HPLC-MS Screening of the Antioxidant Profile of Italian Olive Cultivars

Abstract

UDC 547.944 Freeze-dried olive fruits from Italian cultivars such as Carolea, Cassanese, and Coratina were analyzed by HPLC-MS. During different stages of maturation of olive fruits, the biophenolic (antioxidant) composition was examined. Twelve biophenolic compounds, viz. hydroxytyrosol, tyrosol, oleoside 11-methyl ester, demethyloleuropein, verbascoside, demethylligstoside, oleacin, oleuropeindiale, demethyloleuropeindiale, oleuropein, ligstroside, and elenolate were identified by HPLC-MS. Oleuropein, the major olive fruit soluble biophenolic fraction, decreased significantly during fruit maturation and showed significant differences between olive cultivars. Coratina drupes extracted from October month contained a higher amount of biophenols than other mono-cultivar extracted drupes.

Chemical screening of olive biophenol extracts by hyphenated liquid chromatography

“…4), also known as 4-noroleuropein aglycone [45] and oleacin [9] revealed two peaks eluting at 27.28 and 27.71 min with similar fragmentation pattern suggesting diastereomers. The aldehydic nature of both peaks was confirmed by peak shifting due to formation of bisulfite addition products (eluting approximately 3 min earlier) and methanol acetals.…”

“…The number of compounds that have been detected in bio-extracts is increasing exponentially with the introduction of electrospray ionisation (ESI). RPLC-ESI-MS has recently been adopted as a routine screening technique for these extracts to identify previously reported biophenols, and allow identification of novel unidentified constituents [7][8][9]. However, ESI-MS is extremely sensitive to the elution conditions and suppression effects are not uncommon [10], while some compounds may fail to ionise [11].…”

“…197(17), 151 (100), 107 (51) -b Caffeic acid 179 (100), 135(36) 181(2), 163(18), 135(15), 117(14), 89 (100) Verbascoside 1247 (2), 669 (1), 623(30), 461(9), 207(15), 179(7), 161 (100), 153 (2), 135(11) 647(70), 625 (2), 479 (4), 471 (4), 325 (27), 163 (100), 135 (36), 117 (26), 89 (45) Rutin 655 (7), 611 (6), 610 (29), 609 (88), 461 (2), 302 (16), 301 (97), 300 (100), 179 (7), 161 (12), 151 (4) 633 (37), 611 (2), 519 (10), 485 (4), 465 (1), 331 (9), 304 (28), 303 (100), 219 (3), 169 (3), 137 (5), 85 (33) Oleuropein 1079 (3), 585 (8), 539 (60), 377 (18), 307 (30), 275 (44), 223 (13), 153 (6), 151 (1), 149 (49), 139 (59), 101 (79), 95 (50), 89 (100) 563 (40), 541 (1), 401 (14), 361 (9), 165 (7), 137 (41), 119 (12), 91 (100) Quercetin 603 (7), 369 (4), 301 (100), 265 (1), 247 (1), 147 (2), 97 (8) 325 (14), 303 (98), 285 (10), 257 (29), 229 (65), 201 (25), 165 (25), 153 (100), 137 (47), 121 (19), 111 (27) Luteolin 571 (1), 285 (100), 241 (3), 175 (20), 151 (33), 133 (87), 107 (34) 309 (3), 287 (100), 241 (6), 213 (4), 185 (12), 161 (7), 153 (70), 135 (25), 117 (2)Peaks are in bold and intensities relative to the base peak are given in parentheses. a Very low intensity.…”

The Olive Tree, a Source of Antioxidant Compounds

“…They are strong antioxidants, reducing the incidence of cardiovascular disease and certain types of cancer [27] The main flavonoids in olives are luteolin-7-O-glucoside, cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, rutin, apigenin-7-O-glucoside, quercetin-3-O-rhamnoside and luteolin ( Figure 5, Table 2). [25,26] Secoiridoids are only found in a small group of edible plants. The major ones are oleuropein, ligstroside and demethyloleuropein ( Figure 4).…”

“…Oleuropein is generally the predominant phenol in olive cultivars and is found in the fruits and leaves. Demethyloleuropein is only found in certain varieties of olive and can therefore be exploited as a marker of variety (Table 2) [26].…”