Demethyloleuropein and beta-glucosidase activity in olive fruits.
Demethyloleuropein plays a major role in the defense mechanism of olive fruits. To understand how this molecule is metabolized during different stages of maturation of olive fruits, a biomolecular approach to identify the demethyloleuropein chemistry was employed. The beta-glucosidase activity in crude extracts was assayed spectrophotometrically using the chromogenic substrate p-nitrophenyl-beta-D-glucopyranoside. Demethyloleuropein was extracted and identified by HPLC-MS from both infected and uninfected olive fruits at different physiological stages. The release of more functionally relevant dialdehydes in uninfected fruits was investigated using ESIMS/ MS. In fruits harvested in October, the activity of beta-glucosidase was significantly enhanced in uninfected fruits when compared to the infected fruits. Quantitative differences in the demethyloleuropein content from uninfected fruits showed the highest values (5.09 mg/g) in October, whereas lower levels (4.44 mg/g) were found in infected fruits. The results demonstrated that demethyloleuropein derivatives could be influenced by beta-glucosidase activity to improve the quality of the olive products with the best dialdehyde nutraceutical content.
Sivakumar
Ganapathy
G
Biotech Genomics, ENEA, Casaccia, Rome, Italy. sivakumar@libero.it
Briccoli Bati
Caterina
C
Uccella
Nicola
N
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002863:Chromogenic Compounds / Q000737:chemistry / Q000378:metabolism; D005638:Fruit / Q000378:metabolism* / Q000469:parasitology; D005960:Glucosides / Q000737:chemistry / Q000378:metabolism*; D057888:Iridoid Glucosides; D039823:Iridoids / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D031658:Olea / Q000378:metabolism* / Q000469:parasitology; D010936:Plant Extracts / Q000032:analysis / Q000737:chemistry; D011714:Pyrans / Q000737:chemistry / Q000378:metabolism*; D012621:Seasons; D021241:Spectrometry, Mass, Electrospray Ionization; D033621:Tephritidae / Q000254:growth & development; D001617:beta-Glucosidase / Q000378:metabolism*
D002863:Chromogenic Compounds; D005960:Glucosides; D057888:Iridoid Glucosides; D039823:Iridoids; D010936:Plant Extracts; D011714:Pyrans; C523785:demethyloleuropein; C025193:4-nitrophenyl beta-D-glucoside; C002769:oleuropein; D001617:beta-Glucosidase