Application of ultra performance liquid chromatography-photodiode detector-quadrupole/time of flight-mass spectrometry (UPLC-PDA-Q/TOF-MS) method for the characterization of phenolic compounds of Lepidium sativum L. sprouts

Some of health-protecting phytochemicals can be found in the sprouts in a much higher concentration than in the developed plants. However, the polyphenol composition of Lepidium sativum L. sprouts is still unresolved, especially with regard to flavonoids and phenolic acids. To develop a rapid and reliable UPLC-PDA-Q/TOF-MS method for the identification and quantification of main flavonoids and phenolic acids from L. sativum sprouts, the samples of L. sativum sprouts were grown with and without the exposition to light. Ten phenolic compounds were identified on the basis of their mass spectra in MS mode, MS/MS spectra, PDA spectrum, and retention times as compared with available reference substances. The major compounds were found to be sinapic acid derivatives. Acylated flavonoids in L. sativum sprouts were identified as kaempferol and quercetin with the same glycosidic substitution pattern as the major compounds, and varying degrees of acylation with sinapic and ferulic acids. Total content of phenolics in both samples was similar, but the content of flavonoids was higher and sinapine was lower in the sample of sprouts germinated in light. The determination and the evaluation of L. sativum extracts is very effective while using the UPLC-PDA-Q/TOF-MS. Even though the substances only occur in low concentrations, the combination of the retention time and the accurate molecular mass allows for their fast qualification.