Doctoral School, University of León (ULE), Campus de Vegazana, 24007 León, Spain.
Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, 5300-252 Bragança, Portugal.
Molecules. 2023 Jun 19;28(12):4847. doi: 10.3390/molecules28124847.
Propolis is a natural product produced by bees that contains a complex mixture of compounds, including phenolic compounds and flavonoids. These compounds contribute to its biological activities, such as antioxidant capacity. This study analysed the pollen profile, total phenolic content (TPC), antioxidant properties, and phenolic compound profile of four propolis samples from Portugal. The total phenolic compounds in the samples were determined by six different techniques: four different Folin-Ciocalteu (F-C) methods, spectrophotometry (SPECT), and voltammetry (SWV). Of the six methods, SPECT allowed the highest quantification, while SWV achieved the lowest. The mean TPC values for these methods were 422 ± 98 and 47 ± 11 mg GAE/g sample, respectively. Antioxidant capacity was determined by four different methods: DPPH, FRAP, original ferrocyanide (OFec), and modified ferrocyanide (MFec). The MFec method gave the highest antioxidant capacity for all samples, followed by the DPPH method. The study also investigated the correlation between TPC and antioxidant capacity with the presence of hydroxybenzoic acid (HBA), hydroxycinnamic acid (HCA), and flavonoids (FLAV) in propolis samples. The results showed that the concentrations of specific compounds in propolis samples can significantly impact their antioxidant capacity and TPC quantification. Analysis of the profile of phenolic compounds by the UHPLC-DAD-ESI-MS technique identified chrysin, caffeic acid isoprenyl ester, pinocembrin, galangin, pinobanksin-3--acetate, and caffeic acid phenyl ester as the major compounds in the four propolis samples. In conclusion, this study shows the importance of the choice of method for determining TPC and antioxidant activity in samples and the contribution of HBA and HCA content to their quantification.
蜂胶是蜜蜂产生的一种天然产物，含有复杂的化合物混合物，包括酚类化合物和类黄酮。这些化合物有助于其生物活性，如抗氧化能力。本研究分析了来自葡萄牙的四个蜂胶样本的花粉谱、总酚含量（TPC）、抗氧化性能和酚类化合物谱。通过六种不同的技术：四种不同的福林-肖卡尔特（F-C）方法、分光光度法（SPECT）和伏安法（SWV），确定了样品中的总酚含量。在这六种方法中，SPECT 允许最高的定量，而 SWV 实现了最低的定量。这些方法的平均 TPC 值分别为 422±98 和 47±11mgGAE/g 样品。抗氧化能力通过四种不同的方法确定：DPPH、FRAP、原始亚铁氰化物（OFec）和改良亚铁氰化物（MFec）。MFec 法对所有样本的抗氧化能力最高，其次是 DPPH 法。该研究还调查了 TPC 和抗氧化能力与蜂胶样本中羟基苯甲酸（HBA）、羟基肉桂酸（HCA）和类黄酮（FLAV）存在之间的相关性。结果表明，蜂胶样本中特定化合物的浓度可以显著影响其抗氧化能力和 TPC 定量。通过 UHPLC-DAD-ESI-MS 技术分析酚类化合物的谱图，确定了白杨素、咖啡酸异戊烯酯、乔松素、高良姜素、松柏素-3--乙酸酯和咖啡酸苯酯为四个蜂胶样本中的主要化合物。总之，本研究表明，在确定样品中 TPC 和抗氧化活性的方法选择以及 HBA 和 HCA 含量对其定量的贡献方面非常重要。
