CONTRIBUIÇÃO PARA O CONHECIMENTO DA COMPOSIÇÃO QUÍMICA E PROPRIEDADES BIOLÓGICAS DA PRÓPOLIS DE MATO GROSSO DO SUL: BUSCA DE ATIVOS ANTITUMORAIS, ANTIMICROBIANOS EM UMA AMOSTRA DA REGIÃO DE MATA ATLÂNTICA

Abstract

Propolis, a resinous material produced mainly by bees of the species Apis mellifera L., has a complex chemical composition, reflecting the biodiversity of the flora of the region where it is produced. It is known to have several biological properties, including antitumor and antimicrobial activities, among others. Considering the great plant diversity found in the biomes of Mato Grosso do Sul, the propolis produced in the state becomes, therefore, an important source of substances with pharmacological potential. As part of our continuing research on the bioactive constituents in propolis samples produced in different regions of Mato Grosso do Sul, a sample from the Atlantic Forest region stood out for its cytotoxicity against breast and prostate carcinoma cell lines, with a good selectivity index. The material was extracted with 95% EtOH and subsequently subjected to successive partitions with hexane, CH2Cl2 and AcOEt. The determination of the total phenol content present in the extract and its corresponding phases was performed according to the Folin-Ciocalteau method and the results ranged from 43.73 to 67.29 mg of EAG. The evaluation of the antioxidant potential using the stable radical DPPH provided IC50 values in the range of 40.56 to 73.76 µg/mL GAE/g. The phases resulting from partitioning of the EtOH extract were also submitted to cytotoxicity assays, with the CH2Cl2 phase being the most active, with an IC50 ranging from 24.6 to 26.8 µg/mL against breast, prostate and kidney neoplastic cells. When evaluated for their mutagenic potential in the SMART assay on wing cells of Drosophila melanogaster, using ST and HB crosses, neither the EtOH extract nor its corresponding phases proved mutagenic to the offspring of ST and HB crosses at the concentrations tested. The antibacterial and antibiofilm potential of the EtOH extract and phases was also evaluated against Gram positive Staphilococcus aureus and Gram negative Pseudomonas aeruginosa. The crude extract inhibited bacterial growth of S. aureus and P. aeruginosa at a concentration of 2.0 mg/mL and inhibited biofilm formation against S. aureus at a concentration of 0.1 mg/mL. The CH2Cl2 phase inhibited the growth of P. aeruginosa at a concentration of 0.5 mg/mL, similar to the antibiotic gentamicin. The EtOAc and hydromethanolic phases inhibited biofilm formation against P. aeruginosa at a concentration of 0.5 mg/mL and the EtOAc phase also inhibited the biofilm formation against S. aureus at a concentration of 0.1 mg/mL. After successive chromatographic separation procedures using silica gel 70-230 and 230-400 mesh and Sephadex® LH-20 column chromatography, two isoflavones (biochanin A and pratensein), a flavone (kaempferide), a flavonol (Kaempferol), three coumaric acid derivatives (artepillin C, 2,2-dimethylchromene-6-propenoic acid and 2-phenylethyl p-coumaroate), a triterpenoid (3β-20-dihydroxylupane) and 3-(4-cumaroyl-2-hidroxy-3-methyl)-butyl-coumaric. The hexane phase was also fractionated in a similar way, originating the triterpenoids lupeol and cabraleone. The structural determination of the substances was performed based on 1H and 13C NMR spectroscopic data and by comparison with literature data. 3-(4-cumaroyl-2-hidroxy-3-methyl)-butyl-coumaric acid is a new compound, while the triterpenoids cabraleone and 3β-20-di-hydroxylupane are being reported for the first time in propolis. Pratensein, biochanin A, kaempferol and kaempferide have already been reported in Brazilian propolis and in Cuban, Egyptian and Turkish propolis. The results so far obtained expand the knowledge of the chemical composition of propolis produced in the Midwest region, as well as indicate that the compounds obtained particularly from the CH2Cl2 phase may contribute to the antiproliferative activity presented by the ethanol EtOH of this propolis sample.