葡萄牙棒孢酵母转化对陈皮提取物及抗氧化活性的影响

Effects of transformation of Clavispora lusitaniae CP-1 on the extract and antioxidant activity of Citri Reticulatae Pericarpium

以葡萄牙棒孢酵母(Clavispora lusitaniae CP-1,CP-1)为转化菌株,研究其对陈皮乙醇提取物总酚、总黄酮、主要黄酮类化合物和抗氧化活性的影响。采用高效液相色谱法测定主要黄酮类化合物含量,DPPH法、ABTS法、铁离子还原能力(Ferric reducing ability of plasma,FRAP)法和氧自由基吸收能力(Oxygen radical absorbance capacity,ORAC)法测量抗氧化活性,正交试验设计优化CP-1对橙皮苷的转化条件。结果表明,陈皮乙醇提取物经CP-1转化24 h之后,其总酚、总黄酮含量分别升高42.22%、9.46%;随着转化时间的延长,橙皮素含量升高7.52倍;柚皮素和橙皮素-7-O-葡萄糖苷含量在8 h达到最大值,之后便逐渐降低;芸香柚皮苷、橙皮苷、川陈皮素和橘皮素含量均逐渐降低,分别降低85.10%、88.86%、72.13%和81.82%。CP-1可将芸香柚皮苷、橙皮苷分别转化为柚皮素-7-O-葡萄糖苷和柚皮素、橙皮素-7-O-葡萄糖苷和橙皮素。参与转化的α-L-鼠李糖苷酶和β-D-葡萄糖苷酶主要存在于细胞内酶和细胞碎片中。CP-1亦可增强陈皮乙醇提取物的抗氧化活性,DPPH值、ABTS值和FRAP值分别提高20.66%、9.73%和9.84%,而ORAC值降低3.30%。以橙皮苷为底物建立CP-1的转化工艺,经过正交试验优化得到的最佳工艺条件为:pH 6.5,菌液浓度4.9×10^(9) CFU/mL,橙皮苷浓度2.5 mmol/L。该研究结果为研究微生物转化柑橘黄酮类化合物的作用机制提供理论基础,对于柑橘皮渣高值化利用具有重要意义。

The effects of Clavispora lusitaniae CP-1(CP-1)on total polyphenols(TPs),total flavonoids(TFs),main flavonoids and antioxidant activities of ethanol extracts from Citri Reticulatae Pericarpium(CRP)were studied.The contents of the main flavonoids were determined by HPLC.The antioxidant activity was measured by DPPH assay,ABTS assay,FRAP assay and ORAC assay.The transformation conditions of CP-1 on hesperidin were optimized by orthogonal design.The results showed that the contents of TPs and TFs increased by 42.22%and 9.46%,respectively,after CP-1 transformation for 24 h.With the extension of transformation time,hesperitin content increased 7.52 times.The contents of naringenin and hesperitin-7-O-glucoside reached the maximum value at 8 h,and then gradually decreased.The contents of narirutin,hesperidin,nobiletin and tangeretin were decreased by 85.10%,88.86%,72.13%,and 81.82%,respectively.α-L-rhamnosidase andβ-D-glucosidase involved in transformation mainly exist in intracellular enzymes and cell fragments.CP-1 also enhanced the antioxidant activity of ethanol extract of CRP,increasing DPPH value,ABTS value and FRAP value by 20.66%,9.73%,and 9.84%respectively,while decreasing ORAC value by 3.30%.The transformation condition of CP-1 on hesperidin was optimized.The optimal conditions were as follows:pH 6.5,yeast concentration 4.9×10^(9) CFU/mL and hesperidin concentration 2.5 mmol/L.The results of this study provide a theoretical basis for studying the mechanism of microbial transformation of citrus flavonoids,and have important significance for high-value utilization of citrus peel residues by-products.