In order to compare the differences in polyphenolic compounds of colored onions, polyphenol metabolite compositions and their differences in three different colored onion bulbs (purple, white, and yellow) were analyzed by ultra-high performance liquid chromatography-tandem mass spectrometry widely targeted metabolomics coupled with multivariate statistical methods.The results showed that a total of 528 polyphenolic metabolites were identified in three colored onions, mainly including flavonoids, phenolic acids, lignans, coumarins and other components.The relative content of flavonoids was the highest in yellow onions (92.1%) and the lowest in white onions (60.32%);the content of phenolic acids was the highest in white onions (35.72%) and the lowest in yellow onions (6.34%);the content of lignans and coumarins was the highest in white onions (3.37%) and the lowest in yellow onions (1.18%).Principal component analysis showed that the variance contributions of PC1 and PC2 were 46.43% and 22.06%, respectively, with a cumulative contribution of 68.49%, suggesting that it was possible to achieve differentiation of colored onions by polyphenol metabolites.Orthogonal partial least squares discriminant analysis showed that the sample points of the three onion species were well separated, intuitively indicating significant differences in their metabolic profiles.A total of 115 differential metabolites (1,3,6-trihydroxy-2,5,7-trimethoxy-9-anthracenone, 1-O-feruloylquinic acid, 5′-methoxyisolarchitol-9′-O-glucoside, and others) were screened at multiplicity of difference≥2 or≤0.5, variable importance in projection≥1, and P<0.05.KEGG pathway analysis suggested that anthocyanin biosynthesis, biosynthesis of various plant secondary metabolites and tyrosine metabolism were the core pathways driving the differences.These results reveal a comprehensive polyphenol signature profile among colored onion varieties and provide a scientific basis for developing their phytochemical composition.
[1] TESHIKA J D, ZAKARIYYAH A M, ZAYNAB T, et al.Traditional and modern uses of onion bulb (Allium cepa L.):A systematic review[J].Critical Reviews in Food Science and Nutrition, 2019, 59(sup1):S39-S70.
[2] 曹颖, 张子毓, 戴杨帆, 等.响应面法优化洋葱中多酚的提取工艺研究[J].杭州师范大学学报(自然科学版), 2023, 22(1):52-57.
CAO Y, ZHANG Z Y, DAI Y F, et al.Optimization of the extraction process of polyphenol from onion by response surface methodology[J].Journal of Hangzhou Normal University (Natural Science Edition), 2023, 22(1):52-57.
[3] 唐瑶, 陈洋, 曹婉鑫.多酚类化合物的分类、来源及功能研究进展[J].中国食物与营养, 2016, 22(3):32-34.
TANG Y, CHEN Y, CAO W X.Research progress in classification, origin and function of polyphenols[J].Food and Nutrition in China, 2016, 22(3):32-34.
[4] 曹艳华, 程丽丽, 张小芳.响应面法优化洋葱多酚的提取工艺及抗氧化性研究[J].食品研究与开发, 2020, 41(12):164-170.
CAO Y H, CHENG L L, ZHANG X F.Study on extraction of polyphenol from onion by response surface methods and antioxidant activity[J].Food Research and Development, 2020, 41(12):164-170.
[5] METRANI R, SINGH J, ACHARYA P, et al.Comparative metabolomics profiling of polyphenols, nutrients and antioxidant activities of two red onion (Allium cepa L.) cultivars[J].Plants, 2020, 9(9):1077.
[6] MITROVÁ K, HRBEK V, SVOBODA P, et al.Antioxidant activity, S-alk(en)yl-l-cysteine sulfoxide and polyphenol content in onion (Allium cepa L.) cultivars are associated with their genetic background[J].Czech Journal of Food Sciences, 2016, 34(2):127-132.
[7] 曾雷, 陈颖乐, 王颂, 等.基于UPLC-MS/MS广泛靶向代谢组学分析野生竹叶榕不同部位代谢物差异[J].亚热带植物科学, 2025, 54(2):144-157.
ZENG L, CHEN Y L, WANG S, et al.Metabolite differences in different parts of wild Ficus stenophylla based on widely targeted metabolomics combined with UPLC-MS/MS[J].Subtropical Plant Science, 2025, 54(2):144-157.
[8] ARKORFUL E, YU Y, CHEN C S, et al.Untargeted metabolomic analysis using UPLC-MS/MS identifies metabolites involved in shoot growth and development in pruned tea plants (Camellia sinensis (L.) O.Kuntz)[J].Scientia Horticulturae, 2020, 264:109164.
[9] SUN Y L, YANG Y, ZHOU M C, et al.Widely targeted metabolic profiling reveals differences in polyphenolic metabolites during Rosa xanthina f.spontanea fruit development and ripening[J].Metabolites, 2022, 12(5):438.
[10] 王蓉, 曾文锦, 刘盼, 等.顶空固相微萃取结合气相色谱-质谱联用法对3种洋葱挥发性风味成分的分析[J].食品工业科技, 2022, 43(2):319-327.
WANG R, ZENG W J, LIU P, et al.Analysis of volatile flavor components in three onion by headspace solid phase microextraction combined with gas chromatography-mass spectrometry[J].Science and Technology of Food Industry, 2022, 43(2):319-327.
[11] 景仁, 马驰.“酒泉洋葱”申请地理标志产品保护[N].酒泉日报, 2010-11-16.
JING R, MA C.Jiuquan onions apply for geographical indication product protection[N].Jiuquan Daily, 2010-11-16.
[12] CHENG K Q, XIAO J Z, HE J Y, et al.Unraveling volatile metabolites in pigmented onion (Allium cepa L.) bulbs through HS-SPME/GC-MS-based metabolomics and machine learning[J].Frontiers in Nutrition, 2025, 12:1582576.
[13] JIN W G, ZHAO S B, CHEN X H, et al.Characterization of flavor volatiles in raw and cooked pigmented onion (Allium cepa L) bulbs:A comparative HS-GC-IMS fingerprinting study[J].Current Research in Food Science, 2024, 8:100781.
[14] DÜLGER ALTINER D, YıKMış S, BOZGEYI\U0307K E, et al.Thermosonication as a novel processing technique to enhance phenolic content, amino acids, and health-promoting activities of white onion juice[J].ACS Omega, 2025, 10(23):25051-25067.
[15] ABOTALEB M, LISKOVA A, KUBATKA P, et al.Therapeutic potential of plant phenolic acids in the treatment of cancer[J].Biomolecules, 2020, 10(2):221.
[16] SÁNCHEZ M, ROMERO M, GÓMEZ-GUZMÁN M, et al.Cardiovascular effects of flavonoids[J].Current Medicinal Chemistry, 2019, 26(39):6991-7034.
[17] TAO H, LI L Y, HE Y Q, et al.Flavonoids in vegetables:Improvement of dietary flavonoids by metabolic engineering to promote health[J].Critical Reviews in Food Science and Nutrition, 2024, 64(11):3220-3234.
[18] LI Q L, WANG Y H, MAI Y X, et al.Health benefits of the flavonoids from onion:Constituents and their pronounced antioxidant and anti-neuroinflammatory capacities[J].Journal of Agricultural and Food Chemistry, 2020, 68(3):799-807.
[19] LACHMAN J, PRONĚK D, HEJTMÁNKOVÁ A, et al.Total polyphenol and main flavonoid antioxidants in different onion (Allium cepa L.) varieties[J].Horticultural Science, 2003, 30(4):142-147.
[20] KANG C D, ZHANG Y Y, ZHANG M Y, et al.Screening of specific quantitative peptides of beef by LC-MS/MS coupled with OPLS-DA[J].Food Chemistry, 2022, 387:132932.
[21] ESPINO N, GALIETTA G, VODANOVICH A, et al.Onion skin (Allium cepa L.) of three Landrace varieties produced in Uruguay:Minerals and fatty acids composition, phytochemical compounds, in vitro antioxidant and anti-inflammatory properties[J].Food Bioscience, 2025, 71:107112.
[22] KANEHISA M, FURUMICHI M, SATO Y, et al.KEGG for taxonomy-based analysis of pathways and genomes[J].Nucleic Acids Research, 2023, 51(D1):D587-D592.
[23] LIM I, HA J.Biosynthetic pathway of proanthocyanidins in major cash crops[J].Plants, 2021, 10(9):1792.
[24] SCHENCK C A, MAEDA H A.Tyrosine biosynthesis, metabolism, and catabolism in plants[J].Phytochemistry, 2018, 149:82-102.
