Phytochemical characteristics of bergamot oranges from the Ionian islands of Greece: A multi-analytical approach with emphasis in the distribution of neohesperidose flavanones

Abstract

The present study describes the peculiar phytochemical characteristics of bergamots cultivated in distinct islands of the Ionian Sea. Ultrahigh-performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS) supported by 1 and 2D NMR spectroscopy was used for unambiguous metabolic profiling of albedo, flavedo and juice samples. Profile differences were determined using a multi-analytical clustering approach based on high-performance thin-layer chromatography fingerprints and UHPLC-HRMS data. Finally, a validated HPLC method offering good precision (0.12-0.94%) and accuracy (95.25-103.93%) was proposed for the quantification of the major flavanones. A total of 37 secondary metabolites were characterized belonging to flavonoids, limonoids and coumarins. Their distribution was tissue-dependent and varied significantly from bergamots of other geographical locations. Surprisingly, neoeriocitrin was the major flavanone, reaching 1.69 ± 0.05 g/L in the juice and 5.24 ± 0.12 mg/g in albedo. This is the highest reported amount among Citrus species, rendering Ionian bergamots a promising candidate for novel functional products.

Keywords: 6′,7′-dihydroxybergamottin (PubChem CID12082365); Bergamot orange; Eriodictyol-7-O-glucoside (PubChem CID13254471); HPTLC fingerprinting; Heatmap analysis; Naringin (PubChem CID442428); Naringin 6′'-malonate (PubChem CID74819370); Neoeriocitrin; Neoeriocitrin (PubChem CID114627); Neohesperidin (PubChem CID232990); Neohesperidose flavanones; Nomilinic acid (PubChem CID131751863); Picraquassioside A (PubChem CID85502992); Pinocembrin-7-O-neohesperidoside (PubChem CID442454); Quantification; UHPLC-HRMS.