Hamamelitannin from witch hazel (Hamamelis virginiana) displays specific cytotoxic activity against colon cancer cells.
Hamamelis virginiana (witch hazel) bark is a rich source of condensed and hydrolyzable tannins reported to exert a protective action against colon cancer. The present study characterizes different witch hazel tannins as selective cytotoxic agents against colon cancer. To cover the structural diversity of the tannins that occur in H. virginiana bark, the hydrolyzable tannins, hamamelitannin and pentagalloylglucose, together with a proanthocyanidin-rich fraction (F800H4) were selected for the study. Treatment with these compounds reduced tumor viability and induced apoptosis, necrosis, and S-phase arrest in the cell cycle of HT29 cells, with hamamelitannin being the most efficient. Owing to polyphenol-mediated H(2)O(2) formation in the incubation media, the antiproliferative effect was determined in the presence and absence of catalase to rule out any such interference. The presence of catalase significantly changed the IC(50) only for F800H4. Furthermore, at concentrations that inhibit the growth of HT29 cells by 50%, hamamelitannin had no harmful effects on NCM460 normal colonocytes, whereas pentagalloylglucose inhibited both cancerous and normal cell growth. Using the TNPTM assay, we identified a highly reactive phenolic position in hamamelitannin, which may explain its efficacy at inhibiting colon cancer growth.
Faculty of Biology, Universitat de Barcelona, IBUB, Unit Associated with CSIC, 08028 Barcelona, Spain.
Susana
S
Sánchez-Tena
María L
ML
Fernández-Cachón
Anna
A
Carreras
M Luisa
ML
Mateos-Martín
Noelia
N
Costoya
Mary P
MP
Moyer
María J
MJ
Nuñez
Josep L
JL
Torres
Marta
M
Cascante
D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D003110:Colonic Neoplasms; D004354:Drug Screening Assays, Antitumor; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D029501:Hamamelis / Q000737:chemistry*; D006601:Hexoses / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis; D047348:Hydrolyzable Tannins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D015394:Molecular Structure; D024301:Plant Bark / Q000737:chemistry
D000972:Antineoplastic Agents, Phytogenic; D006601:Hexoses; D047348:Hydrolyzable Tannins; D005707:Gallic Acid; D006861:Hydrogen Peroxide; C093412:hamamelitannin