Exogenous melatonin alleviates sodium chloride stress and increases vegetative growth in Lonicera japonica seedlings via gene regulation.

Melatonin (Mt) functions as a growth regulator and multifunctional signaling molecule in plants, thereby playing a crucial role in promoting growth and orchestrating protective responses to various abiotic stresses. However, the mechanism whereby exogenous Mt protects Lonicera japonica Thunb. (L. japonica) against salt stress has not been fully elucidated. Therefore, this study aimed to elucidate how exogenous Mt alleviates sodium chloride (NaCl) stress in L. japonica seedlings. Salt-sensitive L. japonica seedlings were treated with an aqueous solution containing 150 mM of NaCl and aqueous solutions containing various concentrations of Mt. The results revealed that treatment of NaCl-stressed L. japonica seedlings with a 60 µM aqueous solution of Mt significantly enhanced vegetative plant growth by scavenging reactive oxygen species and thus reducing oxidative stress. The latter was evidenced by decreases in electrical conductivity and malondialdehyde (MDA) concentrations. Moreover, Mt treatment led to increases in the NaCl-stressed L. japonica seedlings' total chlorophyll content, soluble sugar content, and flavonoid content, demonstrating that Mt treatment improved the seedlings' tolerance of NaCl stress. This was also indicated by the NaCl-stressed L. japonica seedlings exhibiting marked increases in the activities of antioxidant enzymes (superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase) and in photosynthetic functions. Furthermore, Mt treatment of NaCl-stressed L. japonica seedlings increased their expression of phenylalanine ammonia-lyase 1 (PAL1), phenylalanine ammonia-lyase 2 (PAL2), calcium-dependent protein kinase (CPK), cinnamyl alcohol dehydrogenase (CAD), flavanol synthase (FLS), and chalcone synthase (CHS). In conclusion, our results demonstrate that treatment of L. japonica seedlings with a 60 µM aqueous solution of Mt significantly ameliorated the detrimental effects of NaCl stress in the seedlings. Therefore, such treatment has substantial potential for use in safeguarding medicinal plant crops against severe salinity.

High-resolution genome mapping and functional dissection of chlorogenic acid production in Lonicera maackii.

Amur honeysuckle (Lonicera maackii) is a widely used medicinal plant of the Caprifoliaceae family that produces chlorogenic acid. Research on this plant mainly focuses on its ornamental value and medicinal compounds, but a reference genome sequence and molecular resources for accelerated breeding are currently lacking. Herein, nanopore sequencing and high-throughput chromosome conformation capture (Hi-C) allowed a chromosome-level genome assembly of L. maackii (2n = 18). A global view of the gene regulatory network involved in the biosynthesis of chlorogenic acid and the dynamics of fruit coloration in L. maackii was established through metabolite profiling and transcriptome analyses. Moreover, we identified the genes encoding hydroxycinnamoyl-CoA quinate transferase (LmHQT) and hydroxycinnamoyl-CoA shikimic/quinate transferase (LmHCT), which localized to the cytosol and nucleus. Heterologous overexpression of these genes in Nicotiana benthamiana leaves resulted in elevated chlorogenic acid contents. Importantly, HPLC analyses revealed that LmHCT and LmHQTs recombinant proteins modulate the accumulation of chlorogenic acid (CGA) using quinic acid and caffeoyl CoA as substrates, highlighting the importance of LmHQT and LmHCT in CGA biosynthesis. These results confirmed that LmHQTs and LmHCT catalyze the biosynthesis of CGA in vitro. The genomic data presented in this study will offer a valuable resource for the elucidation of CGA biosynthesis and facilitating selective molecular breeding.

[Transcriptional regulation mechanism of differential accumulation of flavonoids in different varieties of Lonicera macranthoides based on metabonomics and transcriptomics].

This study aims to explore the molecular regulatory mechanism of the differential accumulation of flavonoids between 'Xianglei' and the wild type of Lonicera macranthoides. The flowers, stems, and leaves of the two varieties of L. macranthoides were collected. Ultra-performance liquid chromatography-mass spectrometry(UPLC-MS) and high-throughput sequencing(RNA-seq) were employed to screen out the differential flavonoids, key differentially expressed genes(DEGs) and transcription factors(TFs). Fourteen DEGs were randomly selected for verification by qRT-PCR. The results showed that a total of 17 differential flavonoids were obtained, including naringin chalcone, apigenin, and quercetin. The transcriptomic analysis predicted 19 DEGs associated with flavonoids, including 2 genes encoding chitin synthase(CHS) and 3 genes encoding chalcone isomerase(CHI). The regulatory network analysis and weighted gene co-expression network analysis(WGCNA) screen out the key enzyme genes CHS1, FLS1, and HCT regulating the accumulation of flavonoids. MYB12 and LBD4 may be involved in the biosynthesis of flavonoids by regulating the expression of key enzyme genes CHS1, FLS1, and HCT. The qRT-PCR and RNA-seq results were similar regarding the expression patterns of the 14 randomly selected DEGs. This study preliminarily analyzed the transcriptional regulatory mechanism for the differential accumulation of flavonoids in the two varieties of L. macranthoides and laid a foundation for further elucidating the regulatory effects of key enzyme genes and TFs on the accumulation of flavonoids.

[Content of secondary metabolites and antioxidant activities of Lonicera japonica flowers at different developmental stages from Shandong province].

This study established an ultrasound-assisted extraction-high performance liquid chromatography method for simulta-neously determinining the content of 11 bioactive compounds including iridoids, phenolic acids, and flavonoids in Lonicera japonica flowers. The flowers at six stages from the rice bud stage(ML) to the golden flower stage(JH) of L. japonica varieties 'Sijuhua' and 'Beihua No.1' in two planting bases in Shandong province were collected. The established method was employed to determine the content of 11 target compounds, on the basis of which the dynamics of active components in L. japonica sampels during different development stages was investigated. The correlation analysis was carried out to reveal the correlations of the content of iridoids, phenolic acids, and flavonoids. Furthermore, the antioxidant activities of samples at different developmental stages were determined, and the relationship between antioxidant activity and chemical components was analyzed by the correlation analysis. The results showed that the total content of the 11 components in 'Sijihua' changed in a "W" pattern from the ML to JH, being the highest at the ML and the second at the slight white stage(EB). The total content of 11 compounds in 'Beihua No.1' was the highest at the ML and decreased gra-dually from the ML to JH. The samples of 'Sijihua' had higher content of iridoids and lower content of phenolic acids than those of 'Beihua No.1'. The content of flavonoids and phenolic acids showed a positive correlation(R~2=0.90, P<0.05) in 'Sijihua' but no obvious correlation in 'Beihua No.1'. The antioxidant activity and phenolic acid content showed positive correlations, with the determination coefficients(R~2) of 0.84(P<0.05) in 'Beihua No.1' and 0.73(P<0.05) in 'Sijihua'. The antioxidant activity of both varieties was the strongest at the ML and the second at the EB. This study revealed that the content dynamics of iridoids, phenolic acids, and flavonoids in 'Sijihua' and 'Beihua No.1' cultivated in Shandong province during different developmental stages. The results indicated that the antioxidant activity of L. japonica flowers was significantly correlated with the content of phenolic acids at different deve-lopmental stages, which provided a basis for determining the optimum harvest time of L. japonica flowers.

Genome-wide analysis of the MADS-box gene family in Lonicera japonica and a proposed floral organ identity model.

BACKGROUND: Lonicera japonica Thunb. is widely used in traditional Chinese medicine. Medicinal L. japonica mainly consists of dried flower buds and partially opened flowers, thus flowers are an important quality indicator. MADS-box genes encode transcription factors that regulate flower development. However, little is known about these genes in L. japonica. RESULTS: In this study, 48 MADS-box genes were identified in L. japonica, including 20 Type-I genes (8 Mα, 2 Mß, and 10 Mγ) and 28 Type-II genes (26 MIKCc and 2 MIKC*). The Type-I and Type-II genes differed significantly in gene structure, conserved domains, protein structure, chromosomal distribution, phylogenesis, and expression pattern. Type-I genes had a simpler gene structure, lacked the K domain, had low protein structure conservation, were tandemly distributed on the chromosomes, had more frequent lineage-specific duplications, and were expressed at low levels. In contrast, Type-II genes had a more complex gene structure; contained conserved M, I, K, and C domains; had highly conserved protein structure; and were expressed at high levels throughout the flowering period. Eleven floral homeotic MADS-box genes that are orthologous to the proposed Arabidopsis ABCDE model of floral organ identity determination, were identified in L. japonica. By integrating expression pattern and protein interaction data for these genes, we developed a possible model for floral organ identity determination. CONCLUSION: This study genome-widely identified and characterized the MADS-box gene family in L. japonica. Eleven floral homeotic MADS-box genes were identified and a possible model for floral organ identity determination was also developed. This study contributes to our understanding of the MADS-box gene family and its possible involvement in floral organ development in L. japonica.

Comparative genomics of the medicinal plants Lonicera macranthoides and L. japonica provides insight into genus genome evolution and hederagenin-based saponin biosynthesis.

Lonicera macranthoides (LM) and L. japonica (LJ) are medicinal plants widely used in treating viral diseases, such as COVID-19. Although the two species are morphologically similar, their secondary metabolite profiles are significantly different. Here, metabolomics analysis showed that LM contained ~86.01 mg/g hederagenin-based saponins, 2000-fold higher than LJ. To gain molecular insights into its secondary metabolite production, a chromosome-level genome of LM was constructed, comprising 9 pseudo-chromosomes with 40 097 protein-encoding genes. Genome evolution analysis showed that LM and LJ were diverged 1.30-2.27 million years ago (MYA). The two plant species experienced a common whole-genome duplication event that occurred ∼53.9-55.2 MYA before speciation. Genes involved in hederagenin-based saponin biosynthesis were arranged in clusters on the chromosomes of LM and they were more highly expressed in LM than in LJ. Among them, oleanolic acid synthase (OAS) and UDP-glycosyltransferase 73 (UGT73) families were much more highly expressed in LM than in LJ. Specifically, LmOAS1 was identified to effectively catalyse the C-28 oxidation of ß-Amyrin to form oleanolic acid, the precursor of hederagenin-based saponin. LmUGT73P1 was identified to catalyse cauloside A to produce α-hederin. We further identified the key amino acid residues of LmOAS1 and LmUGT73P1 for their enzymatic activities. Additionally, comparing with collinear genes in LJ, LmOAS1 and LmUGT73P1 had an interesting phenomenon of 'neighbourhood replication' in LM genome. Collectively, the genomic resource and candidate genes reported here set the foundation to fully reveal the genome evolution of the Lonicera genus and hederagenin-based saponin biosynthetic pathway.

[Mining and identification of members of MYB transcription factor family in Lonicera macranthoides].

As a large family of transcription factors, the MYB family plays a vital role in regulating flower development. We studied the MYB family members in Lonicera macranthoides for the first time and identified three sequences of 1R-MYB, 47 sequences of R2R3-MYB, two sequences of 3R-MYB, and one sequence of 4R-MYB from the transcriptome data. Further, their physicochemical properties, conserved domains, phylogenetic relationship, protein structure, functional information, and expression were analyzed. The results show that the 53 MYB transcription factors had different conserved motifs, physicochemical properties, structures, and functions in wild type and 'Xianglei' cultivar of L. macranthoides, indicating their conservation and diversity in evolution. The transcript level of LmMYB was significantly different between the wild type and 'Xianglei' cultivar as well as between flowers and leaves, and some genes were specifically expressed. Forty-three out of 53 LmMYB sequences were expressed in both flowers and leaves, and 9 of the LmMYB members showed significantly different transcript levels between the wild type and 'Xianglei' cultivar, which were up-regulated in the wild type. The results provide a theoretical basis for further studying the specific functional mechanism of the MYB family.

[Cloning and function analysis of chalcone isomerase gene and chalcone synthase gene in Lonicera macranthoides].

In order to explore the functions of genes of key rate-limiting enzymes chalcone isomerase(CHI) and chalcone synthase(CHS) in the biosynthesis of flavonoids in Lonicera macranthoides, this study screened and cloned the cDNA sequences of CHI and CHS genes from the transcriptome data of conventional variety and 'Xianglei' of L. macranthoides. Online bioinformatics analysis software was used to analyze the characteristics of the encoded proteins, and quantitative reverse-transcription polymerase chain reaction(qRT-PCR) to detect the expression of CHI and CHS in different parts of the varieties at different flowering stages. The content of luteo-loside was determined by high performance liquid chromatography(HPLC) and the correlation with the expression of the two genes was analyzed. The results showed that the CHI and CHS of the two varieties contained a 627 bp and 1170 bp open reading frame(ORF), respectively, and the CHI protein and CHS protein were stable, hydrophilic, and non-secretory. qRT-PCR results demonstrated that CHI and CHS of the two varieties were differentially expressed in stems and leaves at different flowering stages, particularly the key stages. Based on HPLC data, luteoloside content was in negative correlation with the relative expression of the genes. Thus, CHI and CHS might regulate the accumulation of flavonoids in L. macranthoides, and the specific functions should be further studied. This study cloned CHI and CHS in L. macranthoides and analyzed their expression for the first time, which laid a basis for investigating the molecular mechanism of the differences in flavonoids such as luteoloside in L. macranthoides and variety breeding.

[Winter pruning boosts growth and yield of Lonicera japonica by regulating plant hormone content].

Lonicera japonica is a ubiquitous medicinal species in China.Winter pruning has long been used to improve its quality and yield, but the mechanism is rarely studied.Therefore, in this study, the growth phenotypes of L.japonica processed with different pruning methods were observed and the yield-and quality-boosting mechanism of pruning was analyzed.Specifically, the young shoots of the three-year old L.japonica were cut to different degrees(heavy pruning, mild pruning, and no pruning, respectively) in winter in 2020 and 2021, respectively, and the growth phenotypes, hormone content, and gene expression of the lateral buds at the sprouting stage and young shoots at the anthesis stage in the next year were analyzed.The result showed that the length, flower bud number, internode length, and node number of young shoots in the next year were in the order of heavy pruning>mild pruning>no pruning.The content of auxin and zeatin in apical buds of young shoots at the anthesis stage was the highest in the heavy pruning group, followed by the mild pruning group, and coming in the third was the no pruning group.The content of auxin and zeatin in lateral buds at the sprouting stage was in the order of no pruning>mild pruning>heavy pruning.Transcriptome analysis of the lateral buds at sprouting stage yielded the differentially expressed genes related to auxin and cytokinin, such as Lj1A1163T36, Lj3A719T115, Lj7C657T7, Lj9C505T15, and Lj9A505T70.In conclusion, the growth phenotypes of young shoots of L.japonica processed with different pruning methods in winter were related to the difference in hormone content in the apical buds.Therefore, winter pruning influenced the content of auxin and cytokinin in new shoots of L.japonica and further regulated the expression of hormone-related genes, thereby promoting shoot growth and increasing the yield of L.japonica.

Integrated metabolic profiling and transcriptome analysis of pigment accumulation in Lonicera japonica flower petals during colour-transition.

BACKGROUND: Plants have remarkable diversity in petal colour through the biosynthesis and accumulation of various pigments. To better understand the mechanisms regulating petal pigmentation in Lonicera japonica, we used multiple approaches to investigate the changes in carotenoids, anthocyanins, endogenous hormones and gene expression dynamics during petal colour transitions, i.e., green bud petals (GB_Pe), white flower petals (WF_Pe) and yellow flower petals (YF_Pe). RESULTS: Metabolome analysis showed that YF_Pe contained a much higher content of carotenoids than GB_Pe and WF_Pe, with α-carotene, zeaxanthin, violaxanthin and γ-carotene identified as the major carotenoid compounds in YF_Pe. Comparative transcriptome analysis revealed that the key differentially expressed genes (DEGs) involved in carotenoid biosynthesis, such as phytoene synthase, phytoene desaturase and ζ-carotene desaturase, were significantly upregulated in YF_Pe. The results indicated that upregulated carotenoid concentrations and carotenoid biosynthesis-related genes predominantly promote colour transition. Meanwhile, two anthocyanins (pelargonidin and cyanidin) were significantly increased in YF_Pe, and the expression level of an anthocyanidin synthase gene was significantly upregulated, suggesting that anthocyanins may contribute to vivid yellow colour in YF_Pe. Furthermore, analyses of changes in indoleacetic acid, zeatin riboside, gibberellic acid, brassinosteroid (BR), methyl jasmonate and abscisic acid (ABA) levels indicated that colour transitions are regulated by endogenous hormones. The DEGs involved in the auxin, cytokinin, gibberellin, BR, jasmonic acid and ABA signalling pathways were enriched and associated with petal colour transitions. CONCLUSION: Our results provide global insight into the pigment accumulation and the regulatory mechanisms underlying petal colour transitions during the flower development process in L. japonica.

Heat-induced down-regulation of photosystem II protects photosystem I in honeysuckle (Lonicera japonica).

Honeysuckle (Lonicera japonica Thunb.) is a traditional medicinal plant in China which is often threatened by high temperature at midday during summer. Heat-induced effects on the photosynthetic apparatus in honeysuckle are associated with a depression of the photosystem II (PSII) photochemical efficiency. However, very limited information is available on regulation of photosynthetic electron flow in PSI photoprotection in heat-stressed honeysuckle. Simultaneous analyses of chlorophyll fluorescence and the change in absorbance of P700 showed that energy transformation and electron transfer activity in PSII decreased under heat stress, but the fraction of photo-oxidizable PSI (Pm) remained stable. With treatments at 38 and 42 °C, the photochemical electron transport in PSII was suppressed, whereas the cyclic electron flow (CEF) around PSI was induced. In addition, the levels of high energy state quenching (qE) and P700 oxidation increased significantly with increasing temperature. However, a decline of qE in antimycin A (AA)- or 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU)-treated leaves after heat treatment was observed, while P700 oxidation decreased only in the presence of AA. The results indicate that heat-induced inhibition of PSII and induction of CEF cooperatively protect PSI from ROS damages through moderate down-regulation of photosynthetic electron flow from PSII to PSI.

Accumulation Pattern of Flavonoids during Fruit Development of Lonicera maackii Determined by Metabolomics.

Lonicera maackii (Caprifoliaceae) is a large, upright shrub with fruits that contain many bioactive compounds. Flavonoids are common active substances in L. maackii. However, there is a dearth of information about the accumulation of these flavonoids and their possible medicinal value. We used targeted metabolomics analysis based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to analyze five developmental stages of L. maackii fruit. A total of 438 metabolites were identified in the five developmental stages, including 81 flavonoids and derivatives. The 81 flavonoids included 25 flavones and derivatives, 35 flavonols and derivatives, two isoflavones, three cyanidins and derivatives, eight procyanidins, and eight flavanones. In addition, we outlined the putative flavonoid biosynthesis pathway and screened their upstream metabolites. More importantly, we analyzed the accumulation patterns of several typical flavones and flavonols. The results reported here improved our understanding of the dynamic changes in flavonoids during fruit development and contributed to making full use of the medicinal value of L. maackii fruit.

Regulation of chlorogenic acid, flavonoid, and iridoid biosynthesis by histone H3K4 and H3K9 methylation in Lonicera japonica.

Lonicera japonica is used in Chinese herbal medicines with a wide spectrum of pharmacological properties associated with chlorogenic acid, flavonoid and iridoid. The biosynthesis of these compounds could be affected by genetic inheritance and epigenetic modification. However, the mechanisms that regulate the expression of genes involved in the biosynthesis of these compounds are rarely known. The results of qRT-PCR showed that the biosynthesis gene expression of these compounds was related to histone H3K4 and H3K9 methylation levels. These active compounds content of L. japonica were measured by UPLC-MS/MS. H3K4me3 showed a positive correlation with chlorogenic acid and loganic acid content, and H3K9me positively correlated with luteolin content. The correlation between histone methylation levels and the levels of luteolin and loganic acid in L. japonica from different producing areas validate the regulatory role of histone methylation in biosynthesis of bioactive compounds. Our study demonstrated a potential regulatory network of H3K9/H3K4 methylation to gene expression and content of secondary metabolites, and provided a basis for understanding the mechanism underlying the variation of major bioactive compounds in L. japonica.

Critical Phenological Events Affect Chemical Defense of Plant Tissues: Iridoid Glycosides in a Woody Shrub.

Plants are chemically-complex organisms; each individual contains diverse tissue-types, has the ability to differentially allocate secondary metabolites to these tissues and can change this allocation through time. The interaction of variation in chemical defense of different tissue types and variation in chemical defense through time, however, is rarely examined and has not been studied for iridoid glycoside-producing woody plants. In this study, we quantified allocation of iridoid glycosides (IGs) to the leaves, flowers, fruits, and seeds of 25 individuals of a long-lived shrub (Lonicera x bella Zabel, Caprifoliaceae), at five important phenological timepoints (leaf-out, flowering, fruit appearance, fruit ripening, and fruit dispersal) throughout a growing season. We found that leaves had 2x higher IG concentrations during flowering and fruiting than earlier in the season (after leaf-out), and later in the season (after fruit dispersal). The individual IG driving this increase in leaves during reproduction, secologanin, was also the most abundant IG in semiripe fruits. Flowers and seeds were composed of different proportions of individual IGs than fruits or leaves, but did not change across time and had overall low concentrations of IGs. In L. x bella, phenological events such as flowering and fruiting lead to an increase in leaf chemical defense that is likely to influence interactions with leaf-feeders. Our results stress the importance of considering phenology when sampling plants for the quantification of chemical defenses.

Health Properties and Composition of Honeysuckle Berry Lonicera caerulea L. An Update on Recent Studies.

Lonicera caerulea L., also known as haskap or honeysuckle berry, is a fruit commonly planted in eastern Europe, Canada and Asia. The fruit was registered as a traditional food from a third country under European Union regulations only on December 2018. It is resistant to cold, pests, various soil acidities and diseases. However, its attractiveness is associated mostly with its health properties. The fruit shows anticancer, anti-inflammatory, and antioxidant activity-important factors in improving health. These features result from the diverse content of phytochemicals in honeysuckle berries with high concentrations of phytocompounds, mainly hydroxycinnamic acids, hydroxybenzoic acids, flavanols, flavones, isoflavones, flavonols, flavanones and anthocyanins but also iridoids, present in the fruit in exceptional amounts. The content and health properties of the fruit were identified to be dependent on cultivar, genotype and the place of harvesting. Great potential benefits of this nutritious food are its ability to minimize the negative effects of UV radiation, diabetes mellitus and neurodegenerative diseases, and to exert hepato- and cardioprotective activity.

Transcriptional regulation of Lonicera japonica Thunb. during flower development as revealed by comprehensive analysis of transcription factors.

BACKGROUND: Lonicera japonica Thunb. flower has been used for the treatment of various diseases for a long time and attracted many studies on its potential effects. Transcription factors (TFs) regulate extensive biological processes during plant development. As the restricted reports of L. japonica on TFs, our work was carried out to better understand the TFs' regulatory roles under different developmental stages in L. japonica. RESULTS: In this study, 1316 TFs belonging to 52 families were identified from the transcriptomic data, and corresponding expression profiles during the L. japonica flower development were comprehensively analyzed. 917 (69.68%) TFs were differentially expressed. TFs in bHLH, ERF, MYB, bZIP, and NAC families exhibited obviously altered expression during flower growth. Based on the analysis of differentially expressed TFs (DETFs), TFs in MYB, WRKY, NAC and LSD families that involved in phenylpropanoids biosynthesis, senescence processes and antioxidant activity were detected. The expression of MYB114 exhibited a positive correlation with the contents of luteoloside; Positive correlation was observed among the expression of MYC12, chalcone synthase (CHS) and flavonol synthase (FLS), while negative correlation was observed between the expression of MYB44 and the synthases; The expression of LSD1 was highly correlated with the expression of SOD and the total antioxidant capacity, while the expression of LOL1 and LOL2 exhibited a negative correlation with them; Many TFs in NAC and WRKY families may be potentially involved in the senescence process regulated by hormones and reactive oxygen species (ROS). The expression of NAC19, NAC29, and NAC53 exhibited a positive correlation with the contents of ABA and H2O2, while the expression of WRKY53, WRKY54, and WRKY70 exhibited a negative correlation with the contents of JA, SA and ABA. CONCLUSIONS: Our study provided a comprehensive characterization of the expression profiles of TFs during the developmental stages of L. japonica. In addition, we detected the key TFs that may play significant roles in controlling active components biosynthesis, antioxidant activity and flower senescence in L. japonica, thereby providing valuable insights into the molecular networks underlying L. japonica flower development.

Ligand fishing of anti-neurodegenerative components from Lonicera japonica using magnetic nanoparticles immobilised with monoamine oxidase B.

In this work, monoamine oxidase B was immobilised onto magnetic nanoparticles to prepare a new type of affinity solid-phase extraction adsorbent, which was used to extract the possible anti-neurodegenerative components from the Lonicera japonica flower extracts. Coupled with high-performance liquid chromatography with mass spectrometry, two monoamine oxidase B ligands were fished-out and identified as isochlorogenic acid A and isochlorogenic acid C, which were found to be inhibitors of the enzyme for the first time, with similar half maximal inhibitory concentration values of 29.05 ± 0.49 and 29.77 ± 1.03 µM, respectively. Furthermore, equilibrium-dialysis dissociation assay of enzyme-inhibitor complex showed that both compounds have reversible binding patterns to monoamine oxidase B, and kinetic analysis demonstrated that they were mixed-type inhibitors for monoamine oxidase B, with Ki and Kis values of 9.55 and 37.24 µM for isochlorogenic acid A, 9.53 and 35.50 µM for isochlorogenic acid C, respectively. The results indicated that isochlorogenic acid A and isochlorogenic acid C were the major active components responsible for the anti-degenerative activity of the flowers of L. japonica, while magnetic nanoparticles immobilised monoamine oxidase B could serve as an efficient solid-phase extraction adsorbent to specifically extract monoamine oxidase B inhibitors from complex herbal extracts.

Lonicera japonica Thunb. Induces caspase-dependent apoptosis through death receptors and suppression of AKT in U937 human leukemic cells.

Decoctions obtained from the dried flowers of Lonicera japonica Thunb. (Indongcho) have been utilized in folk remedies against inflammatory diseases. Recently, many agents that have used for inflammatory diseases are showing anticancer effects. Here, we have isolated polyphenols extracted from lyophilized Lonicera japonica Thunb (PELJ) and investigated the anticancer effects of PELJ on U937 cells. Here, we demonstrated that PELJ induced apoptosis by upregulation of DR4 and Fas, and further it is augmented by suppression of XIAP. In addition, The PELJ-induced apoptosis is at least in part by blocking PI3K/Akt pathway. These findings suggest that PELJ may provide evidence of anticancer activities on U937 cells. Further study for detailed mechanism and the effects on animal models is warranted to determine whether PELJ provide more conclusive evidence that PELJ which may provide a beneficial effect for treating cancer.

Transcriptome Analysis Reveals Molecular Signatures of Luteoloside Accumulation in Senescing Leaves of Lonicera macranthoides.

Lonicera macranthoides is an important medicinal plant widely used in traditional Chinese medicine. Luteoloside is a critical bioactive compound in L. macranthoides. To date, the molecular mechanisms underlying luteoloside biosynthesis are still largely unknown. In this work, high performance liquid chromatography (HPLC) was employed to determine the luteoloside contents in leaves, stems, and flowers at different developmental stages. Results showed that senescing leaves can accumulate large amounts of luteoloside, extremely higher than that in young and semi-lignified leaves and other tissues. RNA-Seq analysis identified that twenty-four differentially expressed unigenes (DEGs) associated with luteoloside biosynthesis were significantly up-regulated in senescing leaves, which are positively correlated with luteoloside accumulation. These DEGs include phenylalanine ammonia lyase 2, cinnamate 4-hydroxylase 2, thirteen 4-coumarate-CoA ligases, chalcone synthase 2, six flavonoid 3'-monooxygenase (F3'H) and two flavone 7-O-ß-glucosyltransferase (UFGT) genes. Further analysis demonstrated that two F3'Hs (CL11828.Contig1 and CL11828.Contig2) and two UFGTs (Unigene2918 and Unigene97915) might play vital roles in luteoloside generation. Furthermore, several transcription factors (TFs) related to flavonoid biosynthesis including MYB, bHLH and WD40, were differentially expressed during leaf senescence. Among these TFs, MYB12, MYB75, bHLH113 and TTG1 were considered to be key factors involved in the regulation of luteoloside biosynthesis. These findings provide insights for elucidating the molecular signatures of luteoloside accumulation in L. macranthoides.

Variations of metabolites and proteome in Lonicera japonica Thunb. buds and flowers under UV radiation.

Lonicera japonica Thunb., also known as Jin Yin Hua and Japanese honeysuckle, is used as a herbal medicine in Asian countries. Its flowers have been used in folk medicine in the clinic and in making food or healthy beverages for over 1500years in China. To investigate the molecular processes involved in L. japonica development from buds to flowers exposed to UV radiation, a comparative proteomics analysis was performed. Fifty-four proteins were identified as differentially expressed, including 42 that had increased expression and 12 that had decreased expression. The levels of the proteins related to glycolysis, TCA/organic acid transformation, major carbohydrate metabolism, oxidative pentose phosphate, stress, secondary metabolism, hormone, and mitochondrial electron transport were increased during flower opening process after exposure to UV radiation. Six metabolites in L. japonica buds and flowers were identified and relatively quantified using LC-MS/MS. The antioxidant activity was performed using a 1,1-diphenyl-2-picrylhydrazyl assay, which revealed that L. japonica buds had more activity than the UV irradiated flowers. This suggests that UV-B radiation induces production of endogenous ethylene in L. japonica buds, thus facilitating blossoming of the buds and activating the antioxidant system. Additionally, the higher metabolite contents and antioxidant properties of L. japonica buds indicate that the L. japonica bud stage may be a more optimal time to harvest than the flower stage when using for medicinal properties.