Browsing by Author "Jorquera, Bairon"

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    Exudate and Propolis from Escallonia pulverulenta: Phytochemical Characterization and Antibacterial Activity
    (2024) Jorquera, Bairon; Valenzuela-Barra, Gabriela; Mayorga, Ailin; Mejia, Jessica; Nunez, Gabriel; Gomez, Miguel; Montenegro, Gloria; Quezada, Waleska E. Vera; Echeverria, Javier; de Camargo, Adriano Costa; von Poser, Gilsane Lino; Bridi, Raquel
    Propolis is a complex mixture formed from exudates that bees collect from plants and then mix with beeswax and their own salivary enzymes. Chilean propolis is characterized by the presence of phenolic compounds, which are considered responsible for the biological activities. The endemic species Escallonia pulverulenta (Ruiz and Pav.) Pers. [Escalloniaceae] is a recognized source of exudate to produce propolis. This study reports for the first time the chemical profile and antibacterial activity of E. pulverulenta exudate and leaves, as well as two samples of Chilean propolis. Palynological and morphological analysis showed the presence of E. pulverulenta as one of the main species in the propolis samples. UPLC-MS/MS analyses enabled the identification of phenolic acids in the leaves and in the propolis. Conversely, flavonoids are mainly present in exudates and propolis. Quercetin is the most abundant flavonol in the exudate, with similar concentrations in the propolis samples. Nevertheless, the main compound present in both samples of propolis was the flavanone pinocembrin. The antibacterial results obtained for exudate and propolis have shown a similar behavior, especially in the inhibition of Streptococcus pyogenes. These results show the importance of the exudates collected by the bees in the chemical composition and antibacterial capacity of propolis.
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    Phenolics from Chilean Bee Bread Exhibit Antioxidant and Antibacterial Properties: The First Prospective Study
    (2023) Jorquera, Bairon; Mayorga, Ailin; Quintero-Pertuz, Helena; Mejia, Jessica; Nunez, Gabriel; Nunez Pizarro, Paula; Arias-Sante, Maria Fernanda; Montenegro, Gloria; de Camargo, Adriano Costa; Bridi, Raquel
    Bee bread (BB) is a beehive product generated upon fermentation of pollen combined with flower nectar and glandular secretions. The potential application of BB is related to its nutritional and functional components, including phenolic compounds. This is the first prospective study on palynological parameters, phenolics, antioxidant, and antibacterial activity of Chilean bee bread in vitro. The tested material exhibited high levels of phenolics (1340 & PLUSMN;186 mg GAE/100 g BB) and showed antioxidant capacity as determined by the FRAP (51 & PLUSMN;2 & mu;mol Trolox equivalent/g BB) and ORAC-FL (643 & PLUSMN;64 & mu;mol Trolox equivalent/g BB) and antibacterial activity against Streptococcus pyogenes. Furthermore, the phenolic acids and flavonoids was determined using liquid chromatography-mass spectrometry, and the concentration was determined using liquid chromatography with diode array detection. Kaempferol, quercetin, ferulic acid, and rutin were the main phenolics found. This study demonstrates the bioactive potential of Chilean BB and supports the evidence that this bee product is a promising source of antioxidants and antimicrobial compounds.