Production of Phenolic Compounds and Antioxidant Activity in Hairy Root Cultures of Salvia plebeia.

Salvia plebeia (Lamiaceae) is a medicinal plant containing diverse bioactive constituents that have biological properties. In this study, we determined the optimal conditions (media and auxin) for the hairy root culture of S. plebeia for the growth and accumulation of phenolic compounds and evaluated its antioxidant activities. Rosmarinic acid and five phenylpropanoids were detected using high-performance liquid chromatography. The hairy roots grown in 1/2 SH medium with 1 mg/L NAA had a high level of rosmarinic acid content. Hairy roots cultured in 1 mg/L NAA had the highest total content of five phenylpropanoids. Compared to wild-type roots grown in the field, hairy roots (NAA 1) expressed similar levels of rosmarinic acid but significantly enhanced phenylpropanoid accumulation. Furthermore, the total phenolic content and total flavonoid content of hairy roots (NAA 1) were 2.22 and 1.73 times higher than those of wild-type roots. In the results of DPPH, ABTS, and reducing power assays, the hairy roots (NAA 1) showed higher free radical scavenging effects and reduction potential than the wild-type roots. These results suggest that S. plebeia hairy roots cultured under optimal conditions, which exhibit enhanced phenolic compound accumulation and antioxidant activity, can potentially be used as sources of antioxidants.

WUSCHEL controls genotype-dependent shoot regeneration capacity in potato.

Plant cells can reprogram their fate. The combinatorial actions of auxin and cytokinin dedifferentiate somatic cells to regenerate organs, which can develop into individual plants. As transgenic plants can be generated from genetically modified somatic cells through these processes, cell fate transition is an unavoidable step in crop genetic engineering. However, regeneration capacity closely depends on the genotype, and the molecular events underlying these variances remain elusive. In the present study, we demonstrated that WUSCHEL (WUS)-a homeodomain transcription factor-determines regeneration capacity in different potato (Solanum tuberosum) genotypes. Comparative analysis of shoot regeneration efficiency and expression of genes related to cell fate transition revealed that WUS expression coincided with regeneration rate in different potato genotypes. Moreover, in a high-efficiency genotype, WUS silencing suppressed shoot regeneration. Meanwhile, in a low-efficiency genotype, regeneration could be enhanced through the supplementation of a different type of cytokinin that promoted WUS expression. Computational modeling of cytokinin receptor-ligand interactions suggested that the docking pose of cytokinins mediated by hydrogen bonding with the core residues may be pivotal for WUS expression and shoot regeneration in potatoes. Furthermore, our whole-genome sequencing analysis revealed core sequence variations in the WUS promoters that differentiate low- and high-efficiency genotypes. The present study revealed that cytokinin responses, particularly WUS expression, determine shoot regeneration efficiency in different potato genotypes.

Metabolic Discrimination between Adventitious Roots and Standard Medicinal Part of Atractylodes macrocephala Koidz. Using FT-IR Spectroscopy.

This study aims to examine the metabolic discrimination between in vitro grown adventitious roots and the standard medicinal parts of Atractylodes macrocephala. To achieve this goal, firstly, in vitro culture conditions of adventitious roots such as indole-3-butyric acid (IBA) concentrations, types of media, inorganic salt strength of culture medium, and elicitor types and concentrations were optimized. The optimal culture conditions for proliferation of adventitious roots was found to consist of Murashige and Skoog (MS) medium containing 5 mg L-1 IBA. Whole cell extracts from adventitious roots and the standard medicinal parts of A. macrocephala were subjected to Fourier transform infrared spectroscopy (FT-IR). Principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) from FT-IR spectral data showed that adventitious roots and standard medicinal parts were clearly distinguished in the PCA and PLS-DA score plot. Furthermore, the overall metabolite pattern from adventitious roots was changed depending on the dose-dependent manner of chemicals. These results suggest that FT-IR spectroscopy can be applied as an alternative tool for the screening of higher metabolic root lines and for discriminating metabolic similarity between in vitro grown adventitious roots and the standard medicinal parts. In addition, the adventitious roots proliferation system established in this study can be directly applied as an alternative means for the commercial production of A. macrocephala.

Effects of Chilling Treatment on Baicalin, Baicalein, and Wogonin Biosynthesis in Scutellaria baicalensis Plantlets.

When plants are exposed to stressful conditions, they modulate their nutrient balance by regulating their primary and secondary metabolisms to adapt. In this study, changes in primary and secondary metabolites elicited by chilling stress treatment and the effects of treatment duration were examined in roots of Scutellaria baicalensis (S. baicalensis) plantlets. The concentrations of most sugars (maltose, glucose, sucrose, and fructose) and of several amino acids (proline and GABA), which are crucial regarding plant defense mechanisms, increased with increasing duration of chilling stress. Furthermore, salicylic acid levels increased after two-day chilling treatments, which may enhance plant tolerance to cold temperatures. The concentrations of flavones (baicalin, baicalein, and wogonin) increased during chilling stress, and those of phenolic acids (ferulic acid and sinapic acid) increased after two-day chilling treatments. The concentrations of these flavones were positively correlated with sucrose levels which acted as energy sources.

Heterologous Expression of Three Transcription Factors Differently Regulated Astragalosides Metabolic Biosynthesis in Astragalus membranaceus Hairy Roots.

Astragalus membranaceus has been used as a highly popular Chinese herbal medicine for centuries. Triterpenoids, namely astragalosides I, II, III, and IV, represent the main active compounds in this plant species. Transcription factors have a powerful effect on metabolite biosynthesis in plants. We investigated the effect of the Arabidopsis MYB12, production of anthocyanin pigment 1 (PAP1), and maize leaf color (LC) transcription factors in regulating the synthesis of astragaloside metabolites in A. membranaceus. Overexpression of these transcription factors in hairy roots differentially up-regulated these active compounds. Specifically, the overexpression of LC resulted in the accumulation of astragalosides I-IV. The content of astragalosides I and IV were, in particular, more highly accumulated. Overexpression of MYB12 increased the accumulation of astragaloside I in transgenic hairy roots, followed by astragaloside IV, and overexpression of PAP1 resulted in the increased synthesis of astragalosides I and IV. In addition, we found that overexpression of PAP1 together with LC increased astragaloside III levels. At the transcriptional level, several key genes of the mevalonate biosynthetic pathway, especially HMGR1, HMGR2, and HMGR3, were up-regulated differentially in response to these transcription factors, resulting in astragaloside synthesis in the hairy roots of A. membranaceus. Overall, our results indicated that heterologous expression of Arabidopsis MYB12, PAP1, and maize LC differentially affected triterpenoids biosynthesis, leading to the increased biosynthesis of active compounds in A. membranaceus.

Temporally distinct regulatory pathways coordinate thermo-responsive storage organ formation in potato.

Tuberization is an important developmental process in potatoes, but it is highly affected by environmental conditions. Temperature is a major environmental factor affecting tuberization, with high temperatures suppressing tuber development. However, the temporal aspects of thermo-responsive tuberization remain elusive. In this study, we show that FT homolog StSP6A is suppressed by temporally distinct regulatory pathways. Experiments using StSP6A-overexpressing plants show that post-transcriptional regulation plays a major role at the early stage, while transcriptional regulation is an important late-stage factor, suppressing StSP6A at high temperatures in leaves. Overexpression of StSP6A in leaves restores tuber formation but does not recover tuber yield at the late stage, possibly because of suppressed sugar transport at high temperatures. Transcriptome analyses lead to the identification of potential regulators that may be involved in thermo-responsive tuberization at different stages. Our work shows that potato has temporally distinct molecular mechanisms that finely control tuber development at high temperatures.

Impact of copper treatment on phenylpropanoid biosynthesis in adventitious root culture of Althaea officinalis L.

Althaea officinalis has been widely used in various pharmaceutical applications. The biological effects and significance of phenylpropanoids in numerous industries are well studied. However, fulfilling consumer demand for these commercially important compounds is difficult. The effect of heavy-metal toxic influence on plants is primarily due to a strong and rapid suppression of growth processes, as well as the decline in activity of the photosynthetic apparatus, also associated with progressing senescence processes. Some of the secondary metabolite production was triggered by the application of heavy metals, but there was not a stress response. In the adventitious root culture of A. officinalis, copper-mediated phenylpropanoid biosynthesis has been investigated in both concentration-and duration-dependent manners. High-performance liquid chromatography (HPLC) analysis revealed a total of nine different phenolic compounds in response to different concentrations of copper chloride. In this study, high productivity of phenolic compounds was observed in the copper chloride treated-adventitious root culture of A. officianalis. In particular, a low concentration of copper chloride led to a significant accumulation of phenolic compounds under optimal conditions. Moreover, all genes responsible for phenylpropanoid biosynthesis may be sensitive to phenolic compound production following copper treatment. Especially, the highest change in transcript level was observed from AoANS at 6 h. According to our findings, treatment with copper chloride (0.5 mM) for 48 or 96 h can be an appropriate method to maximize phenylpropanoid levels in A. officinalis adventitious root culture.

Evaluation of Growth, Yield, and Biochemical Attributes of Bitter Gourd (Momordica charantia L.) Cultivars under Karaj Conditions in Iran.

Vegetative and reproductive characteristics, fruit yield, and biochemical compounds of six bitter melon cultivars (Iranshahr, Mestisa, No. 486, Local Japanese, Isfahan, and Ilocano) were evaluated under Karaj conditions in Iran. The phytochemical properties of the cultivars were evaluated using both shade-dried and freeze-dried samples at three fruit developmental stages (unripe, semi-ripe, and ripe). There were significant differences in the vegetative and reproductive characteristics among cultivars, where cv. No. 486 was superior to most vegetative attributes. The fruit yield of cultivars varied from 2.98-5.22 kg/plant. The number of days to male and female flower appearance ranged from 19.00-25.33 and from 25-33 days, respectively. The leaf charantin content was in the range of 4.83-11.08 µg/g. Fruit charantin content varied with developmental stage, drying method, and cultivar. The highest charantin content (13.84 ± 3.55 µg/g) was observed at the semi-ripe fruit stage, and it was much higher in the freeze-dried samples than the shade-dried samples. Cultivar No. 486 had the highest (15.43 ± 2.4 µg/g) charantin content, whereas the lowest charantin content (8.51 ± 1.15 µg/g) was recorded in cultivar cv. Local Japanese. The highest total phenol content (25.17 ± 2.27 mg GAE/g) was recorded in freeze-dried samples of ripe fruits of cv. No. 486, whereas the lowest phenol content was detected in the shade-dried samples of semi-ripe fruits of Isfahan. cv. Flavonoid content was higher with the shade-drying method, irrespective of cultivar. In conclusion, considering the fruit yield and active biological compounds in the studied cultivars, cv. No. 486 should be grown commercially because of its higher yield and production of other secondary metabolites.

Overexpression of Ginkgo biloba Hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase 2 gene (GbHDR2) in Nicotiana tabacum cv. Xanthi.

2-C-Methyl-d-erythrol-4-phosphate (MEP) pathway in plant supplies isoprene building blocks for carotenoids and chlorophylls essential in photosynthesis as well as plant hormones such as gibberellin and abscisic acid. To assess the effect of overexpression of the terminal enzyme of the MEP pathway, 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase (HDR), transgenic Nicotiana tabacum overexpressing class 2 HDR from Ginkgo biloba (GbHDR2) under the control of 35S promoter was constructed. Contents of chlorophylls a and b in transgenic tobacco were enhanced by 19 and 7%, respectively, compared to those of the wild type. The carotenoid level was also 18% higher than that in the control plant. As a result, photosynthetic rate of the transgenic tobacco was increased by up to 51%. Diterepenoid duvatrienediol content of transgenic tobacco was also elevated by at least sixfold. To explore the molecular basis of the enhanced isoprenoid accumulation, transcript levels of the key genes involved in the isoprenoid biosynthesis were measured. Transcript levels of geranylgeranyl diphosphate synthase (GGPP), kaurene synthase (KS), gibberellic acid 20 oxidase (GA20ox), and phytoene desaturase (PD) genes in the transgenic tobacco leaves were about twofold higher compared to the wild type. Therefore, upregulation of down-stream genes involved in biosynthesis of di- and tetraterpenoids due to GbHDR2 overexpression was responsible for elevated production of isoprenoids and enhanced photosynthetic rate. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02887-5.

Metabolic Analysis of Root, Stem, and Leaf of Scutellaria baicalensis Plantlets Treated with Different LED Lights.

Light emitting diodes (LEDs) have recently been considered an efficient artificial light source in plant factories for enhancing plant growth and nutritional quality. Accordingly, this study aimed to review blue, red, and white LED light sources for efficiency and length of the growing period to produce seedlings of Scutellaria baicalensis with high nutritional value. The roots, stems, and leaves of S. baicalensis seedlings were grown under different LED lights and harvested after two and four weeks, and analyzed using high-performance liquid chromatography and gas chromatography time-of-flight mass spectrometry to identify and quantify primary and secondary metabolites. Roots, particularly in the seedlings treated with white LEDs were determined to contain the greatest concentrations of the representative compounds present in S. baicalensis: baicalin, baicalein, and wogonin, which show highly strong biological properties compared to the other plant organs. A total of 50 metabolites (amino acids, sugars, sugar alcohols, organic acids, phenolic acids, and amines) were detected in the roots, stems, and leaves of S. baicalensis seedlings, and the concentrations of primary and secondary metabolites were generally decreased with the increasing duration of LED illumination. Therefore, this study suggests that white LED light and a 2-week growing period are the most efficient conditions for the production of baicalin, baicalein, and wogonin.

Effect of Light and Dark on the Phenolic Compound Accumulation in Tartary Buckwheat Hairy Roots Overexpressing ZmLC.

Fagopyrum tataricum 'Hokkai T10' is a buckwheat cultivar capable of producing large amounts of phenolic compounds, including flavonoids (anthocyanins), phenolic acids, and catechin, which have antioxidant, anticancer, and anti-inflammatory properties. In the present study, we revealed that the maize transcription factor Lc increased the accumulation of phenolic compounds, including sinapic acid, 4-hydroxybenzonate, t-cinnamic acid, and rutin, in Hokkai T10 hairy roots cultured under long-photoperiod (16 h light and 8 h dark) conditions. The transcription factor upregulated phenylpropanoid and flavonoid biosynthesis pathway genes, yielding total phenolic contents reaching 27.0 ± 3.30 mg g-1 dry weight, 163% greater than the total flavonoid content produced by a GUS-overexpressing line (control). In contrast, when cultured under continuous darkness, the phenolic accumulation was not significantly different between the ZmLC-overexpressing hairy roots and the control. These findings suggest that the transcription factor (ZmLC) activity may be light-responsive in the ZmLC-overexpressing hairy roots of F. tataricum, triggering activation of the phenylpropanoid and flavonoid biosynthesis pathways. Further studies are required on the optimization of light intensity in ZmLC-overexpressing hairy roots of F. tataricum to enhance the production of phenolic compounds.

Comparative Analysis of Secondary Metabolites and Metabolic Profiling between Diploid and Tetraploid Morus alba L.

We profiled and quantified primary (amine, organic acids, tricarboxylic acid cycle intermediates, amino acids, and carbohydrates) and secondary metabolites (triterpenoids, phenolic acids, carotenoids, flavonoids, and anthocyanins) in the edible parts (leaves and fruits) of the diploid and tetraploid cultivar Morus alba L. 'Cheongil.' Through comprehensive metabolic profiling, the tetraploid mulberry cultivar was able to produce diverse metabolites supported by higher accumulation patterns of primary and secondary metabolites in their edible parts. In particular, the edible parts of the tetraploid showed higher accumulation patterns of most metabolites (amino acids, carbohydrates, carotenoids, and anthocyanins) than the diploid, which was supported by the results of principal component analyses (PCAs) showing a clear separation between the diploid and tetraploid groups. Additionally, this metabolome study comprehensively described the correlation between primary and secondary metabolites in the edible parts of diploid and tetraploid mulberry cultivars and provided information useful for plant breeding strategies to improve metabolite biosynthesis using polyploidy.

Yeast extract improved biosynthesis of astragalosides in hairy root cultures of Astragalus membranaceus.

The dried root of Astragalus membranaceus is a well-known herbal medicine, and it is useful in treating chronic diseases and weakness, as well as for improving overall health and vitality. Astragalosides, which are root quality indicators of A. membranaceus, are natural triterpenoid saponins that are used in the treatment of diabetes and cardiovascular diseases. Currently, there is an urgent need to improve their production because of their low quantity in plants and the difficulty of chemical synthesis. In this study, yeast extract was added to facilitate elicitation in Agrobacterium-mediated hairy root cultures, thereby enhancing astragaloside production in A. membranaceus. Results showed that yeast extract could stimulate astragaloside content effectively in the hairy roots of A. membranaceus. Moreover, astragaloside accumulation was positively correlated with the upregulation of mevalonate biosynthetic gene expression in the presence of yeast extract. Our study demonstrated that pretreatment with yeast extract (3.65 mM) for 72 h serves as an effective strategy to enhance astragaloside levels in A. membranaceus hairy root cultures. Thus, these optimal conditions can provide valuable information for the improvement of astragaloside industrial production in A. membranaceus.

Treasure from garden: Bioactive compounds of buckwheat.

Buckwheat is a gluten-free crop under the family Polygonaceae abundant with beneficial phytochemicals that provide significant health benefits. It is cultivated and adapted in diverse ecological zones all over the world. Recently its popularity is expanding as a nutrient-rich healthy food with low-calories. The bioactive compounds in buckwheat are flavonoids (i.e., rutin, quercetin, orientin, isoorientin, vitexin, and isovitexin), fatty acids, polysaccharides, proteins, and amino acids, iminosugars, dietary fiber, fagopyrins, resistant starch, vitamins, and minerals. Buckwheat possesses high nutritional value due to these bioactive compounds. Additionally, several essential bioactive factors that have long been gaining interest because these compounds are beneficial for healing and preventing several human diseases. The present review demonstrates an overview of the recent researches regarding buckwheat phytochemicals and particularly focusing on the distinct function of bioactive components with their health benefits.

Elevated Ozone Levels Affect Metabolites and Related Biosynthetic Genes in Tartary Buckwheat.

Global climate change and the industrial revolution have increased the concentration of tropospheric ozone, a photochemical air pollutant that can negatively affect plant growth and crop production. In the present study, we investigated the effects of O3 on the metabolites and transcripts of tartary buckwheat. A total of 36 metabolites were identified by gas chromatography coupled with time-of-flight mass spectrometry, and principal component analysis was performed to verify the metabolic differences between nontreated and O3-treated tartary buckwheat. The content of threonic acid increased after 2 days of the O3 treatment, whereas it decreased after 4 days of exposure, after which it gradually increased until the eighth day of exposure. In addition, the levels of most metabolites decreased significantly after the O3 treatment. On the contrary, the levels of two anthocyanins, cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside, increased more than 11.36- and 11.43-fold, respectively, after the O3 treatment. To assess the effect of O3 on the genomic level, we analyzed the expression of anthocyanin biosynthesis pathway genes in O3-treated and nontreated buckwheat using quantitative real-time reverse transcription polymerase chain reaction (PCR). We found that the expression of all anthocyanin pathway genes increased significantly in the O3-treated buckwheat compared to that in the nontreated buckwheat. Altogether, our results suggested that O3 affected the transcripts and metabolites of tartary buckwheat, which would eventually cause phenotypic changes in plants.

Integrated Analysis of Transcriptome and Metabolome in Cirsium japonicum Fisch ex DC.

Cirsium japonicum Fisch ex DC belongs to the Compositae family and has been used as a folk remedy source in Asian countries because of its health-promoting properties. It is known that C. japonicum contains flavonoids, furans, long-chain alcohols, sterols, and volatile oils. Nevertheless, the molecular mechanism of secondary metabolite biosynthesis remains poorly understood. Therefore, transcriptome analysis and metabolic profiling were performed using different parts of C. japonicum to investigate phenylpropanoid metabolism. Based on the BLASTX search results, we identified 29 orthologs of enzymes responsible for phenylpropanoid biosynthesis. Additionally, 75 metabolites were identified in C. japonicum. Most of the flavonoid biosynthetic genes were significantly expressed ranging from 2.6- to 500-fold higher in the flowers than those in the leaves. Correspondently, the total content of flavonols was 21-fold higher in the flowers than in the roots. However, the total level of flavones showed 58-fold higher amounts in the leaves than in the flowers. Additionally, the total content of flavanols was 19-fold higher in the leaves than in the roots. The results of this study provide transcriptomic and metabolic information to elucidate the tissue-specific phenylpropanoid metabolism of C. japonicum.

Accumulation of Anthocyanins through Overexpression of AtPAP1 in Solanum nigrum Lin. (Black Nightshade).

Black nightshade (Solanum nigrum) belongs to the Solanaceae family and is used as a medicinal herb with health benefits. It has been reported that the black nightshade plant contains various phytochemicals that are associated with antitumor activities. Here we employed a genetic approach to study the effects of overexpression of Arabidopsis thaliana production of anthocyanin pigment 1 (AtPAP1) in black nightshade. Ectopic expression of AtPAP1 resulted in enhanced accumulation of anthocyanin pigments in vegetative and reproductive tissues of the transgenic plants. Analysis of anthocyanin revealed that delphinidin 3-O-rutinoside-5-O-glucoside, delphinidin 3,5-O-diglucoside, delphinidin 3-O-rutinoside, petunidin 3-O-rutinoside (cis-p-coumaroyl)-5-O-glucoside, petunidin 3-(feruloyl)-rutinoside-5-glucoside, and malvidin 3-(feruloyl)-rutinoside-5-glucoside are highly induced in the leaves of AtPAP1 overexpression lines. Furthermore, ectopic expression of AtPAP1 evoked expression of early and late biosynthetic genes of the general phenylpropanoid and flavonoid pathways that include phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-coumarate CoA ligase (4CL), chalcone isomerase (CHI), and quinate hydroxycinnamoyl transferase (HCT), which suggests these genes might be transcriptional targets of AtPAP1 in black nightshade. Concomitantly, the total content of anthocyanin in the transgenic black nightshade plants was higher compared to the control plants, which supports phenotypic changes in color. Our data demonstrate that a major anthocyanin biosynthetic regulator, AtPAP1, can induce accumulation of anthocyanins in the heterologous system of black nightshade through the conserved flavonoid biosynthesis pathway in plants.

Metabolic Profiling of Nine Mentha Species and Prediction of Their Antioxidant Properties Using Chemometrics.

Mentha species are well recognized for their medicinal and aromatic properties. The comprehensive metabolite profiles of nine Mentha species have been determined. The extracts of these Mentha species were also screened for antioxidant and free radical scavenging activities. Forty-seven hydrophilic and seventeen lipophilic compounds were identified and quantified from the selected Mentha species. Also, eleven phenolic compounds, riboflavin and eight carotenoids were present, and their composition and content varied among the various Mentha species. The different Mentha species exhibited a range of antioxidant potencies. Horse mint especially exhibited the strongest antioxidant capacities (1,1-diphenyl-2-picryl-hydrazyl (DPPH), hydrogen peroxide, and reducing power assay) among the nine Mentha species. A difference between different samples from the same species was not observed by multivariate analysis. A high correlation between metabolites involved in closely linked biosynthetic pathways has been indicated. The projection to latent structure method, using the partial least squares (PLS) method, was applied to predict antioxidant capacities based on the metabolite profiles of Mentha leaves. According to the PLS analysis, several carotenoid contents, such as E-ß-carotene, 9Z-ß-carotene, 13Z-ß-carotene and lutein, as well as phenolic compounds, showed a positive relationship in reducing the power of Mentha extracts. Horse mint is a good candidate because of its high antioxidant efficacy among the nine Mentha species included in the study.

Estimation of functional components of Chinese cabbage leaves grown in a plant factory using diffuse reflectance spectroscopy.

BACKGROUND: In recent years, protected crop production using plant factories to produce high-value crops with greater functional components has become more popular in many countries. The quantification of the components, however, is mainly conducted by laboratory analyses, which are both time- and labor-consuming. The present study aimed to investigate the potential of a non-destructive diffuse reflectance spectroscopy technique for estimating functional components (i.e. glucosinolates, amino acids, sugars and carotenoids) in the leaves of Chinese cabbage grown in a plant factory. RESULTS: From the overall analysis, better estimations were obtained using the partial least square regression procedure. The important wavelengths for each functional component were identified mainly in the ultraviolet-visible regions. Identified wavelengths were 317, 390, 888 and 940 nm for sugars; 520 and 960 nm for amino acids; 385, 860 and 945 nm for glucosinolates; and 454, 472 and 530 nm for carotenoids. CONCLUSION: Optical reflectance spectroscopy shows potential as a tool for the estimation of functional components in the leaves of Chinese cabbage. The results of the present study provide useful information for the design and application of sensors with respect to on-site quantification of the functional components. © 2018 Society of Chemical Industry.