Avaliação dos efeitos biológicos da geoprópolis produzida por Melipona seminigra pernigra na quimioprevenção aos danos induzidos ao DNA in vitro

Abstract

The identification of natural products with biological activities in combination with the effect of therapeutic agents can be an alternative for the treatment of some diseases, including cancer. Geopropolis, extracted from native stingless bees or stingless bees, is a natural compound widely used by the traditional population for therapeutic purposes, but with few studies in the literature. Due to the antioxidant and anticarcinogenic action of geopropolis from native bees, the proposed study evaluated the biological effects of geopropolis from the subspecies Melipona seminigra pernigra through cytotoxicity and genototoxicity assays in in vitro tests. Cultures of African green monkey kidney fibroblast cells (VERO E6) were used for cytotoxicity assessment and Chinese hamster ovary cells (CHO-K1) for genotoxicity assays with the ethanolic extract of M. seminigra pernigra geopropolis collected from the experimental Meliponary of UFMT – Campus Sinop. For the evaluation of the in vitro cytotoxic activity, the cell viability test by exclusion with trypan blue was used, in which the VERO E6 and CHO-K1 cells were treated with concentrations of 5000 to 50 µg/mL of geopropolis ethanolic extract for 3 hours and the viability was checked in a Neubauer chamber, that is, non-viable cells are stained blue and the test was performed in triplicate. The evaluation of the genotoxic potential was carried out using the in vitro micronucleus test, with pretreatment with the ethanolic extract of geopropolis (50 µg/mL) in CHO-K1 cells. For statistical analysis, the chi-square test was used (significance value of p < 0.05) for the frequency of micronucleated cells. The results indicate that the ethanolic extract of M. seminigra pernigra geopropolis was cytotoxic when used at higher concentrations (5,000, 2,500 and 1,000 μg/mL), with no possibility of cell proliferation in both VERO E6 and CHO-K1 cell cultures, in the conditions fulfilled. On the other hand, at lower concentrations there was cell proliferation, with a better result at a concentration of 50 µg/mL of geopropolis ethanolic extract. In the antigenototoxicity assays, a significant decrease of micronuclei was observed in CHO-K1 cells treated with geopropolis and the mutagenic agent methylmetasulfonate (MMS), when compared with the positive control, indicating a chemoprotective effect of the ethanolic extract. However, the treatment with only the ethanolic extract of geopropolis showed an increase in micronuclei when compared with the negative control, indicating a genotoxic potential of the ethanolic extract. In view of the results obtained, under the conditions carried out, the study suggests that the ethanolic extract of geopropolis of M. seminigra pernigra has a chemoprotective effect against cancer and without cytotoxic potential at low concentrations, but has compounds with possible genotoxic action, emphasizing the importance of some precautions for the indiscriminate therapeutic use of geopropolis in the alternative treatment of diseases.