Characterization of gallotannins and benzophenone derivatives from mango (Mangifera indica L. cv. ‘Tommy Atkins’) peels, pulp and kernels by high‐performance liquid chromatography/electrospray ionization mass spectrometry

Abstract

Polyphenolics were extracted from peels, pulp and kernels of mango fruits (Mangifera indica L. cv. 'Tommy Atkins') and characterized by high-performance liquid chromatography/electrospray ionization mass spectrometry. In the peel 18 gallotannins and five benzophenone derivatives were detected which were tentatively identified as galloylated maclurin and iriflophenone glucosides. Twenty-one and eight gallotannins were found in the kernels and pulp, respectively, whereas no evidence for the presence of benzophenone derivatives was obtained. Gallotannins quantified by the rhodanine assay amounted to 1.4 mg/g dm in the peels (expressed as gallic acid), while only small amounts (0.2 mg/g dm) were found in the pulp. In contrast, mango kernels contained 15.5 mg/g dm and thus proved to be a rich source of gallotannins.

Inhibitory Spectra and Modes of Antimicrobial Action of Gallotannins from Mango Kernels (Mangifera indicaL.)

“…In conclusion, gallotannins exhibit inhibitory activity against a large number of bacteria at physiologically relevant concentrations (0.1 to 1 g kg Ϫ1 ) (6,11), and their activity is attributable to their affinity for iron. Membrane-bound proteins likely are additional targets of gallotannins.…”

“…Mango (Mangifera indica L.) contains gallotannins with degrees of galloylation ranging from 4 to 12 (6,15,16). Gallotannin-rich plant extracts and penta-O-galloylglucose exhibit antibacterial activity (1,10,25) which is remarkably selective.…”

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“…The molecules of gallic acid (170 Da) or ellagic acid, when present, can be lost with the hydrogen transfer, and a double bond in the glucose is formed [137]. Many important fragment ions were not observed by ESI-MS/MS, which could complicate their structural identification [162][163][164][165]. A complex fragmentation pattern obtained from < 300 Da is observed, which complements the information to identify them [59,137,160].…”

Biomass as a Feedstock

“…25) [102], can be used in food manufacturing due to their antioxidant properties. Also found within the kernels are gallotannins 26 [103]; these are of special interest because they have been shown to have antimicrobial properties [104,105]. …”