title: Brazilian red propolis: phytochemical screening, antioxidant activity and effect against cancer cells.
abstract: BACKGROUND
  The implementation of new public healthcare models that stimulate the use of natural products from traditional medicine, as a so-called integrated medicine, refers to an approach that use best of both conventional medicine and traditional medicine. Propolis is a widely used natural product by different ancient cultures and known to exhibit biological activities beneficial for health. The large number of studies conducted with propolis had shown that its chemical composition differs as a function of the climate, plant diversity and bee species and plays an important role on its therapeutic properties. The aim of this study was to analyse the phytochemical profile of the ethanolic extract of red propolis (EEP) and its fractionation, antioxidant action of EEP and its fractions hexane, cloroform and ethyl acetate and cytotoxic activity of EEP on human tumour cell lines SF-295 (glioblastoma), OVCAR-8 (ovary) and HCT-116 (colon).
  
  
  METHODS
  EEP was obtained by maceration with absolute ethanol, then it was concentrated in rotaevaporator up to complete evaporation of the solvent. The crude extract was fractionated with hexane, ethyl acetate, chloroform and methanol and they were subjected to phytochemical screening and total phenolic compounds. Antioxidant activity of EEP and fractions was done by means of the 2,2-diphenyl-1-picryhydrazyl (DPPH) method. Biomarkers of red propolis were identified by LC-Orbitrap-FTMS. To assess cytotoxic activity of the extract, cells were exposed to EEP over 72 h. Cell viability was assessed by means of MTT assay. The percentage of cell growth inhibition (IC50) was analysed by means of non-linear regression, and the absorbance values of the various investigated concentrations were subjected to one-factor analysis of variance (ANOVA) followed by Tukey's or Tamhane's tests (α = 0.05).
  
  
  RESULTS
  The results obtained using phytochemical screening and LC-Orbitrap-FTMS indicated the presence of phlobaphene tannins, catechins, chalcones, aurones, flavonones, flavonols, xanthones, pentacyclic triterpenoids and guttiferones in Brazilian red propolis. EEP and its hexane, chloroform and ethyl acetate fractions obtained by liquid-liquid partitioning exhibited satisfactory antioxidant percentages. EEP (IC50 < 34.27 μg/mL) exhibited high levels of cytotoxicity on all human tumour cell lines tested when compared to negative control.
  
  
  CONCLUSIONS
  C-Orbitrap-FTMS was useful to establish the chemical profile of the red propolis. Brazilian red propolis has antioxidant properties and decreases substantially the percentage of cell survival of human tumour cells; thus, it has potential to serve as an anticancer drug.
authors.affiliation: School of Dentistry, Cesmac University Center, Rua Cônego Machado, 918, Farol, CEP: 57051-160, Maceió, Alagoas, Brazil. belgomess@gmail.com.
authors.forename: Izabel Cristina Gomes
authors.initials: IC
authors.lastname: de Mendonça
authors.affiliation: School of Dentistry, Cesmac University Center, Rua Cônego Machado, 918, Farol, CEP: 57051-160, Maceió, Alagoas, Brazil. isabelcmporto@gmail.comAQ2AQ3.
authors.forename: Isabel Cristina Celerino de Moraes
authors.initials: IC
authors.lastname: Porto
authors.affiliation: School of Nursing and Pharmacy, Federal University of Alagoas, Campus A. C. Simões, University City, Maceió, 57072-970 , AL, Brazil. ticianogn@yahoo.com.br.
authors.forename: Ticiano Gomes
authors.initials: TG
authors.lastname: do Nascimento
authors.affiliation: School of Nursing and Pharmacy, Federal University of Alagoas, Campus A. C. Simões, University City, Maceió, 57072-970 , AL, Brazil. nagari.bc@gmail.com.
authors.forename: Naiana Soares
authors.initials: NS
authors.lastname: de Souza
authors.affiliation: School of Nursing and Pharmacy, Federal University of Alagoas, Campus A. C. Simões, University City, Maceió, 57072-970 , AL, Brazil. jose_marcos_cbjr@hotmail.com.
authors.forename: José Marcos dos Santos
authors.initials: JM
authors.lastname: Oliveira
authors.affiliation: School of Nursing and Pharmacy, Federal University of Alagoas, Campus A. C. Simões, University City, Maceió, 57072-970 , AL, Brazil. rodolfo.elleson@gmail.com.
authors.forename: Rodolfo Elleson dos Santos
authors.initials: RE
authors.lastname: Arruda
authors.affiliation: School of Dentistry, Cesmac University Center, Rua Cônego Machado, 918, Farol, CEP: 57051-160, Maceió, Alagoas, Brazil. kristianamousinho@gmail.com.
authors.forename: Kristiana Cerqueira
authors.initials: KC
authors.lastname: Mousinho
authors.affiliation: School of Dentistry, Cesmac University Center, Rua Cônego Machado, 918, Farol, CEP: 57051-160, Maceió, Alagoas, Brazil. aldenirfeitosa@gmail.com.
authors.forename: Aldenir Feitosa
authors.initials: AF
authors.lastname: dos Santos
authors.affiliation: School of Nursing and Pharmacy, Federal University of Alagoas, Campus A. C. Simões, University City, Maceió, 57072-970 , AL, Brazil. irinaldodiniz@yahoo.com.br.
authors.forename: Irinaldo Diniz
authors.initials: ID
authors.lastname: Basílio-Júnior
authors.affiliation: School of Dentistry, International Medical University, Bukit Jalil , 57000, Kuala Lumpur, Malaysia. abhishek_parolia@imu.edu.my.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Parolia
authors.affiliation: Laboratory of Experimental Oncology (LOE), Medical School, Federal University of Ceará, Rua Cel. Nunes de Melo 1127, 60430-270, Fortaleza, CE, Brazil. franciscostefanio@hotmail.com.
authors.forename: Francisco Stefânio
authors.initials: FS
authors.lastname: Barreto
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D045744:Cell Line, Tumor / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D064209:Phytochemicals / Q000737:chemistry* / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D011429:Propolis / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D000975:Antioxidants; D064209:Phytochemicals; D010936:Plant Extracts; D011429:Propolis