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Metabolic profiling of pale green and purple kohlrabi (Brassica oleracea var. gongylodes)

A Correction to this article was published on 21 May 2018

This article has been updated

Abstract

Kohlrabi (Brassica oleracea var. gongylodes) is a dietary Brassica vegetable with noted health-beneficial properties associated with its numerous metabolites. The aim of this study was to elucidate phenotypic variation between the two cultivars through comprehensive analysis of the relationship of their primary and secondary metabolites. High-performance liquid chromatography (HPLC) and gas chromatography time-of-flight mass spectrometry (GC-TOFMS) are considered useful tools for profiling primary and secondary metabolites. A total of 45 metabolites, including organic acids, amino acids, sugars, and an amine, were identified in pale green and purple kohlrabies using GC-TOFMS-based metabolic profiling. The resulting data sets were analyzed by principal component analysis to determine the overall variation, and the purple and pale green vegetables were separated by the score plots generated. Additionally, HPLC analysis of anthocyanins in both cultivars revealed that green kohlrabies did not contain any anthocyanidins, while 11 anthocyanins were quantified in the purple ones. Cyanidin was the dominant anthocyanin found in the purple cultivar, with cyanidin-3-(feruloyl)-diglucoside-5-glucoside being the major one. This study suggests that GC-TOFMS and HPLC are suitable tools to determine metabolic connection among various metabolites and describe phenotypic variation between green and purple kohlrabies.

Introduction

Because of the continued interest in the promotion of human health, the consumption of Brassica vegetables, including cabbage (Brassica oleracea L. var. captita), brussels sprouts (B. oleracea var. gemmifera), broccoli (B. oleracea var. italica), kale (B. oleracea var. acephala), cauliflower (B. oleracea var. botrytis), kohlrabi (B.oleracea var. gongylodes), and mustard (B. juncea L.), which are associated with the prevention of numerous diseases including diabetes, cancer, and heart disease, has increased [16]. This beneficial effect is associated with anti-diabetic, anticancer, anti-inflammatory, and antioxidant properties attributed to various metabolites including carbohydrates, amino acids, organic acids, vitamins, minerals, phenolic compounds, flavonoids, anthocyanins, carotenoids, and glucosinolates present in Brassica vegetables [716]. Metabolites are the end products and intermediates of complex metabolism. Primary metabolites are directly responsible for the physiological processes including normal growth, development, and reproduction in living organisms, and secondary metabolites are involved in plant defense and are used as medicines for human health [1719].

Anthocyanins, a group of flavonoids, are regarded as important secondary metabolites because of their health-promoting activities including anti-hyperglycemic, antioxidant, anti-angiogenic, anti-inflammatory, anticancer, anti-influenza effects [2023]. Of the approximately 17 aglycone types present in nature, peonidin, delphinidin, cyanidin, malvidin, pelargonidin, delphinidin, and petunidin are the most common in higher plants [24]. Individual anthocyanin has different properties according to the number of hydroxyl group; the number and nature of sugars added to the molecule; the location of sugar attachment; and the number and nature of aromatic or aliphatic acids added to these sugars within the molecule [2527]. Cyanidin, a water-soluble pigment with the C6-C3-C6 structure, is the main aglycone in Brassica vegetables [12, 28, 29]. The nature and intensity of the color exhibited in plants are influenced by pH-dependent structural changes, which may result in red, violet or blue coloration [3032].

Metabolic profiling is commonly defined as the measurement of metabolites of low molecular weight and intermediates produced through many biosynthetic and catabolic pathways in living organisms. Therefore, identification and quantification of numerous metabolites is necessary [33, 34]. GC-TOFMS is a reliable method for performing metabolic profiling since it has been successfully used to quantify and identify a broad range of metabolites such as sugars, sugar alcohols, organic acids, and amino acids in various research fields [35]. Primary metabolic profiling is closely correlated to plant phenotypes and involves important nutritional characteristics. Previously, we successfully performed GC-TOFMS-based metabolic profiling to classify samples of diverse biological quality, origin or status [17, 3639]. Thus, GC-TOFMS could be considered to be a suitable platform for the identification and quantification of individual metabolites in pale green and purple colored kohlrabi, as it provides the high mass resolution and accuracy, high scan speed and good sensitivity [40, 41].

Kohlrabi is a biennial plant with an enlarged bulb-like, fleshy stem that is edible and occurs at its base [11, 42]. Several studies have described the health-promoting properties associated with the secondary metabolites of kohlrabi [11, 4246]. In our previous study, a comparison of the secondary metabolites from the flesh and peel of the pale green and purple colored kohlrabi was made [14]. However, there are no reports on the phenotypic variation between pale green and purple kohlrabi in relation to their primary and secondary metabolites (Fig. 1), though vegetable classification is helpful for dietary guidance and assessment, based on color of vegetables. Thus, this current study aims to describe the relationship among the primary and secondary metabolites via HPLC analysis of their anthocyanins and GC-TOFMS-based analysis of amino acids, carbohydrates, sugar alcohols, organic acids, and an amine.

Fig. 1
figure 1

Pale green (A) and purple (B) kohlrabi cultivars

Materials and methods

Plant materials

The seeds of pale green and purple kohlrabies were purchased from Stokes Seeds Ltd. (St. Catharines, Canada) and then submerged in water for 1 day before germination in a greenhouse. The seedlings of the each cultivar were transferred and cultivated in the experimental field in Daejeon, Republic of Korea. The edible portion (enlarged bulb-like, fleshy stem) of the two cultivars was sampled after 10 weeks.

Anthocyanin extraction and analysis

The edible parts from the two kohlrabi cultivars were ground in the presence of liquid nitrogen and then freeze-dried in a lyophilizer. For each sample, 200 mg of the resultant powder was extracted with 2 mL of formic acid/water (5:95, v/v) and vortexed for 5 min. The sample was gently sonicated for 30 min and then centrifuged at 8000 rpm and 4 °C for 15 min. Subsequently, the supernatant fluid was filtered via a 0.45 µm PTFE syringe filter (Merk Millpore, Daejeon, Korea) into a capped vial. The extractions were carried out in triplicates. First, 10 μL of the extracts were injected on a PerkinElmer Flexar HPLC (Shelton, CT, USA) equipped with a PDA LC detector for anthocyanin analysis. A Synergy 4 μ Polar-RP 80A (250 × 4.6 mm i.d., particle size 4 μm; Phenomenex, Torrance, CA, USA) column with a Security Guard Cartridge Kit (AQ C18, 4 × 3 mm i.d.; Phenomenex, Torrance, CA, USA) controlled at 40 °C and 520 nm was used to separate individual anthocyanins. The composition of the mobile phase was as follows: eluent A: formic acid/water (5:95, v/v), and eluent B: formic acid/acetonitrile (5:95, v/v). The gradient program same as the previously published research [14] was employed: 0–8 min, 10% B; 8–13 min, 10–13% B; 13–15 min, 13% B; 15–18 min, 13–15% B; 18–25 min, 15% B; 25–30 min, 15–18% B; 30–35 min, 18% B; 35–40 min, 18–21% B; 40–45 min, 21% B; 45–45.1 min, 21–5% B; and 45.1–50 min, 5% B (total 50 min).

Polar metabolite extraction and analysis

GC-TOFMS was employed to identify and quantitate a variety of metabolites with low molecular weight in the kohlrabi cultivars. Polar metabolites were extracted using the procedure described by the previous study [36]. Chemicals and reagents, sample preparation procedures, methoxime-derivatization and trimethylsilyl etherification procedures, GC-TOFMS instrument operating conditions, analytical procedures for sample separation, and the identification and quantification of the molecules were carried out as previously described by the previous study [36]. A powdered sample was extracted with 1 mL of 2.5:1:1 (v/v/v) methanol/water/chloroform. Ribitol (60 µL, 0.2 mg/mL) was added an as internal standard (IS). Each derivatized sample (1 µL) was separated on a 30 m × 0.25-mm i.d. fused silica capillary column coated with 0.25-µm CP-SIL 8 CB low bleed (Varian Inc., Palo Alto, CA, USA). MS was performed using a Pegasus HT TOF mass spectrometer (LECO, St. Joseph, MI). ChromaTOF software (version 4.34; LECO, St. Joseph, MI, USA) was used for peak identification using an in-house library and reference compounds. Furthermore, several metabolites were identified by direct comparison with mass chromatogram of the sample with those of commercially available standard compounds acquired by a methoxime-derivatization and trimethylsilyl etherification procedures and GC-TOFMS analysis. All analytes were quantitatively calculated based on the peak area ratios relative to that of the I.S [17, 36, 43, 44].

Statistical analysis

HPLC data were statistically assessed using the Statistical Analysis System (SAS, system 9.4, 2013; SAS Institute, Inc., Cary, NC, USA). The significant difference among means was assessed by Duncan’s multiple range test (DMRT). A probability value less than 0.05 (P ≤ 0.05) was regarded as significant. All data were recorded as mean ± standard deviation of triplicate experiments. The relative quantitation data obtained by GC-TOFMS analysis were subjected to principal component analysis (PCA) accompanied by unit variance scaling (SIMCA-P version 13.0; Umetrics, Umeå, Sweden) to determine differences in the low molecular weight metabolite profiles in kohlrabi with respect to two colors. The PCA outputs were composed of score plots for indicating the sample distributions.

Results and discussion

Metabolite-specific profiling

Using this GC–MS approach, a total of 45 compounds, such as amino acids, organic acids, carbohydrates, sugar alcohols and an amine, were detected and normalized against the internal standard signal intensity. The resulting data were subjected to PCA of the two cultivars (Fig. 2). The first PCA component resolved the measured compound profiles of purple and green kohlrabi, describing 68.8% of the total variation. The 95% confidence interval of the modeled variation was defined by Hotelling’s T2 region, representing an ellipse in the score plots [47]. To investigate the contributors to the principal components, the metabolic loadings in principal component 1 were compared. Shikimate and ferulate, involved in anthocyanin metabolism, were clustered on the left side of the loading plot, indicating that the values of those metabolites in purple kohlrabi were higher than those in green kohlrabi. In addition, alanine, β-alanine, leucine, GABA, serine, glutamine, glutamate, and glycine were clustered on the right side of the loading plot. The results suggest that the amino acids were higher in green kohlrabi than purple kohlrabi.

Fig. 2
figure 2

Scores (A) and loading plots (B) of principal components 1 and 2 of the PCA results obtained from polar metabolite data of purple and green kohlrabi

The most abundant metabolite in both cultivars was sugars. Sugars are critical primary nutrients, partially influencing the growth, development, and morphogenesis of plants. The comparison of carbohydrate levels between purple and green kohlrabi revealed that the level of total carbohydrates in green kohlrabi was 1.08 times higher than that in purple kohlrabi (Supplementary materials). In details, the fructose level in green kohlrabi was higher than that in purple cultivar while the levels of sucrose, raffinose and xylose were statistically higher than those of green cultivar. The quantities of glucose, galactose, myo-inositol, and trehalose were similar to the both cultivars.

A linkage map was constructed with 45 metabolites and 11 anthocyanins to understand metabolic connection between metabolites (Fig. 3). Sixteen proteinogenic and three non- proteinogenic amino acids were detected in the two cultivars and the total amount of amino acids was higher in green kohlrabi. Specifically, the glutamate derivatives (glutamine, arginine, GABA, and pyroglutamate) and pyruvate-derived amino acids (alanine and leucine) were more abundant in green kohlrabi. Note that abundance of glutamate and glutamine (respectively, 1.20- and 1.54-fold higher in green kohlrabi), which are involved in nitrogen assimilation, [48] showed that the green kohlrabi had higher amount of N-compounds, including 19 amino acids and 1 amine, than the purple one. In addition, the larger pool of glutamate and alanine (19.38-fold), which act as important amino donors in photorespiration, [49] reflected that the levels of photorespiratory intermediates, the amino acids serine (1.19-fold) and glycine (1.15-fold), were also higher in green kohlrabi. However, purple kohlrabi contained more proline (1.76-fold) and arginine (2.72-fold) in comparison with green kohlrabi. Additionally, the oxaloacetate family of amino acids (aspartate, asparagine, threonine, methionine and isoleucine) was generally present in higher levels in purple kohlrabi.

Fig. 3
figure 3

A metabolic linkage map comparing primary and secondary metabolites of green and purple kohlrabi. The up arrow indicates that the mean value of the target metabolite is significantly higher (at P < 0.05). The down arrow indicates that the value of the metabolite is significantly lower (at P < 0.05). The horizontal bar means that mean values of the target compounds were not significantly different (at P < 0.05). A different letter (G and P) indicated green and purple kohlrabi, respectively

Four Kreb’s cycle intermediates were identified and quantified. Purple kohlrabi had the larger pools of malate (1.13-fold) and fumarate (1.26-fold), supported by the higher quantity of aspartate (3.00-fold). In contrast, citrate (1.95-fold) and succinate (2.00-fold) pools were higher in green kohlrabi, as explained by the higher level of glutamate (1.20-fold) and GABA (1.73-fold). The shikimate pathway is a main route for aromatic compounds, such as phenylalanine and tryptophan, in plants. These two primary metabolites serve as precursors for various secondary metabolites including flavonoids, glucosinolates, phenolic acids, and anthocyanins [50]. The levels of shikimate (2.07-fold) and tryptophan (1.51-fold) were higher in purple kohlrabi, reflecting that the relative downstream compounds, ferulate and sinapate (1.17-fold), were also more abundant in that cultivar. On the other hand, green kohlrabi contained the larger quantity of phenylalanine. In addition, ethanolamine, which is involved in phospholipid metabolism, [51] was also greater in green kohlrabi.

HPLC analysis of anthocyanin

The HPLC data revealed that the green kohlrabi did not contain any anthocyanins, while a total of 11 anthocyanins were detected in purple kohlrabi, which had a total anthocyanin level of 0.30 ± 0.01 mg/g dry weight (wt) (Table 1). Among the anthocyanin compounds detected, cyanidin-3-(feruloyl)-diglucoside-5-glucoside was the most dominant, and cyanidin-3-(p-coumaroyl)(sinapoyl)-triglucoside-5-glucoside and cyanidin-3-(caffeoyl)(p-coumaroyl)-diglucoside-5-glucoside were present in trace amounts. With the exception of cyanidin-3-diglucoside-5-glucoside, all of the anthocyanins detected were cyanidin glycosides to which phenolic acids including sinapic, caffeic, p-coumaric, and ferulic acids were attached. The identification of individual anthocyanins was confirmed by comparison with MS/MS data from our published research [14].

Table 1 Anthocyanin contents (mg/g dry wt.) in pale green and purple kohlrabis

Anthocyanins, a class of phenylpropanoid-type pigments, are derived from carbohydrates generated during the process of photosynthesis through enzyme mediated reactions of shikimate and the phenylpropanoid biosynthetic pathway [52]. Most anthocyanins occurring in nature are present primarily in the form of anthocyanidins (aglycones) glycosylated with one or more sugar moieties [53]. In this study, a phenotypic (color) difference between green and purple kohlrabi was determined to be due to the presence of anthocyanins. The purple cultivar contained a total of 11 anthocyanins, with cyanidin being the sole aglycone present. The anthocyanidin was glycosylated in various positions and acylated with aromatic acyl substituents including p-coumaryl, caffeoyl, feruryl, and sinapoyl groups. Previous studies on acylated anthocyanins noted that acylation improves the strength of their colors and confers increased stability to heat, light, pH, and SO2. Acylated cyanindin glucosides are also more stable than their deacyl analogues [32, 5457]. Higher levels of ferulate and sinapate in the purple cultivar would be necessary for acylation of the anthocyanins present in the purple cultivar.

Plant primary metabolism is defined as a collection of processes including the generation and utilization of a wide range of substances such as carbohydrates, fatty acids, nucleic acids, amino acids, and biopolymers for the survival of the plants. Secondary metabolism, however, accounts for biochemical reactions which are not essential to sustain plant life but play important roles in specific stages of growth and development, reproduction and defense [5861]. In fact, the border between the primary and secondary metabolism is ambiguous, since intermediates synthesized by primary metabolism are also involved in pathways that generate secondary metabolites. Also, the overlapping interactions of the biochemicals ensure an interplay between the primary and secondary metabolism [61].

Carbon (C) and nitrogen (N) are the most important nutrients for conducting fundamental and normal cellular functions [62]. Carbohydrates, containing C, play a key role as an energy source and in plant metabolism. The total amount of carbons (represented mainly by sugars such as xylose, glucose, mannose, galactose, fructose, sucrose, trehalose, and raffinose) in the purple cultivar was lower than that in the green cultivar, which reflected on carbon and energy demand to support anthocyanin metabolism. Similarly, [63] reported that the enhanced alkaloid production in opium poppy cell cultures treated with a fungal elicitor showed more rapidly depleted pools of carbohydrates.

Nitrogen is the most important inorganic nutrient, being present in nucleic acids, amino acid, proteins, co-factors, and many secondary metabolites in plants [64, 65]. Amino acids are the first products originated from nitrogen assimilation and are synthesized by combination of ammonium and C-skeletons provided by photosynthetic products [62]. In plant species, the composition and concentration of free amino acids vary considerably with different nitrogen sources. In particular, the concentrations of individual free amino acids can be more easily modified than that of total free amino acids [66]. The current analysis of amino acids revealed that the total number (11) of amino acids found in the purple cultivar was lower than that in the green cultivar, reflecting intermediate or precursor supply to support anthocyanin acylation and metabolism. Lee and Finn [67] reported that the higher anthocyanin contents in Lingonberry (Vaccinium vitis-idaea L.) were associated with lower levels of total free amino acids. Additionally, higher levels of shikimate and tryptophan in the purple cultivar suggested greater accumulation of anthocyanins and phenolic acids. This is consistent with a prior study which revealed the high amounts of shikimate and anthocyanin in red- compared with white-colored buckwheat (Fagopyrum esculentum) flowers [68]. Also, the supply of exogenous shikimate enhanced anthocyanin production in maize roots [69].

The phenotypic variation between green and purple kohlrabies was determined by analyzing the correlation between the primary and secondary metabolites of the two cultivars through GC-TOFMS and HPLC analyses. The anthocyanins were considered the key factor in determining the color phenotype of the cultivars. The purple cultivar contained high levels of anthocyanins and low amounts of primary metabolites, reflecting the demand for carbon, energy and metabolic precursors to support its anthocyanin metabolism. Additionally, the high production of ferulate and sinapate might be involved in the acylation of anthocyanins. Lastly, the study confirmed that GC-TOFMS-based metabolite and HPLC-based anthocyanin profiling are useful approaches for determining metabolic interaction among a variety of metabolites and to describe phenotypic variation between green and purple kohlrabies.

Change history

  • 21 May 2018

    Unfortunately, in the online published article, the second author’s given name was wrongly published. The correct given name should be “Hyeon Ji”.

    Similarly the fourth author’s given name and family name was swapped. The given name should be “Ye Eun” and family name should be “Park”.

References

  1. Ambrosone CB, Tang L (2009) Cruciferous vegetable intake and cancer prevention: role of nutrigenetics. Cancer Prev Res 2:298–300

    Article  CAS  Google Scholar 

  2. Asadujjaman M, Hossain M, Khan M, Anisuzzaman A, Ahmed M, Islam A (2011) Antihyperglycemic and glycogenesis effects of different fractions of Brassica oleracea in Alloxan induced diabetic rats. Int J Pharm Sci Rev Res 2:1436

    Google Scholar 

  3. Giovannucci E, Rimm EB, Liu Y, Stampfer MJ, Willett WC (2003) A prospective study of cruciferous vegetables and prostate cancer. Cancer Epidemiol Biomarkers Prev 12:1403–1409

    CAS  PubMed  Google Scholar 

  4. Melchini A, Traka MH (2010) Biological profile of erucin: a new promising anticancer agent from cruciferous vegetables. Toxins 2:593–612

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Sankhari JM, Thounaojam MC, Jadeja RN, Devkar RV, Ramachandran A (2012) Anthocyanin-rich red cabbage (Brassica oleracea L.) extract attenuates cardiac and hepatic oxidative stress in rats fed an atherogenic diet. J Agric Food Chem 92:1688–1693

    Article  CAS  Google Scholar 

  6. Thirumalai T, Therasa SV, Elumalai E, David E (2011) Hypoglycemic effect of Brassica juncea (seeds) on streptozotocin induced diabetic male albino rat. Asian Pac J Trop Biomed 1:323–325

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  7. Abdel-Farid IB, Kim HK, Choi YH, Verpoorte R (2007) Metabolic characterization of Brassica rapa leaves by NMR spectroscopy. J Agric Food Chem 55:7936–7943

    Article  CAS  PubMed  Google Scholar 

  8. Ayaz FA, Hayırlıoglu-Ayaz S, Alpay-Karaoglu S, Grúz J, Valentová K, Ulrichová J, Strnad M (2008) Phenolic acid contents of kale (Brassica oleraceae L. var. acephala DC.) extracts and their antioxidant and antibacterial activities. Food Chem 107:19–25

    Article  CAS  Google Scholar 

  9. Cartea ME, Francisco M, Soengas P, Velasco P (2010) Phenolic compounds in Brassica vegetables. Molecules 16:251–280

    Article  CAS  PubMed  Google Scholar 

  10. Ferreres F, Fernandes F, Oliveira JM, Valentão P, Pereira JA, Andrade PB (2009) Metabolic profiling and biological capacity of Pieris brassicae fed with kale (Brassica oleracea L. var. acephala). Food Chem Toxicol 47:1209–1220

    Article  CAS  PubMed  Google Scholar 

  11. Jung HA, Karki S, Ehom N-Y, Yoon M-H, Kim EJ, Choi JS (2014) Anti-diabetic and anti-inflammatory effects of green and red kohlrabi cultivars (Brassica oleracea var. gongylodes). Prev Nutr Food Sci 19:281

  12. Lin J-Y, Li C-Y, Hwang I-F (2008) Characterisation of the pigment components in red cabbage (Brassica oleracea L. var.) juice and their anti-inflammatory effects on LPS-stimulated murine splenocytes. Food Chem 109:771–781

    Article  CAS  PubMed  Google Scholar 

  13. Lippmann D, Lehmann C, Florian S, Barknowitz G, Haack M, Mewis I, Wiesner M, Schreiner M, Glatt H, Brigelius-Flohé R (2014) Glucosinolates from pak choi and broccoli induce enzymes and inhibit inflammation and colon cancer differently. Food Funct 5:1073–1081

    Article  CAS  PubMed  Google Scholar 

  14. Park WT, Kim JK, Park S, Lee S-W, Li X, Kim YB, Uddin MR, Park NI, Kim S-J, Park SU (2012) Metabolic profiling of glucosinolates, anthocyanins, carotenoids, and other secondary metabolites in kohlrabi (Brassica oleracea var. gongylodes). J Agric Food Chem 60:8111–8116

    Article  CAS  PubMed  Google Scholar 

  15. Podsędek A (2007) Natural antioxidants and antioxidant capacity of Brassica vegetables: a review. LWT-Food Sci Technol 40:1–11

    Article  CAS  Google Scholar 

  16. Singh J, Upadhyay A, Bahadur A, Singh B, Singh K, Rai M (2006) Antioxidant phytochemicals in cabbage (Brassica oleracea L. var. capitata). Sci Hortic 108:233–237

    Article  CAS  Google Scholar 

  17. Park S-Y, Lim S-H, Ha S-H, Yeo Y, Park WT, Kwon DY, Park SU, Kim JK (2013) Metabolite profiling approach reveals the interface of primary and secondary metabolism in colored cauliflowers (Brassica oleracea L. ssp. botrytis). J Agric Food Chem 61:6999–7007

    Article  CAS  PubMed  Google Scholar 

  18. Savithramma N, Rao ML, Suhrulatha D (2011) Screening of medicinal plants for secondary metabolites. Middle East J Sci Res 8:579–584

    Google Scholar 

  19. Stamp N (2003) Out of the quagmire of plant defense hypotheses. Q Rev Biol 78:23–55

    Article  PubMed  Google Scholar 

  20. Bagchi D, Sen C, Bagchi M, Atalay M (2004) Anti-angiogenic, antioxidant, and anti-carcinogenic properties of a novel anthocyanin-rich berry extract formula. Biochemistry (Moscow) 69:75–80

    Article  CAS  Google Scholar 

  21. Bowen-Forbes CS, Zhang Y, Nair MG (2010) Anthocyanin content, antioxidant, anti-inflammatory and anticancer properties of blackberry and raspberry fruits. J Food Comp Anal 23:554–560

    Article  CAS  Google Scholar 

  22. Hayashi K, Mori M, Matsutani-Knox Y, Suzutan T, Ogasawara M, Yoshida I, Hosokawa K, Tsukui A, Azuma M (2003) Anti influenza virus activity of a red-fleshed potato anthocyanin. Food Sci Technol Res 9:242–244

    Article  CAS  Google Scholar 

  23. Matsui T, Ebuchi S, Kobayashi M, Fukui K, Sugita K, Terahara N, Matsumoto K (2002) Anti-hyperglycemic effect of diacylated anthocyanin derived from Ipomoea batatas cultivar Ayamurasaki can be achieved through the α-glucosidase inhibitory action. J Agric Food Chem 50:7244–7248

    Article  CAS  PubMed  Google Scholar 

  24. Kong J-M, Chia L-S, Goh N-K, Chia T-F, Brouillard R (2003) Analysis and biological activities of anthocyanins. Phytochemistry 64:923–933

    Article  CAS  PubMed  Google Scholar 

  25. Mazza G, Miniati E (1993) Anthocyanins in fruits, vegetables, and grains. CRC Press, London, pp 1–362

    Google Scholar 

  26. Pojer E, Mattivi F, Johnson D, Stockley CS (2013) The case for anthocyanin consumption to promote human health: a review. Compr Rev Food Sci Food Saf 12:483–508

    Article  CAS  Google Scholar 

  27. Prior RL, Wu X (2009) Anthocyanins: structural characteristics that result in unique metabolic patterns and biological activities. Free Radic Res 40:1014–1028

    Article  CAS  Google Scholar 

  28. Sun J, Xiao Z, L-z Lin, Lester GE, Wang Q, Harnly JM, Chen P (2013) Profiling polyphenols in five Brassica species microgreens by UHPLC-PDA-ESI/HRMSn. J Agric Food Chem 61:10960–10970

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  29. Tatsuzawa F, Saito N, Shinoda K, Shigihara A, Honda T (2006) Acylated cyanidin 3-sambubioside-5-glucosides in three garden plants of the Cruciferae. Phytochemistry 67:1287–1295

    Article  CAS  PubMed  Google Scholar 

  30. Alkema J, Seager SL (1982) The chemical pigments of plants. J Chem Educ 59:183

    Article  CAS  Google Scholar 

  31. Dyrby M, Westergaard N, Stapelfeldt H (2001) Light and heat sensitivity of red cabbage extract in soft drink model systems. Food Chem 72:431–437

    Article  CAS  Google Scholar 

  32. Stintzing FC, Stintzing AS, Carle R, Frei B, Wrolstad RE (2002) Color and antioxidant properties of cyanidin-based anthocyanin pigments. J Agric Food Chem 50:6172–6181

    Article  CAS  PubMed  Google Scholar 

  33. Clarke CJ, Haselden JN (2008) Metabolic profiling as a tool for understanding mechanisms of toxicity. Toxicol Pathol 36:140–147

    Article  CAS  PubMed  Google Scholar 

  34. Harrigan GG, Goodacre R (2003) Metabolic profiling: its role in biomarker discovery and gene function analysis. Springer, New York, pp 1–335

    Book  Google Scholar 

  35. Lisec J, Schauer N, Kopka J, Willmitzer L, Fernie AR (2006) Gas chromatography mass spectrometry–based metabolite profiling in plants. Nat Protoc 1:387–396

    Article  CAS  PubMed  Google Scholar 

  36. Kim JK, Bamba T, Harada K, Fukusaki E, Kobayashi A (2007) Time-course metabolic profiling in Arabidopsis thaliana cell cultures after salt stress treatment. J Exp Bot 58:415–424

    Article  CAS  PubMed  Google Scholar 

  37. Kim JK, Park S-Y, Lee SM, Lim S-H, Kim HJ, Oh S-D, Yeo Y, Cho HS, Ha S-H (2013) Unintended polar metabolite profiling of carotenoid-biofortified transgenic rice reveals substantial equivalence to its non-transgenic counterpart. Plant Biotechnol Rep 7:121–128

    Article  Google Scholar 

  38. Kim YB, Kim JK, Uddin MR, Xu H, Park WT, Tuan PA, Li X, Chung E, Lee J-H, Park SU (2013) Metabolomics analysis and biosynthesis of rosmarinic acid in Agastache rugosa Kuntze treated with methyl jasmonate. PLoS ONE 8:e64199

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  39. Thwe AA, Kim JK, Li X, Kim YB, Uddin MR, Kim SJ, Suzuki T, Park NI, Park SU (2013) Metabolomic analysis and phenylpropanoid biosynthesis in hairy root culture of tartary buckwheat cultivars. PLoS ONE 8:e65349

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  40. Ding M-Z, Cheng J-S, Xiao W-H, Qiao B, Yuan Y-J (2009) Comparative metabolomic analysis on industrial continuous and batch ethanol fermentation processes by GC-TOF-MS. Metabolomics 5:229–238

    Article  CAS  Google Scholar 

  41. Jiang W, Qiu Y, Ni Y, Su M, Jia W, Du X (2010) An automated data analysis pipeline for GC–TOF–MS metabonomics studies. J Proteome Res 9:5974–5981

    Article  CAS  PubMed  Google Scholar 

  42. Fischer J (1992) Sulphur-and nitrogen-containing volatile components of kohlrabi (Brassica oleracea var. gongylodes L.). Eur Food Res Technol 194:259–262

    CAS  Google Scholar 

  43. Kim D-b, Oh J-W, Shin G-H, Kim Y-H, Lee JS, Park I-J, Cho JH, Lee O-H (2014) Inhibitory effect of kohlrabi juices with antioxidant activity on oxidative stress in human dermal fibroblasts (LB394). FASEB J 28:394

    Google Scholar 

  44. Kim JK, Kim YS, Kim Y, Uddin MR, Kim YB, Kim HH, Park SY, Lee MY, Chung SO, Park SU (2014) Comparative analysis of flavonoids and polar metabolites from hairy roots of Scutellaria baicalensis and Scutellaria lateriflora. World J Microbiol Biotechnol 30:887–892

    Article  CAS  PubMed  Google Scholar 

  45. Lee J-W, Lee D-Y, Baek D-R, Jeong R-H, Lee D-S, Kim Y-C, Kim G-S, Baek N-I, Lee Y-H (2014) Phenylpropanoids from red kohlrabi sprouts inhibits nitric oxide production in RAW 264.7 macrophage cells. Food Sci Biotechnol 23:965–969

    Article  CAS  Google Scholar 

  46. Zhang Y, Hu Z, Zhu M, Zhu Z, Wang Z, Tian S, Chen G (2015) Anthocyanin accumulation and molecular analysis of correlated genes in purple Kohlrabi (Brassica oleracea var. gongylodes L.). J Agric Food Chem 63:4160–4169

    Article  CAS  PubMed  Google Scholar 

  47. Kim YB, Park S-Y, Park CH, Park WT, Kim S-J, Ha S-H, Arasu MV, Al-Dhabi NA, Kim JK, Park SU (2016) Metabolomics of differently colored Gladiolus cultivars. Appl Biol Chem 59:597–607

    Article  CAS  Google Scholar 

  48. Fouad WMM (2004) Metabolic engineering for beta-alanine overproduction and stress tolerance in plants: Expression of Escherichia coli L-aspartate-alpha-decarboxylase in transgenic tobacco. University of Florida, pp 106

  49. Betsche T, Eising R (1986) Refixation of photorespiratory ammonia and the role of alanine in photorespiration: studies with 15 N. Plant Soil 91:367–371

    Article  CAS  Google Scholar 

  50. McCue KF, Conn EE (1990) Induction of shikimic acid pathway enzymes by light in suspension cultured cells of parsley (Petroselinum crispum). Plant Physiol 94:507–510

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  51. Kwon Y, S-i Yu, Lee H, Yim JH, Zhu J-K, B-h Lee (2012) Arabidopsis serine decarboxylase mutants implicate the roles of ethanolamine in plant growth and development. Int J Mol Sci 13:3176–3188

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  52. Hahlbrock K, Scheel D (1989) Physiology and molecular biology of phenylpropanoid metabolism. Annu Rev Plant Biol 40:347–369

    Article  CAS  Google Scholar 

  53. Yonekura-Sakakibara K, Nakayama T, Yamazaki M, Saito K (2008) Modification and stabilization of anthocyanins. Anthocyanins. Springer, New York, pp 169–190

    Chapter  Google Scholar 

  54. Bridle P, Timberlake C (1997) Anthocyanins as natural food colours—selected aspects. Food Chem 58:103–109

    Article  CAS  Google Scholar 

  55. Hernández-Herrero JA, Frutos MJ (2011) Degradation kinetics of pigment, colour and stability of the antioxidant capacity in juice model systems from six anthocyanin sources. Int J Food Sci Technol 46:2550–2557

    Article  CAS  Google Scholar 

  56. Malien-Aubert C, Dangles O, Amiot MJ (2001) Color stability of commercial anthocyanin-based extracts in relation to the phenolic composition. Protective effects by intra-and intermolecular copigmentation. J Agric Food Chem 49:170–176

    Article  CAS  PubMed  Google Scholar 

  57. Saito N, Tatsuzawa F, Yoda K, Yokoi M, Kasahara K, Iida S, Shigihara A, Honda T (1995) Acylated cyanidin glycosides in the violet-blue flowers of Ipomoea purpurea. Phytochemistry 40:1283–1289

    Article  CAS  PubMed  Google Scholar 

  58. Dixon RA (2001) Natural products and plant disease resistance. Nature 411:843–847

    Article  CAS  PubMed  Google Scholar 

  59. Harborne JB (2001) Twenty-five years of chemical ecology. Nat Prod Rep 18:361–379

    Article  CAS  PubMed  Google Scholar 

  60. Nugroho LH, Verpoorte R (2002) Secondary metabolism in tobacco. Plant Cell, Tissue Organ Cult 68:105–125

    Article  CAS  Google Scholar 

  61. Yeoman M, Yeoman C (1996) Manipulating secondary metabolism in cultured plant cells. New Phytol 134:553–569

    Article  CAS  Google Scholar 

  62. Zheng Z-L (2009) Carbon and nitrogen nutrient balance signaling in plants. Plant Signal Behav 4:584–591

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  63. Zulak KG, Weljie AM, Vogel HJ, Facchini PJ (2008) Quantitative 1 H NMR metabolomics reveals extensive metabolic reprogramming of primary and secondary metabolism in elicitor-treated opium poppy cell cultures. BMC Plant Biol 8:1

    Article  CAS  Google Scholar 

  64. Marschner H (1995) Mineral nutrition of higher plants, 2nd edn. Academic Press, Massachusetts, pp 1–889

    Google Scholar 

  65. Scheible W-R, Morcuende R, Czechowski T, Fritz C, Osuna D, Palacios-Rojas N, Schindelasch D, Thimm O, Udvardi MK, Stitt M (2004) Genome-wide reprogramming of primary and secondary metabolism, protein synthesis, cellular growth processes, and the regulatory infrastructure of Arabidopsis in response to nitrogen. Plant Physiol 136:2483–2499

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  66. Causin HF (1996) The central role of amino acids on nitrogen utilization and plant growth. J Plant Physiol 149:358–362

    Article  Google Scholar 

  67. Lee J, Finn CE (2012) Lingonberry (Vaccinium vitis-idaea L.) grown in the Pacific Northwest of North America: anthocyanin and free amino acid composition. J Funct Foods 4:213–218

    Article  CAS  Google Scholar 

  68. Kim YB, Park S-Y, Thwe AA, Seo JM, Suzuki T, Kim S-J, Kim JK, Park SU (2013) Metabolomic analysis and differential expression of anthocyanin biosynthetic genes in white-and red-flowered buckwheat cultivars (Fagopyrum esculentum). J Agric Food Chem 61:10525–10533

    Article  CAS  PubMed  Google Scholar 

  69. Jain A, Srivastava H (1984) Effect of phenolic acids on anthocyanin content in maize roots. Biol Plant 26:241–245

    Article  CAS  Google Scholar 

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Acknowledgments

This research was supported by Agriculture, Food and Rural Affairs Research Center Support Program, Ministry of Agriculture, Food and Rural Affairs and Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries (IPET) through Agri-Bio Industry Technology Development Program, funded by Ministry of Agriculture, Food and Rural Affairs (MAFRA) (316006-5).

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Correspondence to Jae Kwang Kim or Sang Un Park.

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Chang Ha Park and Hyun Ji Yeo have contributed equally to this work.

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Park, C.H., Yeo, H.J., Kim, N.S. et al. Metabolic profiling of pale green and purple kohlrabi (Brassica oleracea var. gongylodes). Appl Biol Chem 60, 249–257 (2017). https://doi.org/10.1007/s13765-017-0274-z

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  • DOI: https://doi.org/10.1007/s13765-017-0274-z

Keywords

  • Anthocyanin
  • GC-TOFMS
  • HPLC
  • Kohlrabi
  • Metabolic profiling