Dietary antioxidants protect gut epithelial cells from oxidant-induced apoptosis

• Main Authors: Bobrowski Paul (Author), Reuter Brian K (Author), Angeles Fausto M (Author), Miller Mark JS (Author), Sandoval Manuel (Author)
• Format: Book
• Published: BMC, 2001-12-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.1186/1472-6882-1-11; 1472-6882
• Keywords: Other systems of medicine; RZ201-999
• Source: BMC Complementary and Alternative Medicine, Vol 1, Iss 1, p 11 (2001)

<p>Abstract</p> <p>Background</p> <p>The potential of ascorbic acid and two botanical decoctions, green tea and cat's claw, to limit cell death in response to oxidants were evaluated in vitro.</p> <p>Methods</p> <p>Cultured human gastric epithelial cells (AGS) or murine small intestinal epithelial cells (IEC-18) were exposed to oxidants - DPPH (3 μM), H₂O₂ (50 μM), peroxynitrite (300 μM) - followed by incubation for 24 hours, with antioxidants (10 μg/ml) administered as a 1 hour pretreatment. Cell number (MTT assay) and death via apoptosis or necrosis (ELISA, LDH release) was determined. The direct interactions between antioxidants and DPPH (100 μM) or H₂O₂ (50 μM) were evaluated by spectroscopy.</p> <p>Results</p> <p>The decoctions did not interact with H₂O₂, but quenched DPPH although less effectively than vitamin C. In contrast, vitamin C was significantly less effective in protecting human gastric epithelial cells (AGS) from apoptosis induced by DPPH, peroxynitrite and H₂O₂ (P < 0.001). Green tea and cat's claw were equally protective against peroxynitrite and H₂O₂, but green tea was more effective than cat's claw in reducing DPPH-induced apoptosis (P < 0.01). Necrotic cell death was marginally evident at these low concentrations of peroxynitrite and H₂O₂, and was attenuated both by cat's claw and green tea (P < 0.01). In IEC-18 cells, all antioxidants were equally effective as anti-apoptotic agents.</p> <p>Conclusions</p> <p>These results indicate that dietary antioxidants can limit epithelial cell death in response to oxidant stress. In the case of green tea and cat's claw, the cytoprotective response exceed their inherent ability to interact with the injurious oxidant, suggestive of actions on intracellular pathways regulating cell death.</p>