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Evidence-Based Complementary and Alternative Medicine
Volume 2012, Article ID 490136, 8 pages
http://dx.doi.org/10.1155/2012/490136
Research Article

Cucurbitacin L 2-O-β-Glucoside Demonstrates Apoptogenesis in Colon Adenocarcinoma Cells (HT-29): Involvement of Reactive Oxygen and Nitrogen Species Regulation

1Department of Pharmacy, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
2Department of Botany, Faculty of Science & Technology, Omdurman Islamic University, P.O. Box 383, Omdurman, Sudan
3Department of Pharmacology, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang, 11800 Minden, Malaysia
4Department of Botany, Faculty of Science, University of Khartoum, P.O. Box 321, Khartoum, Sudan
5Centre of Natural Products and Drug Discovery (CENAR), Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
6Department of Biochemistry, Faculty of Biotechnology, Universiti Putra Malaysia, UPM, 43400 Serdang, Selangor, Malaysia
7School of Medicine, Faculty of Medical Sciences, UCSI University, 56000 Kuala Lumpur, Malaysia
8Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia

Received 29 November 2011; Revised 30 January 2012; Accepted 31 January 2012

Academic Editor: Jae Youl Cho

Copyright © 2012 Siddig Ibrahim Abdelwahab et al. This 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.

Abstract

Emerging evidence suggests that reactive oxygen (ROS) and nitrogen (RNS) species can contribute to diverse signalling pathways of inflammatory and tumour cells. Cucurbitacins are a group of highly oxygenated triterpenes. Many plants used in folk medicine to treat cancer have been found to contain cucurbitacins displaying potentially important anti-inflammatory actions. The current study was designed to investigate the anti-ROS and -RNS effects of cucurbitacin L 2-O-β-glucoside (CLG) and the role of these signaling factors in the apoptogenic effects of CLG on human colon cancer cells (HT-29). This natural cucurbitacin was isolated purely from Citrullus lanatus var. citroides (Cucurbitaceae). The results revealed that CLG was cytotoxic to HT-29. CLG increased significantly () RNA and protein levels of caspase-3 in HT-29 cells when verified using a colorimetric assay and realtime qPCR, respectively. The results showed that lipopolysaccharide/interferon-gamma (LPS/INF-γ) increased nitrous oxide (NO) production inR AW264.7macrophages, whereas N(G)-nitro-L-argininemethyl ester (L-NAME) and CLG curtailed it. This compound did not reveal any cytotoxicity on RAW264.7 macrophages and human normal liver cells (WRL-68) when tested using the MTT assay. Findings of ferric reducing antioxidant power (FRAP) and oxygen radical absorption capacity (ORAC) assays demonstrate the antioxidant properties of CLG. The apoptogenic property of CLG on HT-29 cells is thus related to inhibition of reactive nitrogen and oxygen reactive species and the triggering of caspase-3-regulated apoptosis.