Search

Propolis has gained wide popularity over the last decades in several parts of the world. In parallel, the literature about propolis composition and biological properties increased markedly. A great number of papers have demonstrated that propolis from different parts of the world is composed mainly of phenolic substances, frequently flavonoids, derived from plant resins. Propolis has a relevant role in increasing the social immunity of bee hives. Experimental evidence indicates that propolis and its components have activity against bacteria, fungi, and viruses. Mechanisms of action on bacteria, fungi, and viruses are known for several propolis components. Experiments have shown that propolis may act synergistically with antibiotics, antifungals, and antivirus drugs, permitting the administration of lower doses of drugs and higher antimicrobial effects. The current trend of growing resistance of microbial pathogens to the available drugs has encouraged the introduction of propolis in therapy against infectious diseases. Because propolis composition is widely variable, standardized propolis extracts have been produced. Successful clinical trials have included propolis extracts as medicine in dentistry and as an adjuvant in the treatment of patients against COVID-19. Present world health conditions encourage initiatives toward the spread of the niche of propolis, not only as traditional and alternative medicine but also as a relevant protagonist in anti-infectious therapy. Production of propolis and other apiary products is environmentally friendly and may contribute to alleviating the current crisis of the decline of bee populations. Propolis production has had social-economic relevance in Brazil, providing benefits to underprivileged people.

Numerous papers have shown that propolis contributes favorably to worker honey bee (Apis mellifera L.) immune response and colony social immunity. Moreover, resin-foraging specialists are more sensitive than pollen foragers to tactile information in the nest interior, and they respond to these stimuli by collecting more resin. In this study, we show that in-hive propolis deposition is increased, compared with nonmodified controls, with any one of the three methods for increasing textural complexity of hive wall interior surfaces: 1) plastic propolis trap material stapled to wall interior, 2) parallel saw kerfs cut into wall interior, or 3) roughening wall interior with a mechanized wire brush. Pairwise comparisons showed that propolis deposition was not significantly different among the three textural treatments; however, textural treatments interacted with time to show a more consistent benefit from plastic propolis trap material or roughened interior surface over saw kerfs. Although direct health benefits were not measured, this work shows that it is comparatively simple to increase propolis deposition above background levels by increasing textural stimuli in hive interiors., (© The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Honey bees, Apis mellifera , collect antimicrobial plant resins from the environment and deposit them in their nests as propolis. This behavior is of practical concern to beekeepers since the presence of propolis in the hive has a variety of benefits, including the suppression of disease symptoms. To connect the benefits that bees derive from propolis with particular resinous plants, we determined the identity and botanical origin of propolis compounds active against bee pathogens using bioassay-guided fractionation against the bacterium Paenibacillus larvae , the causative agent of American foulbrood. Eleven dihydroflavonols were isolated from propolis collected in Fallon, NV, including pinobanksin-3-octanoate. This hitherto unknown derivative and five other 3-acyl-dihydroflavonols showed inhibitory activity against both P. larvae (IC 50 = 17–68 μM) and Ascosphaera apis (IC 50 = 8–23 μM), the fungal agent of chalkbrood. A structure-activity relationship between acyl group size and antimicrobial activity was found, with longer acyl groups increasing activity against P. larvae and shorter acyl groups increasing activity against A. apis . Finally, it was determined that the isolated 3-acyl-dihydroflavonols originated from Populus fremontii , and further analysis showed these compounds can also be found in other North American Populus spp. [ABSTRACT FROM AUTHOR]

Extensive employment of plant resins and propolis, as an antiseptic agents dating from ancient times in numerous cultures indicating that it may have antimicrobial and other biological properties. Resins from deciduous trees from the Populus and Salix genera, several fruit trees from the genus Prunus and a few other species were analyzed for their phenolic composition and antibacterial activity. Phenolic profiling of the plant resins was performed by high-performance thin-layer chromatography (HPTLC) and ultra-high-performance liquid chromatography (UHPLC) coupled with hybrid mass spectrometry. Antimicrobial activity against seven bacterial species was determined by minimum inhibitory concentration (MIC) assays and bioautography. The synergism, additivism, and antagonism of phenolic compounds were used to define the nature and type of interactions. Populus spp. showed higher amounts of p -hydroxybenzoic acid, p -coumaric acid, caffeic acid, chrysin, apigenin, quercetin, pinocembrin, pinobanksin and galangin, which confirmed the botanical origin of the orange and blue types of propolis. In addition, Gram-positive bacteria exhibited high susceptibility to poplar samples while being resistant to samples from other origins. Cherry bud samples had high amounts of naringenin and showed strong activity against Bacillus subtilis and Listeria monocytogenes . The combinations of tested phenolics showed mainly additive or indifferent effects. [ABSTRACT FROM AUTHOR]