@PHDTHESIS{ 2023:307837355,
 	title = {METABOLOMIC STUDY OF EXTRACTS OF BRAZILIAN GEOPROPOLIS BY UHPLC-HRMS (ORBITRAP), 1H AND 13C NMR, AND GC-MS},
 	year = {2023},
 	url = "http://tede.unicentro.br:8080/jspui/handle/jspui/2152",
 	abstract = "The stingless bees (Meliponini) make propolis by mixing resins, waxes, and oils from 
 vegetal sources, with salivary secretions rich in enzymes. Small portions of soil particles 
 are added to the mixture to give geopropolis the needed consistence to be used as part of 
 many internal and external hive structures. In order to protect the colony from external 
 pathogens, geopropolis present diverse pharmacological effects, especially antibiotic, 
 antiviral, antifungal. Commonly in poor countries, communities of less assisted rural 
 workers, and indigenous people benefit from these characteristics of geopropolis. Its 
 chemical composition is complex and related to its geographic origin, which botanic 
 sources are available, and the species of the stingless bees. In general, geopropolis is rich 
 in flavonoids, phenolic compounds, phenylpropanoids, sugars, and lipids. Despite the 
 importance of this natural product, studies on geopropolis are still scarce and focused on 
 punctual characteristics, on few species, rather than on a broader approach on larger 
 numbers of species. The objective of this study was to employ metabolomics and 
 lipidomics approaches, through chromatographic hyphenated techniques, and NMR in 
 order to investigate the composition and possible biomarkers of geopropolis. Firstly, 
 ethanolic extracts of geopropolis (EEGs) from 14 species and two sub-species of 
 Brazilian stingless bees, from five Brazilian States (Paraná, Pernambuco, Maranhão, São 
 Paulo, and Sergipe) were made. Samples were given by local beekeepers. The EEGs were 
 kept in freezer until transported, at room temperature, to the Proteomics and 
 Metabolomics Facility at London Institute of Medical Sciences (Imperial College 
 London, campus Hammersmith), United Kingdom. The mass fingerprints of the EEGs
 were acquired using a high-resolution mass spectrometer (HRMS, Orbitrap), firstly by 
 direct flow injection technique (FIA) and analysed using multivariate analysis such as 
 PCA and HA. Also, possible correlations between the mass fingerprint data and total 
 flavonoid content (TFC) and antioxidant capacity in terms of quercetin equivalent
 (DPPH) and ascorbic acid equivalents (VCEAC) were assessed by PLS regression. After
 FIA, EEGs were injected into an UHPLC-HRMS and subsequent partition with water and 
 chloroform allowed the investigation of the CHCl3 lipidic rich fraction. The water-soluble
 fraction was derivatised and analysed by GC-MS. In this way, the potentialities of each 
 analytical technique were explored to make it possible a comprehensive analysis of 
 geopropolis. Using GC-MS identification was based on spectral data comparison with the 
 instrument internal library, also the calculated retention index. In the case of 
 UHPLC-HRMS compound annotation was based on sequential mass spectrometry 
 experiments and carried out by the Compound Discoverer V. 3.3 (Thermo) software, 
 using specialised local and online libraries. The composition analysis by UHPLC-HRMS
 and GC-MS revealed the presence of flavonoids, sugars, esters, terpenes, phenolics, 
 organic acids, and phenylpropanoids. The lipidomic analysis revealed the presence of 
 fatty acids, fatty acyls, phenolic lipids, steroids, and resorcinols. Exploratory multivariate 
 analysis indicated that bee species and genus strongly affect the chemical composition of 
 geopropolis as well as the geographical origin. The extension of the later factor depends 
 on the bee specie. On one hand, it was observed that geopropolis from Tetragonisca 
 angustula have similar chemical composition regardless of geographical origin indicating 
 that this bee gathers similar vegetal resins throughout Brazil to make its propolis. On the 
 other hand, Melipona quadrifasciata and Melipona marginata seen to have generalist
 collection patterns as their geopropolis have a more variable composition depending on 
 the geographical origin. NMR analysis of the CDCl3 extract (CEG) of geopropolis allowed 
 confirmation of chemical classes already identified by chromatography hyphenated techniques 
 and also corroborated the importance of bee species and geographical origin on the chemical 
 composition of geopropolis. Finally, the application of PLS models to FIA mass fingerprints, using less than 3 latent variables, produced accurate models with low values for the errors of calibration and 
 prediction (RMSEC < 0.79 mg.g-1; RMSECV < 2.662 mg.g-1; RMSEP < 1,0448 mg.g-1). 
 Additionally, acceptable determination coefficients (0.6613 < R² < 0.8815) indicated that 
 mass fingerprints accurately estimate TFC and antioxidant capacity of geopropolis.",
 	publisher = {Universidade Estadual do Centro-Oeste},
 	scholl = {Programa de Pós-Graduação em Química (Doutorado)},
 	note = {Unicentro::Departamento de Ciências Exatas e de Tecnologia}
}