A Bioguided Approach for the Screening of Antibacterial Compounds Isolated From the Hydroalcoholic Extract of the Native Brazilian Bee's Propolis Using Mollicutes as a Model

• Published in: Frontiers in microbiology Vol. 11; p. 558
• Main Authors: Hochheim, Sabrina, Pacassa Borges, Pamela, Boeder, Ariela Maína, Scharf, Dilamara Riva, Simionatto, Edésio Luiz, Yamanaka, Celina Noriko, Alberton, Michele D, Guedes, Alessandro, de Cordova, Caio Mauricio Mendes
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 07-04-2020
• Subjects: antimicrobials; bioguided fractioning; Brazilian native bees; Microbiology; mollicutes; mycoplasmas; propolis; Brazilian native bees; propolis; mollicutes; antimicrobials; mycoplasmas; bioguided fractioning
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2020.00558

Nature is a vast source of medicinal substances, including propolis, which has been extensively investigated. Propolis is a resinous substance produced by bees from the exudates of plants that they collect and modify in their jaws; it is a rich and complex matrix with secondary metabolites of diverse botanical origins. The objective of this study was to apply an
bioguided approach using as a model system the mollicutes with a sample of propolis from the Brazilian native bee
(mandaçaia) in order to identify potential new molecules with antimicrobial activity. A crude hydroalcoholic extract was obtained and submitted to liquid-liquid partitioning with solvents of different polarities, generating four different fractions: aqueous, dichloromethane, butanol, and ethyl acetate fractions. The antimollicute activity assays served as a basis for the bioguided fractionation. The dichloromethane fraction was the most promising, exhibiting a minimal inhibitory concentration (MIC) of 125 μg/mL against
. After purification by column liquid chromatography, a subfraction presenting MIC of 15.6 μg/mL against
was highlighted. The fractions were also tested against
,
, and
. Using gas chromatography coupled to a mass spectrometer (GC-MS), several volatile compounds were identified in the non-polar fractions of this propolis. However, the more purified molecules had no better antimollicute activity than their original subfraction. Apparently, the synergism among its compounds is largely responsible for the antibacterial activity of the propolis of this native Brazilian bee.