Penthorum chinense Pursh leaf tea debittering mechanisms via green tea manufacturing process and its influence on NAFLD-alleviation activities

The green-tea manufacturing process showed good effect of flavor improving, debittering and shaping in making Penthorum chinensePursh leaf (PL) tea (PLT), which serves as a polyphenol dietary supplement and beverage raw material. GC-MS results showed that its unpleasant grassy odor decreased by 42.8% due to dodecanal, geranylacetone, and (E)-2-nonenal reduction, coupled with 1-hexadecanol increasing. UPLC-ESI-TOF-MS identified 95 compounds and showed that the debittering effect of green-tea manufacturing process was attributed to decreasing of flavonols and lignans, especially quercetins, kaempferols and luteolins, and increasing of dihydrochalcones which act as sweeteners bitterness-masking agents, while astringency was weakened by reducing delphinidin-3,5-O-diglucoside chloride, kaempferol-7-O-β-d-glucopyranoside, and tannins. The increase of pinocembrins and catechins in aqueous extracts of PLT, maintained its hepatoprotective, NAFLD-alleviation, and hepatofibrosis-prevention activities similar to PL in high fat-diet C57BL/6 mice, with flavonoids, tannins, tannic acids, and some newfound chemicals, including norbergenin, gomisin K2, pseudolaric acid B, tanshinol B, as functional ingredients.

Integration of widely targeted metabolomics and the e-tongue reveals the chemical variation and taste quality of Yunnan Arabica coffee prepared using different primary processing methods

UPLC-Q-TOF-MS and electronic tongue analysis were applied to analyse the metabolic profile and taste quality of Yunnan Arabica coffee under seven primary processing methods. The total phenolic content ranged from 34.44 to 44.42 mg/g DW, the e-tongue results revealed the strongest umami sensor response value in the sample prepared with traditional dry processing, while the samples prepared via honey processing II had the strongest astringency sensor response value. Metabolomics analysis identified 221 differential metabolites, with higher contents of amino acids and derivatives within dry processing II sample, and increased contents of lipids and phenolic acids in the honey processing III sample. The astringency and aftertaste-astringency of the coffee samples positively correlated with the trigonelline, 3,5-di-caffeoylquinic acid and 4-caffeoylquinic acid content. The results contributed to a better understanding of how the primary processing process affects coffee quality, and supply useful information for the enrichment of coffee biochemistry theory.

Foodomics uncovers functional and volatile metabolite dynamics in red raspberry chewable tablet optimized processing

Raspberries are known to contain valuable metabolites and possess a robust antioxidant capacity. However, the impact of different tablet processing stages on the nutritional content and flavor profile of raspberries remains unclear. The dynamic profile of functional and volatile metabolites was investigated through foodomics combined with UPLC-MS/MS-based widely targeted metabolomics and HS-SPME-GC-MS, and antioxidant capacities were assessed during tablet processing. 1336 functional metabolites and 645 volatile metabolites were identified. Results indicated tablets retained 34% ∼ 61% of the total volatile contents. In addition, the conversion intensity of functional metabolites was consistent with the order of "Tableting > Freeze-drying > Crushing". Compared to raspberry, tablets showed higher antioxidant activity, which was positively correlated with vitamin contents. This study elucidated that tablet formation demonstrated advantages in antioxidation and aroma retention, which may provide insights for enhancing quality during the tableting process.

Dynamic changes of key metabolites in Longjing green tea during processing revealed by widely targeted metabolomic profiling and sensory experiments

In this study, widely targeted metabolomics and chemometrics were utilized to comprehensively analyse the formation of taste compounds in Longjing green tea. A total of 580 non-volatile metabolites were identified by using ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, and alterations in three metabolic pathways were investigated. Notably, the fixation process reduced phosphatidic acid levels, resulting in the formation of lyso-phosphatidylcholine and lyso-phosphatidylethanolamine, as well as the release of esterified polyunsaturated fatty acids. Baiye No.1 had high levels of L-glutamic acid and l-glutamine, while Longjing 43 showed elevated levels of flavones. Correlation analysis and sensory verification indicated that the specific concentration of L-leucine could decrease the umami of the tea. These findings advance our understanding of Longjing green tea quality improvement and cultivar development.

Nutrient composition and functional constituents of daylily from different producing areas based on widely targeted metabolomics

Daylily is a functional food with high nutritional value in China. Datong (DT) in Shanxi Province is one of the four main production areas of daylily. Therefore, Linfen (LF), Lvliang (LL), and Yangquan (YQ) in Shanxi Province have also introduced daylily from DT. However, geographical and climatic conditions and producing patterns cause variations in the daylily quality. In the present study, we found that the nutrient composition of daylilies from different producing areas of Shanxi Province varied. The key environmental factors affecting the nutrition of daylily in different regions were altitude and temperature. The widely targeted metabolomics results showed that 1642 metabolites were found in daylily. The differential metabolites between DT and YQ, LL and LF were 557, 667, and 359, respectively. Notably, 9 metabolic pathways and 59 metabolite markers were associated with daylily from different areas. This study provides a theoretical basis for the quality maintenance and health efficacy research of daylily.

Tiegun quality formation during harvest

Dioscorea opposita Thumb. cv. Tiegun is commonly consumed as both food and traditional Chinese medicine, which has a history of more than two thousand years. Harvest time directly affects its quality, but few studies have focused on metabolic changes during the harvesting process. Here, a comprehensive metabolomics approach was performed to determine the metabolic profiles during six harvest stages. Thirty eight metabolites with significant differences were determined as crucial participants. Related metabolic pathways including phenylalanine, tyrosine and tryptophan biosynthesis, stilbenoid, diarylheptanoid and gingerol biosynthesis, phenylpropanoid biosynthesis, flavonoid biosynthesis and tryptophan metabolism were the most active pathways during harvest. The results revealed that temperature has a significant impact on quality formation, which suggested that Dioscorea opposita thumb. cv. Tiegun harvested after frost had higher potential value of traditional Chinese medicine. This finding not only offered valuable guidance for yam production, but also provided essential information for assessing its quality.

Comparative metabolome profiling of Paris polyphylla var. yunnanensis cultivars and Paris luquanensis and their biological activity in zebrafish model

ETHNOPHARMACOLOGICAL RELEVANCE

Paris polyphylla var. Yunnanensis (Franch.) Hand.-Mazz., a perennial medicinal herb commonly known as "Chonglou" in Chinese, is mainly effective against innominate toxin swelling, insect sting, snake bite, traumatic injuries and various inflammatory. It is also recorded with mild toxicity. The rare species Paris luquanensis H. Li has been also used as folk medicine in Yunnan province for the same effects. Compared with P. polyphylla var. Yunnanensis (35-100 cm in height), this species has variegated leaves, and grows slower and is therefore shorter (6-23 cm in height). There are a number of different cultivars based on the shape of the petal and the height of Paris plant. However, currently, investigations into the differences of the chemical profiling of these cultivars are lacking.

AIM OF THE STUDY

This study aims to: (1) examine metabolites variations in Paris polyphylla var. Yunnanensis cultivars and Paris luquanensis; (2) investigate the different metabolite accumulation patterns between rhizomes and leaves and provide more useful information for the application of P. polyphylla var. Yunnanensis leaves; (3) compare in vivo effects on the recruitment of reactive oxygen species (ROS) and Neutrophils and toxic effects in zebrafish model between leaves and rhizomes of P. polyphylla var. Yunnanensis and P. luquanensis.

MATERIALS AND METHODS

The change patterns of metabolites in the leaves and rhizomes of four P. polyphylla var. Yunnanensis cultivars and one P. luquanensis cultivar were analyzed using an UPLC-ESI-MS/MS system. The total phenolic acid, total flavonoid, total saponin components and in vitro antioxidant activities were determined by spectrophotometric methods. The in vivo toxicity and their effects on the recruitment of ROS and neutrophils in zebrafish model were performed.

RESULTS

The widely targeted metabolomics method detected 695 metabolites in tested samples and classified as 15 known classes according to structures of the metabolites. By overall-comparing the SDMs discerned between leaves and rhizomes of each samples, 161 metabolites were substantially altered in all the cultivars. There are 62 and 64 SDMs showing constitutive differential accumulation between leaves and rhizomes of P. polyphylla var. Yunnanensis (samples A-D) and P. luquanensis (sample E), respectively. The levels of TSC, TPC and TFC decreased significantly in leaves as compared to rhizomes for all cultivars, with the exception of TPC in cultivar A, which is almost the same in leave and rhizome. The DPPH scavenging property and FRAP values of rhizomes are higher than those of leaves for all cultivars. However, there is no distinct different between leaves and rhizomes of different sample extracts for in vivo effects on the recruitment of ROS and neutrophils in zebrafish model. BL extracts showed high toxicity to the developing embryos.

CONCLUSION

As far as we are concerned, this study analyzes the P. polyphylla var. Yunnanensis and P. luquanensis variegation from the perspective of the metabolites pattern for the first time. The results give a valuable insight into the specie metabolic profiling and in vivo anti-oxidant, anti-inflammatory and toxic effects of these Paris plants.

Widely targeted metabolomics unveils baicalin-induced hippocampal metabolic alternations in a rat model of chronic unpredictable mild stress

Baicalin has various neuroprotective effects in models of nervous system disease. Our study has shown baicalin could alleviate depressive-like behaviors in a neuroendocrine mouse model. But the systematic metabolic characteristic and particular targets of baicalin in regulating depressive behaviors have never been investigated. Therefore, this study aims to reveal the hippocampal metabolic profiling of chronic unpredictable mild stress (CUMS) induced depressive rats and the potential metabolic variations after baicalin treatment. We first used the sucrose preference test and open field test to access the antidepressant effects of baicalin. Then, metabolites of the hippocampus after baicalin therapy were monitored by widely-targeted metabolomics based on ultra-performance liquid chromatography-tandem mass spectrometry technology. Finally, the potential mechanism associated with neurogenesis obtained from metabolomics was verified by immunohistochemistry. The results showed that baicalin(40,80 mg/kg) could significantly alleviate depressive behaviors induced by CUMS as demonstrated by an increase in sucrose preference and movement distance and stand-up times in open field test. In the metabolomic analysis, a total of 733 metabolites were identified after baicalin treatment including 15 differential metabolites such as organic acid and its derivatives, heterocyclic compounds, fatty acid, bile acids, amino acid and its metabolites, and so on. Enrichment for differential metabolites showed that the differential metabolites might be involved in the process of folate and cofactor biosynthesis, cholesterol metabolism, primary bile acid biosynthesis, tyrosine metabolism and dopaminergic synapse. Moreover, immunohistochemical analysis confirmed baicalin could facilitate hippocampal neurogenesis of depressive rats in CUMS model. These results suggested baicalin might exert antidepressant effects through regulating the differential metabolites which might play a crucial role in inhibiting oxidative stress and improving neurogenesis. Our findings wish to discover the potential mechanism of baicalin on depression from the metabolomics perspective and promote its clinical application.

Comparative analysis of flavonoid metabolites from different parts of Hemerocallis citrina

BACKGROUND

Hemerocallis citrina Baroni is a traditional medical and edible plant. It is rich in flavonoid compounds, which are a kind of important bioactive components with various health benefits and pharmaceutical value. However, the flavonoid metabolomics profile and the comparison of flavonoid compounds from different parts of H. citrina is scarce.

RESULTS

In this study, flavonoid metabolites were investigated from roots, stems, leaves and flowers of H. citrina. A total of 364 flavonoid metabolites were identified by UPLC-MS/MS based widely targeted metabolomics, and the four plant parts showed huge differences at flavonoid metabolic level. Compared to roots, 185, 234, and 119 metabolites accounted for upregulated differential flavonoid metabolites (DFMs) in stems, leaves, and flowers, respectively. Compared to stems, 168 and 29 flavonoid metabolites accounted for upregulated DFMs in leaves and flowers, respectively. Compared to leaves, only 29 flavonoid metabolites accounted for upregulated DFMs in flowers. A number of 35 common flavonoid metabolites were observed among six comparison groups, and each comparison group had its unique differential metabolites. The most abundant flavonoid metabolites in the four parts are flavonols and flavones, followed by flavanones, chalcones, flavanols, flavanonols, anthocyanidins, tannin, and proanthocyanidins. 6,7,8-Tetrahydroxy-5-methoxyflavone, 7,8,3',4'-tetrahydroxyflavone, 1-Hydroxy-2,3,8-trimethoxyxanthone, Farrerol-7-O-glucoside, 3',7-dihydroxy-4'-methoxyflavone, 3,3'-O-Dimethylellagic Acid, 5-Hydroxy-6,7-dimethoxyflavone, Nepetin (5,7,3',4'-Tetrahydroxy-6-methoxyflavone), (2s)-4,8,10-trihydroxy-2-methoxy-1 h,2 h-furo[3,2-a]xanthen-11-one are dominant in roots. Isorhamnetin-3-O-(6''-malonyl)glucoside-7-O-rhamnoside, 7-Benzyloxy-5-hydroxy-3',4'-methylenedioxyflavonoid, 3-Hydroxyphloretin-4'-O-glucoside are dominant in stems. Chrysoeriol-7-O-glucoside, Epicatechin glucoside, Kaempferol-3-O-rhamnoside (Afzelin)(Kaempferin)*, Azaleatin (5-O-Methylquercetin), Chrysoeriol-5-O-glucoside, Nepetin-7-O-glucoside(Nepitrin), 3,5,7,2'-Tetrahydroxyflavone; Datiscetin, Procyanidin B2*, Procyanidin B3*, Procyanidin B1, Isorhamnetin-3-O-(6''-acetylglucoside) are dominant in leaves. kaempferol-3-p-coumaroyldiglucoside, Delphinidin-3-O-sophoroside-5-O-glucoside, Limocitrin-3-O-sophoroside, Kaempferol-3-O-rutinoside(Nicotiflorin), Luteolin-7-O-(6''-malonyl)glucoside-5-O-rhamnoside are dominant in flowers.

CONCLUSION

There was significant difference in flavonoid metabolites among different parts of H. citrina. Leaves had relative higher metabolites contents than other parts. This study provided biological and chemical evidence for the different uses of various plant parts of H. citrina, and these informations are important theoretical basis for the food industry, and medical treatment.

Identification of nonvolatile chemical constituents in Chinese Huangjiu using widely targeted metabolomics

Huangjiu is a traditional Chinese alcoholic beverage, whose non-volatile chemical profile remains unclarified. Here, the non-volatile compounds of Huangjiu were first identified using a widely targeted metabolomics analysis. In total, 1146 compounds were identified, 997 of them were identified in Huangjiu for the first time. Moreover, 113 compounds were identified as key active ingredients of traditional Chinese medicines and 78 components were found as active pharmaceutical ingredients against 389 diseases. In addition, the comparative analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that Huangjiu from different regions differ in metabolite composition. Cofactor and amino acid biosynthesis and ABC transport were the dominant metabolic pathways. Furthermore, 7 metabolic pathways and 77 metabolic pathway regulatory markers were further found to be related with the different characteristics of different Huangjius. This study provides a theoretical and material basis for the quality control, health efficacy, and industrial development of Huangjiu.

Integrated omic profiling of the medicinal mushroom Inonotus obliquus under submerged conditions

BACKGROUND

The Inonotus obliquus mushroom, a wondrous fungus boasting edible and medicinal qualities, has been widely used as a folk medicine and shown to have many potential pharmacological secondary metabolites. The purpose of this study was to supply a global landscape of genome-based integrated omic analysis of the fungus under lab-growth conditions.

RESULTS

This study presented a genome with high accuracy and completeness using the Pacbio Sequel II third-generation sequencing method. The de novo assembled fungal genome was 36.13 Mb, and contained 8352 predicted protein-coding genes, of which 365 carbohydrate-active enzyme (CAZyme)-coding genes and 19 biosynthetic gene clusters (BCGs) for secondary metabolites were identified. Comparative transcriptomic and proteomic analysis revealed a global view of differential metabolic change between seed and fermentation culture, and demonstrated positive correlations between transcription and expression levels of 157 differentially expressed genes involved in the metabolism of amino acids, fatty acids, secondary metabolites, antioxidant and immune responses. Facilitated by the widely targeted metabolomic approach, a total of 307 secondary substances were identified and quantified, with a significant increase in the production of antioxidant polyphenols.

CONCLUSION

This study provided the comprehensive analysis of the fungus Inonotus obliquus, and supplied fundamental information for further screening of promising target metabolites and exploring the link between the genome and metabolites.

Key secondary metabolite markers for Wuchang Daohuaxiang rice discrimination in China

This study aimed to comprehensively elucidate the vital secondary metabolites of Wuchang Daohuaxiang (DHX) rice through widely targeted metabolomics analysis. Among the secondary metabolites detected, a total of 30 differential ones were screened out and categorized into 4 different classes, including 6 alkaloids (20%), 15 flavonoids (50%), 6 phenolic acids (20%), and 3 terpenoids (10%) between DHX and control groups. Of these, compounds as zarzissine, fagomine, arbutin, p-Hydroxypheny-β-D-allopyranoside, pimaric acid, kaurenoic acid, and isopimaric acid were more abundant in DHX than control group, with the possibility in serve as key secondary metabolites of DHX rice. Furthermore, arbutin, trigonelline and 6'-O-Feruloyl-D-sucrose were optimized as potential biomarkers for DHX rice discrimination. This study would supply data support for DHX rice authenticity and quality improvement.

Analysis of the utilization value of different tissues of Taxus×Media based on metabolomics and antioxidant activity

BACKGROUND

Taxaceae, is a class of dioecious and evergreen plant with substantial economic and ecology value. At present many phytochemical analyses have been performed in Taxus plants. And various biological constituents have been isolated from various Taxus species. However, the difference of compounds and antioxidant capacity of different tissues of T. media is not clear.

RESULTS

In the present study, we investigated the metabolites and antioxidant activity of four tissues of T. media, including T. media bark (TB), T. media fresh leaves (TFL), T. media seeds (TS), T. media aril (TA). In total, 808 compounds, covering 11 subclasses, were identified by using UPLC-MS/MS. Paclitaxel, the most popular anticancer compound, was found to accumulate most in TS, followed by TB, TFL and TA in order. Further analysis found that 70 key differential metabolites with VIP > 1.0 and p < 0.05, covering 8 subclasses, were screened as the key differential metabolites in four tissues. The characteristic compounds of TFL mainly included flavonoids and tanninsis. Alkaloids and phenolic acids were major characteristic compounds of TS and TB respectively. Amino acids and derivatives, organic acids, saccharides and lipids were the major characteristic compounds of TA. Additionally, based on FRAP and ABTS method, TS and TFL exhibited higher antioxidant activity than TB and TA.

CONCLUSION

There was significant difference in metabolite content among different tissues of T. media. TFL and TS had higher metabolites and antioxidant capacity than other tissues, indicating that TFL and TS were more suitable for the development and utilization of T. media in foods and drinks.

Phytotoxicity of microplastics to the floating plant Spirodela polyrhiza (L.): Plant functional traits and metabolomics

Freshwater ecosystems are gradually becoming sinks for terrestrial microplastics (MPs), posing a potential ecological risk. Although the effects of MPs on plankton and aquatic animals in freshwater ecosystems have been given increasing attention, the toxicity of MPs to the metabolism of aquatic plants remains unclear. Here, the model aquatic plant Spirodela polyrhiza (L.) Schleid. (S. polyrhiza) was exposed to polyvinyl chloride (PVC; 0, 10, 100 and 1000 mg/L) MPs, and changes in the plant functional traits and physiological metabolism were monitored. The results showed that the high dose of PVC MPs decreased the adventitious root elongation ratio by 41.68% and leaf multiplication ratio by 61.03% of S. polyrhiza, and resulted in the decrease in anthocyanin and nitrogen contents to 63.45% and 84.21% of the control group, respectively. Moreover, the widely targeted metabolomics analysis results showed 37 differential metabolites in the low-dose treatment and 119 differential metabolites in the high-dose treatment. PVC MPs interfered with organic matter accumulation by affecting carbon metabolism, nitrogen metabolism, amino acid metabolism and lipid metabolism, and S. polyrhiza resists PVC MP stress by regulating the synthesis and metabolism of secondary metabolites. PVC MPs had concentration-related toxicological effects on plant functional traits, inhibited plant growth and reproduction, affected plant nutrient metabolism, and exhibited profound effects on the nitrogen fate of aquatic plant habitats. Overall, we systematically summarized the metabolic response mechanisms of aquatic plants to PVC MP stress, providing a new perspective for studying the effects of MPs on plant trait function and ecological risks.

CsMYC2 is involved in the regulation of phenylpropanoid biosynthesis induced by trypsin in cucumber (Cucumis sativus) during storage

Trypsin has a new activity of scavenging superoxide anion and generating hydrogen peroxide. Trypsin can significantly improve the storage quality of C. sativus. To illustrate the mechanism of trypsin-induced resistance in fruits and vegetables, an integrated analysis of widely targeted metabolomics and transcriptomics was carried out. Transcriptomic results showed that 1068 genes highly related to phenylpropanoid biosynthesis gathered in the brown module were obtained by WGCNA. In KEGG analysis, differentially expressed genes (DEGs) were also highly enriched in EIP (Environmental Information Processing) pathways "Plant hormone signal transduction (map04075)" and "MAPK signaling pathway-plant (map04016)". Next, 87 genes were identified as the leading edge by GSEA analysis. So far, CsMYC2 was highlighted as a key transcription factor that regulates phenylpropanoid biosynthesis identified by GSEA and WGCNA. Furthermore, the major route of biosynthesis of phenylpropanoid compounds including coumarins, lignins, chlorogenic acid, flavonoids, and derivatives regulated by trypsin was also illustrated by both transcriptomic and metabolomic data. Results of O2PLS showed that CsMYC2 was positively correlated with Rosmarinic acid-3-O-glucoside, Epigallocatechin, Quercetin-3-O-sophoroside (Baimaside), and so on. Correlation between CsMYC2, phenylpropanoid related genes, and metabolites in C. sativus was illustrated by co-expression networks. Roles of CsMYC2 were further checked in C. sativus by VIGS. The results of this study might give new insight into the exploration of the postharvest resistance mechanism of C. sativus induced by trypsin and provide useful information for the subsequent mining of resistance genes in C. sativus.

Combined widely targeted metabolomics and transcriptomics analysis reveals differentially accumulated metabolites and the underlying molecular bases in fleshy taproots of distinct radish genotypes

Radish is an important taproot crop with medicinal and edible uses that is cultivated worldwide. However, the differences in metabolites and the underlying molecular bases among different radish types remain largely unknown. In the present study, a combined analysis of liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) and RNA-Seq data was conducted to uncover important differentially accumulated metabolites (DAMs) among radish accessions with green, white and red taproot flesh colours. A total of 657 metabolites were identified and 138 DAMs were commonly present in red vs. green and red vs. white accessions. Red accessions were rich in phenolic compounds, while green and white accessions had more amino acids. Additionally, 41 metabolites and 98 genes encoding 37 enzymes were enriched in the shikimate and phenolic biosynthesis pathways. CHS is the rate-limiting enzyme determining flavonoid differences among accessions. A total of 119 candidate genes might contribute to red accession-specific accumulated metabolites. Specifically, one gene cluster consisting of 16 genes, including one RsMYB1, RsMYBL2, RsTT8, RsDFR, RsANS, Rs4CL3, RsSCPL10, Rs3AT1 and RsSAP2 gene, two RsTT19 and RsWRKY44 genes and three RsUGT genes, might be involved in anthocyanin accumulation in red radish fleshy taproots. More importantly, an InDel marker was developed based on an RsMYB1 promoter mutation, and the accuracy reached 95.9% when it was used to select red-fleshed radishes. This study provides comprehensive insights into the metabolite differences and underlying molecular mechanisms in fleshy taproots among different radish genotypes and will be beneficial for the genetic improvement of radish nutritional quality.

Comparative nutritional and metabolic analysis reveals the taste variations during yellow rambutan fruit maturation

The metabolic reasons for rambutan taste variations during maturity are unknown. Here, we obtained a unique rambutan cultivar Baoyan No.2 (BY2) with a strong yellow pericarp and excellent taste, the sugar-acid ratios of which ranged from 21.7 to 94.5 during maturation. Widely targeted metabolomics analysis was performed to reveal the metabolic reasons behind these taste variations. The results showed that 51 metabolites were identified as common different metabolites (DMs), including 16 lipids, 12 amino acids and others. Among them, the abundance level of 3,4-digalloylshikimic acid exhibited a positive correlation with the titratable acids (R² = 0.9996) and a negative correlation with the sugar-acid ratio (R² = 0.9999). Therefore, it could be a taste biomarker of BY2 rambutan. Moreover, all DMs were enriched in "galactose metabolism", "fructose and mannose metabolism" and "biosynthesis of amino acids" pathways, which predominantly accounted for the taste variation. Our findings provided new metabolic evidence for the taste variation of rambutan.

Integration of metabolomics and transcriptomics analyses investigates the accumulation of secondary metabolites in maturing seed plumule of sacred lotus (Nelumbo nucifera)

Lotus seed plumule (LP) is rich in a variety of antioxidant and anti-inflammatory secondary metabolites, making it a traditional food and medicine widely used in China. Physiological and histological evidences indicated that LP mainly accumulated metabolites in 15-24 days after pollination (DAP) during their development. To systematically investigate the dynamic accumulation of major secondary metabolites, the UPLC-HRMS-based widely targeted metabolomics analyses were performed on maturing LP at 15, 18, 21, and 24 DAP. In total, 767 metabolites were identified, including many secondary metabolites, e.g., 27 % flavonoids and 8 % alkaloids. Among them, 591 were identified as differentially accumulated metabolites (DAMs). The majority of secondary metabolites showed great accumulation after 18 DAP even at the late stage of LP maturation, such as hesperidin, neohesperidin, orobol, serotonin, and lotus special O-nornuciferine, endowing mature LP with effective pharmaceutical properties. The paralleled transcriptomic analysis identified 11,019 differentially expressed genes (DEGs). Based on the comprehensive data, several systematical metabolic regulation maps were established for different secondary metabolites, and 18 DAP was found as a switching point for LP maturing from active primary metabolism to massive secondary metabolites deposition. This study provides valuable information for understanding the mechanism of secondary metabolite accumulation in maturing LP and facilitates its pharmaceutical application.

Influence of ripening stage and meteorological parameters on the accumulation pattern of polyphenols in greengages (Prunus mume Sieb. Et Zucc) by widely targeted metabolomic

Greengage is a Chinese traditional medicine food homology plant that contains abundant polyphenols. Greengages with different levels of maturity have different medicinal functions and applications. Therefore, this study comprehensively analysed the phenolic compounds in greengage of whole mature stage. Notably, the influence of climate conditions on greengage polyphenol synthesis was deeply explored. The polyphenols of greengages were profiled based on the widely targeted metabolomic technology using ultra-performance liquid chromatography-electrospray ionisation triple quadrupole mass spectrometry (UPLC-QTRAP-MS/MS). A total of 214 polyphenols were detected, covering 11 subclasses. During the ripening of greengages, these polyphenols first increased and then decreased, peaking during the swell stage. Multivariate statistical methods, including redundancy analysis (RDA), random forest analysis, Mantel test, and Spearman's correlation indicated that temperature, sunshine hours, humidity, and radiation were important factors driving the formation and changes in the polyphenols of greengages. In particular, flavanones and flavonols, showed a structure-dependent response to temperature and radiation.

Underlying antihypertensive mechanism of egg white-derived peptide QIGLF using renal metabolomics analysis

The kidney is an important target organ in the treatment of hypertension, but the effect of peptide QIGLF with antihypertensive activity on kidneys remains unknown. In the work, we aimed to further understand the hypotensive effects of QIGLF in spontaneously hypertensive rats (SHRs) using widely targeted metabolomics technology to investigate the kidney metabolic profiling variations. After four weeks of oral administration, the results showed different renal metabolomics profiles between QIGLF and model groups. Besides, a total of 10 potential biomarkers were identified, that is, 3-hydroxybutanoate, 20-hydroxyeicosatetraenoic acid, 19(S)-hydroxyeicosatetraenoic acid, 15-oxoETE, L-ornithine, malonate, uridine, uridine 5'-monophosphate, argininosuccinic acid, and N-carbamoyl-L-aspartate. These metabolites might exhibit antihypertensive activity of QIGLF by regulating synthesis and degradation of ketone bodies, arachidonic acid metabolism, pyrimidine metabolism, and arginine biosynthesis. These findings suggest that QIGLF might alleviate hypertension by inhibiting renal inflammation, promoting natriuresis, and regulating renal nitric oxide production.

sinensis) using the widely targeted metabolomics

In this study, we produced roasted, baked, steamed, and sun-dried green tea products using the same batch of fresh tea leaves (FTL) of Longjing 43 (Camellia sinensis var. sinensis), and explored processing effects on the metabolic profiles of four types of green teas (FGTs) using the widely targeted metabolomics. Results showed that 146 differential metabolites including flavonoids, amino acids, lipids, and phenolic acids were screened among 1034 non-volatiles. In addition, nineteen differential metabolites were screened among 79 volatiles. Most of non-volatiles and volatiles metabolites changed notably in different manufacturing processes, whereas there were no significant differences (p＞0.05) in the levels of total catechins between FGTs and FTL. The transformation of metabolites was the dominant trend during green tea processing. The results contribute to a better understanding of how the manufacturing process influences green tea quality, and provide useful information for the enrichment of tea biochemistry theory.

Comparison of metabolome characteristics and screening of chemical markers in Chrysanthemum indicum from different habitats

Chrysanthemum indicum is a polymorphic species with many ecological, geographical or eco-geographic populations, but there are few studies on the metabolic characteristics of different populations. This study conducted widely targeted metabolomics studies on Ch. indicum from seven typical producing areas. As a result, a total of 802 metabolites were detected and identified, among which the top three categories of metabolites were flavonoids, organic acids and amino acids and derivatives. Through multivariate statistical analysis, the seven samples from different habitats could be divided into four categories, and the significantly changed metabolites between different categories were mainly concentrated in the flavonoid synthesis pathway. Through a variety of cluster analysis, it was observed that the Ch. nankingense (Nakai) Tzvel (Chinese name Juhuanao) had the largest separation degree from other samples and were clustered into a single category. Furthermore, the corresponding candidate chemical markers were screened in this study to distinguish the Juhuanao. Correlation analysis showed that climatic factors were not the main reason for the differences in the metabolic characteristics of Ch. indicum in different populations, which indicated that Ch. indicum is indeed a species with rich variation.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-022-01137-z.

Catechin gallate acts as a key metabolite induced by trypsin in Hylocereus undatus during storage indicated by omics

Trypsin is a novel superoxide scavenger. The storage quality of H. undatus was significantly improved by trypsin. To investigate the mechanism of flavonoid metabolism regulated by trypsin, combined analysis of widely targeted metabolomic and transcriptome were performed. GO and KEGG enrichment analyses of the transcriptome profiles of H. undatus revealed that some of the flavonoid related biosynthesis pathways were regulated by up or down patterns with the treatment of trypsin. Correlation analysis of flavonoid related genes expression in H. undatus provided a rationale for the functional significance of them. Furthermore, it has been revealed that the most significantly regulated flavonoid was catechin gallate in metabolomic profiles of H. undatus. The major route of flavonoid biosynthesis regulated by trypsin was also illustrated by both transcriptomic and metabolomic data. Finally, the results of PPI network revealed that C4H, HCT, and CYP75B1 acted as hub proteins involved in flavonoid metabolism regulated by trypsin.

Widely targeted metabolomic analyses unveil the metabolic variations after stable knock-down of NME4 in esophageal squamous cell carcinoma cells

NME4, also designated nm23-H4 or NDPK-D, has been known for years for its well-established roles in the synthesis of nucleoside triphosphates, though; little has been known regarding the differential metabolites involved as well as the biological roles NME4 plays in proliferation and invasion of esophageal squamous cell carcinoma (ESCC) cells. To understand the biological roles of NME4 in ESCC cells, lentiviral-based short hairpin RNA interference (shRNA) vectors were constructed and used to stably knock down NME4. Then, the proliferative and invasive variations were assessed using MTT, Colony formation and Transwell assays. To understand the metabolites involved after silencing of NME4 in ESCC cells, widely targeted metabolomic screening was taken. It was discovered that silencing of NME4 can profoundly suppress the proliferation and invasion in ESCC cells in vitro. Metabolically, a total of 11 differential metabolites were screened. KEGG analyses revealed that Tryptophan, Riboflavin, Purine, Nicotinate, lysine degradation, and Linoleic acid metabolism were also involved in addition to the well-established nucleotides metabolism. Some of these differential metabolites, say, 2-Picolinic Acid, Nicotinic Acid and Pipecolinic Acid were suggested to be associated with tumor immunomodulation. The data we described here support the idea that metabolisms occurred in mitochondrial was closely related to tumor immunity.

Metabolome-based discrimination of chrysanthemum cultivars for the efficient generation of flower color variations in mutation breeding

INTRODUCTION

The color variations of ornamental flowers are often generated by ion-beam and gamma irradiation mutagenesis. However, mutation rates differ significantly even among cultivars of the same species, resulting in high cost and intensive labor for flower color breeding.

OBJECTIVES

We aimed to establish a metabolome-based strategy to identify biomarkers and select promising parental lines with high mutation rates using Chrysanthemum as the case study.

METHODS

The mutation rates associated with flower color were measured in 10 chrysanthemum cultivars with pink, yellow, or white flowers after soft X-ray irradiation at the floret-formation stage. The metabolic profiles of the petals of these cultivars were clarified by widely targeted metabolomics and targeted carotenoid analysis using liquid chromatography-tandem quadrupole mass spectrometry. Metabolome and carotenoid data were subjected to an un-supervised principal component analysis (PCA) and a supervised logistic regression with least absolute shrinkage and selection operator (LASSO).

RESULTS

The PCA of the metabolic profile data separated chrysanthemum cultivars according to flower color rather than mutation rates. By contrast, logistic regression with LASSO generated a discrimination model to separate cultivars into two groups with high or low mutation rates, and selected 11 metabolites associated with mutation rates that can be biomarkers candidates for selecting parental lines for mutagenesis.

CONCLUSION

This metabolome-based strategy to identify metabolite markers for mutation rates associated with flower color might be applied to other ornamental flowers to accelerate mutation breeding for generating new cultivars with a wider range of flower colors.

Widely targeted metabolomics of Alzheimer's disease postmortem cerebrospinal fluid based on 9-fluorenylmethyl chloroformate derivatized ultra-high performance liquid chromatography tandem mass spectrometry

Confirmed biomarkers of postmortem cerebrospinal fluid (pCSF) are used to differentiate between Alzheimer's disease (AD) patients and healthy seniors with high diagnostic accuracy. However, the extent to which the performance of specific metabolic profiling facilitates reliable estimations of the concentrations of the different pCSF biomarkers and their ratios remains unclear. The interpretation of the lower levels of molecules of metabolic profiling and their concentration ratios in pCSF related to brain disorders could facilitate an unchallenging detection of peripheral biomarkers of AD stages and other dementia types. In this study, we proposed the use of widely targeted metabolomics for pCSF metabolic profiling using 9-fluorenylmethyl chloroformate- (FMOC) derivatized ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) to evaluate the diversity of 97 amine-mediated metabolic patterns and pathways from confirmed diagnosis based on AD brain pathology. Our results identified the metabolites that contributed toward and mutually influenced the principal component analysis plot with integrated analytes. Furthermore, the AD group showed a significant variation in several analyte concentration levels compared to those of control subjects. These trends of the concentration levels expressed by the amine metabolic pathways indicated the decreased activity of polyamine and tryptophan-kynurenine (Trp-Kyn) metabolisms. Moreover, increased metabolites such as methionine sulfoxide, 3-methoxy-anthranilate, cadaverine, guanine, and histamine were observed by widely targeted metabolomics of pCSF from the AD subjects. According to their metabolic pathway analysis using FMOC-derivatized UHPLC-MS/MS assay, we supposed that the involvement of polyamine and Trp-Kyn metabolisms was observed in the pCSF samples.

Iterative cycle of widely targeted metabolic profiling for the improvement of 1-butanol titer and productivity in Synechococcus elongatus

BACKGROUND

Metabolomics is the comprehensive study of metabolites that can demonstrate the downstream effects of gene and protein regulation, arguably representing the closest correlation with phenotypic features. Hence, metabolomics-driven approach offers an effective way to facilitate strain improvement. Previously, targeted metabolomics on the 1-butanol-producing cyanobacterial strain Synechococcus elongatus BUOHSE has revealed the reduction step from butanoyl-CoA to butanal, catalyzed by CoA-acylating propionaldehyde dehydrogenase (PduP), as a rate-limiting step in the CoA-dependent pathway. Moreover, an increase in acetyl-CoA synthesis rate was also observed in this strain, by which the increased rate of release of CoA from butanoyl-CoA was used to enhance formation of acetyl-CoA to feed into the pathway.

RESULTS

In the present study, a new strain (DC7) with an improved activity of PduP enzyme, was constructed using BUOHSE as the background strain. DC7 showed a 33% increase in 1-butanol production compared to BUOHSE. For a deeper understanding of the metabolic state of DC7, widely targeted metabolomics approach using ion-pair reversed-phase LC/MS was performed. Results showed a decreased level of butanoyl-CoA and an increased level of acetyl-CoA in DC7 compared to BUOHSE. This served as an indication that the previous bottleneck has been solved and free CoA regeneration increased upon the improvement of the PduP enzyme. In order to utilize the enhanced levels of acetyl-CoA in DC7 for 1-butanol production, overexpression of acetyl-CoA carboxylase (ACCase) in DC7 was performed by inserting the gene encoding an ACCase subunit from Yarrowia lipolytica into the aldA site. The resulting strain, named DC11, was able to reach a production titer of 418.7 mg/L in 6 days, compared to DC7 that approached a similar titer in 12 days. A maximum productivity of 117 mg/L/day was achieved between days 4 and 5 in DC11.

CONCLUSIONS

In this study, the iterative cycle of genetic modification based on insights from metabolomics successfully resulted in the highest reported 1-butanol productivity for engineered Synechococcus elongatus PCC 7942.

Highly sensitive and selective analysis of widely targeted metabolomics using gas chromatography/triple-quadrupole mass spectrometry

In metabolomics studies, gas chromatography coupled with time-of-flight or quadrupole mass spectrometry has frequently been used for the non-targeted analysis of hydrophilic metabolites. However, because the analytical platform employs the deconvolution method to extract single-metabolite information from co-eluted peaks and background noise, the extracted peak is artificial product depending on the mathematical parameters and is not completely compatible with the pure component obtained by analyzing a standard compound. Moreover, it has insufficient ability for quantitative metabolomics. Therefore, highly sensitive and selective methods capable of pure peak extraction without any complicated mathematical techniques are needed. For this purpose, we have developed a novel analytical method using gas chromatography coupled with triple-quadrupole mass spectrometry (GC-QqQ/MS). We developed a selected reaction monitoring (SRM) method to analyze the trimethylsilyl derivatives of 110 metabolites, using electron ionization. This methodology enables us to utilize two complementary techniques-non-targeted and widely targeted metabolomics in the same sample preparation protocol, which would facilitate the formulation or verification of novel hypotheses in biological sciences. The GC-QqQ/MS analysis can accurately identify a metabolite using multichannel SRM transitions and intensity ratios in the analysis of living organisms. In addition, our methodology offers a wide dynamic range, high sensitivity, and highly reproducible metabolite profiles, which will contribute to the biomarker discoveries and quality evaluations in biology, medicine, and food sciences.