Electrochemical, spectroscopic and pharmacological approaches toward the understanding of biflorin DNA damage effects Marne Carvalho de Vasconcellos a , Cícero de Oliveira Costa b,c , Emanuella Gomes da Silva Terto b,d , Maria Aline F.B. de Moura b,d , Camila Calado de Vasconcelos b , Fabiane Caxico de Abreu b , Telma Leda Gomes de Lemos e , Letícia Veras Costa-Lotufo f , Raquel Carvalho Montenegro g, ⁎, Marília Oliveira Fonseca Goulart b, ⁎ a Faculdade de Ciências Farmacêuticas, Universidade Federal do Amazonas, Rua Alexandre Amorim, 330-Aparecida, Manaus, AM, Brazil b Instituto de Química e Biotecnologia, Universidade Federal de Alagoas, Av. Lourival Melo Mota, s/n, Cidade Universitária, 57072900 Maceió, AL, Brazil c Instituto Federal de Alagoas, Campus Satuba, Rua 17 de Agosto s/n, Zona Rural, Satuba, AL, Brazil d Escola de Enfermagem e Farmácia, Universidade Federal de Alagoas, Av. Lourival Melo Mota, s/n, Cidade Universitária, Maceió, AL, Brazil e Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Campus do Pici, bloco 940 Bairro Pici, Fortaleza, CE, Brazil f Instituto de Ciências Biomédicas, Universidade de São Paulo. Av. Lineu Prestes 1524, Cidade Universitária, São Paulo, SP, Brazil g Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Corrêa 01-Guamá, Belém, PA, Brazil abstract article info Article history: Received 9 September 2015 Received in revised form 27 September 2015 Accepted 28 September 2015 Available online xxxx Keywords: Biflorin DNA interaction DNA sensors Electrochemistry of quinones Cytotoxicity Comet assay Clastogenicity Aneuploidogenicity The present study aims to evaluate some aspects of the pharmacoelectrochemistry of biflorin, a biologically active 1,2-naphthoquinone derivative, isolated from the roots of Capraria biflora. Electrochemical experiments involving biflorin using single, double-strand DNA and isolated bases had shown interaction of this quinone with DNA. Sim- ilar results were obtained using spectrophotometry (UV–Vis experiments and fluorimetry). Binding constants DNA–biflorin were obtained, through differential pulse voltammetry and fluorimetry. Spectroscopic studies and thermodynamic data had shown that biflorin can intercalate through dsDNA by van der Waals interactions and hy- drogen bonds. The effects of biflorin–dsDNA interaction were addressed through a molecular cytogenetic ap- proach, using comet assay and chromosome aberration induction evaluation. Indeed, biflorin, compared to the negative control, presented approximately 4- and 6-fold increases in DNA damage index and 4.1 and 13-fold en- hanced damage frequencies at 40 and 80 μM, respectively. However, biflorin did not significantly induce chromo- some aberrations, suggesting that this molecule does not possess clastogenic potential, but cytotoxic potential. The absence of either clastogenic or aneuploidogenic activity of the compound reinforced its safety. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Natural products are the largest contributor to the production of active metabolites, and many of them are used as drugs, cosmetics and pesticides. Redox active secondary metabolites from plants, fungi, bacteria and other (micro-)organisms often have been at the forefront of the most interesting developments [1]. Quinones, naphthoquinones and hydroquinones are ubiquitous in na- ture [1]. Today, the interest on these substances is related, not only to their importance in vital biochemical processes, but also due to the prom- ising results achieved in several pharmacological studies [2]. These mole- cules have been associated with a wide range of biological properties, such as antibacterial, antimalarial, antiviral, trypanocidal, antifungal and antitumor [1–4]. Quinones have an intriguing dual behavior. Depending on the particular system, they act as an antioxidant and protect cell homeostasis against reactive oxygen species (ROS) or they can behave as cytotoxic agents, generating toxic species in an unhealthy cell environ- ment [5]. Their cytotoxicity has been extensively studied and used as models to understand chemically induced toxicity in cellular mechanisms [5–7]. Quinones are Michael acceptors for endobiotic nucleophiles [8], and cellular damage/detoxification can occur through alkylation of cru- cial cell proteins e.g., topoisomerase and protein tyrosine phosphatases [9] and/or DNA [5,10–11]. The majority of these activities are based on redox reactions [3,5,7,8,10,12], justifying electrochemical studies. Among the quinones, biflorin (Fig. 1) is a prenylated οrtho- naphthoquinone (6,9-dimethyl-3-(4-methyl-3-pentenyl)naphtha[1,8- bc]-pyran-7,8-dione), easily isolated from the roots of Capraria biflora, a perennial shrub distributed in North and South Americas [13]. Biflorin demonstrated cytotoxic activity against several tumor cell lines with IC 50 ranging from 1.2 μM in B16 (murine melanoma) to 6.3 μM in HL-60 (human leukemia) cells [13], along with antitumor activity on mice bearing sarcoma 180, Erhlich carcinoma and melano- ma, indicating a promising antitumor therapeutical potential [14,15]. Journal of Electroanalytical Chemistry xxx (2015) xxx–xxx ⁎ Corresponding authors. E-mail address: mariliaofg@gmail.com (M.O.F. Goulart). JEAC-02303; No of Pages 11 http://dx.doi.org/10.1016/j.jelechem.2015.09.040 1572-6657/© 2015 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Journal of Electroanalytical Chemistry journal homepage: www.elsevier.com/locate/jeac Please cite this article as: M.C. de Vasconcellos, et al., Electrochemical, spectroscopic and pharmacological approaches toward the understanding of biflorin DNA damage effects, Journal of Electroanalytical Chemistry (2015), http://dx.doi.org/10.1016/j.jelechem.2015.09.040