Research Article Effect of Uncaria tomentosa Extract on Apoptosis Triggered by Oxaliplatin Exposure on HT29 Cells Liliane Z. de Oliveira, 1,2 Iria Luiza G. Farias, 1 Melânia L. Rigo, 3 Werner G. Glanzner, 3 Paulo Bayard D. Gonçalves, 3 Francine C. Cadoná, 4 Ivana B. Cruz, 4 Júlia G. Farias, 5 Marta M. M. F. Duarte, 6 Luzia Franco, 7 Gustavo Bertol, 7 Elisangela Colpo, 4 Patricia C. Brites, 1 João Batista T. Rocha, 4 and Daniela B. R. Leal 2 1 University Hospital of Santa Maria, Federal University of Santa Maria (UFSM), Avenida Roraima, Pr´ edio 20, 97105-900 Santa Maria, RS, Brazil 2 Postgraduate Program in Pharmaceutical Sciences, UFSM, 97105-900 Santa Maria, RS, Brazil 3 Laboratory of Biotechnology and Animal Reproduction, UFSM, 97105-900 Santa Maria, RS, Brazil 4 Postgraduate Program in Biochemistry and Toxicology, UFSM, 97105-900 Santa Maria, RS, Brazil 5 Postgraduate Program in Agronomy, UFSM, 97105-900 Santa Maria, RS, Brazil 6 Lutheran University of Brazil (ULBRA), BR 287, Km 252, 97020-001 Santa Maria, RS, Brazil 7 Herbarium Laborat´ orio Botˆ anico Ltda., Avenida Santos Dumont 1100, 83403-500 Colombo, PR, Brazil Correspondence should be addressed to Liliane Z. de Oliveira; lilianeoliv@gmail.com and Iria Luiza G. Farias; irialuiza@hotmail.com Received 17 June 2014; Accepted 17 October 2014; Published 11 November 2014 Academic Editor: Vincenzo De Feo Copyright © 2014 Liliane Z. de Oliveira et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background/Aim. he use of herbal products as a supplement to minimize the efects of chemotherapy for cancer treatment requires further attention with respect to the activity and toxicity of chemotherapy. Uncaria tomentosa extract, which contains oxindole alkaloids, is one of these herbal products. he objective of this study was to evaluate whether Uncaria tomentosa extract modulates apoptosis induced by chemotherapy exposure. Materials and Methods. Colorectal adenocarcinoma cells (HT29 cells) were grown in the presence of oxaliplatin and/or Uncaria tomentosa extract. Results. he hydroalcoholic extract of Uncaria tomentosa enhanced chemotherapy-induced apoptosis, with an increase in the percentage of Annexin positive cells, an increase in caspase activities, and an increase of DNA fragments in culture of the neoplastic cells. Moreover, antioxidant activity may be related to apoptosis. Conclusion. Uncaria tomentosa extract has a role for cancer patients as a complementary therapy. Further studies evaluating these beneicial efects with other chemotherapy drugs are recommended. 1. Introduction he association among reactive oxygen species (ROS), cel- lular oxidative stress, and cancer risk has been well estab- lished, resulting in studies demonstrating that the use of herbal products with antioxidant properties can reverse or minimize these negative efects, thereby improving the health of individuals. However, the nature of this association is complex and at times may appear paradoxical [1]. In 2006, Schumacker [2] summarized this relationship in ive points: (1) oxidative stress and ROS can cause cancer, (2) transformed cells generate more ROS compared with normal cells, (3) antioxidant systems, such as thioredoxin and superoxide dismutase (SOD), are enhanced in certain malignant cells, (4) stimulation of cell cycle progression by growth factors or mutations, which activate signaling via the tyrosine kinase receptor, involves an increase in ROS, and (5) various chemotherapeutic agents may be selectively toxic to tumor cells because they increase oxidative stress and drive already “stressed” cells beyond their limit. Highlighting the relation- ship to oxidative stress, H 2 O 2 levels in particular play a key role in the induction of apoptosis. In this way, antioxidant Hindawi Publishing Corporation Evidence-Based Complementary and Alternative Medicine Volume 2014, Article ID 274786, 10 pages http://dx.doi.org/10.1155/2014/274786