Thistle (Galactites tomentosa Moench) Honey

Abstract

HPLC-DAD-MS/MS chromatograms of thistle (Galactites tomentosa Moench) unifloral honeys, previously selected by sensory evaluation and melissopalynological analysis, showed high levels of two compounds. One was characterized as phenyllactic acid, a common acid found in honeys, but the other compound was very unusual for honeys. This compound was extracted from honey with ethyl acetate and purified by SPE using C(18), SiOH, and NH(2) phases. Its structure was elucidated on the basis of extensive 1D and 2D NMR experiments as well as HPLC-MS/MS and Q-TOF analysis, and it was identified as lumichrome (7,8-dimethylalloxazine). Lumichrome is known to be the main product of degradation obtained in acid medium from riboflavin (vitamin B(2)), and this is the first report of the presence of lumichrome in honeys. Analysis of the G. tomentosa raw honey and flowers extracts confirmed the floral origin of this compound. The average amount of lumichrome in thistle honey was 29.4 ± 14.9 mg/kg, while phenyllactic acid was 418.6 ± 168.9 mg/kg. Lumichrome, along with the unusual high level of phenyllactic acid, could be used as a marker for the botanical classification of unifloral thistle (G. tomentosa) honey.

Screening of Polish Fir Honeydew Honey Using GC/MS, HPLC‐DAD, and Physical‐Chemical Parameters: Benzene Derivatives and Terpenes as Chemical Markers

“…Before each injection, the system was stabilized for 10 min with the initial A / B ratio (90:10, v / v ). The injection volume was 10 μl . Quantitative determination of identified compounds was determined based on calibration curves obtained using appropriate standard solutions.…”

Metabolic mechanism of phenyllactic acid naturally occurring in Chinese pickles

“…To the best of our knowledge, it is the first report of PLA occurred in pickles. It provided a new natural source of PLA in food system, besides the reported source like sourdough (Lavermicocca et al, 2000) and honey (Tuberoso et al, 2010).…”

Phenyllactic Acid: A Potential Antimicrobial Compound in Lactic acid Bacteria

“…PhLA content in thistle unifloral honey was around 100-800 mg/kg [19] but the high concentrations of PLA were found in heather (820 mg/kg), ling heather (875 mg/kg) and manuka honeys (243 mg/kg) [20]. Very recently, anti-staphylococcal activity against methicillin resistant Staphylococcus aureus was reported in manuka honey which contained high levels of acetic and lactic acids [21].…”

“…It was found that LAB produced PhLA as a reaction product of amino acid metabolism [22,23]. Its detection by reverse-phase HPLC is simple and widely adopted method for quantitative measurement of PhLA present in fermentation broth [24], honey [19] and rumen fluid [25]. GC/MS and capillary electrophoresis were also used for quantitative measurement of PLA.…”