Khalil Noha, Gad Haidy A, Al Musayeib Nawal M, Bishr Mokhtar, Ashour Mohamed L
Department of Pharmacognosy and Medicinal Plants, Faculty of Pharmacy, Future University in Egypt, Cairo 11835, Egypt.
Department of Pharmacognosy, Faculty of Pharmacy, Ain-Shams University, Cairo 11566, Egypt.
Plants (Basel). 2022 Apr 20;11(9):1116. doi: 10.3390/plants11091116.
Brassicaceae comprises various species representing an economically important source of industrial or pharmaceutical crops. The present study aimed to identify glucosinolates (GSLs) and volatile compounds in six Brassicaceae seeds cultivated in Egypt. An (High Performance Liquid Chromatography-Photodiode Array) HPLC-PDA analysis of GSLs in the alcoholic extracts of L. (Rr), L. (Rs), var. L. (Boc), var. L. (Bob), L. (Br), and L. (Es) was carried out using a mixture of 23 standard GSLs. Nineteen GSLs were detected in the studied seeds. Rs had the highest GSL content (135.66 μmol/g Dry weight, DW), while Boc had the lowest GSL content (93.66 μmol/g DW). Glucobrassicin was the major identified compound in Rr, Rs, and Bob. Its highest content was in Rs (28.96 μmol/g DW). Sinigrin was the major identified GSL in Boc (18.02 μmol/g DW), although present with higher content in Bob (22.02 μmol/g DW). Neoglucobrassicin was the major GSL in Br (30.98 μmol/g DW), while glucoerucin was the major GSL in Es (17.84 μmol/g DW). The yields of the steam-distilled oils of the studied seeds ranged between 3.25 ± 0.36 and 9.68 ± 0.25% /. A GC-MS analysis of the oils could detect 3, 23, 18, 16, 7, and 9 compounds in Rr, Rs, Boc, Bob, Br, and Es oils, respectively. Sulfur and nitrogenous compounds predominated in all studied oils except Rs, which contained a higher percentage of alkanes. The major identified compound in Rr oil was 4-isothiocyanato-1-(methylthio)-1-butene (94.77 ± 1.25%), while in Br it was 3-butenyl isothiocyanate (69.55 ± 1.02%), thiolane in Rs (15.15 ± 0.22%), and erucin in Es (97.02 ± 1.514%). Both Boc and Bob had the same major compound 4-(methylthio) butanenitrile, which represented 40.35 ± 1.15 and 50.52 ± 1.02% in both oils, respectively. Radical scavenging activity for both GSL extracts and essential oils on DPPH radical ranged between 18.01 ± 0.72 and 114.28 ± 1.15 µg/mL (IC). The highest antioxidant capacity was for Es oil, while the lowest one was for Rr oil. Generally, it was observed that the GSLs had better antioxidant activity than their corresponding essential oils except for Es oil, which had higher activity. A principal component analysis (PCA) was successfully applied to discriminate among six Brassicaceae seeds based on both HPLC and GC-MS, where complete segregation was achieved among all samples with high correlation between Boc and Bob. Partial Least Squares-Regression (PLS-R) models showed that there is a better correlation between the antioxidant activity and glucosinolate profile when being compared to that of a volatile one. This profiling and variation of GSLs and volatile metabolites of the studied Brassicaceae seeds may be employed in further studies regarding their health-promoting properties.
十字花科包含多种物种，是工业作物或药用作物的重要经济来源。本研究旨在鉴定在埃及种植的六种十字花科种子中的硫代葡萄糖苷（GSLs）和挥发性化合物。使用23种GSL标准品混合物对萝卜（Rr）、黑芥（Rs）、芜菁（Boc）、甘蓝（Bob）、油菜（Br）和埃塞俄比亚芥（Es）种子乙醇提取物中的GSLs进行了高效液相色谱 - 光电二极管阵列（HPLC - PDA）分析。在所研究的种子中检测到了19种GSLs。Rs的GSL含量最高（135.66 μmol/g干重，DW），而Boc的GSL含量最低（93.66 μmol/g DW）。新硫代葡萄糖苷是Rr、Rs和Bob中主要鉴定出的化合物。其最高含量在Rs中（28.96 μmol/g DW）。异硫氰酸烯丙酯是Boc中主要鉴定出的GSL（18.02 μmol/g DW），尽管在Bob中的含量更高（22.02 μmol/g DW）。新新硫代葡萄糖苷是Br中主要的GSL（30.98 μmol/g DW），而葡萄糖芥苷是Es中主要的GSL（17.84 μmol/g DW）。所研究种子的水蒸气蒸馏油产量在3.25±0.36%至9.68±0.25%/之间。对这些油进行气相色谱 - 质谱（GC - MS）分析，分别在Rr、Rs、Boc、Bob、Br和Es油中检测到3、23、18、16、7和9种化合物。除Rs含有较高百分比的烷烃外，所有研究油中硫和含氮化合物占主导。Rr油中主要鉴定出的化合物是4 - 异硫氰酸根合 - 1 - （甲硫基） - 1 - 丁烯（94.77±1.25%），Br中是3 - 丁烯基异硫氰酸酯（69.55±1.02%），Rs中是硫杂环戊烷（15.15±0.22%），Es中是山嵛酸（97.02±1.514%）。Boc和Bob具有相同的主要化合物4 - （甲硫基）丁腈，在两种油中分别占40.35±1.15%和50.52±1.02%。GSL提取物和精油对DPPH自由基清除活性在18.01±0.72至114.28±1.15 μg/mL（IC）之间。抗氧化能力最高的是Es油，最低的是Rr油。一般来说，观察到除Es油活性较高外，GSLs的抗氧化活性比其相应的精油更好。基于HPLC和GC - MS成功应用主成分分析（PCA）对六种十字花科种子进行区分，所有样品实现了完全分离，Boc和Bob之间具有高度相关性。偏最小二乘回归（PLS - R）模型表明，与挥发性成分相比，抗氧化活性与硫代葡萄糖苷谱之间具有更好的相关性。所研究十字花科种子中GSLs和挥发性代谢物的这种分析和变化可用于关于其健康促进特性的进一步研究。
