title: Synergistic cytotoxicity of red beetroot (Beta vulgaris L.) extract with doxorubicin in human pancreatic, breast and prostate cancer cell lines.
abstract: 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.
authors.affiliation: College of Pharmacy, Howard University, 2300 4th St. NW, Washington, DC 20059, USA. gkapadia@howard.edu
authors.forename: Govind J
authors.initials: GJ
authors.lastname: Kapadia
authors.forename: G Subba
authors.initials: GS
authors.lastname: Rao
authors.forename: Cheppail
authors.initials: C
authors.lastname: Ramachandran
authors.forename: Akira
authors.initials: A
authors.lastname: Iida
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Suzuki
authors.forename: Harukuni
authors.initials: H
authors.lastname: Tokuda
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D027461:Beta vulgaris; D001943:Breast Neoplasms / Q000188:drug therapy*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology / Q000627:therapeutic use*; D004338:Drug Combinations; D004357:Drug Synergism; D005260:Female; D041743:Herb-Drug Interactions; D006801:Humans; D061986:MCF-7 Cells; D008297:Male; D010190:Pancreatic Neoplasms / Q000188:drug therapy*; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D011471:Prostatic Neoplasms / Q000188:drug therapy*
chemical_list: D000970:Antineoplastic Agents; D004338:Drug Combinations; D010936:Plant Extracts; D004317:Doxorubicin