Although a wide variety of cytotoxic plant extracts and phytochemicals are known to act synergistically with anticancer drug doxorubicin (D), their clinical application is hindered by safety concerns of such combination therapy. Our earlier studies showed that red beetroot (Beta vulgaris L.) extract (B), approved by Food and Drug Administration and European Union as red food color E162, reduced multi-organ tumor formations in various animal models when administered in drinking water. This led us to postulate that a long-term daily exposure to low doses of B through diet might be safe and sufficient to produce cancer chemopreventive effect in humans. Further, our recent comparative cytotoxic investigation with B and D in several human cancer cell lines indicated their potential for synergistic activity. Since B is considered safe for human use with no known toxicity, we conducted the present study to evaluate its synergistic antiproliferative activity with D against pancreatic (PaCa), breast (MCF-7) and prostate (PC-3) tumor cells of human origin. Different concentrations of B and D (0.29–290 μg/ml) and in various combinations (B:D ratio = 1:0, 1:1, 5:1, 1:5 and 0:1) were tested for cytotoxic effects against the three cancer cells. The viability of cells was assessed after 72 h incubation with various combinations of B and D using the trypan-blue staining method. The cytotoxic data were analyzed by the combination index method of Chou and Talalay to establish synergy between B and D. The results indicated that an overall positive reduction in drug concentration was achieved by D when combined with B in its cytotoxicity profile in the three human cancer cells tested. The synergistic cytotoxicity was best when the B:D ratio of 1:5 was used in PaCa cells at IC50, IC75 and IC90 dose levels and in MCF-7 cells at IC90 dose level. These results warrant further studies on the potential of red beetroot extract–doxorubicin combination in treating human cancers.
Government of India, Ministry of Health and Family Welfare. The Ayurvedic Pharmacopoeia of India, Parts I and II. New Delhi: Government of India Press, 1978 and 2007.
Bensky D, Gamble A. Chinese herbal medicine: materia medica, rev. ed. Seattle, WA: Eastland Press, 1993.
Patwardhan B, Warude D, Pushpnagadan P, Bhat N. Ayurveda and traditional Chinese medicine: a comparative overview. Evid Based Complement Alternat Med 2005;2:465–73.
Chou TC. Theoretical basis, experimental design, and computerized simulation of synergism and antagonism of drug combination studies. Pharmacol Rev 2006;58:621–81.
Chou TC. Drug combination studies and their synergy quantification using the Chou-Talalay method. Cancer Res 2010;70:440–6.
Ulrich-Merzenich G, Panek D, Zeitler H, Vetter H, Wagner H. Drug development from natural products: exploiting synergistic effects. Indian J Exp Biol 2010;48:208–19.
Tanos V, Brzezinski A, Drize O, Strauss N, Peretz T. Synergistic inhibitory effects of genistein and tamoxifen on human dysplastic and malignant epithelial breast cells in vitro. Eur J Obstet Gynecol Reprod Biol 2002;102:188–94.
Wang MY, West BJ, Jensen CJ, Nowicki D, Chen SU, Palu AK, et al. Morinda citrifolia (Noni): A literature review and recent advances in Noni research. Acta Pharmacol Sin 2002:12:1127–47.
Sharma G, Tyagi AK, Singh RP, Chan DC, Agarwal R. Synergistic anticancer effects of grape seed extract and conventional cytotoxic agent doxorubicin against human breast carcinoma cells. Breast Cancer Res Treat 2004;85:1–12.
Tyagi AK, Agarwal C, Chan DC, Agarwal R. Synergistic anticancer effects of silibinin with conventional cytotoxic agents doxorubicin, cisplatin and carboplatin against human breast carcinoma MCF-7 and MDA-MB468 cells. Oncol Res 2004;11:493–9.
Hemaiswarya S, Doble M. Potential synergism of natural products in the treatment of cancer. Phytother Res 2006;20:239–49.
Wang CZ, Luo X, Zhang B, Song WX, Ni M, Mehendale S, et al. Notoginseng enhances anti-cancer effects of 5-fluorouracil on human colorectal cancer cells. Cancer Chemother Pharmacol 2007;60:69–79.
Wei J, Liu B, Wang L, Qian X, Ding Y, Yu L. Synergistic interaction between tetrandrine and chemotherapeutic agents and influence of tetrandrine on therapeutic agent-associated genes in human gastric cancer cell lines. Cancer Chemother Pharmacol 2007;60:703–11.
Akao Y, Nakagawa Y, Inuma M, Nozawa Y. Anti-cancer effects of xanthones from pericarps of mangosteen: Int J Mol Sci 2008;9:355–70.
Banerjee S, Kaseb AO, Wang Z, Kong D, Mohammad M, Padhye S, et al. Antitumor activity of gemcitabine and oxaliplatin is augmented by thymoquinone in pancreatic cells. Cancer Res 2009;69:5575–83.
Griggs JJ. Reducing the toxicity of anticancer therapy: new strategies. Leuk Res 1998;22(Suppl 1):S27–33.
Borek C. Dietary antioxidants and human cancer. Integr Cancer Ther 2004;3:333–41.
Liu HR. Potential synergy of phytochemicals in cancer prevention: mechanisms of action. J Nutr 2004;134:3479S–85S.
Huang XZ, Wang J, Huang C, Chen YY, Shi GY, Hu QS, Yi J. Emodin enhances cytotoxicity of chemotherapeutic drugs in prostate cancer cells: the mechanisms involve ROS-mediated suppression of multidrug resistance and hypoxia inducible factor-1. Cancer Biol Ther 2008;7:468–75.
Chai S, To KKW, Lin G. Circumvention of multi-drug resistance of cancer cells by Chinese herb medicine. Chin Med 2010;5:26–35.
Tan W, Lu J, Huang M, Li Y, Chen M, Wu G, et al. Review: anti-cancer natural products isolated from Chinese medicinal herbs. Chin Med 2011;6:27–42.
Lown JW. Anthracycline and anthraquinone anticancer agents. Current status and recent developments. Pharmacol Ther 1993;60:185–214.
Carvalho C, Santos RX, Cardoso S, Correia S, Oliveira PJ, Santos MS, Moreira PI. Doxorubicin: the good, the bad and the ugly effect. Curr Med Chem 2009;16:3267–85.
Abdel-Wahab MH, El-Mahdy MA, Abd-Ellah MF, Helat GK, Khalifa F, Hamada FMA. Influence of p-coumaric acid on doxorubicin-induced oxidative stress in rat’s heart. Pharmacol Res 2003;48:461–5.
Psotova J, Chlopcikova S, Miketova P, Hrbac J, Simanek V. Chemoprotective effect of plant phenolics against anthracycline-induced toxicity on rat cardiomyocytes. Part III. Apigenin, baicalenin, kaempherol, luteolin and quercetin. Phytother Res 2004;18:516–21.
Teiten MH, Eifes S, Dicato M, Diedrich M. Review: Curcumin – the paradigm of a multi-target natural compound with applications in cancer prevention and treatment. Toxins 2010;2:128–62.
Ravizza R, Gariboldi MB, Molteni R, Monti E. Linalool, a plant-derived monoterpene alcohol, reverses doxorubicin resistance in human breast adenocarcinoma cells. Oncol Rep 2008;20:625–30.
Effenberger K, Schobert R. Combinational effects of thymoquinone on the anti-cancer activity of doxorubicin. Cancer Chemother Pharmacol 2010;67:867–74.
Kaneez FS, Al-Salam S, Alaaeldin AH. Sesame oil as a protective agent against doxorubicin induced cardiotoxicity in rat. Am J Pharmacol Toxicol 2007;2:159–63.
Alkreathy H, Damanhouri ZA, Ahmed N, Slevin M, Ali SS and Osman AMM. Aged garlic extract protects against doxorubicin-induced cardiotoxicity in rats. Food Chem Toxicol 2010;48:951–6.
Liu TJ, Yeh YC, Ting CT, Lee WL, Wang LC, Lee HW, et al. Ginkgo biloba extract 761 reduces doxorubicin-induced apoptoic damage in rat hearts and neonatal cardiomyocytes. Cardiovasc Res 2008;80:227–35.
Wattanapitayakul SK, Chularojmontri L, Herunsalee A, Charuchongkolwongse S, Niumsakul S, Bauer JA. Screening of antioxidants from medicinal plants for cardioprotective effect against doxorubicin toxicity. Basic Clin Pharmacol Toxicol 2005;96:80–7.
Breibart E. Effects of water-soluble antioxidants from spinach, NAO, on doxorubicin-induced heart injury. Hum Exp Toxicol 2001;20:337–45.
Liang G, Tang A, Lin X, Li L, Zhang S, Huang Z, et al. Green tea catechins augment the antitumor activity of doxorubicin in an in vivo mouse model for chemoresistant liver cancer. Int J Oncol 2010;37:111–23.
Sarkar A, Sreenivasan Y, Ramesh GT, Manna SK. D-Glucoside suppresses tumor necrosis factor-induced activation of nuclear transcription factor kB but potentiates apoptosis. J Biol Chem 2004;279:33768–81.
Kolarovic J, Popovic M, Zlinska J, Trivic S, Vojnovic M. Antioxidant activities of celery and parsley juices in rats treated with doxorubicin. Molecules 2010;15:6193–204.
Nair PKR, Melnick S, Wnuk SF, Rapp M, Escalon E, Ramachandran C. Isolation and Characterization of an anticancer catechol compound from Semecarpus anacradium. J Ethnopharmacol 2009;122:450–6.
Colombo V, Lupi M, Falcetta F, Forestieri D, D’Incalci M, Ubezio P. Chemotherapeutic activity of silymarin combined with doxorubicin or paclitaxel in sensitive and multidrug-resistant colon cancer cells. Cancer Chemother Pharmacol 2011;67:369–79.
Chen HM, Wu YC, Chia YC, Chang FR, Hsu HK, Hseih YC, et al. Gallic acid, a major component of Toona sinensis leaf extracts, contains ROS-mediated anti-cancer activity in human prostate cancer cells. Cancer Lett 2009;286:161–71.
Pandey MK, Sung B, Ahn KS, Kunnumakkara AB, Chaturvedi MM, Aggarwal BB. Gambogic acid, a new ligand for transferring receptor, potentiates TNF-induced apoptosis through modulation of the nuclear factor-kB signaling pathway. Blood 2007;110:3517–25.
Scambia G, Ranelletti FO, Panici PB, De Vencenzo R, Bonanno G, Piantelli M, et al. Quercetin potentiates the effect of adriamycin in a multi-drug resistant MCF-7 human breast cancer line: P- glycoprotein as a possible target. Cancer Chemother Pharmacol 1994:34:459–64. Comment by Sarkar MA. Quercetin not only inhibits P-glycoprotein efflux but also inhibits CYP3A isoenzyme. Cancer Chemother Pharmacol 1995:36:448–50.
Sun AX, Ye XG, Li CY, Xue BY, Li LF, Cao XF, et al. Synergistic anticancer effects of tetrandrine combined with doxorubicin or vincristine in vitro. Acta Pharmacol Sin 1999;20:69–73.
Chanamahasathein W, Ampasavate C, Greger H, Limtrakul P. Stemona alkaloids, from traditional Thai medicine, increase chemosensitivity via P-glycoprotein-mediated multidrug resistance. Phytomedicine 2011;18:199–204.
Fenig E, Nordenberg J, Beery E, Sulkes J, Wasserman L. Combined effect of aloe-emodin and chemotherapeutic agents on the proliferation of an adherent variant cell line of Merkel cell carcinoma. Oncol Rep 2004;11:213–7.
Gao RL, Lin XJ, Qian XD, Chen XH, Nu YP. Effect of ginsenosides and panaxatriol extracted from ginseng on inhibition of proliferation, inducing apoptosis and cytotoxic drug sensitivity in leukemic cells. J Chin Med Res 2004;4:97–9.
Zheng Y, Zhou F, Wu X, Wen X, Li Y, Yan B, et al. 23-Hydroxybetulinic acid from Pulsatilla chinensis (Bunge) Regel synergizes the antitumor activities of doxorubicin in vitro and in vivo. J Ethnopharmacol 2010;128:615–22.
Pinmai K, Chunlaratthanabhorn S, Ngamkitidechakul C, Soonthornchareon N, Hahnvajanawong C. Synergistic growth inhibitory effects of Phyllanthus emblica and Terminalia bellerica extracts with conventional cytotoxic agents: Doxorubicin and cisplatin against human hepatocelluar carcinoma and lung cancer cells. World J Gastroenterol 2008;14:1491–7
Kapadia GJ, Azuine MA, Rao GS, Arai T, Iida A, Tokuda H. Cytotoxic effect of the red beetroot (Beta vulgaris L.) extract compared to doxorubicin (Adriamycin) in the human prostate (PC-3) and breast (MCF-7) cancer cell lines. Anti-Cancer Agent Med Chem 2011;11:280–4.
Kapadia GJ, Rao GS, Elinor-Reid T, Iida A, Suzuki N, Tokuda H. Synergistic cytotoxic effect of red beetroot (Beta vulgaris L.) food colorant E162 with anticancer drug doxorubicin (Adriamycin) against human prostate, breast and pancreatic tumor cells. In: Abstracts of Papers, American Society of Pharmacognosy 52nd Annual Meeting, San Diego, CA, 2011:P241.
Kapadia GJ, Tokuda H, Konoshima T, Nishino H. Chemoprevention of lung and skin cancer by Beta vulgaris (beet) root extract. Cancer Lett 1996;100:211–4.
Kapadia GJ, Azuine MA, Sridhar R, Okuda Y, Tsuruta A, Ichishi E, et al. Chemoprevention of DMBA-induced UV-B promoted, NOR-1-induced TPA promoted skin carcinogenesis and DEN-induced phenobarbital promoted liver tumors in mice by extract of beetroot. Pharmacol Res 2003;47:141–8.
Kapadia GJ, Rao GS. Anticancer effects of red beet pigments. In: Neelwarne B, editor. Red beet biotechnology: metabolites for food and pharmaceutical applications. New York, NY: Springer 2013:125–54.
Chou TC, Talalay P. Analysis of combined drug effects: a new look at a very old problem. Trend Pharmacol Sci 1983;4:450–4.
Reznikoff CA, Bertram JS, Brankow DW, Heidelberger C. Quantitative and qualitative studies of chemical transformation of cloned C3H mouse embryo cells sensitive to post confluence inhibition of cell division. Cancer Res 1973;33:3239–49.
Kakunga TA. A quantitative system for assay of malignant trans- formation by chemical carcinogens using a clone of BALB-373. Int J Cancer 1973;12:463–73.
Tolnai S. A method for viable cell count. Method Cell Sci 1975;1:37–8.
Azeredo HMC. Betalains: properties, sources, applications, and stability – a review. Int J Food Sci Technol 2009;44:2365–76.
Ferreira ALA, Yeum KJ, Matsubara LS, Matsubara BB, Correa CR, Periera EJ, et al. Doxorubicin as an antioxidant: maintenance of myocardial levels of lycopene under doxorubicin treatment. Free Radic Biol Med 2007;43:740–51.
The Journal of Complementary and Integrative Medicine focuses on evidence concerning the efficacy and safety of complementary and alternative medical (CAM) whole systems, practices, interventions and natural health products, including herbal medicines.