High-Resolution Liquid Chromatography-Mass Spectrometry-Based Metabolomic Discrimination of Citrus-Type Crude Drugs and Comparison with Nuclear Magnetic Resonance Spectroscopy-Based Metabolomics

Green and highly effective extraction of bioactive flavonoids from Fructus aurantii employing deep eutectic solvents-based ultrasonic-assisted extraction protocol

In China, Jiang Fructus aurantii (JFA) has attracted increasing interest as a famous traditional herbal medicine and valuable economic food for its valuable medicinal and industrial properties. In the current work, contrasted with conventional extraction techniques, natural flavonoids from JFA (naringin and neohesperidin) were extracted with remarkable effectiveness utilizing a sustainable deep eutectic solvents combined ultrasonic-assisted extraction (DESs-UAE) protocol. The optimal extraction capacity can be achieved by mixing 30 % water with a molar ratio of 1:3 for choline chloride and ethylene glycol, as opposed to the classical extraction solvents of 95 % ethanol, methanol, and water. Moreover, the DESs-UAE extraction programs were also systematically optimized employing Box-Behnken design (BBD) trials, and the eventual findings suggested that the best parameters were a 27 % water content in DES, a 16 mL/g liquid-solid ratio, a 72 min extraction time, and a 62 °C extraction temperature, along with the corresponding greatest contents of NAR (48.18 mg/g) and NEO (34.50 mg/g), respectively. Notably, by comparison with the pre-optimization data, the optimized DES extraction efficiency of flavonoids is markedly higher. Thereafter, the characterization of the solvents before and after extraction, as well as the differences between the four extraction solvent extracts, were compared using the FT-IR analyses. Furthermore, SEM results suggested that the penetration and erosion abilities of the plant cell wall of DES-1 were stronger than those of the other three traditional solvents, thus allowing more release of flavonoid compounds. In conclusion, the present research develops a straightforward, sustainable, and exceedingly efficient approach for the extraction of bioactive flavonoids from JFA, which has the potential to facilitate the efficient acquisition of active ingredients from TCM.

Exploring the roles of microorganisms and metabolites in the 30-year aging process of the dried pericarps of Citrus reticulata 'Chachi' based on high-throughput sequencing and comparative metabolomics

GuangChenpi (GCP), the dried pericarps of Citrus reticulata 'Chachi', has been consumed daily as a food and dietary supplement in China for centuries. Its health benefits are generally recognized to be dependent on storage time. However, the specific roles of microorganisms and metabolites during long-term storage are still unclear. In this study, comparative metabolomics and high-throughput sequencing techniques were used to investigate the effects of co-existing microorganisms on the metabolites in GCP stored from 1 to 30 years. In total, 386 metabolites were identified and characterized. Most compounds were flavonoids (37%), followed by phenolic acids (20%). Seventeen differentially upregulated metabolites were identified as potential key metabolites in GCP, and 8 of them were screened out as key active ingredients by Venn diagram comparative analyses and verified by network pharmacology and molecular docking. In addition, long-term storage could promote the accumulation of secondary metabolites. Regarding the GCP microbiota, Xeromyces dominated the whole 30-year aging process.Moreover, Spearman correlation analysis indicated that Bacillus thuringiensis and Xeromyces bisporus, the dominant bacterial and fungal species, were strongly associated with the key active metabolites. Our results suggested that the change of active ingredients caused by the dominant microbial is one of the mechanisms affecting the GCP aging process. Our study provides novel functional insights and research perspectives on microorganism-associated metabolite changes that may improve the GCP aging process.

Narirutin. A flavonoid found in citrus fruits modulates cell cycle phases and inhibits the proliferation of hormone-refractory prostate cancer cells by targeting hyaluronidase

Narirutin is a dietary flavanone found in lemons, oranges, passion fruit, bergamot and grapefruit. It possesses anti-allergic, cardioprotective, neuroprotective, hepatoprotective potential, and its enriched fraction suppresses the growth of prostate cancer cells; however, there is currently no information on the chemopreventive potential of narirutin alone against hormone-refractory prostate cancer cells (PC-3) and its mode of action. Thus, the chemopreventive possibility of narirutin was investigated in PC-3 cells by utilising cytotoxicity assays. Further, a mechanism was deduced targeting hyaluronidase, an early-stage diagnosis marker, by cell-free, cell-based and in silico studies. The results indicate that narirutin reduced the viability of PC-3 cells with the inhibitory concentration range of 66.87-59.80 μM. It induced G0/G1 phase arrest with a fold change of 1.12. Besides, it increased the generation of reactive oxygen species (ROS) with a fold change of 1.34 at 100 μM. Narirutin inhibited hyaluronidase's activity in cell-free (11.17 μM) and cell-based assays (67.23 μM) and showed a strong binding interaction with hyaluronidase. Finally, the MD simulation analysis supported the idea that narirutin binding enhanced compactness and stability and created a stable complex with hyaluronidase. In addition, ADMET prediction indicates that it is a non-toxic, non-CYPs inhibitor and thus didn't alter the metabolism. The results reveal that narirutin may be a potential chemopreventive agent for hormone-resistant prostate cancer cells in addition to offering data for supporting diet-based nutraceutical agents to prevent prostate cancer.

Effect of Transgenic Rootstock Grafting on the Omics Profiles in Tomato

Grafting of non-transgenic scion onto genetically modified (GM) rootstocks provides superior agronomic traits in the GM rootstock, and excellent fruits can be produced for consumption. In such grafted plants, the scion does not contain any foreign genes, but the fruit itself is likely to be influenced directly or indirectly by the foreign genes in the rootstock. Before market release of such fruit products, the effects of grafting onto GM rootstocks should be determined from the perspective of safety use. Here, we evaluated the effects of a transgene encoding β-glucuronidase (GUS) on the grafted tomato fruits as a model case. An edible tomato cultivar, Stella Mini Tomato, was grafted onto GM Micro-Tom tomato plants that had been transformed with the GUS gene. The grafted plants showed no difference in their fruit development rate and fresh weight regardless of the presence or absence of the GUS gene in the rootstock. The fruit samples were subjected to transcriptome (NGS-illumina), proteome (shotgun LC-MS/MS), metabolome (LC-ESI-MS and GC-EI-MS), and general food ingredient analyses. In addition, differentially detected items were identified between the grafted plants onto rootstocks with or without transgenes (more than two-fold). The transcriptome analysis detected approximately 18,500 expressed genes on average, and only 6 genes were identified as differentially expressed. Principal component analysis of 2,442 peaks for peptides in proteome profiles showed no significant differences. In the LC-ESI-MS and GC-EI-MS analyses, a total of 93 peak groups and 114 peak groups were identified, respectively, and only 2 peak groups showed more than two-fold differences. The general food ingredient analysis showed no significant differences in the fruits of Stella scions between GM and non-GM Micro-Tom rootstocks. These multiple omics data showed that grafting on the rootstock harboring the GUS transgene did not induce any genetic or metabolic variation in the scion.

UHPLC/MS and NMR-Based Metabolomic Analysis of Dried Water Extract of Citrus-Type Crude Drugs

Citrus-type crude drugs (CCDs) are commonly used to formulate decoctions in Kampo formula (traditional Japanese medicine). Our previous study reported metabolomic analyses for differentiation of the methanol extracts of Citrus-type crude drugs (CCDs) using ultra-HPLC (UHPLC)/MS, and ¹³C- and ¹H-NMR. The present study expanded the scope of its application by analyzing four CCD water extracts (Kijitsu, Tohi, Chimpi, and Kippi); these CCDs are usually used as decoction ingredients in the Kampo formula. A principal component analysis score plot of processed UPLC/MS and NMR analysis data indicated that the CCD water extracts could be classified into three groups. The loading plots showed that naringin and neohesperidin were the distinguishing components. Three primary metabolites, α-glucose, β-glucose, and sucrose were identified as distinguishing compounds by NMR spectroscopy. During the preparation of CCD dry extracts, some compounds volatilized or decomposed. Consequently, fewer compounds were detected than in our previous studies using methanol extract. However, these results suggested that the combined NMR- and LC/MS-based metabolomics can discriminate crude drugs in dried water extracts of CCDs.

A Combined Phytochemistry and Network Pharmacology Approach to Reveal the Effective Substances and Mechanisms of Wei-Fu-Chun Tablet in the Treatment of Precancerous Lesions of Gastric Cancer

Wei-Fu-Chun (WFC) tablet is a commercial medicinal product approved by China Food and Drug Administration, which is made of Panax ginseng C.A.Mey., Citrus aurantium L., and Isodon amethystoides (Benth.). WFC has been popularly used for the treatment of precancerous lesions of gastric cancer (PLGC) in clinical practice. In this study, a UHPLC-ESI-Q-TOF/MS method in both positive and negative ion mode was employed to rapidly survey the major constituents of WFC. 178 compounds including diterpenoids, triterpenes, sesquiterpenes, flavonoids, saponins, phenylpropanoids, lignans, coumarins, organic acids, fatty acids, quinones, and sterols, were identified by comparing their retention times, accurate mass within 5 ppm error, and MS fragmentation ions. In addition, 77 absorbed parent molecules and nine metabolites in rat serum were rapidly characterized by UHPLC-ESI-Q-TOF/MS. The network pharmacology method was used to predict the active components, corresponding therapeutic targets, and related pathways of WFC in the treatment of PLGC. Based on the main compounds in WFC and their metabolites in rat plasma and existing databases, 13 active components, 48 therapeutic targets, and 61 pathways were found to treat PLGC. The results of PLGC experiment in rats showed that WFC could improve the weight of PLGC rats and the histopathological changes of gastric mucosa partly by inhibiting Mitogen-activated protein kinase (MAPK) signaling pathway to increase pepsin secretion. This study offers an applicable approach to identify chemical components, absorbed compounds, and metabolic compounds in WFC, and provides a method to explore bioactive ingredients and action mechanisms of WFC.

Esterified carotenoids are synthesized in petals of carnation (Dianthus caryophyllus) and accumulate in differentiated chromoplasts

Although yellow and orange petal colors are derived from carotenoids in many plant species, this has not yet been demonstrated for the order Caryophyllales, which includes carnations. Here, we identified a carnation cultivar with pale yellow flowers that accumulated carotenoids in petals. Additionally, some xanthophyll compounds were esterified, as is the case for yellow flowers in other plant species. Ultrastructural analysis showed that chromoplasts with numerous plastoglobules, in which flower-specific carotenoids accumulate, were present in the pale yellow petals. RNA-seq and RT-qPCR analyses indicated that the expression levels of genes for carotenoid biosynthesis and esterification in pale yellow and pink petals (that accumulate small amounts of carotenoids) were similar or lower than in green petals (that accumulate substantial amounts of carotenoids) and white petals (that accumulate extremely low levels of carotenoids). Pale yellow and pink petals had a considerably lower level of expression of genes for carotenoid degradation than white petals, suggesting that reduced degradation activity caused accumulation of carotenoids. Our results indicate that some carnation cultivars can synthesize and accumulate esterified carotenoids. By manipulating the rate of biosynthesis and esterification of carotenoids in these cultivars, it should be feasible to produce novel carnation cultivars with vivid yellow flowers.

Formulation of Orange Juice with Dietary Fibers Enhances Bioaccessibility of Orange Flavonoids in Juice but Limits Their Ability to Inhibit In Vitro Glucose Transport

The effect of formulating orange juice (OJ) with dietary fibers (DFs) on in vitro bioaccessibility of flavonoids and their ability to inhibit glucose transport in Caco-2 cells were investigated on Valencia orange fruit (OF), OJ, and OJ formulated with 1 and 2.8% DFs. DFs were either orange pomace (P) or commercial pulverized citrus pulp fiber (CF). Juice extraction and formulation with CF led to minimal loss of flavonoids compared to formulation with P (474 μmol/100 g for OF vs 315-368 μmol/100 g for OJ and OJ with CF, and 266-280 μmol/100 g for OJ with P). Addition of DFs led to similar or improved flavonoid bioaccessibility compared to OJ (9.5% in OJ vs 7.9-33.4% with DFs) but higher glucose transport in Caco-2 cells (0.45 μmol/min in OJ alone vs 0.64-0.94 μmol/min with DFs). This paradoxical effect was attributed to potential complexation of flavonoids and DFs, preventing flavonoids from interfering with glucose transport.