title: Absence of chemopreventive influence of propolis on the rat liver altered foci development.
abstract: Propolis (bee glue) is a complex mixture of natural substances that exhibits a broad spectrum of biological activities. As the possibility exists that it may exert a chemopreventive role against cancer development, the present study aimed to evaluate the chemopreventive influence of a Brazilian aqueous propolis extract (APE) in a rat two-stage (initiation-promotion) medium-term bioassay for chemical liver carcinogenesis. Male Wistar rats were sequentially initiated with diethylnitrosamine (DEN, 200mg/kgb.w.) and, 2 weeks later, exposed to a diet containing hexachlorobenzene (HCB, 100ppm) and to APE 0.1% through drinking water for 6 weeks. Appropriate control groups were also established. The animals were sacrificed at the weeks 8th and 30th when liver samples were processed to evaluate the development of altered hepatocyte foci (AHF) identified under hematoxylin and eosin (H&E) staining and by the immunohistochemical expression of the enzyme glutathione S-transferase placental form (GST-P). The results indicate that APE 0.1% did not protect against the development of any of the differentially identified putative preneoplastic foci in DEN-initiated animals, exposed or not to the promoting agent HCB. Also, APE 0.1% by itself did not significantly induce any AHF, what is in line with its already known absence of genotoxic potential. Our results indicate that an aqueous extract of Brazilian propolis did not exert chemoprevention on the hepatocarcinogenesis process chemically induced in the rat.
authors.affiliation: Department of Environmental and Agrarian Sciences, Santa Cruz State University, Ilhéus, Bahia, Brazil.
authors.forename: Roueda Abou
authors.initials: RA
authors.lastname: Said
authors.forename: Tony Fernando
authors.initials: TF
authors.lastname: Grassi
authors.forename: Clarissa
authors.initials: C
authors.lastname: Scolastici
authors.forename: Rodrigo Otávio
authors.initials: RO
authors.lastname: Alves de Lima
authors.forename: Bruno R
authors.initials: BR
authors.lastname: Darros
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: Barbisan
authors.forename: João Lauro V
authors.initials: JL
authors.lastname: de Camargo
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001835:Body Weight / Q000187:drug effects; D001938:Brazil; D003043:Cocarcinogenesis; D004052:Diethylnitrosamine / Q000633:toxicity; D005982:Glutathione Transferase / Q000096:biosynthesis; D006581:Hexachlorobenzene / Q000633:toxicity; D007150:Immunohistochemistry; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008113:Liver Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D008519:Medicine, Traditional; D009929:Organ Size / Q000187:drug effects; D011230:Precancerous Conditions / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D011429:Propolis / Q000008:administration & dosage / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D017211:Treatment Failure
chemical_list: D016588:Anticarcinogenic Agents; D004052:Diethylnitrosamine; D006581:Hexachlorobenzene; D011429:Propolis; D005982:Glutathione Transferase