Identification and quantification of antioxidant compounds in cowpea

ABSTRACT Dietary antioxidant compounds have been widely studied because of their ability to delay or inhibit oxidative damage, which allows them to play an important role in the prevention of diseases and the promotion of health. The identification and characterization of such compounds are required before their use in humans. This study aimed to identify and quantify antioxidant compounds in the cowpea cultivar, BRS Tumucumaque, and the cowpea strain, Pingo de Ouro 1-2, in view of their potential use in the development of new products with potent antioxidant activity. Here, we report the antioxidant activity and the phenolic compound content of the aforementioned cowpeas. The antioxidant extracts were analyzed by HPLC in a Shimadzu LC-20AT chromatograph model equipped with a manual injector using standard solutions of pure phenolic compounds, including gallic acid, quercetin, caffeic acid, chlorogenic acid, ferulic acid, . -coumaric acid, catechin, and epicatechin. Gallic acid was the phenolic compound with the highest level in both BRS Tumucumaque and Pingo de Ouro 1-2 (45.4 ± 2.66 and 93.4 ± 1.25 mg/100 g, respectively). Moreover, we identified and quantified catechin (5.67 ± 0.34 and 6.48 ± 0.51 mg/100 g, respectively), epicatechin (8.67 ± 0.47 and 2.95 ± 0.17 mg/100 g, respectively), ferulic acid (11.1 ± 1.42 and 13.8 ± 0.55 mg/100 g, respectively), and chlorogenic acid (2.39 ± 0.24 and 0.59 ± 0.28 mg/100 g, respectively). In contrast, caffeic acid was only identified in BRS Tumucumaque and quantified at 27.8 ± 2.99 mg/100 g. We conclude that Vigna unguiculata demonstrates functional potential, as both the strain and the cultivar contain antioxidant compounds that help in disease prevention and health maintenance.

【摘要】膳食抗氧化化合物因能够延缓或抑制氧化损伤，故而在疾病预防与健康促进中发挥重要作用，因此得到了广泛研究。在将此类化合物应用于人体之前，需对其进行鉴定与表征。本研究旨在对豇豆栽培品种BRS Tumucumaque与豇豆品系Pingo de Ouro 1-2中的抗氧化化合物进行鉴定与定量分析，以期开发具有强效抗氧化活性的新型产品。本研究报道了上述两种豇豆的抗氧化活性与酚类化合物含量。
采用配备手动进样器的岛津LC-20AT型色谱仪，通过高效液相色谱（High Performance Liquid Chromatography, HPLC）对抗氧化提取物进行分析，以纯酚类化合物标准溶液作为参照，包括没食子酸（gallic acid）、槲皮素（quercetin）、咖啡酸（caffeic acid）、绿原酸（chlorogenic acid）、阿魏酸（ferulic acid）、对香豆酸（p-coumaric acid）、儿茶素（catechin）及表儿茶素（epicatechin）。
分析结果显示，没食子酸为BRS Tumucumaque与Pingo de Ouro 1-2中含量最高的酚类化合物，其含量分别为45.4 ± 2.66 mg/100 g与93.4 ± 1.25 mg/100 g。此外，本研究还鉴定并定量了儿茶素、表儿茶素、阿魏酸及绿原酸，二者在两个样品中的含量分别为：儿茶素5.67 ± 0.34 mg/100 g与6.48 ± 0.51 mg/100 g，表儿茶素8.67 ± 0.47 mg/100 g与2.95 ± 0.17 mg/100 g，阿魏酸11.1 ± 1.42 mg/100 g与13.8 ± 0.55 mg/100 g，绿原酸2.39 ± 0.24 mg/100 g与0.59 ± 0.28 mg/100 g。相较而言，咖啡酸仅在BRS Tumucumaque中被检出，其定量含量为27.8 ± 2.99 mg/100 g。
本研究表明，豇豆（Vigna unguiculata）具备功能食品开发潜力，其两个品系/栽培品种均含有有助于疾病预防与健康维持的抗氧化化合物。