Comprehensive metabolite profile of multi-bioactive extract from tree peony (Paeonia ostii and Paeonia rockii) fruits based on MS/MS molecular networking

Comprehensive chemical and bioactive investigation of Chinese peony flower: a case of valorization of by-products as a new food ingredient from Chinese herb

Introduction

In the present study, the flower of Chinese peony (CPF), major waste by-product of Chinese Herb Radix paeoniae, was comprehensively investigated for the first time.

Methods

A validated UHPLC Orbitrap Mass spectrometry combined a three-levels characterization strategy were used to analyze CPF samples from four representative cultivars. The anti-inflammatory and antioxidant activities were analyzed using RAW264.7 cells, and DPPH, ABTS, FRAP, and ORAC antioxidant assays.

Results

A total of 150 chemical components were identified in CPF, among them, more than 50 components were reported from this species for the first time, with potential new chemicals reported. 67 quantified or semi-quantified targeted metabolomics analysis indicated a clear distinction between flower parts and four cultivars. CPF demonstrated significant antioxidant activities and displayed anti-inflammatory effects by reducing nitric oxide, IL-6, and TNF-a release in LPS-induced macrophages. Correlation analysis highlighted a strong positive correlation between total phenolic content and DPPH ABTS, and FRAP antioxidant activities.

Discussion

The present study is the first to comprehensively investigate the chemical profile and bioactivities of CPF, which provide insights into further understanding of its health-promoting potential.

The Optimization of the Debittering Process and the Exploration of Bitter Metabolites of Paeonia ostii 'Fengdan' Seeds

Tree peony seeds, traditionally used for edible oil production, are rich in α-linolenic acid (ALA). However, little attention is paid to their development as a healthcare food due to their bitter and astringent taste. The aim of this study was to optimize the debittering process of peony seeds on the basis of maintaining nutritional value and to identify the compounds that cause the taste of bitterness. We first optimized the debittering process by orthogonal experiments which reduced the polyphenol content by 90.25%, and we measured the main nutritional value of fatty acid composition, indicating that the high content of ALA is not affected by debittering. Then, we identified and determined the types and content of polyphenols, the metabolites causing bitter taste, in the samples based on LC-ESI-QQQ-MS. Principal component analysis (PCA) and orthogonal partial least square discriminant analysis (OPLS-DA) were used to compare and analyze the seeds at different stages of debittering. Thirty-eight key metabolites were identified, of which paeoniflorin, taxifolin, alibiflorin, protocatechuic acid, benzoyl paeoniflorin, quercetin-3-galactoside, and oxpaeoniflorin were significantly compared, and most of them were positively correlated with bitter taste. These results are conducive to the exploration and study of the bitter taste and nutritional value of tree peony seeds in the future.

Investigating the Optimal Membrane-Based Separation of Cynaroside From Peony Seed Meals and Assessing Its Biomedical Implications

This comprehensive study focused on evaluating and selecting seven distinct commercial membranes to develop BTESE/PA membranes. This method effectively facilitated the extraction of cynaroside from the complex composition of peony seed meal. We subsequently conducted a thorough investigation into its biological properties. These findings establish a robust foundation for future research and the development of related products. The peak concentration achieved by peony seed meal filtration (PSMF) was 234.84 ± 1.17 μg/mL. Among the commercial membranes evaluated, the PA membrane exhibited superior separation capabilities, leading to its selection for BTESE loading. Compared with BTESE treated with HCl and NH3, the HCl variant, once incorporated into the BTESE/PA membrane, enhanced cynaroside separation, achieving an impressive 90.23% recovery rate. A comprehensive investigation of the biological effects of cynaroside revealed its crucial antioxidant role, especially in SOD binding. Additionally, cynaroside has the potential to induce apoptosis in K562 cells through interactions with BCL-2 and CDK-2 enzymes. Pharmacophore screening revealed the affinity of cynaroside for the PDE5A, TNKS2, and DAPK1 proteins, suggesting that it has diverse potential applications.

Metabolite Profiling and Biological Activity Assessment of Paeonia ostii Anthers and Pollen Using UPLC-QTOF-MS

Paeonia ostii is an important economic oil and medicinal crop. Its anthers are often used to make tea in China with beneficial effects on human health. However, the metabolite profiles, as well as potential biological activities of P. ostii anthers and the pollen within anthers have not been systematically analyzed, which hinders the improvement of P. ostii utilization. With comprehensive untargeted metabolomic analysis using UPLC-QTOF-MS, we identified a total of 105 metabolites in anthers and pollen, mainly including phenylpropanoids, polyketides, organic acids, benzenoids, lipids, and organic oxygen compounds. Multivariate statistical analysis revealed the metabolite differences between anthers and pollen, with higher carbohydrates and flavonoids content in pollen and higher phenolic content in anthers. Meanwhile, both anthers and pollen extracts exhibited antioxidant activity, antibacterial activity, α-glucosidase and α-amylase inhibitory activity. In general, the anther stage of S4 showed the highest biological activity among all samples. This study illuminated the metabolites and biological activities of anthers and pollen of P. ostii, which supports the further utilization of them.

Phytochemical Analysis, Biological Activities, and Molecular Docking Studies of Root Extracts from Paeonia Species in Serbia

Without being aware of their chemical composition, many cultures have used herbaceous peony roots for medicinal purposes. Modern phytopreparations intended for use in human therapy require specific knowledge about the chemistry of peony roots and their biological activities. In this study, ethanol-water extracts were prepared by maceration and microwave- and ultrasound-assisted extractions (MAE and UAE, respectively) in order to obtain bioactive molecules from the roots of Paeonia tenuifolia L., Paeonia peregrina Mill., and Paeonia officinalis L. wild growing in Serbia. Chemical characterization; polyphenol and flavonoid content; antioxidant, multianti-enzymatic, and antibacterial activities of extracts; and in vitro gastrointestinal digestion (GID) of hot water extracts were performed. The strongest anti-cholinesterase activity was observed in PT extracts. The highest anti-ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical potential was observed in PP extracts, whereas against DPPH (2,2-diphenyl-1-picrylhydrazyl radicals), the best results were achieved with PO extracts. Regarding antibacterial activity, extracts were strongly potent against Bacillus cereus. A molecular docking simulation was conducted to gather insights into the binding affinity and interactions of polyphenols and other Paeonia-specific molecules in the active sites of tested enzymes. In vitro GID of Paeonia teas showed a different recovery and behavior of the individual bioactives, with an increased recovery of methyl gallate and digallate and a decreased recovery of paeoniflorin and its derivatives. PT (Gulenovci) and PP (Pirot) extracts obtained by UAE and M were more efficient in the majority of the bioactivity assays. This study represents an initial step toward the possible application of Paeonia root extracts in pharmacy, medicine, and food technologies.

Identification of tyrosinase inhibitors in defatted seeds of evening primrose (Oenothera biennis L.) by affinity-labeled molecular networking

The defatted seeds of evening primrose (DE), a by-product of evening primrose oil extraction, are currently underutilized. This study aimed to valorize DE by examining its effects on melanogenesis and tyrosinase activity in zebrafish embryos and in vitro, and an innovative affinity-labeled molecular networking workflow was proposed for the rapid identification of tyrosinase inhibitors in DE. Our results indicated DE significantly reduced melanin content (53.3 % at 100 μg/mL) and tyrosinse activity (80.05 % for monophenolase and 70.40 % for diphenolase at 100 μg/mL). Furthermore, through the affinity-labeled molecular networking approach, 20 compounds were identified as potential tyrosinase inhibitors within DE, predominantly flavonoids and tannins characterized by catechin and galloyl substructures. Seven of these compounds were isolated and their inhibitory effects on tyrosinase were validated using functional assays. This study not only underscores the potential of DE as a rich source of natural tyrosinase inhibitors but also establishes the effectiveness of affinity-labeled molecular networking in pinpointing bioactive compounds in complex biological matrices.

Integrated Metabolomics Approach Reveals the Dynamic Variations of Metabolites and Bioactivities in Paeonia ostii 'Feng Dan' Leaves during Development

Paeonia ostii 'Feng Dan' is widely cultivated in China for its ornamental, medicinal, and edible properties. The whole plant of tree peony is rich in bioactive substances, while the comprehensive understanding of metabolites in the leaves is limited. In this study, an untargeted metabolomics strategy based on UPLC-ESI-TOF-MS was conducted to analyze the dynamic variations of bioactive metabolites in P. ostii 'Feng Dan' leaves during development. A total of 321 metabolites were rapidly annotated based on the GNPS platform, in-house database, and publications. To accurately quantify the selected metabolites, a targeted method of HPLC-ESI-QQQ-MS was used. Albiflorin, paeoniflorin, pentagalloylglucose, luteolin 7-glucoside, and benzoylpaeoniflorin were recognized as the dominant bioactive compounds with significant content variations during leaf development. Metabolite variations during the development of P. ostii 'Feng Dan' leaves are greatly attributed to the variations in antioxidant activities. Among all tested bacteria, the leaf extract exhibited exceptional inhibitory effects against Streptococcus hemolytis-β. This research firstly provides new insights into tree peony leaves during development. The stages of S1-S2 may be the most promising harvesting time for potential use in food or pharmaceutical purposes.

Comprehensive phytochemical analysis of lingonberry (Vaccinium vitis-idaea L.) from different regions of China and their potential antioxidant and antiproliferative activities

Lingonberry are underutilised due to the lack of evaluating active compounds in different parts. In this study, the phytochemical profiles, antioxidant and antiproliferative activities of lingonberry's fruits, leaves and stems from different regions of China were compared. Ninety-five bioactive compounds were rapidly identified using a molecular network based on UPLC-Q-Exactive Orbitrap mass spectrometry. The UPLC-QqQ-MS/MS method combined with principal component analysis (PCA) quantified 18 bioactive components in 6 classes. The highest content of arbutin (15 mg/100 g DW) was found in leaves of Huzhong (P6). Ursolic acid and cyanidin-3-O-galactoside were highest in fruits of Tahe (P4) (4.5 mg/100 g DW and 3.2 mg/100 g DW, respectively). Antioxidant activities determined by DPPH, ABTS+ and FRAP methods were significantly correlated with total phenolic content (TPC), total flavonoid content (TFC) and total anthocyanin content (TAC). The results indicate that the strongest antioxidant activity and antiproliferative efficacy are observed in the fruits of Tahe (P4) and leaves of Huzhong (P6), respectively. Our results provide valuable insights into lingonberry's comprehensive development and utilization.

Comprehensive Metabolite Profile Uncovers the Bioactive Components, Antioxidant and Antibacterial Activities in Wild Tree Peony Leaves

Tree peonies (Paeonia Section Moutan)-including nine wild species, which belong to subsections Vaginatae and Delavayanae-are economically important plants with ornamental, nutritional, and medicinal applications. In this study, for the first time, we determined the bioactive components and antioxidant activities and antibacterial activities of the newly grown leaves of nine wild tree peony species (WTPS). A total of 276 bioactive components were identified through non-targeted metabolomics; more than 80% of the 276 metabolites identified are terpenoids and flavonoids. A total of 42 differential metabolites were quantitatively determined. The main differential metabolites were Paeoniflorin, Luteoloside, Hyperin, Apigenin-7-glucoside, Rhoifolin, and Cantharidin. Such a high terpenoid and flavonoid content of the leaf extracts renders them as species with strong antibacterial capacities, and most of the bacteria tested showed greater sensitivity derived from the members of subsection Vaginatae than those of subsection Delavayanae. All WTPS have significant antioxidant activity; this activity is attributed to high levels of the total phenolic content (TPC) and total flavonoid content (TFC), of which, among the nine WTPS, P. lutea has the strongest antioxidant capacity. Our results provided a theoretical basis for the in-deep application of tree peony leaves for food, medical, and pharmaceutical industries.

The efficient removal of congo red and ciprofloxacin by peony seeds shell activated carbon with ultra-high specific surface area

Preparation of high-performance activated carbon from agroforestry waste biomass can effectively improve the shortcomings of traditional biomass carbon performance. Using the waste biomass peony seeds shell (PSS) as the precursors in this study, high performance activated carbon was prepared by the KOH two-step activation method and used to remove congo red (CR) and ciprofloxacin (CIP) in water pollution. The obtained PSS-based activated carbons (PSACs) were characterized by SEM, EDS, N₂ adsorption-desorption isotherm, FTIR, and XRD methods. The results showed that the activated carbon at 700 °C (PSAC-700) had an ultra-high specific surface area (2980.96 m²/g), excellent micropore volume (1.12 cm³/g), and abundant surface functional groups. The results of adsorption performance revealed that PSAC-700 exhibited excellent adsorption capacity for CR (q_max = 2003.2 mg/g) and CIP (q_max = 782.3 mg/g), which was superior to the carbon-based adsorbents reported reviously in the literature. Langmuir model could well describe the adsorption process of PSACs for CR and CIP, indicating that the pollutant molecules were uniformly adsorbed on the surface monolayer. The regeneration experiment suggested that after three cycles, the adsorption capacities of PSAC-700 for CR and CIP reached 1814 mg/g and 697 mg/g, respectively, with good repeatability. The preparation of PSAC-700 in this study has high adsorption capacity and strong application, which is an ideal material for wastewater purification adsorbent and has broad application prospect.

Trans-gnetin H isolated from the seeds of Paeonia species induces autophagy via inhibiting mTORC1 signalling through AMPK activation

Paeonia is a well-known species of ornamental plants, traditional Chinese medicines, and emerging oilseed crops. Apart from nutritional unsaturated fatty acids, the seeds of peonies are rich in stilbenes characterized by their wide-ranging health-promoting properties. Although the typical stilbene resveratrol has been widely reported for its multiple bioactivities, it remains uncertain whether the trimer of resveratrol trans-gnetin H has properties that regulate cancer cell viability, let alone the underlying mechanism. Autophagy regulated by trans-gnetin H was detected by western blotting, immunofluorescence, and quantitative real-time PCR. The effects of trans-gnetin H on apoptosis and proliferation were examined by flow cytometry, colony formation and Cell Counting Kit-8 assays. Trans-gnetin H significantly inhibits cancer cell viability through autophagy by suppressing the phosphorylation of TFEB and promoting its nuclear transport. Mechanistically, trans-gnetin H inhibits the activation and lysosome translocation of mTORC1 by inhibiting the activation of AMPK, indicating that AMPK is a checkpoint for mTORC1 inactivation induced by trans-gnetin H. Moreover, the binding of TSC2 to Rheb was markedly increased in response to trans-gnetin H stimulation. Similarly, trans-gnetin H inhibited the interaction between Raptor and RagC in an AMPK-dependent manner. More importantly, trans-gnetin H-mediated autophagy highly depends on the AMPK-mTORC1 axis. We propose a regulatory mechanism by which trans-gnetin H inhibits the activation of the mTORC1 pathway to control cell autophagy.

Suffruticosol C-Mediated Autophagy and Cell Cycle Arrest via Inhibition of mTORC1 Signaling

Paeonia species are well-known ornamental plants that are used in traditional Chinese medicines. The seeds of these species are rich in stilbenes, which have wide-ranging health-promoting effects. In particular, resveratrol, which is a common stilbene, is widely known for its anticancer properties. Suffruticosol C, which is a trimer of resveratrol, is the most dominant stilbene found in peony seeds. However, it is not clear whether suffruticosol C has cancer regulating properties. Therefore, in the present study, we aimed to determine the effect of suffruticosol C against various cancer cell lines. Our findings showed that suffruticosol C induces autophagy and cell cycle arrest instead of cell apoptosis and ferroptosis. Mechanistically, suffruticosol C regulates autophagy and cell cycle via inhibiting the mechanistic target of rapamycin complex 1 (mTORC1) signaling. Thus, our findings imply that suffruticosol C regulates cancer cell viability by inducing autophagy and cell cycle arrest via the inhibition of mTORC1 signaling.

Phytochemicals and anti-tyrosinase activities of Paeonia ostii leaves and roots

Tree peony (sect. Moutan) is a kind of Traditional Chinese Medicine and ornamental plant, which has been widely cultivated and utilized for thousands of years. To further study the active components of Paeonia ostii (Moutan, Fengdan), six fractions (soluble free (F), soluble esterification, soluble glycosylation, insoluble bound, insoluble esterification and insoluble glycosylation) were extracted from the leaves and roots by alkaline and acid treatment for the first time. Twenty-one typical compounds were identified and quantified by HPLC-MS. The results showed that total phenolic content (TPC) in peony roots (PR) and peony leaves (PL) were as high as 125.48 and 280.38 mg GAE·g^-1 dw, which maximizes the extraction efficiency of phenolic compounds, especially leaves, compared with the conventional method. PR-F and PL-F had the highest TPC, antioxidant and anti-tyrosinase activities. Paeoniflorin was the main compounds in PL and PR. It and pentagalloylglucose (PGG) almost reached the anti-tyrosinase level of kojic acid, but they showed different inhibitory mechanisms by molecular docking. On the whole, PR-F, PL-F, PGG and paeoniflorin might be potential for skin whitening products.

A Novel Strategy for Unveiling Spatial Distribution Pattern of Gallotannins in Paeonia rockii and Paeonia ostii Based on LC–QTRAP–MS

Gallotannins (GTs) are a series of hydrolyzable tannins with multiple health-promoting effects. In this study, an integrated liquid chromatography tandem mass spectrometry (LC–MS/MS) strategy was developed for unveiling the spatial distribution pattern of GTs in the emerging oilseed crops Paeonia rockii and P. ostii. According to the fragmentation behavior of the representative GT (1,2,3,4,6-penta-O-galloyl-β-D-glucose, PGG), the diagnostic neutral loss (NL) of 170 Da was chosen for the non-targeted screening of GT precursors. Simultaneously, the tandem mass spectrometry spectrum (MS/MS) information was acquired through an enhanced product ion (EPI) scan. Nine major GTs were identified in tree peony. To quantify the targeted GTs in different tissues of tree peony, we established a multiple reaction monitoring (MRM)–enhanced product ion (EPI)-based pseudo-targeted approach under the information-dependent acquisition (IDA) mode. The quantitative results show that the GT compounds were ubiquitous in tree peony plants with diverse structures. The typical GT PGG was mainly distributed in roots, leaves, and petals. This strategy can also be utilized for metabolite characterization and quantification in other substrates.

In situ net fishing of α-glucosidase inhibitors from evening primrose (Oenothera biennis) defatted seeds by combination of LC-MS/MS, molecular networking, affinity-based ultrafiltration, and molecular docking

Defatted seeds of evening primrose (DSEP), the by-product of evening primrose oil manufacture, exhibit potential α-glucosidase inhibitory activity; however, presently they are routinely discarded as waste. In this study, an in situ net fishing strategy was proposed for rapid recognition of α-glucosidase inhibitors from DSEP. Firstly, the DSEP extraction method was optimized employing a response surface methodology for the recovery of α-glucosidase inhibitors, just like "finding a good fishery before net fishing". Then, molecular networks of DSEP were generated by GNPS-based molecular networking after LC-MS/MS analysis, just like "casting tight nets in the fishery". Subsequently, affinity-based ultrafiltration was carried out for fishing the "hit" together with its structural analogues according to the molecular networks, just like "hauling the specific net fishing". Finally, molecular docking analysis was performed to rapidly verify α-glucosidase inhibitory activities of the potential bioactive components and predict their inhibition mechanisms. In the results, DSEP displayed significant inhibitory effects against yeast and rat intestinal α-glucosidase, and the results of an oral starch tolerance test suggested that DSEP showed postprandial blood-glucose-lowering activity. Moreover, 1-galloyl-glucose, gallic acid, methyl gallate, 1,6-digalloyl-β-D-glucose, and 1,3,6-trigalloylglucose were rapidly identified as potential α-glucosidase inhibitors present in DSEP.

Metabolite Profiling and Classification of Highbush Blueberry Leaves under Different Shade Treatments

Blueberry belongs to the genus Vaccinium L. in the Ericaceae and is an economically important shrub that produces small berries that are rich in nutrients. There were differences in the appearance of blueberry leaves under different shade treatments. To explore the differences in metabolites in blueberry leaves under different shading treatments, nontargeted liquid chromatography-mass spectrometry (LC-MS) metabonomic analysis was performed. Different shade intensities resulted in significant differences in the contents of metabolites. A total of 6879 known metabolites were detected, including 750 significantly differentially expressed metabolites, including mainly lipids and lipid-like molecules and phenylpropanoid and polyketide superclass members. Based on a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, the flavone and flavonol biosynthesis pathways were the most significantly enriched. The results of this study provide a reference and scientific basis for the establishment of a high-quality and high-yield shaded blueberry cultivation system.