Genus Paeonia monoterpene glycosides: A systematic review on their pharmacological activities and molecular mechanisms

BACKGROUND

Genus Paeonia, which is the main source of Traditional Chinese Medicine (TCM) Paeoniae Radix Rubra (Chishao in Chinese), Paeoniae Radix Alba (Baishao in Chinese) and Moutan Cortex (Mudanpi in Chinese), is rich in active pharmaceutical ingredient such as monoterpenoid glycosides (MPGs). MPGs from Paeonia have extensive pharmacological effects, but the pharmacological effects and molecular mechanisms of MPGs has not been comprehensively reviewed.

PURPOSE

MPGs compounds are one of the main chemical components of the genus Paeonia, with a wide variety of compounds and strong pharmacological activities, and the structure of the mother nucleus-pinane skeleton is similar to that of a cage. The purpose of this review is to summarize the pharmacological activity and mechanism of action of MPGs from 2012 to 2023, providing reference direction for the development and utilization of Paeonia resources and preclinical research.

METHODS

Keywords and phrases are widely used in database searches, such as PubMed, Web of Science, Google Scholar and X-Mol to search for citations related to the new compounds, extensive pharmacological research and molecular mechanisms of MPGs compounds of genus Paeonia.

RESULTS

Modern research confirms that MPGs are the main compounds in Paeonia that exert pharmacological effects. MPGs with extensive pharmacological characteristics are mainly concentrated in two categories: paeoniflorin derivatives and albiflflorin derivatives among MPGs, which contains 32 compounds. Among them, 5 components including paeoniflorin, albiflorin, oxypaeoniflorin, 6'-O-galloylpaeoniflorin and paeoniflorigenone have been extensively studied, while the other 28 components have only been confirmed to have a certain degree of anti-inflammatory and anticomplementary effects. Studies of pharmacological effects are widely involved in nervous system, endocrine system, digestive system, immune system, etc., and some studies have identified clear mechanisms. MPGs exert pharmacological activity through multilateral mechanisms, including anti-inflammatory, antioxidant, inhibition of cell apoptosis, regulation of brain gut axis, regulation of gut microbiota and downregulation of mitochondrial apoptosis, etc. CONCLUSION: This systematic review delved into the pharmacological effects and related molecular mechanisms of MPGs. However, there are still some compounds in MPGs whose pharmacological effects and pharmacological mechanisms have not been clarified. In addition, extensive clinical randomized trials are needed to verify the efficacy and dosage of MPGs.

RAD-sequencing improves the genetic characterization of a threatened tree peony (Paeonia ludlowii) endemic to China: Implications for conservation

Compared with traditional genetic markers, genomic approaches have proved valuable to the conservation of endangered species. Paeonia ludlowii having rarely and pure yellow flowers, is one of the world's most famous tree peonies. However, only several wild populations remain in the Yarlung Zangbo Valley (Nyingchi and Shannan regions, Xizang) in China due to increasing anthropogenic impact on the natural habitats. We used genome-wide single nucleotide polymorphisms to elucidate the spatial pattern of genetic variation, population structure and demographic history of P. ludlowii from the fragmented region comprising the entire range of this species, aiming to provide a basis for conserving the genetic resources of this species. Unlike genetic uniformity among populations revealed in previous studies, we found low but varied levels of intra-population genetic diversity, in which lower genetic diversity was detected in the population in Shannan region compared to those in Nyingzhi region. These spatial patterns may be likely associated with different population sizes caused by micro-environment differences in these two regions. Additionally, low genetic differentiation among populations (Fst = 0.0037) were detected at the species level. This line of evidence, combined with the result of significant genetic differentiation between the two closest populations and lack of isolation by distance, suggested that shared ancestry among now remnant populations rather than contemporary genetic connectivity resulted in subtle population structure. Demographic inference suggested that P. ludlowii probably experienced a temporal history of sharp population decline during the period of Last Glacial Maximum, and a subsequent bottleneck event resulting from prehistoric human activities on the Qinghai-Tibet Plateau. All these events, together with current habitat fragment and excavation might contribute to the endangered status of P. ludlowii. Our study improved the genetic characterization of the endangered tree peony (P. ludlowii) in China, and these genetic inferences should be considered when making different in situ and ex situ conservation actions for P. ludlowii in this evolutionary hotspot region.

The plastome reveals new insights into the evolutionary and domestication history of peonies in East Asia

BACKGROUD

Paeonia holds considerable value in medicinal, ornamental horticultural, and edible oil industries, but the incomplete state of phylogenetic research in this genus poses a challenge to the effective conservation and development of wild germplasm, and also impedes the practical utilization of existing cultivars. Due to its uniparental inheritance and lack of recombination, the plastome (i.e., plastid genome), which is a valuable molecular marker for phylogenetic analyses, is characterized by an appropriate rate of nucleotide evolution.

METHODS

In this study, 10 newly assembled data and available reported data were combined to perform a comparative genomics and phylogenetics analysis of 63 plastomes of 16 Paeonia species, primarily from East Asia, which is the origin and diversity center of Paeonia.

RESULTS

Ranging between 152,153 and 154,405 bp, most plastomes displayed a conserved structure and relatively low nucleotide diversity, except for six plastomes, which showed obvious IR construction or expansion. A total of 111 genes were annotated in the Paeonia plastomes. Four genes (rpl22, rps3, rps19 and ycf1) showed different copy numbers among accessions while five genes (rpl36, petN, psbI, rpl33 and psbJ) showed strong codon usage biases (ENC < 35). Additional selection analysis revealed that no genes were under positive selection during the domestication of tree peony cultivars whereas four core photosynthesis-related genes (petA, psaA, psaB and rbcL) were under positive selection in herbaceous peony cultivars. This discovery might contribute to the wide adaption of these cultivars. Two types of molecular markers (SSR and SNP) were generated from the 63 plastomes. Even though SSR was more diverse than SNP, it had a weaker ability to delimit Paeonia species than SNP. The reconstruction of a phylogenetic backbone of Paeonia in East Asia revealed significant genetic divergence within the P. ostii groups. Evidence also indicated that the majority of P. suffruticosa cultivars had a maternal origin, from P. ostii. The results of this research also suggest that P. delavayi var. lutea, which likely resulted from hybridization with P. ludlowii, should be classified as a lineage within the broader P. delavayi group.

CONCLUSIONS

Overall, this study's research findings suggest that the Paeonia plastome is highly informative for phylogenetic and comparative genomic analyses, and could be useful in future research related to taxonomy, evolution, and domestication.

Phylogenetic analysis based on the ITS, matK and rbcL DNA barcodes and comparison of chemical contents of twelve Paeonia taxa in Türkiye

BACKGROUD

Twelve taxa of herbaceous Paeonia species were recorded in Türkiye. All definitions were performed morphologically and/or anatomically and there is no study based on DNA barcode sequences. Three barcode regions were sequenced to determine the phylogenetic relationships of Turkish Paeonia taxa. The chemical comparison of roots was also investigated.

METHODS AND RESULTS

The taxons were collected between May and June 2021 from nine cities. Leaf materials were used for DNA isolation and ITS, matK and rbcL regions were amplified and sequenced. There was no difference among taxa in terms of rbcL sequences. But the ITS and matK regions distinguished 12 taxa and structured them in two groups. ITS region distinguished P. peregrina, P. arietina, and P. tenuifolia from other taxa, while matK region distinguished P. arietina and P. witmanniana from other taxa. Both barcode sequences actually showed that the registration of P. mascula subsp. arasicola was actually 100% similar to P. arietina. ITS was the most polymorphic region (n = 54) followed by matK (n = 9). These sequences could successfully discriminate Paoenia species from each other and diploid P. tenuifolia. The methanolic root (100 gr) extracts were examined for total phenolic and flavonoid content, and antioxidant activities. Significant variation was found for polyphenolic content, and antioxidant properties (TPC from 204.23 to 2343.89 mg, TFC from 7.73 to 66.16 mg, and FRAP from 523.81 to 4338.62 mg). SC₅₀ values of ABTS and DPPH were ranged from 115.08 to 1115.52 μg/ml and 73.83 to 963.59 μg/ml, respectively.

CONCLUSION

It was concluded that 11 of 12 taxa had differences in terms of ITS and matK sequences and these region must be used for the correct identification of Turkish Paeonia.

Functional identification of anthocyanin glucosyltransferase genes: a Ps3GT catalyzes pelargonidin to pelargonidin 3-O-glucoside painting the vivid red flower color of Paeonia

Glycosylation from an anthocyanidin 3-O-glucosyltransferase Ps3GT (PsUGT78A27) facilitates the accumulation of pelargonidin 3-O-glucoside, which defines the vivid red flower color and occurs only in specific peony tree cultivars. Although tree peony cultivars of Chinese and Japanese both originated from China, vivid red color is only found in flowers of Japanese cultivars but not of Chinese cultivar groups. In this study, a Japanese tree peony cultivar 'Taiyoh' with vivid red petals and a Chinese tree peony cultivar 'Hu Hong' with reddish pink petals were chosen as the experimental materials. Flavonoids profiling indicated that pelargonidin 3-O-glucoside (Pg3G) detected only in Japanese cultivar contributed to vivid red color of tree peony petals, while pelargonidin 3,5-di-O-glucoside (Pg3G5G) found in both of Japanese and Chinese cultivars was responsible for pink flower color. Through the integration of full-length transcriptome sequencing and in vitro enzymatic activity analysis, two anthocyanin glucosyltransferase genes PsUGT78A27 and PsUGT75L45 were isolated from the petals of tree peony, and their encoding products exhibited enzymatic activities of pelargonidin 3-O-glucosyltransferase and anthocyanin 5-O-glucosyltransferase, respectively. Further quantitative real-time PCR revealed that PsUGT78A27 displayed high expression in petals of both cultivars and PsUGT75L45 was expressed at high levels in cultivar 'Hu Hong' only. Using a gene gun technique, the GFP fusion proteins of PsUGT78A27 and PsUGT75L45 were visualized to be cytoplasmic and nuclear localization in the epidermal cells of tree peony petals, and the glucosylation function of PsUGT78A27 and PsUGT75L45 to alter petal color of tree peony and herbaceous peony had been directly validated in vivo. These results demonstrated that PsUGT78A27 and PsUGT75L45 are key players for the presence or absence of vivid red flower color in tree peony cultivars. Our findings further elucidated the chemical and molecular mechanism of petal pigmentation of Paeonia and could help breed the Paeonia cultivars possessing novel flower colors.

PhUGT78A22, a novel glycosyltransferase in Paeonia 'He Xie', can catalyze the transfer of glucose to glucosylated anthocyanins during petal blotch formation

BACKGROUND

Flower color patterns play an important role in the evolution and subsequent diversification of flowers by attracting animal pollinators. This interaction can drive the diversity observed in angiosperms today in many plant families such as Liliaceae, Paeoniaceae, and Orchidaceae, and increased their ornamental values. However, the molecular mechanism underlying the differential distribution of anthocyanins within petals remains unclear in Paeonia.

RESULTS

In this study, we used an intersectional hybrid between the section Moutan and Paeonia, hereafter named Paeonia 'He Xie', which has purple flowers with dark purple blotches. After Ultra-high performance liquid chromatography-diode array detector (UPLC-DAD) analysis of blotched and non-blotched parts of petals, we found the anthocyanin content in the blotched part was always higher than that in the non-blotched part. Four kinds of anthocyanins, namely cyanidin-3-O-glucoside (Cy3G), cyanidin-3,5-O-glucoside (Cy3G5G), peonidin-3-O-glucoside (Pn3G), and peonidin-3,5-O-glucoside (Pn3G5G) were detected in the blotched parts, while only Cy3G5G and Pn3G5G were detected in the non-blotched parts. This suggests that glucosyltransferases may play a vital role in the four kinds of glucosylated anthocyanins in the blotched parts. Moreover, 2433 differentially expressed genes (DEGs) were obtained from transcriptome analysis of blotched and non-blotched parts, and a key UDP-glycosyltransferase named PhUGT78A22 was identified, which could use Cy3G and Pn3G as substrates to produce Cy3G5G and Pn3G5G, respectively, in vitro. Furthermore, silencing of PhUGT78A22 reduced the content of anthocyanidin 3,5-O-diglucoside in P. 'He Xie'.

CONCLUSIONS

A UDP-glycosyltransferase, PhUGT78A22, was identified in P. 'He Xie', and the molecular mechanism underlying differential distribution of anthocyanins within petals was elucidated. This study provides new insights on the biosynthesis of different kinds of anthocyanins within colorful petals, and helps to explain petal blotch formation, which will facilitate the cultivar breeding with respect to increasing ornamental value. Additionally, it provides a reference for understanding the molecular mechanisms responsible for precise regulation of anthocyanin biosynthesis and distribution patterns.

Isolation and Characterization of Galloylglucoses Effective against Multidrug-Resistant Strains of Escherichia coli and Klebsiella pneumoniae

The search for new antibiotics against multidrug-resistant (MDR), Gram-negative bacteria is crucial with respect to filling the antibiotics development pipeline, which is subject to a critical shortage of novel molecules. Screening of natural products is a promising approach for identifying antimicrobial compounds hosting a higher degree of novelty. Here, we report the isolation and characterization of four galloylglucoses active against different MDR strains of Escherichia coli and Klebsiella pneumoniae. A crude acetone extract was prepared from Paeonia officinalis Linnaeus leaves, and bioautography-guided isolation of active compounds from the extract was performed by liquid–liquid extraction, as well as open column, flash, and preparative chromatographic methods. Isolated active compounds were characterized and elucidated by a combination of spectroscopic and spectrometric techniques. In vitro antimicrobial susceptibility testing was carried out on E. coli and K. pneumoniae using 2 reference strains and 13 strains hosting a wide range of MDR phenotypes. Furthermore, in vivo antibacterial activities were assessed using Galleria mellonella larvae, and compounds 1,2,3,4,6-penta-O-galloyl-β-d-glucose, 3-O-digalloyl-1,2,4,6-tetra-O-galloyl-β-d-glucose, 6-O-digalloyl-1,2,3,4-tetra-O-galloyl-β-d-glucose, and 3,6-bis-O-digalloyl-1,2,4-tri-O-galloyl-β-d-glucose were isolated and characterized. They showed minimum inhibitory concentration (MIC) values in the range of 2–256 µg/mL across tested bacterial strains. These findings have added to the number of known galloylglucoses from P. officinalis and highlight their potential against MDR Gram-negative bacteria.

A comprehensive study of three species of Paeonia stem and leaf phytochemicals, and their antioxidant activities

ETHNOPHARMACOLOGICAL RELEVANCE

Paeonia plants have been widely used as traditional Chinese medicinal materials for more than 2,000 years in the treatment of cardiovascular, extravasated blood and female genital diseases; paeoniflorin and paeonol have been implicated as the plants' primary active ingredients.

AIM OF THE STUDY

Previous studies have been singularly focused on the chemical constituents and content variation of the Paeonia roots in the advancement of traditional Chinese medicine, with the plants' stems and leaves considered useless. This study aims to explore the chemical constituents, content variation, and antioxidant capacity in Paeonia stems and leaves for the future utilization of traditional Chinese medicine, given that current practices of digging and trade endanger Paeonia in the wild.

MATERIALS AND METHODS

Herein, secondary metabolites from the stems and leaves from six developmental stages of the annual growth cycle of Paeonia ostii T. Hong & J. X. Zhang, P. 'Hexie', and P. lactiflora Pall. were qualitatively and quantitatively analyzed via high-performance liquid chromatography with a diode array detector (HPLC-DAD) and high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS). Antioxidant capacity at each stage was also evaluated by various free radical scavenging assays.

RESULTS

A total of 24 metabolites were detected and identified, including 5 monoterpene glycosides, 4 tannins, 5 phenols, 9 flavonoids, and paeonol. Excepting paeonol and the phenols, the levels of each metabolite category were significantly higher in the leaves than the stems during all developmental stages. The paeoniflorin content in the P. ostii leaves was the highest during the first developmental stage and higher than the standards of the Chinese Pharmacopoeia, suggesting it to be the optimal harvesting stage for medicinal uses. Notably, the antioxidant capacity of the leaves was significantly greater than in the stems, particularly for the leaves of P. 'Hexie'.

CONCLUSION

Our study indicates that the leaves of P. 'Hexie' have the potential to be a worthy medicinal substitute to Paeonia roots due to their high monoterpene glycosides, phenols, and flavonoids as well as their strong antioxidant capacity. Further, this study provides a theoretical basis for the development and utilization of non-root Paeonia plant sections as medicinal plant resources.

Genus Paeonia: A comprehensive review on traditional uses, phytochemistry, pharmacological activities, clinical application, and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Paeonia, which comprises approximately 52 shrubs or herbaceous perennials around the world, is the only genus of the Paeoniaceae and is pervasively distributed in Asia, southern Europe, and North America. Many species of the genus Paeonia have been used for centuries in ethnomedical medical systems.

AIM OF THE REVIEW

The present study aims to summarize the traditional uses, clinical applications, and toxicology of the genus Paeonia, to critically evaluate the state-of-the-art phytochemical and pharmacological studies of this genus published between 2011 and 2020, and to suggest directions for further in-depth research on Paeonia medicinal resources.

MATERIALS AND METHODS

Popular and widely used databases such as PubMed, Scopus, Science Direct, and Google Scholar were searched using the various search strings; from these searches, a number of citations related to the traditional uses, phytochemistry, biological activities, clinical application, and toxicology of the genus Paeonia were retrieved.

RESULTS

The use of 21 species, 2 subspecies, and 7 varieties of the genus Paeonia as traditional herbal remedies has been reported, and many ethnomedicinal uses, such as the treatment of hematemesis, blood stasis, dysmenorrhea, amenorrhea, epilepsy, spasms, and gastritis, have been recorded. The roots and root bark are the most frequently reported parts of the plants used in medicinal applications. In phytochemical investigations, 451 compounds have been isolated from Paeonia plants to date, which contains monoterpenoid glucosides, flavonoids, tannins, stilbenes, triterpenoids and steroids, and phenols. Studies of their pharmacological activities have revealed the antioxidant, anti-inflammatory, antitumour, antibacterial, antiviral, cardiovascular protective, and neuroprotective properties of the genus Paeonia. In particular, some bioactive extracts and compounds (total glucosides of peony (TGP), paeonol, and paeoniflorin) have been used as therapeutic drugs or tested in clinical trials. In addition to the "incompatibility" of the combined use of "shaoyao" and Veratrum nigrum L. roots in traditional Chinese medicine theory, Paeonia was considered to have no obvious toxicity based on the available toxicological tests.

CONCLUSION

A large number of phytochemical and pharmacological reports have indicated that Paeonia is an important medicinal herb resource, and some of its traditional uses including the treatment of inflammation and cardiovascular diseases and its use as a neuroprotective agent, have been partially confirmed through modern pharmacological studies. Monoterpenoid glucosides are the main active constituents. Although many compounds have been isolated from Paeonia plants, the biological activities of only a few of these compounds (paeoniflorin, paeonol, and TGP) have been extensively investigated. Some paeoniflorin structural analogues and resveratrol oligomers have been preliminarily studied. With the exception of several species (P. suffruticosa, P. ostii, P. lactiflora, and P. emodi) that are commonly used in folk medicine, many medicinal species within the genus do not receive adequate attention. Conducting phytochemical and pharmacological experiments on these species can provide new clues that may lead to the discovery of medicinal resources. It is necessary to identify the effective phytoconstituents of crude extracts of Paeonia that displayed pharmacological activities by bioactivity-guided isolation. In addition, comprehensive plant quality control, and toxicology and pharmacokinetic studies are needed in the future studies.

Climatic Refugia and Geographical Isolation Contribute to the Speciation and Genetic Divergence in Himalayan-Hengduan Tree Peonies (Paeonia delavayi and Paeonia ludlowii)

Himalaya and Hengduan Mountains (HHM) is a biodiversity hotspot, and very rich in endemic species. Previous phylogeographical studies proposed different hypotheses (vicariance and climate-driven speciation) in explaining diversification and the observed pattern of extant biodiversity, but it is likely that taxa are forming in this area in species-specific ways. Here, we reexplored the phylogenetic relationship and tested the corresponding hypotheses within Paeonia subsect. Delavayanae composed of one widespread species (Paeonia delavayi) and the other geographically confined species (Paeonia ludlowii). We gathered genetic variation data at three chloroplast DNA fragments and one nuclear gene from 335 individuals of 34 populations sampled from HHM. We performed a combination of population genetic summary statistics, isolation-with-migration divergence models, isolation by environment, and demographic history analyses. We found evidence for the current taxonomic treatment that P. ludlowii and P. delavayi are two different species with significant genetic differentiation. The significant isolation by environment was revealed within all sampled populations but genetic distances only explained by geographical distances within P. delavayi populations. The results of population divergence models and demographic history analyses indicated a progenitor–derivative relationship and the Late Quaternary divergence without gene flow between them. The coalescence of all sampled cpDNA haplotypes could date to the Late Miocene, and P. delavayi populations probably underwent a severe bottleneck in population size during the last glacial period. Genetic variation in Paeonia subsect. Delavayanae is associated with geographical and environmental distances. These findings point to the importance of geological and climatic changes as causes of the speciation event and lineage diversification within Paeonia subsect. Delavayanae.

Root Extracts of Two Cultivars of Paeonia Species: Lipid Composition and Biological Effects on Different Cell Lines: Preliminary Results

The roots of two cultivars of Paeonia, namely Paeonia officinalis “Rubra Plena” and Paeonia “Pink Hawaiian Coral”, have been extracted with chloroform. The composition of the lipid fraction, analyzed by GC–MS technique, revealed the absence of paeonol and the presence of phenol, benzoic acid, fatty acid—and some sterol—derivatives. The chloroformic extracts have been tested on normal and several cancer cell lines but showed antiproliferative activity only on the ovarian carcinoma and the osteosarcoma. The biological activity of extracts was investigated mainly by confocal microscopy, flow cytometry and quantum phase imaging. The results indicated that the root extracts induced a hyperpolarization of mitochondria and an increase in reactive oxygen species levels, without inducing cell death. These effects are associated to an increased doubling time and a retarded confluence.

Analysis of Chemical Components in the Roots of Eight Intersubgeneric Hybrids of Paeonia

Paeonia cultivars are famous ornamental plants, and some of them are also traditional Chinese medicinal resources. Intersubgeneric hybrids of Paeonia (IHPs) are formed by the hybridization of herbaceous peony (Paeonia lactiflora) and tree peony (Paeonia×suffruticosa or lutea hybrid tree peony). The phenotypic characteristics of IHPs are similar to those of herbaceous peony, and their root systems are large and vigorous. However, their medicinal value has not been reported yet. In this study, the roots of eight IHP samples were analyzed by high performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS/MS). A total of 18 compounds were identified, including phenols, paeonols, monoterpene glycosides, and tannins. The contents of monoterpene glycosides and tannins in IHPs were higher than herbaceous peony and tree peony, exceeding 44.76 mg/g DW and 11.50 mg/g DW, respectively. Three IHPs, 'Prairie Charm', 'Garden Treasure', and 'Yellow Emperor', with more types and a higher content of medicinal compounds, were screened out by cluster analysis. These IHPs have considerable potential for the development of medicinal resources.

Paeoniflorin ameliorates Aβ-stimulated neuroinflammation via regulation of NF-κB signaling pathway and Aβ degradation in C6 glial cells

BACKGROUND/OBJECTIVES

Alzheimer's disease is common age-related neurodegenerative condition characterized by amyloid beta (Aβ) accumulation that leads cognitive impairment. In the present study, we investigated the protective effect of paeoniflorin (PF) against Aβ-induced neuroinflammation and the underlying mechanism in C6 glial cells.

MATERIALS/METHODS

C6 glial cells were treated with PF and Aβ_25–35, and cell viability, nitric oxide (NO) production, and pro-inflammatory cytokine release were measured. Furthermore, the mechanism underlying the effect of PF on inflammatory responses and Aβ degradation was determined by Western blot.

RESULTS

Aβ_25–35 significantly reduced cell viability, but this reduction was prevented by the pretreatment with PF. In addition, PF significantly inhibited Aβ_25–35-induced NO production in C6 glial cells. The secretion of interleukin (IL)-6, IL-1β, and tumor necrosis factor-alpha was also significantly reduced by PF. Further mechanistic studies indicated that PF suppressed the production of these pro-inflammatory cytokines by regulating the nuclear factor-kappa B (NF-κB) pathway. The protein levels of inducible NO synthase and cyclooxygenase-2 were downregulated and phosphorylation of NF-κB was blocked by PF. However, PF elevated the protein expression of inhibitor kappa B-alpha and those of Aβ degrading enzymes, insulin degrading enzyme and neprilysin.

CONCLUSIONS

These findings indicate that PF exerts protective effects against Aβ-mediated neuroinflammation by inhibiting NF-κB signaling, and these effects were associated with the enhanced activity of Aβ degradation enzymes.

Acuta Kudo may increase the endometrial receptivity through expression of leukemia inhibitory factor and adhesion molecules

OBJECTIVE

To find out the combination of the extracts from Paeonia lactiflora Pallas (PL), Reh- mannia Glutinosa var. Purpurea Makino (RG), Perilla Frutescens var. Acuta Kudo (PF) to increase endometrial receptivity.

METHODS

Herbal medicines were extracted with boiling water and polysaccharides were removed. We examined the effect of PL, RG, and PF (PRP), a most effective herbal formula deduced from constitutive ingredient herbs of Antai Yin which is composed of PRP, on the leukemia inhibitory factor (LIF) expression and endometrial receptivity.

RESULTS

The combination of the extracts from PRP induced the LIF expression in Ishikawa cells and increased the adhesion between Ishikawa and JAr cells. In addition, PRP-induced attachment of JAr cells onto Ishikawa cells and expression of adhesion molecules, ITGAV, ITGB5, CD44s, and L-selectin, are significantly reduced by knock-down of LIF expression.

CONCLUSION

Induced by the combination of the PRP extracts, the adhesion between trophoblast and endometrial cells are mediated by expression of LIF and adhesion molecules. Thus, we suggest the combination of the PRP extracts may be a novel therapy for enhancing embryo implantation rate.

A review of the seed biology of Paeonia species (Paeoniaceae), with particular reference to dormancy and germination

Most Paeonia species have epicotyl dormancy. Germination of peony seeds requires warm stratification for embryo growth and radicle protrusion followed by cold stratification for epicotyl growth. The genus Paeonia (Paeoniaceae) includes many popular ornamentals, has colorful flowers and contains several Chinese medicinal species. The germination protocol for seeds of Paeonia species is complex and impedes the breeding of new cultivars and contributes to the rarity and high cost of the plants. Although numerous reports on seed dormancy/germination in peonies are scattered throughout the literature, most of them are in Chinese. The primary aims of this paper are to provide a general overview of the available information on seed dormancy/germination in peonies and to make some suggestions regarding propagation for the peony industry and breeders. Most Paeonia species have epicotyl dormancy. The embryo is differentiated into organs, but it is underdeveloped (small) and must grow inside the seed before the radicle can emerge. Germination of peony seeds requires warm stratification for embryo growth and radicle protrusion followed by cold stratification for epicotyl growth. In addition, the epicotyl is sensitive to cold stratification only after the root has grown to a certain length. GA₃ treatment enhances embryo growth and subsequent germination percentages. Further investigations on the physiology, genetics and proteomics would contribute to a better understanding of seed dormancy in Paeonia.

[Chemical constituents from water-soluble extract of dry roots of Paeonia lactiflora]

Nineteen compounds were isolated from the water-soluble extract of the dry roots of Paeonia lactiflora by using various chromatographic techniques. Their structures were identified by MS， NMR and other spectroscopic analysis as paeoniflorin(1)， 4-O-ethylpaeoniflorin(2)， 2'-O-benzoylpaeoniflorin(3)， benzoylpaeoniflorin(4)， 4"-hydroxy-benzoyloxypaeoniflorin(5)， moudanpioside C(6)， 6'-O-benzoyl-4"-hydroxy-3"-methoxy-paeoniflorin(7)， paeoniflorin B(8)， 6-O-benzoylalbiflorin(9)， secoisolariciresinol (10)， (+)-lyoniresinol(11)， dihyrodehydrodiconiferyl alcohol(12)， (7S，8S)-threo-7，9，9'-trihydroxy-3，3'-dimethoxy-8-O-4'-neolignan(13)， (+)-neo-olivil (14)， [(3S)-5-methyl-2，3-dihydro-1-benzofuran-3-yl]methanol(15)， 5-hydroxy-3S-hydroxymethyl-6-methyl-2，3-dihydrobenzofuran(16)， (+)-(R)-2-hydroxy-1-(4-methoxyphenyl)-1-propan-1-one(17)， (+)-(2R)-1-(4-hydroxy-3-methoxyphenyl)-2-propanol(18)， (+)-(4S)-(2E)-4-hydroxy-2-nonenoic acid(19). Compounds 15 and 18 are new natural products， while compounds 10， 11， 13， 14， 17 and 19 are isolated from the genus Paeonia for the first time.

Identification of microRNAs and long non-coding RNAs involved in fatty acid biosynthesis in tree peony seeds

MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) act as important molecular regulators in a wide range of biological processes during plant development and seed formation, including oil production. Tree peony seeds contain >90% unsaturated fatty acids (UFAs) and high proportions of α-linolenic acid (ALA, > 40%). To dissect the non-coding RNAs (ncRNAs) pathway involved in fatty acids synthesis in tree peony seeds, we construct six small RNA libraries and six transcriptome libraries from developing seeds of two cultivars (J and S) containing different content of fatty acid compositions. After deep sequencing the RNA libraries, the ncRNA expression profiles of tree peony seeds in two cultivars were systematically and comparatively analyzed. A total of 318 known and 153 new miRNAs and 22,430 lncRNAs were identified, among which 106 conserved and 9 novel miRNAs and 2785 lncRNAs were differentially expressed between the two cultivars. In addition, potential target genes of the microRNA and lncRNAs were also predicted and annotated. Among them, 9 miRNAs and 39 lncRNAs were predicted to target lipid related genes. Results showed that all of miR414, miR156b, miR2673b, miR7826, novel-m0027-5p, TR24651|c0_g1, TR24544|c0_g15, and TR27305|c0_g1 were up-regulated and expressed at a higher level in high-ALA cultivar J when compared to low-ALA cultivar S, suggesting that these ncRNAs and target genes are possibly involved in different fatty acid synthesis and lipid metabolism through post-transcriptional regulation. These results provide a better understanding of the roles of ncRNAs during fatty acid biosynthesis and metabolism in tree peony seeds.

Delavayanae

According to the present taxonomical treatment, Paeonia subsect. Delavayanae consists of only two species (P. delavayi and P. ludlowii) endemic to the Himalayan-Hengduan Mountains. Although P. ludlowii can be distinguished from P. delavayi on the basis of a series of morphological characters, the species delimitation remains controversial because the more widespread one, P. delavayi, exhibits considerable morphological diversity. Both chloroplast DNA markers and nuclear microsatellites or simple sequence repeats (nSSR) are used herein to reveal genetic diversity and relationships of the two taxa included in this subsection, and ecological niche modeling (ENM) is employed to get insights into their paleodistribution. Our results show that genetic boundaries between the two currently recognized species are unclear, probably due to recent divergence. Paeonia ludlowii is budding from P. delavayi, probably by genetic isolation but also by shifting its niche to the harsher upland Tibetan conditions. Paeonia delavayi itself would be, however, under active speciation, showing significant genetic differentiation and morphological diversity. Whereas P. ludlowii would have endured the Pleistocene glacial periods by in situ persistence in local, small refugia, a 'dual' model seems to apply for P. delavayi (in situ persistence and retreat to refugia). The rarity of P. ludlowii and high evolutionary potential of P. delavayi imply high priority for in situ conservation of both taxa. The Himalayan-Hengduan Mountains are an ideal arena for differentiation within subsect. Delavayanae of Paeonia, by means of expansions/contractions/displacements, vertical migrations, and local survival/extinctions in response to the Neogene climate fluctuations and geological changes.

Phytochemical variation among the traditional Chinese medicine Mu Dan Pi from Paeonia suffruticosa (tree peony)

Mu Dan Pi is a traditional Chinese medicine used to treat inflammation, cancer, allergies, diabetes, angiocardiopathy, and neurodegenerative diseases. In this study, the metabolome variation within Mu Dan Pi collected from 372 tree peony cultivars was systematically investigated. In total, 42 metabolites were identified, comprising of 14 monoterpene glucosides, 11 tannins, 8 paeonols, 6 flavonoids, and 3 phenols. All cultivars revealed similar metabolite profiles, however, they were further classified into seven groups on the basis of their varying metabolite contents by hierarchical cluster analysis. Traditional cultivars for Mu Dan Pi were found to have very low metabolite contents, falling into clusters I and II. Cultivars with the highest amounts of metabolites were grouped in clusters VI and VII. Five potential cultivars, namely, 'Bai Yuan Qi Guan', 'Cao Zhou Hong', 'Da Zong Zi', 'Sheng Dan Lu', and 'Cheng Xin', with high contents of monoterpene glycosides, tannins, and paeonols, were further screened. Interestingly, the majority of investigated cultivars had relatively higher metabolite contents compared to the traditional medicinal tree peony cultivars.

Botrytis euroamericana, a new species from peony and grape in North America and Europe

A novel species of Botrytis isolated from peony in Alaska, USA, and grape in Trento District, Italy, was identified based on morphology, pathogenicity, and sequence data. The grape and peony isolates share sequence homology in the glyceraldehyde-3-phosphate dehydrogenase (G3PDH), heat shock protein 60 (HSP60), DNA-dependent RNA polymerase subunit II (RPB2), and necrosis- and ethylene-inducing protein 1 and 2 (NEP1 and NEP2) genes that place them in a distinct group closely related to B. aclada, a globally distributed pathogen of onions. Genetic results were corroborated with morphological and pathogenicity trials that included two isolates of B. cinerea and two isolates of B. paeoniae from peony in Alaska and one isolate of B. aclada. The authors observed differences in colony and conidia morphology and ability to cause lesions on different host tissues that suggest that the grape and peony isolates represent a distinct species. Most notably, the grape and peony isolates did not colonize onion bulbs, whereas B. aclada readily produced lesions and prolific sporulation on onion tissue. The new species Botrytis euroamericana is described herein.

Methylation mediated by an anthocyanin, O-methyltransferase, is involved in purple flower coloration in Paeonia

Anthocyanins are major pigments in plants. Methylation plays a role in the diversity and stability of anthocyanins. However, the contribution of anthocyanin methylation to flower coloration is still unclear. We identified two homologous anthocyanin O-methyltransferase (AOMT) genes from purple-flowered (PsAOMT) and red-flowered (PtAOMT) Paeonia plants, and we performed functional analyses of the two genes in vitro and in vivo. The critical amino acids for AOMT catalytic activity were studied by site-directed mutagenesis. We showed that the recombinant proteins, PsAOMT and PtAOMT, had identical substrate preferences towards anthocyanins. The methylation activity of PsAOMT was 60 times higher than that of PtAOMT in vitro. Interestingly, this vast difference in catalytic activity appeared to result from a single amino acid residue substitution at position 87 (arginine to leucine). There were significant differences between the 35S::PsAOMT transgenic tobacco and control flowers in relation to their chromatic parameters, which further confirmed the function of PsAOMT in vivo. The expression levels of the two homologous AOMT genes were consistent with anthocyanin accumulation in petals. We conclude that AOMTs are responsible for the methylation of cyanidin glycosides in Paeonia plants and play an important role in purple coloration in Paeonia spp.

Multiple species of wild tree peonies gave rise to the 'king of flowers', Paeonia suffruticosa Andrews

The origin of cultivated tree peonies, known as the 'king of flowers' in China for more than 1000 years, has attracted considerable interest, but remained unsolved. Here, we conducted phylogenetic analyses of explicitly sampled traditional cultivars of tree peonies and all wild species from the shrubby section Moutan of the genus Paeonia based on sequences of 14 fast-evolved chloroplast regions and 25 presumably single-copy nuclear markers identified from RNA-seq data. The phylogeny of the wild species inferred from the nuclear markers was fully resolved and largely congruent with morphology and classification. The incongruence between the nuclear and chloroplast trees suggested that there had been gene flow between the wild species. The comparison of nuclear and chloroplast phylogenies including cultivars showed that the cultivated tree peonies originated from homoploid hybridization among five wild species. Since the origin, thousands of cultivated varieties have spread worldwide, whereas four parental species are currently endangered or on the verge of extinction. The documentation of extensive homoploid hybridization involved in tree peony domestication provides new insights into the mechanisms underlying the origins of garden ornamentals and the way of preserving natural genetic resources through domestication.

Systematic qualitative and quantitative assessment of fatty acids in the seeds of 60 tree peony (Paeonia section Moutan DC.) cultivars by GC-MS

Seeds from Paeonia ostii and Paeoniarockii have been recently identified as novel resources of α-linolenic acid (ALA) in China. To assess whether tree peony cultivars can be used as oil resource, fatty acids (FAs) in 60 cultivars were monitored and evaluated in this study. The results indicated that the composition and content of FAs varied dramatically among different cultivars, in which ALA, linoleic acid, oleic acid, palmitic acid, and stearic acid were the dominant. The 60 cultivars were classified into six clusters by hierarchical cluster analysis, and they were quite distinct from each other. Finally, six cultivars with high yield and high quality were screened out, comprising of 'Liuliguanzhu', 'Hongguanyupei', 'LSS-2', 'LSS-1', 'Jingshenhuanfa' and 'LSS-11'. These cultivars were appropriately applied in practical oil production. Overall, tree peony oil with abundant unsaturated fatty acids especially ALA was proved to be a top-grade source for edible oil and nutritional supplements.

Antioxidant and anti-inflammatory effects of Schisandra and Paeonia extracts in the treatment of asthma

The aim of the present study was to investigate the antioxidant and anti-inflammatory effects of Paeonia and Schisandra extracts in asthmatic rats. An ethanol extraction method was used to prepare the Schisandra and Paeonia extracts, and the levels of hydroxyl radical, total antioxidant activity and total phenolic content were detected. The rats were divided into three groups: Treatment (group A), model (group B) and control (group C). The treatment group received traditional Chinese antiasthmatic medicine (mixed extract, 2 ml/day) for 10 days. Levels of malondialdehyde (MDA), Cu-Zn-superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were detected in the serum, while interleukin (IL)-4, IL-6, interferon (IFN)-γ, IL-13 and IL-22 levels were analyzed in the serum, bronchoalveolar lavage fluid and lung tissue homogenates of the three groups. In addition, pathological changes of the tracheal tissues were observed via biopsies and the NF-κB p65 level was measured in the lung tissue using immunohistochemistry. Total antioxidant activity, hydroxyl radical levels and total phenolic content in the mixed herbal extracts were higher than those in the single herbal extracts. At day 5 following the treatment, the number of eosinophils was significantly reduced in the tracheal tissues. At day 10 following the treatment, the mucosa was significantly repaired. In vivo antioxidant levels revealed that the serum and erythrocyte SOD activity and GSH-Px were higher in group A as compared with group B, while the level of MDA in group A was lower than that in group B (P<0.05). The levels of serum and erythrocyte SOD activity and GSH-Px in group B were lower than those in group C, while the level of MDA in group B was higher than that in group C (P<0.05). IL-4, IL-6 and IL-13 levels in the serum, bronchoalveolar lavage fluid and lung tissue in group A were not significantly different from those in group B (P>0.05). However, IFN-γ levels in group A significantly increased as compared with the level in group B, while IL-22 levels decreased significantly in group A as compared with group B (P<0.05). IL-4, IL-6, IL-13 and IL-22 levels in the lung tissue, bronchoalveolar lavage fluid and serum in group B were significantly higher than those in group C. In addition, the IFN-γ level decreased significantly in group B as compared with the level in group C (P<0.05). Immunohistochemical analysis revealed that the protein expression of NF-κB p65 in group A was significantly lower compared with group B (P<0.05). Therefore, Paeonia and Schisandra extracts may be used to treat asthma through their in vivo antioxidant and anti-inflammatory effects.