Identification and quantification of gallotannins in mango (Mangifera indica L.) kernel and peel and their antiproliferative activities

Mango (Mangifera indica L.) fruit is rich in polyphenolic compounds. Identification of individual gallotannins and evaluation of antiproliferative activities of gallotannin-rich extracts from kernel and peel of three Chinese mango cultivars were carried out in the present study. Five gallotannins, i.e. penta-, hexa-, hepta-, octa-, and nona-O-galloyl-glucoside were isolated and identified by LC-ESI-MS/MS and NMR, and quantified by HPLC. Mango kernel was a much richer source of gallotannins than its peel, and its antiproliferative effects on MDA-MB-231 breast, HepG2 liver, and HL-60 leukemia cancer cells were reported for the first time. DPPH
- scavenging and antiproliferative activities of the mango kernel and peel extracts may be partially caused by penta-O-galloyl-glucoside or its analogs with different galloyl groups since penta-O-galloyl-glucoside and gallic acid also revealed high antioxidant and antiproliferative activities. Therefore, the gallotannin-rich extracts of mango kernel and peel may serve as natural sources of anticancer agents and may have important pharmaceutical potential.