Antitumor effect of Psidium guajava extract in A172 cells

Introduction: Psidium guajava (guava) is a fruit tree used against numerous diseases; it even has antitumor action. Glioblastoma (GBM) is an aggressive primary brain tumor that confers low survival and high mortality. In this sense, the investigation of new compounds with antitumor action becomes promising, to identify compounds capable of regulating important processes in tumorigenesis and improving prognosis. Objectives: the objective of this investigation was to carry out the phytochemical, cytotoxic, antioxidant and chromatographic characterization of extractive solutions of Psidium guajava leaves; as well as to evaluate the effect of treatments with crude extract and Ethyl Acetate fraction (FAE) in GBM tumor cell lines. Methods: The crude extract (EP) was obtained by infusion (20 g of dried and crushed leaves in 100 m of 70% alcohol for 24 hours). Alcohol was extracted by rotary evaporation and organic solvents such as ethyl acetate, chloroform and hexane were mixed with EC 10% in the same proportion for 24 hours to obtain the fractions (FAE, FC and FH). Then, qualitative and quantitative phytochemical studies, chromatographic analysis and antioxidant profile were performed. Cytotoxicity was investigated by the hemolysis method, as well as cytotoxicity and viability of glioblastoma cell (A172) after treatment with FAE at different concentrations. Results: Secondary metabolites with pharmacological potential were identified, mainly in EP and FAE, in addition to a high antioxidant profile and low cytotoxicity. Chromatographic analysis confirmed the presence of Quercetin, Gallic Acid, Catechin and Myricetin. In A172 cells, the effect of cell proliferation inhibition was observed by the influence of treatment with FAE at concentrations of 5%, 10% and 25%, demonstrating a reduction in the growth of these tumorigenic cells in 24 hours, when compared to control samples. However, we found no significance. Through this test and the cell proliferation test, those that were close to 50% of cell viability were considered the best concentrations. Therefore, the following experiments were carried out at concentrations of 25% (800 µg/mL) for A172 in 24 hours of treatment. It was possible to observe through the comet assay that there was significant damage after treatment with the FAE. In the A172 cell line, treatment with FAE increased INF-gamma expression in treated cells, with significant differences when compared to untreated cells p<0.05. Treatment with FAE also reduced IL-6 expression p<0.001. The expression of Annexin A1, Quinase Complex (IKK), Mouse Double Minute 2 Homolog (MDM2) and Signal Transducer and Activator of Transcription 3 (STAT3) increased in the A172 after treatment with FAE, respectively, (p=0.0001), (p<0.0001), (p=0.0001), (p< 0.0001). The expression of Janus Quinase 1 (JAK1) and Janus Quinase 3 (JAK3) reduced after treatment (p<0.0001), (p=0.0178). Conclusion: FAE caused DNA damage, increased IFN-gama and reduced IL-6 expression. JAK1 and JAK3 expression was reduced, but the expression of Annexin A1, IKK, MDM2 and STAT3 increased, which suggests that STAT3 may have been induced by another signaling pathway.