Herbaceous peony seed oil: A rich source of unsaturated fatty acids and γ-tocopherol

A review of the ethnopharmacology, phytochemistry, pharmacology, pharmacokinetics and quality control of Paeonia lactiflora Pall

ETHNOPHARMACOLOGICAL RELEVANCE

Paeonia lactiflora Pall. (called Shaoyao in China) is a common herb cultivated all over the world. In some Asian and European countries, such as China, Japan, South Korea and Britain, P. lactiflora has a long history of ethnomedical uses, which is widely used to relieve pain, treat gynecological diseases, anti-infection and so on. It is attributed to the extensive pharmacological activities of total glucosides of P. lactiflora. Up to now, it is still commonly used in clinical medicine.

THE AIM OF THE REVIEW

The paper aims to make a comprehensive review on the botanical characterization and distribution, ethnopharmacology, phytochemistry, biosynthesis pathway, pharmacology, pharmacokinetics and quality control of P. lactiflora, so as to provide new insights and scientific evidence for the subsequent research.

MATERIALS AND METHODS

The information of P. lactiflora was obtained from books related to traditional Chinese medicine and electronic databases, including Scifinder, PubMed, Web of Science, CNKI and Google Scholar.

RESULTS

P. lactiflora is a kind of herb with a long history and it is used for medicine, food and ornamental, and shows high utilization value. There are 200 compounds have been identified from it, including terpenoids, flavonoids, polyphenols, organic acids and others, among those paeoniflorin, a monoterpenoid glycoside, has multiple activities and is currently the focus of pharmacological research. A great deal of pharmacological experiments supported the anti-inflammatory, anti-oxidant, hepatoprotective, neuroprotective, antibacterial, antitumor, dermatosis treating and other effects of P. lactiflora. In addition, evaluating the quality of P. lactiflora is essential to safe use of drug in humans.

CONCLUSIONS

The chemical components of P. lactiflora are diverse and have a wide range of activities. Modern pharmacological studies have provided reliable evidence for the traditional efficacy, such as suppressing liver yang, regulating menstruation and relieving pain. However, there are still some problems to be solved, such as part of the pharmacological mechanism has not been clarified and the biosynthetic pathway of cage-like monoterpenoids remains poorly defined. In addition, further studies on compounds other than paeoniflorin are clearly warranted. It is hoped that P. lactiflora will serve the clinic better in the future.

Identification of key genes for triacylglycerol biosynthesis and storage in herbaceous peony (Paeonia lactifolra Pall.) seeds based on full-length transcriptome

BACKGROUND

The herbaceous peony (Paeonia lactiflora Pall.) is extensively cultivated in China due to its root being used as a traditional Chinese medicine known as 'Radix Paeoniae Alba'. In recent years, it has been discovered that its seeds incorporate abundant unsaturated fatty acids, thereby presenting a potential new oilseed plant. Surprisingly, little is known about the full-length transcriptome sequencing of Paeonia lactiflora, limiting research into its gene function and molecular mechanisms.

RESULTS

A total of 484,931 Reads of Inserts (ROI) sequences and 1,455,771 full-Length non-chimeric reads (FLNC) sequences were obtained for CDS prediction, TF analysis, SSR analysis and lncRNA identification. In addition, gene function annotation and gene structure analysis were performed. A total of 4905 transcripts were related to lipid metabolism biosynthesis pathway, belonging to 28 enzymes. We use these data to identify 10 oleosin (OLE) and 5 diacylglycerol acyltransferase (DGAT) gene members after de-redundancy. The analysis of physicochemical properties and secondary structure showed them similarity in gene family respectively. The phylogenetic analysis showed that the distribution of OLE and DGAT family members was roughly the same as that of Arabidopsis. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed expression changes in different seed development stages, and showed a trend of increasing and then decreasing.

CONCLUSION

In summary, these results provide new insights into the molecular mechanism of triacylglycerol (TAG) biosynthesis and storage during the seedling stage in Paeonia lactiflora. It provides theoretical references for selecting and breeding oil varieties and understanding the functions of oil storage as well as lipid synthesis related genes in Paeonia lactiflora.

Nutritional composition, health-promoting effects, bioavailability, and encapsulation of tree peony seed oil: a review

Tree peony is cultivated worldwide in large quantities due to its exceptional ornamental and medicinal value. In recent years, the edible value of tree peony seed oil (TPSO) has garnered significant attention for its high content of alpha-linolenic acid (ALA, >40%) and other beneficial minor components, including phytosterols, tocopherols, squalene, and phenolics. This review provides a systematic summary of the nutritional composition and health-promoting effects of TPSO, with a specific focus on its digestion, absorption, bioavailability, and encapsulation status. Additionally, information on techniques for extracting and identifying adulteration of TPSO, as well as its commercial applications and regulated policies, is included. Thanks to its unique nutrients, TPSO offers a wide range of health benefits, such as hypolipidemic, anti-obesity, cholesterol-lowering, antioxidant and hypoglycemic activities, and regulation of the intestinal microbiota. Consequently, TPSO shows promising potential in the food and cosmetic industries and should be cultivated in more countries. However, the application of TPSO is hindered by its low bioavailability, poor stability, and limited water dispersibility. Therefore, it is crucial to develop effective delivery strategies, such as microencapsulation and emulsion, to overcome these limitations. In conclusion, this review provides a comprehensive understanding of the nutritional value of TPSO and emphasizes the need for further research on its nutrition and product development.

Widely targeted metabolomics reveals stamen petaloid tissue of Paeonia lactiflora Pall. being a potential pharmacological resource

Paeonia lactiflflora Pall. has a long edible and medicinal history because of the very high content of biologically active compounds. However, little information is available about the metabolic basis of pharmacological values of P. lactiflora flowers. In this study, we investigated metabolites in the different parts of P. lactiflora flowers, including petal, stamen petaloid tissue and stamen, by widely targeted metabolomics approach. A total of 1102 metabolites were identified, among which 313 and 410 metabolites showed differential accumulation in comparison groups of petal vs. stamen petaloid tissue and stamen vs. stamen petaloid tissue. Differential accumulated metabolites analysis and KEGG pathway analysis showed that the flavonoids were the most critical differential metabolites. Furthermore, difference accumulation of flavonoids, phenolic acids, tannins and alkaloids might lead to the differences in antioxidant activities and tyrosinase inhibition effects. Indeed, stamen petaloid tissue displayed better antioxidant and anti-melanin production activities than petal and stamen through experimental verification. These results not only expand our understanding of metabolites in P. lactiflora flowers, but also reveal that the stamen petaloid tissues of P. lactiflora hold the great potential as promising ingredients for pharmaceuticals, functional foods and skincare products.

Can omic tools help generate alternative newer sources of edible seed oil?

There are three pathways for triacylglycerol (TAG) biosynthesis: De novo TAG biosynthesis, phosphatidylcholine-derived biosynthesis, and cytosolic TAG biosynthesis. Variability in fatty acid composition is mainly associated with phosphatidylcholine-derived TAG pathway. Mobilization of TAG-formed through cytosolic pathway into lipid droplets is yet unknown. There are multiple regulatory checkpoints starting from acetyl-CoA carboxylase to the lipid droplet biogenesis in TAG biosynthesis. Although a primary metabolism, only a few species synthesize oil in seeds for storage, and less than 10 species are commercially exploited. To meet out the growing demand for oil, diversifying into newer sources is the only choice left. The present review highlights the potential strategies targeting species like Azadirachta, Callophyllum, Madhuca, Moringa, Pongamia, Ricinus, and Simarouba, which are not being used for eating but are otherwise high yielding (ranging from 1.5 to 20 tons per hectare) with seeds having a high oil content (40-60%). Additionally, understanding the toxin biosynthesis in Ricinus and Simarouba would be useful in developing toxin-free oil plants. Realization of the importance of cell cultures as "oil factories" is not too far into the future and would soon be a commercially viable option for producing oils in vitro, round the clock.

Aqueous extracts of tree peony petals: renin and angiotensin I-converting enzyme inhibitory activities in different colours and flowering stages

Tree peony (Paeonia suffruticosa Andr.) is an ornamental and medicinal plant from China. Previous studies have detected novel blood pressure-regulating substances in this species, which potentiate its value of utilization. To explore these substances, the aqueous extracts of 7 different colours of tree peony petals were assessed for inhibitory activity on renin and angiotensin-converting enzyme (ACE). The results showed that the activity of dark-coloured samples was significantly stronger than that of light-coloured ones. Furthermore, the inhibitory activity of the red tree peony petals ‘Hong TaiYang’ on renin and ACE indicated a downward trend from bud compaction to the full opening stage. The antioxidant activities of the aqueous extracts, on one side, and the correlations between phenolics and flavonoids functionalities and total contents, on the other, were also evaluated. In this regard, the extracts of different samples had ABTS free radical scavenging capacities of 17.28–210.41 mg TE per g DW, DPPH radical scavenging capacities of 35.45–150.78 mg TE per g DW, iron ion reduction capacities of 16.66–150.77 mg TE per g DW, and total phenolic content of 23.94–150.78 mg GAE per g DW. Correlation analysis revealed that the renin and ACE inhibitory activities, the DPPH and ABTS free radical scavenging capacities, and the iron reduction ability of different sample extracts were positively correlated with total phenolic contents (p < 0.01). Finally, the aqueous phenolic compounds in the sample extracts tended to show strong renin and ACE inhibitory activities and therefore exhibit a potential auxiliary blood pressure control prospect.

Tree peony petals with different colours and flowering stages were assessed for renin/ACE inhibition. Dark-coloured samples showed higher inhibition than light-coloured ones, and a downward inhibitory trend was found from bud to full opening stage.

Effect of Different Solvents on the Extraction of Oil from Peony Seeds (Paeonia suffruticosa Andr.): Oil Yield, Fatty Acids Composition, Minor Components, and Antioxidant Capacity

Peony seed oil is full of nutrition and exert positive effects on human's health. The influences of seven solvents (isopropanol, acetone, Hx:Iso (n-hexane/isopropanol, 3:2 v/v), Chf:Me (chloroform/methanol, 1:1 v/v), ethyl acetate, n-hexane, and petroleum ether) on the oil yields, lipid composition, minor components and antioxidant capacity of peony seed oil were compared in this study. Results indicated that the highest oil yield (35.63%) was obtained using Hx:Iso, while Chf:Me showed the best extraction efficiency for linolenic acid (43.68%), trilinolenoyl-glycerol (15.00%), and dilinolenoyl-linoleoyl-glycerol (18.01%). For minor components, Chf:Me presented a significant advantage in the extraction of tocopherol (601.49 mg/kg), and the peony seed oil extracted with petroleum ether had the highest sterols (4089.82 mg/kg) and squalene contents (66.26 mg/kg). Although the use of isopropanol led to a lower sterol content, its extracts showed a significant higher polyphenol content (68.88 mg GAE/kg) than other solvents and exhibited the strongest antioxidant capacity. Additionally, correlation analysis revealed that polyphenols were the most important minor component for predicting the antioxidant capacity of peony seed oil. The above information is valuable for manufacturers to select suitable solvents to produce peony seed oil with the required levels of fatty acids and minor components for targeted end-use.

Effects of Radio Frequency Pretreatment on Quality of Tree Peony Seed Oils: Process Optimization and Comparison with Microwave and Roasting

In this study, we explored the technical parameters of tree peony seeds oil (TPSO) after their treatment with radio frequency (RF) at 0 °C-140 °C, and compared the results with microwave (MW) and roasted (RT) pretreatment in terms of their physicochemical properties, bioactivity (fatty acid tocopherols and phytosterols), volatile compounds and antioxidant activity of TPSO. RF (140 °C) pretreatment can effectively destroy the cell structure, substantially increasing oil yield by 15.23%. Tocopherols and phytosterols were enhanced in oil to 51.45 mg/kg and 341.35 mg/kg, respectively. In addition, antioxidant activities for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power (FRAP) were significantly improved by 33.26 μmol TE/100 g and 65.84 μmol TE/100 g, respectively (p < 0.05). The induction period (IP) value increased by 4.04 times. These results are similar to those of the MW pretreatment. The contents of aromatic compounds were significantly increased, resulting in improved flavors and aromas (roasted, nutty), by RF, MW and RT pretreatments. The three pretreatments significantly enhanced the antioxidant capacities and oxidative stabilities (p < 0.05). The current findings reveal RF to be a potential pretreatment for application in the industrial production of TPSO.

Enzyme-assisted Solvent Extraction of High-yield Paeonia suffruticosa Andr. Seed Oil and Fatty Acid Composition and Anti-Alzheimer's Disease Activity

Enzyme-assisted solvent extraction (EASE) of Paeonia suffruticosa Andr. seed oil (PSO) was optimized by response surface methodology (RSM). The fatty acid composition and anti-Alzheimer's disease (AD) activity of PSO were analyzed. An enzyme mixture composed of cellulase and hemicellulase (1:1, w/w) was most effective in determining the extraction yield of PSO. The ideal extraction conditions were a pH value of 5.1, an enzymolysis time of 68 min, and a temperature of 50℃. The average extraction yield of PSO was 38.2 mL/100 g, 37.4% higher than that of untreated peony seed (27.8 mL/100 g). The fatty acid composition of PSO under optimal conditions for EASE was analyzed by gas chromatography-mass spectrometry (GC-MS). The predominant unsaturated fatty acids of PSO were determined to be more than 90.00%, including n-3 α-linolenic acid (43.33%), n-6 linoleic acid (23.40%) and oleic acid (23.59%). In this experiment, the anti-AD effect of PSO was also analyzed by performing learning and memory ability tests with Drosophila. PSO retarded the decrease in climbing ability in AD Drosophila. The 1% and 5% PSO groups were significantly different from the model group (^b p < 0.05). The smell short-term memory ability test revealed the number of Drosophila in barrier and barrier-free centrifuge tubes in each group. PSO feeding improved learning and memory in AD Drosophila, with the highest number entering the barrierfree centrifuge tube. The performance index (PI) measured by the Pavlov olfactory avoidance conditioning test also demonstrated the effect of PSO on the learning and memory abilities of Drosophila. The PI of the PSO group was significantly increased compared to that of the model group. HE-stained brain tissue sections of AD Drosophila showed higher neurodegenerative changes, while PSO significantly reduced neurodegenerative damage. These results indicated that PSO can significantly improve the cognitive function of AD Drosophila and may help to prevent AD.

Rapid detection of Chinese-specific peony seed oil by using confocal Raman spectroscopy and chemometrics

Peony seed oil (PSO) is a new woody nut oil which is unique to China. Its unsaturated fatty acids are over 90% and are rich in α - linolenic acid. Although the PSO industry is in its infancy, it is bound to become a top vegetable oil food material because of its own advantages. The potential high commercial profit of its adulteration with cheap vegetable oil will be an important factor hindering the healthy development of PSO industry. It is of great significance to study the adulteration of PSO for preventing large-scale adulteration. In this study, the qualitative and quantitative analysis of PSO was realised based on Raman spectroscopy combined with chemometrics analysis, and the fatty acid composition of PSO was analysed according to Raman characteristic peaks. The technology can be applied to routine analysis and quality control of PSO.

UPLC-ESI-MS/MS Analysis and Evaluation of Antioxidant Activity of Total Flavonoid Extract from Paeonia lactiflora Seed Peel and Optimization by Response Surface Methodology (RSM)

In this study, the ultrasound-assisted extraction (UAE) of flavonoid from Paeonia lactiflora seed peel was optimized by response surface methodology (RSM). Single-factor experiments and a three-factor three-level Box-Behnken design (BBD) were performed to explore the effects of the following parameters on flavonoid extraction: ethanol concentration (X₁), liquid-solid ratio (X₂), and ultrasonic time (X₃). The results showed that the optimal flavonoid yield (10.9045 mg RE/g) was as follows: ethanol concentration 62.93%, ultrasonic time 64.56 min, and liquid-solid ratio 24.86 mL/g. The optimized extract of P. lactiflora seed shell was further analyzed by UPLC-ESI-MS/MS, and 20 main flavonoids were identified and quantified, among which protocatechuic acid, vanillic acid, 4-hydroxybenzoic acid, and 3,4-dihydroxybenzaldehyde had the highest content. Furthermore, the results of the antioxidant test showed that the P. lactiflora seed peel extract obtained under optimized UAE conditions exhibited good antioxidant activity. The experimental results showed that ultrasound-assisted extraction was a fast, efficient, and simple method for extracting active ingredients from P. lactiflora seed peel, thereby making this byproduct a promising source of compounds in food and healthcare sectors.

Identification of genes associated with the biosynthesis of unsaturated fatty acid and oil accumulation in herbaceous peony 'Hangshao' (Paeonia lactiflora 'Hangshao') seeds based on transcriptome analysis

Background

Paeonia lactiflora ‘Hangshao’ is widely cultivated in China as a traditional Chinese medicine ‘Radix Paeoniae Alba’. Due to the abundant unsaturated fatty acids in its seed, it can also be regarded as a new oilseed plant. However, the process of the biosynthesis of unsaturated fatty acids in it has remained unknown. Therefore, transcriptome analysis is helpful to better understand the underlying molecular mechanisms.

Results

Five main fatty acids were detected, including stearic acid, palmitic acid, oleic acid, linoleic acid and α-linolenic acid, and their absolute contents first increased and then decreased during seed development. A total of 150,156 unigenes were obtained by transcriptome sequencing. There were 15,005 unigenes annotated in the seven functional databases, including NR, NT, GO, KOG, KEGG, Swiss-Prot and InterPro. Based on the KEGG database, 1766 unigenes were annotated in the lipid metabolism. There were 4635, 12,304, and 18,291 DEGs in Group I (60 vs 30 DAF), Group II (90 vs 60 DAF) and Group III (90 vs 30 DAF), respectively. A total of 1480 DEGs were detected in the intersection of the three groups. In 14 KEGG pathways of lipid metabolism, 503 DEGs were found, belonging to 111 enzymes. We screened out 123 DEGs involved in fatty acid biosynthesis (39 DEGs), fatty acid elongation (33 DEGs), biosynthesis of unsaturated fatty acid (24 DEGs), TAG assembly (17 DEGs) and lipid storage (10 DEGs). Furthermore, qRT-PCR was used to analyze the expression patterns of 16 genes, including BBCP, BC, MCAT, KASIII, KASII, FATA, FATB, KCR, SAD, FAD2, FAD3, FAD7, GPAT, DGAT, OLE and CLO, most of which showed the highest expression at 45 DAF, except for DGAT, OLE and CLO, which showed the highest expression at 75 DAF.

Conclusions

We predicted that MCAT, KASIII, FATA, SAD, FAD2, FAD3, DGAT and OLE were the key genes in the unsaturated fatty acid biosynthesis and oil accumulation in herbaceous peony seed. This study provides the first comprehensive genomic resources characterizing herbaceous peony seed gene expression at the transcriptional level. These data lay the foundation for elucidating the molecular mechanisms of fatty acid biosynthesis and oil accumulation for herbaceous peony.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-020-07339-7.

Seed Proteomic Profiles of Three Paeonia Varieties and Evaluation of Peony Seed Protein as a Food Product

Peony (Paeonia) has high ornamental, edible, and medicinal values. In order to distinguish seeds varieties, describe the proteomic profiles correlated with stress tolerance, and evaluate peony seed protein (PSP) as a functional food product, we characterized the seed protein profiles of these three species and their glucosidase inhibition activities. Results showed that the intensity of protein bands in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and specific protein ID (especially for specifically expressed proteins (SEPs)) was effective to distinguish these peony seed varieties. Proteomic analysis of the three species showed that P. ostii "Fengdan" has heat and pathogen tolerance-related proteins, while P. rockii has higher content of proteins related to cold resistance, which were all highly consistent with their adaptation of heat or cold habitat. Moreover, stress-related proteins were also accumulated in P. lactiflora Pall "Hangshao" seeds, showing its potential for stress resistance. Further protein analysis showed that the primary composition of PSP was albumin and globulin. And the solubility of PSP was good. Furthermore, PSP also showed high glucosidase inhibition activity, indicating that PSP might have some potential function for the remission of hyperglycemia. And P. ostii "Fengdan" seeds may be a better source for protein production than seeds of the other two species in terms of protein solubility and the content of total protein, albumin, and globulin. In addition, an optimal protocol of microwave-assisted alkali extraction was developed to produce PSP. In conclusion, the evaluated stress-related proteins in three peony seed species by proteomic analysis quite agreed with their adaptation of heat or cold stress; proteomics could also be a very useful tool for distinguishing species in the production; and peony seeds may be a good source for protein production.

In vitro protective effects of Paeonia mascula subsp. hellenica callus extract on human keratinocytes

Natural ingredients have been used to improve the state of health in humans. The genus Paeonia has been studied only limited yet it’s reported to have many activities such as antioxidant and anti-inflammatory. To this context, here we focused on an endemic Paeonia species in Attica. This study aims to present the development of the Paeonia mascula subsp. hellenica callus extract and its pleiotropic bioactivity on human primary keratinocytes exploring its potential application as an active agent in skin-related products. This extract showed a high scavenging activity with high phenolic content and an interesting metabolic profile. At a molecular level, the study on the transcript accumulation of genes revealed that this extract exhibits in vitro skin-related protection properties by mediating mitochondrial energy, cell proliferation, immune and inflammatory response and positively regulates genes involved in epidermal and in stratum corneum function. Besides, the extract is proven not skin irritant on reconstructed human skin model. These findings indicate that the specific P. mascula subsp. hellenica extract possesses significant in vitro protection activity on human epidermis and provides new insights into its beneficial role in skin confirming that the advent of biotechnology contribution the past few decades.

Effects of Different Harvest Times on Nutritional Component of Herbaceous Peony Flower Petals

Herbaceous peony (Paeonia lactiflora Pall.) flowers can be used as edible flowers, but few studies concerned about their edible values and the optimal harvest season. In this study, petals of three herbaceous peony cultivars including “Dafugui,” “Hongyan Zhenghui,” and “Yangfei Chuyu” at four different development stages were used as materials to measure the content of soluble sugar, organic acid, protein, vitamin C (Vc), total phenolics, total flavonoids, mineral elements, and superoxide dismutase (SOD) activity, with the aim to understand the variation tendency of the nutritional ingredients and bioactive components in herbaceous peony flower petals during development and to determine the optimal harvest time for herbaceous peony flowers with better edible qualities. The results demonstrated that the content of individual nutritional and bioactive components was varied with cultivars and developmental stages. The soluble sugar content was 63.69–225.97 mg/g FW, organic acid 10.13–24.60 mg/g FW, soluble protein 9.83–39.17 mg/g FW, Vc 12.31–33.52 mg/100 g FW, total phenolics 83.23–136.19 mg/g DW, total flavonoids 10.20–24.98 mg/g DW, and SOD activity 62.92–284.09 U/g FW. For mineral elements, the content of Na, Mg, K, Ca, Mn, Fe, Ni, and Zn was 20.96–65.51 μg/g DW, 810.85–1342.36 μg/g DW, 6723.68–12253.63 μg/g DW, 848.67–3038.46 μg/g DW, 1.14–8.44 μg/g DW, 48.70–149.72 μg/g DW, 1.20–2.17 μg/g DW, and 16.69–25.50 μg/g DW, respectively. The content of soluble sugar, protein, total flavonoids, and SOD activity in flower petals was the highest, and the content of organic acid was the lowest at the full bloom period (S3) for all three cultivars, while the highest Vc and total phenolics were at the early bloom stage (S2) and flower bud stage (S1), respectively. In conclusion, it is recommended to harvest herbaceous peony flowers at S3 with the best edible quality considering nutrients and bioactive components.

The bioactive compounds and cellular antioxidant activity of Herbaceous peony (Paeonia lactiflora Pall) seed oil from China

Herbaceous peony (HP) seed oil has been consumed in some regions of China, yet little information is available on its bioactive composition and antioxidant activity. This study aimed to evaluate the fatty acid compositions, micronutrients contents, and cellular antioxidant activity (CAA) of HP seed oil from five varieties. Results indicated that this oil had high percentages of monounsaturated (32.15 to 45.92%) and polyunsaturated fatty acids (58.65 to 61.95%), and the α-linolenic acid C18:3 was the highest in Fushao seed oil. Additionally, the high concentrations of tocopherol and phytosterol were found in all seed oils, and 10 individual polyphenols have been evaluated. Fushao seed oil had the highest polyphenols levels and showed higher CAA values. Both hierarchical cluster analysis and principal component analysis have been used to distinguish HP seed oil from different varieties. This information is valuable for the nutritional value and industrial interest of HP seed oil in China. PRACTICAL APPLICATION: This research showed that Herbaceous peony seed oil had higher levels of minor components and polyunsaturated fatty acids, especially, α-linolenic acid, and our results could also provide the theoretical foundation for the health benefits of Herbaceous peony seed oil as the vegetable oils. However, the variety of Herbaceous should be considered when extracting oil from Herbaceous peony seeds in the industry.

Edible Plant Oil: Global Status, Health Issues, and Perspectives

Edible plant oil (EPO) is an indispensable nutritional resource for human health. Various cultivars of oil-bearing plants are grown worldwide, and the chemical compositions of different plant oils are diverse. The extremely complex components in oils lead to diverse standards for evaluating the quality and safety of different EPOs. The environment poses great challenges to the EPO safety and quality during the entire industrial chain, including plant cultivation, harvesting, oil processing, and storage. Environmental risk factors include heavy metal or pesticide residue pollution, insect or harmful microbial infestation, and rancidity. Here, the diverse components in oil and various oil-producing processes are discussed, including plant species, oil yield, and composition complexity, environmental factors that degrade oil quality. Additionally, we propose a whole-industrial-chain monitoring system instead of current single-link-monitoring approach by monitoring and tracking the quality and safety of EPOs during the entire process of plant cultivation, raw materials harvest, oil process, and EPOs storage. This will provide guidance for monitoring the quality and safety of EPOs, which were challenged by the deteriorating environment.

Insights into the Phytochemical Composition and Bioactivities of Seeds from Wild Peony Species

Peony is an important medicinal and ornamental plant widely cultivated in the world. Its seeds as a functional food source have attracted much more attention in recent years, and they are rich in monoterpene glycosides and phenolic compounds. To assess the application value of wild peony seeds, the main chemical composition and content, such as total phenolic content (TPC), total flavonoid content (TFC), total flavanol content (TAC), and α and γ tocopherol content, of the seeds from 12 species and 2 subspecies were systematically explored in the present study. Four different antioxidant assays (DPPH, ABTS, FRAP, and HRSA), antibacterial, and antifungal assays were also performed using various in vitro biochemical methods. The results showed that the seeds of P. delavayi, P. obovata. subsp. obovata, and P. rockii. subsp. rockii had a high content of TPC, TFC, and TAC, respectively. Twenty-five individual chemical compounds were qualitatively and quantitatively measured by HPLC-MS, with paeoniflorin being the most abundant compound in all samples. P. mairei was grouped individually into a group via hierarchical cluster analysis according to its relatively highest monoterpene glycosides and TPC content. This work has provided a basis for the development and utilization of seeds for the selection of wild peony species of dietary interest.

Isolation of Strong Antioxidants from Paeonia Officinalis Roots and Leaves and Evaluation of Their Bioactivities

Paeonia officinalis extracts from leaves and roots were tested for their antioxidant potential using in vitro chemical (Folin-Ciocalteu, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), oxygen radical absorbance capacity (ORAC), hydroxyl radical antioxidant capacity (HORAC), hydroxyl radical scavenging capacity HOSC)) and cellular antioxidant activity (CAA) assays. Leaf extracts were stronger antioxidants than root extracts, while methanol was a more effective solvent than water in chemical assays. However, the selected water extract of leaves was a stronger antioxidant in CAA than the methanol extract (0.106 vs. 0.046 µmol quercetin equivalents/mg). Twenty compounds were identified by ultra performance liquid chromatography-quadrupole-time-of-flight (UPLC-Q-TOF) mass spectrometer, while on-line screening of their antioxidant capacity by high performance liquid chromatography (HPLC) with a DPPH^•-scavenging detector revealed that gallic acid derivatives are the major peony antioxidants. Root water and leaf methanol extracts inhibited α-amylase in a dose dependent manner. The IC₅₀ value for the strongest inhibitor, the methanol extract of leaves, was 1.67 mg/mL. In addition, the cytotoxicity assessment of extracts using human Caco-2 cells demonstrated that none of them possessed cytotoxic effects.

Antidiabetic Stilbenes from Peony Seeds with PTP1B, α-Glucosidase, and DPPIV Inhibitory Activities

One unusual resveratrol tetramer, paeonilactiflorol (1), and 14 known compounds (2-15) were isolated from peony seeds ( Paeonia lactiflora) under the guidance of bioassay. Paeonilactiflorol (1) was determined by extensive HRESIMS, UV, IR, 1D and 2D NMR spectroscopic analyses. Most of the stilbenes showed obvious inhibition on PTP1B and α-glucosidase, superior to the monoterpene glycosides. Especially, the stilbene tetramer (1) and trimer (8) exhibited high activity inhibiting both PTP1B with IC₅₀ values of 27.23 and 27.81 μM and α-glucosidase with IC₅₀ values of 13.57 and 14.39 μM. Two trans-dimers (4 and 5) also showed dipeptidyl peptidase-4 (DPPIV) inhibitory activity (55.35% and 61.26%, 500 μM) in addition to PTP1B and α-glucosidase. Enzyme kinetic study indicated that the types of inhibition on PTP1B were noncompetitive for 3 and 5 and mixed for 8 and 10. Quantitative analysis suggested that the stilbene trimers 8 (23.17 ± 0.36 mg/g) and 10 (15.24 ± 0.25 mg/g) were the main contents in peony seeds and should be responsible for the antidiabetic effects. This investigation supports the therapeutic potential of peony seeds in the treatment of diabetes with stilbenes as the active constituents.

Phenotypic Characteristics and Fatty Acid Composition of Seeds from Different Herbaceous Peony Species Native to China

Herbaceous peony has been widely cultivated in China due to its substantial ornamental and medicinal value. In the present study, the phenotypic characteristics, total fatty acid (FA) content, and nine FA compositions of herbaceous peony seeds from 14 populations belonging to six species and one subspecies were determined by normal test and gas chromatography/mass spectrometry (GC/MS). The results showed that the phenotypic characteristics of seeds varied dramatically among species. The concentrations of five major FAs in seed oils were as follows: linoleic acid (173.95-236.51 μg/mg), linolenic acid (227.82-302.71 μg/mg), oleic acid (135.32-208.81 μg/mg), stearic acid (6.52-11.7 μg/mg), and palmitic acid (30.67-47.64 μg/mg). Correlation analysis demonstrated that oleic acid had the highest partial correlation coefficient with total FAs and might be applied to develop a model of phenotypic characteristics. FAs were significantly influenced by the following environmental factors: latitude, elevation, and annual average temperature. Based on the FA levels in the seed oils, clustering analysis divided 14 populations into two clusters. It was found that the average contents of oleic acid, linoleic acid, and total FAs in cluster I (147.16 μg/mg, 200.31 μg/mg, and 671.24 μg/mg, respectively) were significantly lower than those in cluster II (196.65 μg/mg, 220.16 μg/mg, and 741.78 μg/mg, respectively). Cluster I was perfectly consistent with subsect. Foliolatae, while cluster II was in good agreement with subsect. Dissectifoliae. Therefore, the FA composition of wild herbaceous peony seed oil might be used as a chemotaxonomic marker.

Purification and identification of an antioxidative peptide from peony (Paeonia suffruticosa Andr.) seed dreg

The present study demonstrated the hydrolysis of peony seed protein isolate (PSPI) by using alcalase and resulted in the generation of an anti-oxidative peptide. In brief, a model was used to illustrate the enzymolysis of PSPI with the determination of kinetic factors as per investigation information. The model proved suitable to explain the PSPI hydrolysis by alcalase. A novel anti-oxidative peptide was obtained successfully by ultrafiltration and a series of chromatography techniques. Subsequently, a purified fragment was identified with the amino acid sequence of SMRKPPG followed by its synthesis and evaluation of its anti-oxidative activities. After hydrolysis, the peony seed protein hydrolysate (PSPH) with the degree of hydrolysis of 18% displayed the most significant antioxidant action which was further used to isolate the anti-oxidative peptide.

Cloning, Characterization, and Expression Analysis of Three FAD8 Genes Encoding a Fatty Acid Desaturase from Seeds of Paeonia ostii

The FAD8 gene catalyzes the conversion of diene fatty acids to triene fatty acids and is a key enzyme that determines the synthesis of alpha-linolenic acid. In this study, the full-length cDNAs of FAD8-1, FAD8-2, and FAD8-3 are cloned from Paeonia ostii T. Hong & J. X. Zhang and named as PoFAD8-1, PoFAD8-2, and PoFAD8-3. Their open reading frame is 1203 bp, 1152 bp, and 1353 bp which encoded 400, 371, and 450 amino acids. The molecular weights of the amino acids are 46 kDa, 43 kDa, and 51 kDa while the isoelectric points are 7.34, 8.74, and 9.23, respectively. Bioinformatics analysis shows that all three genes are hydrophobic-hydrophobic, PoFAD8-1 has three transmembrane domains, and PoFAD8-2 and PoFAD8-3 have two transmembrane domains. Multiple series alignment and phylogenetic analysis revealed that PoFAD8-1 and PoFAD8-2 are closely related while PoFAD8-3 is more closely related to Paeonia delavayi. Subcellular localization results showed that PoFAD8-1 was located on the ER membrane and PoFAD8-2 and PoFAD8-3 were located on the chloroplast membrane. The relative expression level of PoFAD8-1 in seeds is very high. PoFAD8-2 expressed more in the ovary than the other two genes. PoFAD8-3 was highly expressed in roots, stems, leaves, petals, and ovaries.

Chemical Profile and Antioxidant Activity of the Oil from Peony Seeds (Paeonia suffruticosa Andr.)

Peony seed oil (PSO) is a novel vegetable oil developed from the seeds of Paeonia suffruticosa Andr. The present study aimed to make an overall investigation on the chemical profile and antioxidant activities of PSO for reasonable development and utilization of this new resource food. Chemical analysis revealed that PSO was characterized by an uncommon high portion of α-linolenic acid (>38%), fairly low ratio of n-6 to n-3 polyunsaturated fatty acids (0.69), and much higher content of γ-tocopherol than various conventional seed oils. In vitro assay indicated that PSO is a more potent scavenger of free radicals than extra virgin olive oil. Moderate intake of PSO exhibited obvious protection against various oxidative damages such as tetrachloromethane-induced acute liver injury in mice and diet-induced hyperlipidemia in rats. The changes in the key indicators of oxidative injury and fatty acid composition in the liver caused by PSO administration were measured, and the results demonstrated that antioxidant properties of PSO are closely related to their characteristic chemical composition. Consequently, the present study provided new evidence for the health implications of PSO, which deserves further development for medical and nutritional use against oxidative damages that are associated with various diseases.

The effects of process technology on the physicochemical properties of peony seed oil

Peony seed oils (PSOs) were prepared using supercritical CO2 (SC) and compared with soxhlet extraction (SE) and mechanical screw press extraction (SPE) methods. The fatty acid compositions of the oils were determined, and the physicochemical properties of the oils, including free radical-scavenging activity, α-amylase and α-glucosidase inhibition, thermal and rheological properties were evaluated. The unsaturated fatty acids in the SE oils were higher than SC and SPE oils due to the higher percentage of olefinic, allylic methylene and allylic methine protons in the SE oils. The SPE oils also displayed the highest DPPH and ABTS+ radical scavenging activity at the tested concentrations. However, the SE oils showed stronger inhibitory effects on α-amylase and α-glucosidase enzymes under in vitro conditions when compared with the other oil samples. The three oils had similar melting and crystalline point due to similar contents of fatty acids (FAs). The SC oils had a lower Ea than the others.

Quality evaluation of peony seed oil spray-dried in different combinations of wall materials during encapsulation and storage

This study aimed at evaluating the performance of peony seed oil microencapsulated by spray drying during encapsulation and storage. Four different combinations of gum arabic (GA), corn syrup (CS), whey protein concentrate (WPC) and sodium caseinate (CAS) were used to encapsulate peony seed oil. The best encapsulation efficiency was obtained for CAS/CS followed by the CAS/GA/CS combination with the encapsulation ratio of 93.71 and 92.80 %, respectively, while the lowest encapsulation efficiency was obtained for WPC/GA/CS (85.96 %). Scanning electron microscopy and confocal laser scanning microscopy revealed that the particles were spherical in shape and did not exhibit apparent cracks or fissures, and gum arabic was uniformly distributed across the wall of the microcapsules. Oxidative stability study indicated that the CAS/GA/CS combination presented the best protection against lipid oxidation and the smallest loss of polyunsaturated fatty acid content among all of the formulas as measured by gas chromatography. Therefore, CAS/GA/CS could be promising materials encapsulate peony seed oil with high encapsulation efficiency and minimal lipid oxidation.

Anti-diabetic activity of peony seed oil, a new resource food in STZ-induced diabetic mice

Peony seed oil rich in α-linolenic acid (38.66%), linoleic acid (26.34%) and oleic acid (23.65%) reduced fasting blood glucose of diabetic mice induced by STZ.