Synergistic Anticancer Activity of Curcumin and Catechin: An In Vitro Study Using Human Cancer Cell Lines R. MANIKANDAN, 1 * M. BEULAJA, 2 C. ARULVASU, 2 S. SELLAMUTHU, 2 D. DINESH, 2 D. PRABHU, 2 G. BABU, 2 B. VASEEHARAN, 1 AND N.M. PRABHU 1 1 Department of Animal Health and Management, Alagappa University, Karaikudi-630 003, Tamil Nadu, India 2 Department of Zoology, University of Madras, Guindy Campus, Chennai-600 025, Tamil Nadu, India KEY WORDS curcumin; catechin; apoptosis ABSTRACT The most practical approach to reduce morbidity and mortality of cancer is to delay the process of carcinogenesis by usage of anticancer agents. This necessitates that safer compounds are to be critically examined for anticancer activity especially, those derived from nat- ural sources. A spice commonly found in India and the surrounding regions, is turmeric, derived from the rhizome of Curcuma longa and the major active component is a phytochemical termed curcumin. Green tea is one of the most popular beverages used worldwide, produced from the leaves of evergreen plant Camellia sinensis and the major active ingredients are polyphenolic compounds known as catechins. In this study, synergistic anticancer activity of curcumin and catechin was evaluated in human colon adenocarcinoma HCT 15, HCT 116, and human larynx carcinoma Hep G-2 cell lines. Although, both curcumin or catechin inhibited the growth of above cell lines, interestingly, in combination of both these compounds highest level of growth control was observed. The anticancer activity shown is due to cytotoxicity, nuclear fragmentation as well as condensation, and DNA fragmentation associated with the appearance of apoptosis. These results suggest that curcumin and catechin in combination can inhibit the proliferation of HCT 15, HCT 116, as well as Hep G-2 cells efficiently through induction of apoptosis. Microsc. Res. Tech. 75:112–116, 2012. V V C 2011 Wiley Periodicals, Inc. INTRODUCTION Cancer is one of the most dreaded diseases from the 20 th century spreading further with continuance and increasing its incidence in 21 st century. It is one of the leading cause of death in humans (Balachandran and Govindarajan, 2005), and chemoprevention of cancer has lead to a new frontier in research (Singh and Lipp- man, 1998). The interest in chemoprevention research has thus led to identification of many phytochemicals as effective chemopreventive agents (Pezzuto, 1997). Plants and plant products are known to be effective and versatile chemopreventive agents against various types of cancer (Graham, 1992; Moongkarndi et al., 2004). Polyphenolic compounds occur widely in the plant kingdom and naturally occurring polyphenols have received great attention in recent years. These compounds have strong antioxidative activities in vitro and various beneficial health effects (Yang et al., 2001). The polyphenolic flavonoid curcumin (1,7-bis [4- hydroxy 3-methoxy phenyl]-1,6-heptadiene-3,5-dione) found in turmeric is a yellow curry spice with long his- tory of use in traditional Indian diets and herbal medi- cine. Curcumin has many pharmacological activities including anti-inflammatory property (Santel et al., 2008), powerful antioxidant activity (Manikandan et al., 2010; Masuda et al., 1999), and iron- chelating activity (Daniel et al., 2004). Curcumin has chemopreventive and therapeutic properties against many tumors, both in vitro and in vivo models. Curcu- min is able to suppress cell proliferation, inflammation, induce apoptosis, sensitize tumor cells to cancer thera- pies, and suppress invasion, angiogenesis, and metas- tasis of cancer cells (Song et al., 2009; Su et al., 2006). Curcumin plays a key role in modulation of several important molecular targets, including transcription factors (e.g., NF-jB and AP-1), antiapoptotic proteins (Bcl-2, Bcl-XL, and IAP), enzymes (e.g., COX-2 and iNOS), cytokines (e.g., TNFa , IL-1b, and IL-6), and che- mokines (Shishodia et al., 2005; Tomita et al., 2005). Recently, green tea has attracted significant attention both in scientific and in consumer communities for its healthy benefits against variety of disorders, ranging from cancer to weight loss. This publicity has led to the increased consumption of green tea by the general as well as patient population, and inclusion of green tea extract as a featured ingredient in several nutritional supplements, including multivitamin supplements. Historically, green tea has been consumed by the Japanese, Chinese populations for centuries, and is probably the most consumed beverage in the world (Graham, 1992). Green tea contains many polyphenols such as flavanols, flavandiols, and phenolic acid. These polyphenols account for a third of the dry weight of the leaves. The major green tea catechins are (2)-epigallo- catechin-3-gallate (EGCG), (2)-epigallocatechin (EGC), (2)-epicatechin-3-gallate (ECG), and (b)-catechin (Graham, 1992). The catechins possess good antioxi- dant properties which vary as follows: epicatechin gal- *Correspondence to: Dr. R. Manikandan, Department of Animal Health and Management, Alagappa University, Karaikudi-630 003, Tamil Nadu, India. E-mail: manizoo_78@rediffmail.com; manikandanramar@yahoo.co.in Received 16 March 2011; accepted in revised form 21 April 2011 DOI 10.1002/jemt.21032 Published online 21 July 2011 in Wiley Online Library (wileyonlinelibrary.com). V V C 2011 WILEY PERIODICALS, INC. MICROSCOPY RESEARCH AND TECHNIQUE 75:112–116 (2012)