Scores of fibrosis, glycogen stores and the number of nucleolus organizing regions were not altered. On the other hand, the percentage of cells presenting megalocytosis (P = 0.0001) and vacuolar degeneration (P = 0.0001) was increased. Comfrey treatment reduced the number of pre-neoplastic macroscopic lesions up to 1 mm (P ≤ 0.05), the percentage of oval cells (P = 0.0001) and mitotic figures (P = 0.007), as well as the number of Proliferating Cell Nuclear Antigen (PCNA) positive cells (P = 0.0001) and acidophilic pre-neoplastic nodules (P = 0.05). Non-parametric statistical tests (Mann–Whitney and χ2) were used, and the level of significance was set at P ≤ 0.05. Macroscopic/microscopic quantitative analysis of PNL was performed. Wistar rats were sequentially treated with N-nitrosodiethylamine (ip) and 2-acetilaminofluorene (po), and submitted to hepatectomy to induce carcinogenesis promotion. Herein, the effects of chronic oral treatment of rats with 10% Comfrey ethanolic extract were evaluated in a RHM. In these studies, it is possible to observe easily the phenomena related to the early phases of tumor development, since pre-neoplastic lesions (PNLs) rise in about 1–2 months of chemical induction. However, the literature on this topic is very poor considering the studies performed under short-term carcinogenesis protocols, such as the ‘resistant hepatocyte model’ (RHM). Since the 1980s, its effects have been studied in long-term carcinogenesis studies, in which Comfrey extract is administered at high doses during several months and the neoplastic hepatic lesions are evaluated. Gomes, Maria Fernanda Pereira Lavieri de Oliveira Massoco, Cristina Xavier, José GuilhermeĬomfrey or Symphytum officinale (L.) (Boraginaceae) is a very popular plant used for therapeutic purposes. l.) and Experimental Hepatic Carcinogenesis: A Short-term Carcinogenesis Model Study Consequently, regulatory agencies and international health organizations have recomm.Ĭomfrey ( Symphytum Officinale. USDA-ARS?s Scientific Manuscript databaseĬomfrey ( Symphytum officinale), a commonly used herb, contains dehydropyrrolizidine alkaloids (DHPAs) that, as a group of bioactive metabolites, are potentially hepatotoxic, pneumotoxic, genotoxic and carcinogenic. The comparative toxicity of a reduced, crude comfrey ( Symphytum officinale) alkaloid extract and the pure, comfrey-derived pyrrolizidine alkaloids, lycopsamine and intermedine in chicks (Gallus gallus domesticus)
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