Bioprospecção da geoprópolis de Melipona fasciculata smith para descoberta de novos produtos bioativos

Abstract

The geopropolis of Melipona (Melikerria) fasciculata Smith has several biological activities such as antimicrobial, leishmanicidal, immunomodulatory, wound healing, antioxidant, anthelmintic and cytotoxic. However, there is a scarcity of studies on the antitumor action of M. fasciculata geopropolis. Thus, considering the pharmacological potential of geopropolis and the need for new therapeutic alternatives for cancer, this work aimed to evaluate the antioxidant, anti-inflammatory, acute toxicity, antitumor activity, identify the chemical composition of the hydroethanolic extract of geopropolis from M. fasciculata and perform in silico assay to determine which compounds are associated with bioactivity. The geopropolis samples were collected in the municipalities of Viana and Pinheiro in the state of Maranhão, submitted to extraction to obtain the hydroethanolic extracts of geopropolis and coded as EHGV and EHGP. The antioxidant action (DPPH, ABTS•+ e FRAP), the in vitro inhibition potential of the cyclooxygenase enzyme activity (COX-1 and COX-2), acute toxicity in Danio rerio and antitumor activity in ovarian cancer lines (A2780; ES2) and lung (A549; H460), through the assays were evaluated: MTT, for cell proliferation; flow cytometry analysis for cell cycle and western blotting for apoptosis analysis by expression of cleaved caspase-3 and cleaved PARP. The chemical composition was identified by liquid chromatography coupled to mass spectrometry, and these compounds were used in silico studies by molecular docking. From these results, three articles were prepared. In the first article are the results of the chemical profile of EHGV and EHGP that showed the predominant presence of compounds of the saponins, terpenes and steroids classes, in addition to the result of acute toxicity where the extracts showed low toxicity and lethal concentration above 450 𝜇g/mL to Danio rerio. In the second article, the results showed that the extract EHGV showed better antioxidant activity with IC50 values in DPPH (76.16 ± 1.05 μg/mL), FRAP (2.91 ± 0.12 mmol Fe2+/g) and ABTS•+ (13.28 ± 0, 11 μg/mL) and higher inhibition capacity for COX-2 (61%) with less than 5% inhibition of COX-1 at 50 µg/mL, indicating a higher affinity for the isoform involved in inflammatory processes and carcinogenesis. EHGV also showed higher cytotoxic effect to ovarian cancer strain A280 (GI50:16.92 𝜇g/mL), low cytotoxicity to normal cells (HUVEC) and induction of apoptosis through caspase-3 activation and PARP cleavage. In silico assays demonstrate that hydrolysable tannins, glycosylated flavonoids, and triterpenes identified in EHGV may be associated with anti-inflammatory and antitumor activities. In the third article, an integrative review of metabolic classes with antitumor action in ovarian cancer was presented to better understand and discuss the mechanisms of action involved. Therefore, the results derived from the thesis demonstrate for the first time that the geopropolis of M. fasciculata has cytotoxic activity in ovarian and lung cancer cell lines inducing apoptosis by activation of caspase 3, with low toxicity to non-malignant cell lines, highlighting the biotechnological potential of geopropolis in the development of new therapeutic agents.