Investigação de geoprópolis produzida por Melipona scutellaris: procedimentos de extração, análise polínica e estudo antimicrobiano in silico e in vitro

Abstract

The geopropolis produced by the stingless bee Melipona scutellaris is a product of the mixture of plant resins, wax, and clay. Studies show its anti-inflammatory, antimicrobial, and antioxidant potential. This work aims to identify the appropriate conditions for the extraction system and the collection period of geopropolis, as well as to identify the main chemical compounds and subject them to in silico and in vitro antimicrobial evaluation. This thesis is organized into three chapters. In the first chapter, the results of the study on the influence of extraction methods (maceration, ultrasound, reflux, Soxhlet, and supercritical fluid) on the yield, chemical composition, and biological activity of the geopropolis collected in Cruz das Almas, BA, are presented. The extraction yields varied from 7.37 ± 0.40% to 15.67 ± 3.45%. The total phenolic and flavonoid contents were determined using spectrophotometric techniques, with phenolic values ranging from 16.57 ± 0.87 to 19.16 ± 0.11 mg EAG/100g, while flavonoid values varied from 1.61 ± 0.26 to 2.14 ± 0.34 mg QE/100g. The antioxidant potential of the extracts was assessed using the radicals 1,1- diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), with values ranging from 7.09 ± 0.32 to 10.88 ± 0.41 (μg/mL) for DPPH and from 2.14 ± 0.34 to 7.43 ± 1.33 (µM/Trolox g) for ABTS. To evaluate the minimum inhibitory concentration, the microorganisms Staphylococcus aureus, Streptococcus mutans, and Streptococcus mitis were used. The antimicrobial potential values ranged from 0.24 ± 0.01 to 1.96 ± 0.07 mg/mL. Chapter 1 also shows the influence of extraction methods on the chemical composition of the geopropolis collected in Cruz das Almas, BA. The geopropolis was subjected to extraction by maceration, ultrasound, reflux, Soxhlet, and supercritical fluid. The comparison of the extracts was conducted through the identification and quantification of compounds using high-performance liquid chromatography (HPLC-DAD). Chapter 2 presents the in silico study of the antimicrobial activity of the compounds identified and quantified in the geopropolis from Cruz das Almas, BA. The results show that ellagic acid, identified in the extract, stood out as a potential inhibitor of the enzyme lactate dehydrogenase (LDH). Chapter 3 consists of the palynological diagnosis of the geopropolis collected in the municipality of Mata de São João, BA. The palynological profile was determined through the analysis of pollen present in the geopropolis collected over the 12 months of the year 2021. A total of 84 pollen types were found, distributed across 31 botanical families. For the analysis of the influence of the collection period, parameters such as the yield of the resinous part, phenolic content, flavonoids, and chemical profile were used. The extraction yields obtained during different collection months (January to December) varied from 8.04 ± 0.19% to 19.16 ± 0.92%. Using spectrophotometric techniques, total phenolic concentrations were determined to be between 3.20 ± 0.19 mg EAG/100g and 1.12 ± 0.01 to 3.08 ± 0.06 mg QE/100g for total flavonoids. The collection period influenced the chemical composition obtained through HPLC-DAD. The results obtained allow for the standardization of geopropolis extracts and provide scientific data that demonstrate the relevance of using geopropolis. Thus, it is possible to add scientific, environmental, and economic value, reaching various sectors of society, such as farmers, meliponiculturists, and researchers. Furthermore, the data provide unprecedented information about the extraction of geopropolis using conventional and non-conventional methods.