Bartella Lucia, Mazzotti Fabio, Talarico Ines Rosita, De Luca Giuseppina, Santoro Ilaria, Prejanò Mario, Riccioni Costanza, Marino Tiziana, Di Donna Leonardo
QUASIORA Laboratory, AGRINFRA Research Net, Università Della Calabria, Via P. Bucci Cubo 12/D, I-87036 Arcavacata di Rende, CS, Italy.
Dipartimento di Chimica e Tecnologie Chimiche, Università Della Calabria, Via P. Bucci, Cubo 12/D, I-87030 Rende, CS, Italy.
Antioxidants (Basel). 2022 Sep 20;11(10):1847. doi: 10.3390/antiox11101847.
The structural characterization of a new flavonoid from bergamot fruit (Citrus bergamia Risso) carrying the 3-hydroxy-3-methyl glutaryl (HMG) ester moiety has been accomplished, and its antioxidant ability was tested from a chemical point of view. The peculiarity of the new molecule, named peripolin, relies on the presence of the HMG chemical group linked to the sugar portion of neoeriocitrin; the structure was elucidated using both high-resolution mass spectrometry and nuclear magnetic resonance experiments performed on the purified molecule extracted from the fruit. The antioxidant ability of the new molecule was tested by classical chemical approaches, such as DPPH, ABTS and FRAP assays, and from a theoretical point of view. H and C NMR experiments and HR-ESI-MS/MS experiments show unequivocally that the HMG moiety is linked to the primary position of the glucose unit of neohesperidose, while the chemical tests and the computational results show that peripolin possesses strong antioxidant behavior, similar to that of neoeriocitrin and remarkably higher respect to the other flavonoids present in the fruit. Furthermore, the quantitative assays carried out by UPLC-MS/MS showed that its amount in the fruit is similar to that of the other main flavonoids. Furthermore, molecular dynamics simulations allowed us to investigate the possible conformations adopted by the antioxidants in the presence of water molecules. In particular, the switch of open-closed conformations of HMG-containing species was evidenced. As far as the reaction with DPPH, the calculation of ΔG supported the experimental outcomes regarding the peripolin and neoeriocitrin activity. In conclusion, bergamot fruit, already known for its potential to lower the level of blood cholesterol, has been proven to contain molecules such as neoeriocitrin and the newly characterized peripolin, which could have important in-vivo antioxidant characteristics.
已完成对一种来自佛手柑果实（Citrus bergamia Risso）的新型黄酮类化合物的结构表征，该化合物带有3-羟基-3-甲基戊二酰（HMG）酯部分，并从化学角度测试了其抗氧化能力。这种名为peripolin的新分子的独特之处在于，HMG化学基团与新橙皮苷的糖部分相连；通过对从果实中提取的纯化分子进行高分辨率质谱和核磁共振实验来阐明其结构。通过经典化学方法，如DPPH、ABTS和FRAP测定法，并从理论角度测试了新分子的抗氧化能力。H和C NMR实验以及HR-ESI-MS/MS实验明确表明，HMG部分与新橙皮糖的葡萄糖单元的伯位相连，而化学测试和计算结果表明，peripolin具有很强的抗氧化行为，类似于新橙皮苷，并且相对于果实中存在的其他黄酮类化合物明显更高。此外，通过UPLC-MS/MS进行的定量分析表明，其在果实中的含量与其他主要黄酮类化合物相似。此外，分子动力学模拟使我们能够研究抗氧化剂在水分子存在下可能采取的构象。特别是，证实了含HMG物种的开闭构象的转换。就与DPPH的反应而言，ΔG的计算支持了关于peripolin和新橙皮苷活性的实验结果。总之，佛手柑果实因其降低血液胆固醇水平的潜力而闻名，已被证明含有新橙皮苷和新表征的peripolin等分子，它们可能具有重要的体内抗氧化特性。
