CITAB, Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Minho, Braga, Portugal; Department of Biology, School of Sciences, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.
CITAB, Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Minho, Braga, Portugal; Department of Biology, School of Sciences, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal; CEB - Centre of Biological Engineering, University of Minho, Braga 4710-057, Portugal; CBMA - Centre of Molecular and Environmental Biology, University of Minho, Braga 4710-057, Portugal.
Food Res Int. 2019 May;119:622-633. doi: 10.1016/j.foodres.2018.10.040. Epub 2018 Oct 11.
Natural products, like propolis, have been subject of interest by several industries mainly due to their biological activities. However, besides being produced in low amounts propolis has a great variability in terms of chemical composition and bioactivities' profiles, constituting a problem for the development of propolis-based products and for its acceptance by the medical community. The aim of this work relates to the study of the bioactivities, in particular the antioxidant and the antimicrobial properties, as well as the chemical characterization of Portuguese propolis samples collected in an apiary sited at Gerês (G) along four consecutive years. Ethanol extracts of the four propolis samples (G.EEs) display antimicrobial activity, especially against Gram-positive spore forming bacteria. Antioxidant activity, evaluated by three different in vitro assays, was confirmed in vivo by flow cytometry using Saccharomyces cerevisiae as eukaryotic cell model. Cells incubated with G.EEs prior to HO incubation, or incubated with G.EEs and HO simultaneously, display higher viability than cells incubated only with HO, suggesting that G.EEs protect yeast cells against induced oxidative stress. All tested propolis samples exhibit very similar antimicrobial and antioxidant activities. Chemical analysis of G.EEs revealed no significant differences in terms of phenolic profiles, namely in the compounds to which propolis bioactivities are ascribed, thus supporting the more constant behavior evidenced by these propolis samples. This work highlights the valuable properties of this bee product and reveals a constancy of bioactivities in a Portuguese propolis sample over four years, raising awareness to the potentialities of this natural product often regarded as a beekeeping waste.
天然产物，如蜂胶，一直是多个行业关注的焦点，主要是因为它们具有生物活性。然而，除了产量低之外，蜂胶在化学成分和生物活性谱方面也存在很大的变异性，这给蜂胶产品的开发和医学界的认可带来了问题。这项工作的目的是研究生物活性，特别是抗氧化和抗菌特性，以及收集于盖雷斯（G）养蜂场的四年间的四个葡萄牙蜂胶样本的化学特征。四个蜂胶样本的乙醇提取物（G.EEs）显示出抗菌活性，特别是对革兰氏阳性孢子形成细菌。三种不同的体外测定法证实了抗氧化活性，通过使用酿酒酵母作为真核细胞模型的体内流式细胞术进行了验证。与仅用 HO 孵育的细胞相比，先用 G.EEs 孵育然后用 HO 孵育的细胞，或同时用 G.EEs 和 HO 孵育的细胞，显示出更高的活力，这表明 G.EEs 可保护酵母细胞免受诱导的氧化应激。所有测试的蜂胶样本均表现出非常相似的抗菌和抗氧化活性。G.EEs 的化学分析在酚类谱方面没有显示出显著差异，即与蜂胶生物活性相关的化合物，这支持了这些蜂胶样本表现出的更稳定的行为。这项工作突出了这种蜜蜂产品的有价值的特性，并揭示了葡萄牙蜂胶样本在四年内的生物活性的稳定性，提高了对这种天然产物的潜力的认识，这种天然产物通常被视为养蜂的废物。
