Traditional uses, phytochemistry, and pharmacology of the genus Acer (maple): A review

Application of sandpaper spray ionization mass spectrometry to comprehensively examine maple leaves infected with distinct fungi

This study describes a novel application for sandpaper spray ionization mass spectrometry (SPS-MS), to examine the surface of maple tree (Acer sp.) leaves. By comparing mass spectrometry fingerprints, healthy leaves from those infected with powdery mildew and Rhytisma acerinum were distinguished. Leaves were grated with sandpaper, cut into triangles, and placed before the mass spectrometer, with the addition of a methanol-formic acid solution. Multivariate statistical analysis categorized the samples into three groups. Overall, SPS-MS effectively analyzed leaves with infectious microorganisms, potentially aiding in the creation of fungal identification databanks.

High-quality maple genome reveals duplication-facilitated leaf color diversity

Acer truncatum is a horticultural tree species with individuals that display either yellow or red leaves in autumn, giving it high ornamental and economic value. 'Lihong' of A. truncatum is an excellent cultivar due to its characteristic of having autumn leaves that turn a bright and beautiful shade of red, while its closely related cultivar 'Bunge' does not. However, the molecular mechanism underlying the color change in the cultivar 'Lihong' is still unclear. Here, we assembled a high-quality genome sequence of Acer truncatum 'Lihong' (genome size = 688 Mb, scaffold N50 = 9.14 Mb) with 28,438 protein-coding genes predicted. Through comparative genomic analysis, we found that 'Lihong' had experienced more tandem duplication events although it's a high degree of collinearity with 'Bunge'. Especially, the expansion of key enzymes in the anthocyanin synthesis pathway was significantly uneven between the two varieties, with 'Lihong' genome containing a significantly higher number of tandem/dispersed duplication key genes. Further transcriptomic, metabolomic, and molecular functional analyses demonstrated that several UFGT genes, mainly resulting from tandem/dispersed duplication, followed by the promoter sequence variation, may contribute greatly to the leaf color phenotype, which provides new insights into the mechanism of divergent anthocyanin accumulation process in the 'Lihong' and 'Bunge' with yellow leaves in autumn. Further, constitutive expression of two UFGT genes, which showed higher expression in 'Lihong', elevated the anthocyanin content. We proposed that the small-scale duplication events could contribute to phenotype innovation.

Preparation of Self-microemulsion Solids of Kaempferia galanga (L.) Volatile Oil and Its Effect on Rats with Gastric Ulcer

Kaempferia galanga volatile oil (KVO), the main effective component of the medicinal plant Kaempferia galanga L., possesses a variety of pharmacological activities such as anti-inflammatory, antioxidant, and anti-angiogenic activities and has therapeutic potential for gastric ulcer (GU). However, poor solubility as well as instability limits the clinical application of KVO. In this study, K. galanga volatile oil self-microemulsion solids (KVO-SSMEDDS) were prepared to improve its bioavailability and stability, and the therapeutic effects were evaluated in a rat model with GU. The ratio of oil phase, emulsifier, and co-emulsifier in the KVO-SMEDDS prescription were optimized by plotting the pseudo-ternary phase diagram with the star point design-response surface method. Based on the optimal prescription, self-microemulsifying drug delivery system (SMEDDS) was prepared as solid particles (S-SMEDDS). The prepared KVO-SSMEDDS had a rounded and non-adhesive appearance, formed an O/W emulsion after dissolution in water, and had a uniform particle size distribution with good stability and solubility. It was administered to GU model animals, and the results showed that a certain dose of KVO-SSMEDDS solution could increase the content of gastric mucosal protective factors PGE2, TGF-α, and EGF in gastric tissues and serum, and the expression of inflammatory factors IL-8 and TNF-α was downregulated. Meanwhile, the expression of the NF-κB/COX-2 pathway proteins was inhibited. In conclusion, the prepared KVO-SSMEDDS has good dispersion, solubility, and stability and has a therapeutic effect on rats with GU.

Lignan-containing maple products inhibit Listeria monocytogenes biofilms on fresh produce

Major listeriosis outbreaks have been associated with fresh produce contaminated with Listeria monocytogenes. Strains that synthesize the Pss exopolysaccharide (EPS) have an estimated 102 to 104-fold advantage over nonsynthesizing strains in causing listeriosis. They more readily attach to the surfaces of fruit and vegetables forming EPS-biofilms that better withstand stresses associated with produce storage and consumption. Here, we show that the threat to fresh produce safety posed by the listerial EPS-biofilms may be countered by broadly available maple products. We serendipitously discovered that aqueous extracts of wood from several Acer (maple) and Carya (pecan, hickory) species inhibit the formation of listerial EPS-biofilms without affecting bacterial viability. One active ingredient in maple wood was identified as nortrachelogenin-8'-O-β-D-glucopyranoside (NTG). At 120 μM, this lignan decreased colonization of the EPS-synthesizing L. monocytogenes on cantaloupe pieces by approximately 150-fold, and on cut celery and lettuce by 10 to 11-fold. Another lignan, lariciresinol, which is abundant in a common food sweetener, maple syrup, had antibiofilm activity comparable to that of NTG. Diluted in the range of 1:200 to 1:800 maple syrup from two random manufacturers prevented formation of listeiral EPS-biofilms. Importantly, not only did maple products drastically decrease colonization of fresh produce by the EPS-synthesizing strains, they also decreased, by 6 to 30-fold, colonization by the L. monocytogenes strains that do not synthesize measurable EPS, including strains from the infamous 2011 cantaloupe listeriosis outbreak. Inhibition of surface colonization by various listerial strains, broad availability of maple sap and syrup as well as maple lumber processing waste position maple products as potential antibiofilm agents for protecting fresh produce from L. monocytogenes.

Seasonal Variation in Plant Polyphenols and Related Bioactivities across Three Years in Ten Tree Species as Visualized by Mass Spectrometric Fingerprint Mapping

The currently changing climates and environments place plants under many types of stresses that affect both their survival and levels of chemical defenses. The gradual induction of defenses in stressed plant populations could be monitored on a yearly basis unless a seasonal and yearly variation in natural defense levels obscures such monitoring schemes. Here, we studied the stability of the species-specific polyphenol composition and content of 10 tree species over three growing seasons using five replicate trees per species. We specifically measured hydrolyzable tannins (galloyl and hexahydroxydiphenoyl derivatives), proanthocyanidins (procyanidins and prodelphinidins), flavonols (kaempferol, quercetin and kaempferol derivatives) and quinic acid derivatives with the group-specific UHPLC-DAD-MS/MS tool, together with two bioactivities, the protein precipitation capacity and oxidative activity. With the help of a fingerprint mapping tool, we found out that species differed a lot in their seasonal and between-year variation in polyphenols and that the variation was also partially specific to compound groups. Especially ellagitannins tended to have declining seasonal patterns while the opposite was true for proanthocyanidins. Some of the species showed minimal variation in all measured variables, while others showed even induced levels of certain polyphenol groups during the 3-year study. For every species, we found either species-specific baseline levels in qualitative and quantitative polyphenol chemistry or the compound groups with the most plasticity in their production. The used tools could thus form a good combination for future studies attempting to monitor the overall changes in polyphenol chemistry due to various biotic or abiotic stress factors in plant populations or in more controlled environments.

Phenolic mapping and associated antioxidant activities through the annual growth cycle of sugar maple leaves

Concentrations of antioxidant components (analyzed by HPLC-UV) and antioxidant attributes (assayed by radical scavenging and non-radical redox potential methods) of sugar maple leaves (SML) from different harvesting times were investigated. Moreover, measurements of colorimetry, SEM, and FTIR spectroscopy-based characterization of leaves composition, throughout the growth cycle, were performed. Results showed that the antioxidant activities of SML are strongly correlated with phenolic contents and significantly (p < 0.05) varied with harvesting time where minimum amount of total phenolics (105.67 ± 13.16 mg GAE/g DM) and total flavonoids (3.27 ± 0.26 mg CTE/g DM) were found to be concentrated in Fall leaves. The absorption bands obtained from FTIR spectra revealed the presence of functional groups that have great significance towards the antioxidant activity of SML. Principal component analysis revealed that biosynthesis of maximum phenolic compounds in SML mostly occurs during the leaf expansion and growth phases. The obtained data provided a better understanding towards the effect of harvesting time on the phenolic mapping of SML in favor of its valorization into functional food ingredients.

Isolation and characterization of phosphate-solubilizing bacterium Pantoea rhizosphaerae sp. nov. from Acer truncatum rhizosphere soil and its effect on Acer truncatum growth

The Acer truncatum Bunge, widely distributed in North China, shows excellent tolerance to low-P soils. However, little information is available on potential phosphate-solubilizing bacterial (PSB) strains from the A. truncatum rhizosphere. The objectives of this work were to isolate and characterize PSB from A. truncatum rhizosphere soil and to evaluate the effect of inoculation with the selected strain on A. truncatum seedlings. The strains were characterized on the basis of phenotypic characteristics, carbon source utilization pattern, fatty acid methyl esters analysis, 16S rRNA gene and the whole-genome sequence. A Gram-negative and rod-shaped bacterium, designated MQR6^T, showed a high capacity to solubilize phosphate and produce indole-3-acetic acid (IAA) and siderophores. The strain can solubilize tricalcium phosphate (TCP) and rock phosphate (RP), and the solubilization of TCP was about 60% more effective than RP. Phylogenetic analyses based on the 16S rRNA gene and whole-genome sequences revealed that strain MQR6^T formed a distinct phyletic lineage as a new species within the genus Pantoea. The digital DNA-DNA hybridization value between strain MQR6^T and the closely related strains was 19.5-23.3%. The major cellular fatty acids were summed feature 3 (C_16:1ω7c and/or C_16:1ω6c), summed feature 8 (C_18:1ω6c and/or C_18:1ω7c), C_14:0, C_16:0, and C_17:0 cyclo. Several genes related to IAA production, phosphonate transport, phosphate solubilization and siderophore biogenesis were found in the MQR6^T genome. Furthermore, inoculation with the strain MQR6^T significantly improved plant height, trunk diameter, dry weight and P accumulation in roots and shoot of A. truncatum seedlings compared to non-inoculated control. These plant parameters were improved even further in the treatment with both inoculation and P fertilization. Our results suggested that MQR6^T represented a new species we named Pantoea rhizosphaerae, as a plant growth-promoting rhizobacterium that can solubilize inorganic P and improve growth of A. truncatum seedlings, emerging as a potential strategy to improve A. truncatum cultivation.

1,5-Anhydro-d-glucitol derivative and galloylated flavonoids isolated from the leaves of Acer ginnala Maxim. as dual inhibitors of PTP1B and α-glucosidase enzymes: In vitro and in silico studies

Four undescribed compounds (two 1,5-anhydro-d-glucitol derivatives and two galloyl derivatives) and fourteen known compounds were isolated and structurally identified from leaves of Acer ginnala Maxim. (Amur maple). Structures and absolute configurations of the four undescribed compounds were determined using extensive analysis of NMR spectroscopic, HRESI-MS, modified Mosher ester method, and comparison with spectroscopic data of known compounds. Bioactivity evaluation revealed that the isolated 1,5-anhydro-d-glucitol derivative, galloylated flavonol rhamnosides, and galloylated flavanols had inhibitory effects on both protein tyrosine phosphatase-1B (PTP1B, IC₅₀ values ranging of 3.46-12.65 μM) and α-glucosidase (IC₅₀ values ranging of 0.88-6.06 μM) in comparison with a positive control for PTP1B (ursolic acid, IC₅₀ = 5.10 μM) or α-glucosidase (acarbose, IC₅₀ = 141.62 μM). A combination of enzyme kinetic analysis and molecular docking provided additional evidence in favor of their inhibitory activities and mechanism. These data demonstrate that A. ginnala Maxim. together with its constituents are promising sources of potent candidates for developing novel anti-diabetic medications.

A multi-omics approach identifies bHLH71-like as a positive regulator of yellowing leaf pepper mutants exposed to high-intensity light

Light quality and intensity can have a significant impact on plant health and crop productivity. Chlorophylls and carotenoids are classes of plant pigments that are responsible for harvesting light energy and protecting plants from the damaging effects of intense light. Our understanding of the role played by plant pigments in light sensitivity has been aided by light-sensitive mutants that change colors upon exposure to light of variable intensity. In this study, we conducted transcriptomic, metabolomic, and hormone analyses on a novel yellowing mutant of pepper (yl1) to shed light on the molecular mechanism that regulates the transition from green to yellow leaves in this mutant upon exposure to high-intensity light. Our results revealed greater accumulation of the carotenoid precursor phytoene and the carotenoids phytofluene, antheraxanthin, and zeaxanthin in yl1 compared with wild-type plants under high light intensity. A transcriptomic analysis confirmed that enzymes involved in zeaxanthin and antheraxanthin biosynthesis were upregulated in yl1 upon exposure to high-intensity light. We also identified a single basic helix-loop-helix (bHLH) transcription factor, bHLH71-like, that was differentially expressed and positively correlated with light intensity in yl1. Silencing of bHLH71-like in pepper plants suppressed the yellowing phenotype and led to reduced accumulation of zeaxanthin and antheraxanthin. We propose that the yellow phenotype of yl1 induced by high light intensity could be caused by an increase in yellow carotenoid pigments, concurrent with a decrease in chlorophyll accumulation. Our results also suggest that bHLH71-like functions as a positive regulator of carotenoid biosynthesis in pepper.

Integrative Transcriptomic and Metabolomic Analysis Reveals the Molecular Mechanism of Red Maple (Acer rubrum L.) Leaf Coloring

This study employed a combination of ultraviolet spectrophotometry, LC-ESI-MS/MS system, and RNA-sequencing technology; the extracts and isolation of total RNA from the red and yellow leaf strains of red maple (Acer rubrum L.) at different developmental stages were subjected to an intercomparison of the dynamic content of chlorophyll and total anthocyanin, flavonoid metabolite fingerprinting, and gene expression. The metabonomic results indicated that one hundred and ninety-two flavonoids were identified, which could be classified into eight categories in the red maple leaves. Among them, 39% and 19% were flavones and flavonols, respectively. The metabolomic analysis identified 23, 32, 24, 24, 38, and 41 DAMs in the AR1018r vs. AR1031r comparison, the AR1018r vs. AR1119r comparison, the AR1031r vs. AR1119r comparison, the AR1018y vs. AR1031y comparison, the AR1018y vs. AR1119y comparison, and the AR1031y vs. AR1119y comparison, respectively. In total, 6003 and 8888 DEGs were identified in AR1018r vs. AR1031r comparison and in the AR1018y vs. AR1031y comparison, respectively. The GO and KEGG analyses showed that the DEGs were mainly involved in plant hormone signal transduction, flavonoid biosynthesis, and other metabolite metabolic processes. The comprehensive analysis revealed that caffeoyl-CoA 3-O-methyltransferase (Cluster-28704.45358 and Cluster-28704.50421) was up-regulated in the red strain but down-regulated in the yellow strain, while Peonidin 3-O-glucoside chloride and Pelargonidin 3-O-beta-D-glucoside were up-regulated in both the red and yellow strains. By successfully integrating the analyses on the behavior of pigment accumulation, dynamics of flavonoids, and differentially expressed genes with omics tools, the regulation mechanisms underlying leaf coloring in red maple at the transcriptomic and metabolomic levels were demonstrated, and the results provide valuable information for further research on gene function in red maple.

Acertannin Prevented Dextran Sulfate Sodium-induced Colitis by Inhibiting the Colonic Expression of IL-23 and TNF-α in C57BL/6J Mice

The present study investigates the effects of acertannin on colitis induced by dextran sulfate sodium (DSS) and changes in the colonic levels of the cytokines interleukin (IL)-1β, IL-6, IL-10, IL-23, tumor necrosis factor (TNF)-α, the chemokine monocyte chemoattractant protein (MCP)-1, and vascular endothelial growth factor (VEGF).We examine the following: inflammatory colitis was induced in mice by 2% DSS drinking water given ad libitum for 7 days. Red blood cell, platelets, and leukocyte counts and hematocrit (Ht), hemoglobin (Hb), and colonic cytokine and chemokine levels were measured. The disease activity index (DAI) was lower in DSS-treated mice orally administered acertannin (30 and 100 mg/kg) than in DSS-treated mice. Acertannin (100 mg/kg) inhibited reductions in the red blood cell count and Hb and Ht levels in DSS-treated mice. Acertannin prevented DDS-induced mucosal membrane ulceration of the colon and significantly inhibited the increased colonic levels of IL-23 and TNF-α. Our findings suggest that acertannin has potential as a treatment for inflammatory bowel disease (IBD).

Acertannin prevents azoxymethane/dextran sulfate sodium-induced colon cancer growth by inhibiting the colonic expression of interleukin-1β, monocyte chemoattractant protein-1, cyclooxygenase-2, and thymocyte selection-associated high mobility group box proteins (TOX)/TOX2 in C57BL/6J mice

Colon cancer was the second leading cause of cancer-related death in 2019. We herein investigated the effects of acertannin containing Acer species on azoxymethane (AOM)/dextran sulfate sodium (DDS)-induced colon cancer growth and changes in the colonic levels of interleukin (IL)-1β, monocyte chemoattractant protein (MCP)-1, IL-10, and programmed cell death-1 (PD-1). Colorectal carcinogenesis was induced by an intraperitoneal injection of AOM (10 mg/kg) on days 0 and 27. Mice were given 1% (w/v) DSS drinking water ad libitum on days 7-14, 32-33, and 35-38. Acertannin (30 and 100 mg/kg) was orally administered on days 1-16, discontinued for 11 days (days 16-26), and then administered again on days 27-41. The colonic levels of cytokines, a chemokine, and PD-1 were measured using the respective ELISA kits. The number and area of tumors in mice treated with acertannin (100 mg/kg) decreased by 53.9 and 63.1%, respectively. Furthermore, the colonic levels of IL-1β, MCP-1, IL-10, and PD-1 showed reductions of 57.3, 62.9, 62.8, and 100%, respectively, while the numbers of cyclooxygenase-2 (COX-2)-, thymocyte selection-associated high mobility group box proteins (TOX)/TOX2-, PD-1-, and signal transducer and activator of transcription 3 (STAT3) phosphorylation-positive numbers decreased by 79.6, 77.9, 93.8, and 100%, respectively. In conclusion, the inhibitory effects of acertannin on AOM/DSS-induced colon tumor growth appear to be associated with reductions in the colonic levels of IL-1β, MCP-1, IL-10, and PD-1 through the down-regulated expression of COX-2 and TOX/TOX2 in the tumor microenvironment.

Chemopreventive Activity of Ellagitannins from Acer pseudosieboldianum (Pax) Komarov Leaves on Prostate Cancer Cells

Several studies have shown that compounds from Acer pseudosieboldianum (Pax) Komarov leaves (APL) display potent anti-oxidative, anti-inflammatory, and anti-proliferative activities. Prostate cancer (PCa) is the most common cancer among older men, and DNA methylation is associated with PCa progression. This study aimed to investigate the chemopreventive activities of the compounds which were isolated from APL on prostate cancer cells and elucidate the mechanisms of these compounds in relation to DNA methylation. One novel ellagitannin [komaniin (14)] and thirteen other known compounds, including glucose derivatives [ethyl-β-D-glucopyranose (3) and (4R)-p-menth-1-ene-7,8-diol 7-O-β-D-glucopyranoside (4)], one phenylpropanoid [junipetrioloside A (5)], three phenolic acid derivatives [ellagic acid-4-β-D-xylopyranoside (1), 4-O-galloyl-quinic acid (2), and gallic acid (8)], two flavonoids [quercetin (11) and kaempferol (12)], and five hydrolysable tannins [geraniin (6), punicafolin (7), granatin B (9), 1,2,3,4,6-penta-galloyl-β-D-glucopyranoside (10), and mallotusinic acid (13)] were isolated from APL. The hydrolyzable tannins (6, 7, 9, 10, 13, and 14) showed potent anti-PCa proliferative and apoptosis-promoting activities. Among the compounds, the ellagitannins in the dehydrohexahydroxydiphenoyl (DHHDP) group (6, 9, 13, and 14), the novel compound 14 showed the most potent inhibitory activity on DNA methyltransferase (DNMT1, 3a and 3b) and glutathione S-transferase P1 methyl removing and re-expression activities. Thus, our results suggested that the ellagitannins (6, 9, 13, and 14) isolated from APL could be a promising treatment option for PCa.

Bioactive Molecules from Myrianthus arboreus, Acer rubrum, and Picea mariana Forest Resources

Forest trees are the world's most important renewable natural resources in terms of their dominance among other biomasses and the diversity of molecules that they produce. Forest tree extractives include terpenes and polyphenols, widely recognized for their biological activity. These molecules are found in forest by-products, such as bark, buds, leaves, and knots, commonly ignored in forestry decisions. The present literature review focuses on in vitro experimental bioactivity from the phytochemicals of Myrianthus arboreus, Acer rubrum, and Picea mariana forest resources and by-products with potential for further nutraceutical, cosmeceutical, and pharmaceutical development. Although these forest extracts function as antioxidants in vitro and may act on signaling pathways involved in diabetes, psoriasis, inflammation, and skin aging, much still remains to be investigated before using them as therapeutic candidates, cosmetics, or functional foods. Traditional forest management systems focused on wood must evolve towards a holistic approach, allowing the use of these extractives for developing new value-added products.

Effects of Bee Pollen Derived from Acer mono Maxim. or Phellodendron amurense Rupr. on the Lipid Composition of Royal Jelly Secreted by Honeybees

Royal jelly is a specific product secreted by honeybees, and has been sought after to maintain health because of its valuable bioactive substances, e.g., lipids and vitamins. The lipids in royal jelly come from the bee pollen consumed by honeybees, and different plant source of bee pollen affects the lipid composition of royal jelly. However, the effect of bee pollen consumption on the lipid composition of royal jelly remains unclear. Herein, we examined the influence of two factors on the lipid composition of royal jelly: first, two plant sources of bee pollen, i.e., Acer mono Maxim. (BP-Am) and Phellodendron amurense Rupr. (BP-Pa); secondly, different feeding times. Lipidomic analyses were conducted on the royal jelly produced by honeybees fed BP-Am or BP-Pa using ultra-high performance liquid chromatography (UPLC)-Q-Exactive Orbitrap mass spectrometry. The results showed that the phospholipid and fatty acid contents differed in royal jelly produced by honeybees fed BP-Am compared to those fed BP-Pa. There were also differences between timepoints, with many lipid compounds decreasing in abundance soon after single-pollen feeding began, slowly increasing over time, then decreasing again after 30 days of single-pollen feeding. The single bee pollen diet destroyed the nutritional balance of bee colonies and affected the development of hypopharyngeal and maxillary glands, resulting in differences in royal jelly quality. This study provides guidance for optimal selection of honeybee feed for the production of high-quality royal jelly.

Chromosomal-level genome and multi-omics dataset provides new insights into leaf pigmentation in Acer palmatum

Acer palmatum (A. palmatum), a deciduous shrub or small arbour which belongs to Acer of Aceraceae, is an excellent greening species as well as a beautiful ornamental plant. In this study, a high-quality chromosome-level reference genome for A. palmatum was constructed using Oxford Nanopore sequencing and Hi-C technology. The assembly genome was ∼745.78 Mb long with a contig N50 length of 3.20 Mb, and 95.30 % (710.71 Mb) of the assembly was anchored into 13 pseudochromosomes. A total of 28,559 protein-coding genes were obtained, ∼90.02 % (25,710) of which could be functionally annotated. The genomic evolutionary analysis revealed that A. palmatum is most closely related to A. yangbiense and A. truncatum, and underwent only an ancient gamma whole-genome duplication event. Despite lacking a recent independent WGD, 25,795 (90.32 %) genes of A. palmatum were duplicated, and the unique/expanded gene families were linked with genes involved in plant-pathogen interaction and several metabolic pathways, which might underpin adaptability. A combined genomic, transcriptomic, and metabolomic analysis related to the biosynthesis of anthocyanin in leaves during the different season were characterized. The results indicate that the dark-purple colouration of the leaves in spring was caused by a high amount of anthocyanins, especially delphinidin and its derivatives; and the red colouration of the leaves in autumn by a high amount of cyanidin 3-O-glucoside. In conclusion, these valuable multi-omic resources offer important foundations to explore the molecular regulation mechanism in leaf colouration and also provide a platform for the scientific and efficient utilization of A. palmatum.

Transcriptome profiling provides insights into leaf color changes in two Acer palmatum genotypes

BACKGROUND

Ornamental trees with seasonally-dependent leaf color, such as Acer palmatum, have gained worldwide popularity. Leaf color is a main determinant of the ornamental and economic value of A. palmatum. However, the molecular mechanisms responsible for leaf color changes remain unclear.

RESULTS

We chose A. palmatum cultivars with yellow ('Jinling Huangfeng') and red ('Jinling Danfeng') leaves as the ideal material for studying the complex metabolic networks responsible for variations in leaf coloration. The 24 libraries obtained from four different time points in the growth of 'Jinling Huangfeng' and 'Jinling Danfeng' was subjected to Illumina high-throughput sequencing. We observed that the difference in cyanidin and delphinidin content is the primary reason behind the varying coloration of the leaves. Transcriptomic analyses revealed 225,684 unigenes, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of differentially expressed genes (DEGs) confirmed that they were involved in 'anthocyanin biosynthesis.' Eighteen structural genes involved in anthocyanin biosynthesis were thought to be related to anthocyanin accumulation, whereas 46 MYBs, 33 basic helix-loop-helixs (bHLHs), and 29 WD40s were presumed to be involved in regulating anthocyanin biosynthesis. Based on weighted gene co-expression network analysis (WGCNA), three candidate genes (ApRHOMBOID, ApMAPK, and ApUNE10) were screened in the significant association module with a correlation coefficient (r²) of 0.86.

CONCLUSION

In this study, the leaf color changes of two A. palmatum genotypes were analyzed. These findings provide novel insights into variations in leaf coloration and suggest pathways for targeted genetic improvements in A. palmatum.

UPLC-ESI-Q-TOF-MSE-based metabolomics analysis of Acer mono sap and evaluation of osteogenic activity in mouse osteoblast cells

Investigation of phytochemicals and bioactive molecules is tremendously vital for the applications of new plant resources in chemistry, food, and medicine. In this study, the chemical profiling of sap of Acer mono (SAM), a Korean syrup known for its anti-osteoporosis effect, was performed using UPLC-ESI-Q-TOF-MS^E analysis. A total of 23 compounds were identified based on the mass and fragmentation characteristics and most of the compounds have significant biomedical applications. The in vitro antioxidant assessment of SAM indicated excellent activity by scavenging DPPH and ABTS-free radicals and were found to be 23.35 mg mL^-1 and 29.33 mg mL^-1, respectively, as IC₅₀ concentrations. As well, the in vitro proliferation effect of the SAM was assessed against mouse MC3T3-E1 cells, and the results showed that the SAM enhanced the proliferation of the cells, and 12.5 mg mL^-1 and 25 mg mL^-1 of SAM were selected for osteogenic differentiation. The morphological analysis clearly evidenced the SAM enhanced the osteogenic activity in MC3T3-E1 cells by the increased deposition of extracellular calcium and nodule formation. Moreover, the qRT-PCR analysis confirmed the increased expression of osteoblast marker gene expression including ALP, osteocalcin, osteopontin, collagen1α1, Runx2, and osterix in SAM-treated MC3T3-E1 cells. Together, these results suggest that SAM possesses osteogenic effects and can be used for bone regeneration and bone loss-associated diseases such as osteoporosis.

Therapeutic Effects of Acer palmatum Thumb. Leaf Extract (KIOM-2015E) on Benzalkonium Chloride-Induced Dry Eye in a Mouse Model

We determined the effects of two extracts from Acer palmatum Thumb. leaves (hot water extract KIOM-2015EW and 25% ethanol extract KIOM-2015EE) in a benzalkonium chloride (BAC)-induced dry eye mouse model. Dry eye was induced by 0.2% BAC for 2 weeks, followed by treatment three times (eye drop) or once (oral administration) daily with KIOM-2015E for 2 weeks. Treatment with both KIOM-2015EE and KIOM-2015EW resulted in a marked increase in tear volume production for the 4 days of treatment. The Lissamine Green staining score, TUNEL-positive cells, and inflammatory index were significantly decreased after 2 weeks. Topical KIOM-2015EE administration exhibited a greater improvement in decreasing the ocular surface staining scores, inflammation, dead cells, and increasing tear production in a dose-dependent manner compared with the other groups. Furthermore, KIOM-2015E significantly reduced the phosphorylation of NF-κB, which was activated in the BAC-treated cornea. Topical administration was much more effective than oral administration for KIOM-2015E and KIOM-2015EE was more effective than KIOM-2015EW. Application of KIOM-2015E resulted in clinical improvement, inhibited the inflammatory response, and alleviated signs of dry eye. These results indicate that KIOM-2015E has potential as a therapeutic agent for the clinical treatment of dry eye.

Structural Characterization of the Acer ukurunduense Chloroplast Genome Relative to Related Species in the Acer Genus

Acer ukurunduense refers to a deciduous tree distributed in Northeast Asia and is a widely used landscaping tree species. Although several studies have been conducted on the species’ ecological and economic significance, limited information is available on its phylo-genomics. Our study newly constitutes the complete chloroplast genome of A. ukurunduense into a 156,645-bp circular DNA, which displayed a typical quadripartite structure. In addition, 133 genes were identified, containing 88 protein-coding genes, 37 tRNA genes, and eight rRNA genes. In total, 107 simple sequence repeats and 49 repetitive sequences were observed. Thirty-two codons indicated that biased usages were estimated across 20 protein-coding genes (CDS) in A. ukurunduense. Four hotspot regions (trnK-UUU/rps16, ndhF/rpl32, rpl32/trnL-UAG, and ycf1) were detected among the five analyzed Acer species. Those hotspot regions may be useful molecular markers and contribute to future population genetics studies. The phylogenetic analysis demonstrated that A. ukurunduense is most closely associated with the species of Sect. Palmata. A. ukurunduense and A. pubipetiolatum var. pingpienense diverged in 22.11 Mya. We selected one of the hypervariable regions (trnK-UUU/rps16) to develop a new molecular marker and designed primers and confirmed that the molecular markers could accurately discriminate five Acer species through Sanger sequencing. By sequencing the cp genome of A. ukurunduense and comparing it with the relative species of Acer, we can effectively address the phylogenetic problems of Acer at the species level and provide insights into future research on population genetics and genetic diversity.

Comparative analysis of the complete mitochondrial genomes of four cordyceps fungi

Cordyceps is a large group of entomogenous, medicinally important fungi. In this study, we sequenced, assembled, and annotated the entire mitochondrial genome of Ophiocordyceps xuefengensis, in addition to comparing it against other three complete cordyceps mitogenomes that were previously published. Comparative analysis indicated that the four complete mitogenomes are all composed of circular DNA molecules, although their sizes significantly differ due to high variability in intron and intergenic region sizes in the Ophiocordyceps sinensis and O. xuefengensis mitogenomes. All mitogenomes contain 14 conserved genes and two ribosomal RNA genes, but varying numbers of tRNA introns. The Ka/Ks ratios for all 14 PCGs and rps3 were all less than 1, indicating that these genes have been subject to purifying selection. Phylogenetic analysis was conducted using concatenated amino acid and nucleotide sequences of the 14 PCGs and rps3 using two different methods (Maximum Likelihood and Bayesian analysis), revealing highly supported relationships between O. xuefengensis and other Ophiocordyceps species, in addition to a close relationship with O. sinensis. Further, the analyses indicated that cox1 and rps3 play important roles in population differentiation. These mitogenomes will allow further study of the population genetics, taxonomy, and evolutionary biology of medicinally important cordyceps species.

Programmed Cell Death Alterations Mediated by Synthetic Indole Chalcone Resulted in Cell Cycle Arrest, DNA Damage, Apoptosis and Signaling Pathway Modulations in Breast Cancer Model

Although new chemotherapy significantly increased the survival of breast cancer (BC) patients, the use of these drugs is often associated with serious toxicity. The discovery of novel anticancer agents for BC therapy is expected. This study was conducted to explore the antiproliferative effect of newly synthesized indole chalcone derivative ZK-CH-11d on human BC cell lines. MTT screening, flow cytometry, Western blot, and fluorescence microscopy were used to evaluate the mode of cell death. ZK-CH-11d significantly suppressed the proliferation of BC cells with minimal effect against non-cancer cells. This effect was associated with cell cycle arrest at the G2/M phase and apoptosis induction. Apoptosis was associated with cytochrome c release, increased activity of caspase 3 and caspase 7, PARP cleavage, reduced mitochondrial membrane potential, and activation of the DNA damage response system. Furthermore, our study demonstrated that ZK-CH-11d increased the AMPK phosphorylation with simultaneous inhibition of the PI3K/Akt/mTOR pathway indicating autophagy initiation. However, chloroquine, an autophagy inhibitor, significantly potentiated the cytotoxic effect of ZK-CH-11d in MDA-MB-231 cells indicating that autophagy is not principally involved in the antiproliferative effect of ZK-CH-11d. Taking together the results from our experiments, we assume that autophagy was activated as a defense mechanism in treated cells trying to escape from chalcone-induced harmful effects.

Inhibitory Effect of Acer truncatum Bunge Seed Coat Extract on Fatty Acid Synthase, Differentiation and Lipid Accumulation in 3T3-L1 Adipocytes

Acer truncatum Bunge is now widely cultivated throughout the world. Fatty acid synthase (FAS) is a potential target in the treatment of both obesity and cancer. Only a few FAS inhibitors have been reported. In this study, the inhibitory effect of A. truncatum seed coat (ESA) on FAS and the inhibition mechanisms were investigated using a FAS activity assay and an enzyme kinetics study. The main chemicals of ESA were analyzed with UPLC-MS/MS. The effects of ESA on 3T3-L1 adipocyte differentiation and lipid accumulation were investigated using Oil red O staining. We first identified seven main compounds (quinic acid, malic acid, gentisic acid, procyanidin dimer, procyanidin trimer, catechin, and quercetin) from 50% ethanol extracts of seed coats of A. truncatum (ESAs), which were then found to inhibit 3T3-L1 adipocyte differentiation at the concentration of 50 μg/mL. ESA obviously reduced the visible triglyceride droplets accumulation, and dramatically decreased the number of the adipocytes at a comparatively high concentration. It is suggested that the effects are due to the inhibition of FAS by ESA; FAS activity is inhibited by ESA at a half inhibition concentration (IC₅₀) of 0.57 μg/mL, which is lower than that of classically known FAS inhibitors. Meanwhile, ESA displayed different inhibition kinetics and reacting sites for FAS. These results provide new clues for the development of novel products for obesity treatment and a scientific basis for the full use of byproducts for future industrial production of vegetable oil.

Insights Into Comparative Analyses and Phylogenomic Implications of Acer (Sapindaceae) Inferred From Complete Chloroplast Genomes

Acer L. (Sapindaceae) is one of the most diverse and widespread plant genera in the Northern Hemisphere. It comprises 124-156 recognized species, with approximately half being native to Asia. Owing to its numerous morphological features and hybridization, this genus is taxonomically and phylogenetically ranked as one of the most challenging plant taxa. Here, we report the complete chloroplast genome sequences of five Acer species and compare them with those of 43 published Acer species. The chloroplast genomes were 149,103-158,458 bp in length. We conducted a sliding window analysis to find three relatively highly variable regions (psbN-rps14, rpl32-trnL, and ycf1) with a high potential for developing practical genetic markers. A total of 76-103 SSR loci were identified in 48 Acer species. The positive selection analysis of Acer species chloroplast genes showed that two genes (psaI and psbK) were positively selected, implying that light level is a selection pressure for Acer species. Using Bayes empirical Bayes methods, we also identified that 20 cp gene sites have undergone positive selection, which might result from adaptation to specific ecological niches. In phylogenetic analysis, we have reconfirmed that Acer pictum subsp. mono and A. truncatum as sister species. Our results strongly support the sister relationships between sections Platanoidea and Macrantha and between sections Trifoliata and Pentaphylla. Moreover, series Glabra and Arguta are proposed to promote to the section level. The chloroplast genomic resources provided in this study assist taxonomic and phylogenomic resolution within Acer and the Sapindaceae family.

Acer truncatum Bunge: A comprehensive review on ethnobotany, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Acer truncatum Bunge is a multifunctional plant in northern China. It has traditionally been used to prevent cardiovascular and cerebrovascular diseases and treat skin trauma by different linguistic groups including Mongolian, Tibetan, and Korean. Although research has verified that A. truncatum contains a variety of active ingredients, especially nervonic acid, an important component in delaying brain aging, to date no review has been made to compile its traditional use, phytochemistry, and pharmacology.

AIMS OF THE REVIEW

This review aimed to update the traditional uses, phytochemistry, and pharmacology of A. truncatum, which expect to provide theoretical support for the future utilization as well as highlight the further investigation of this important plant.

MATERIALS AND METHODS

The ethnobotanical, phytochemical, and pharmacological information related to A. truncatum from 1949 to March 2021 were collated by surveying the traditional medicinal books and ethnomedicinal publications and searching the online databases including Google Scholar, Sci Finder, Web of Science, Springer Link, PubMed, Wiley, China National Knowledge Infrastructure (CNKI), Baidu Scholar, and Wan Fang Database.

RESULTS

A. truncatum has traditionally been used for medicinal, edible and ornamental purposes in northern China for many centuries. Different parts of the plant including leaves, fruits and bark, are mainly used as herbal medicine to treat hyperpiesia, hyperlipidemia, bruises, back pain, etc. A total of 288 compounds in A. truncatum, including polyphenols, organic acids or lipids, and biological volatile organic compounds were isolated or identified by phytochemical studies. Pharmacological research showed that A. truncatum has various bioactivities such as acetylcholinesterase inhibition, antibacterial, antioxidant, antitumor, and fatty acid synthase inhibition effects.

CONCLUSION

A. truncatum has been used as a traditional herbal medicine for centuries in northern China. Polyphenols, organic acids, lipids and other compounds were isolated or identified from different parts of the plant. Most of the pharmacological activities of A. truncatum have been reported, which showed its potential in the development of new drugs or nutraceuticals. However, detailed information on the molecular mechanisms, metabolic activity, and toxicology of active components is limited. Further comprehensive research to evaluate the medicinal properties of A. truncatum will be necessary.

Quality Characteristics of Senior-Friendly Gelatin Gels Formulated with Hot Water Extract from Red Maple Leaf as a Novel Anthocyanin Source

The objectives of this study were to evaluate antioxidant capacity of hot water extract from red maple leaf with different extraction times (experiment I) and to determine their impacts on color, free anthocyanin content, and hardness of gelatin gels (experiment II). In experiment I, hot water extraction time (30, 60, 120, 180, and 360 min at 60 °C) was fixed as a main effect. The different extraction times had no impacts on total polyphenol content and DPPH radical scavenging activity (p > 0.05). However, extraction time for 360 min could decrease anthocyanin content as well as ferric reducing antioxidant power (p < 0.05). In experiment II, 6%, 18%, and 30% gelatin gels were prepared without/with red maple leaf extract (1000 mg/L). The red maple leaf extract significantly increased redness, yellowness, and hardness, but decreased free anthocyanin content. Such impacts were obviously observed at high gelatin concentration. Thus, red maple leaf extract could be a novel anthocyanin source for improving antioxidant capacity and reddish color of gelatin gels. However, the addition amount of red maple leaf extract may be limited in the development of senior-friendly jelly food for soft texture in that it could increase the hardness of the gelatin gel.

Whole-Genome Sequencing of Acer catalpifolium Reveals Evolutionary History of Endangered Species

Acer catalpifolium is an endangered species restricted to remote localities of West China. Understanding the genomic content and evolution of A. catalpifolium is essential to conservation efforts of this rare and ecologically valuable plant. Here, we report a high-quality genome of A. catalpifolium consisting of ∼654 Mbp and ∼35,132 protein-coding genes. We detected 969 positively selected genes in two Acer genomes compared with four other eudicots, 65 of which were transcription factors. We hypothesize that these positively selected mutations in transcription factors might affect their function and thus contribute to A. catalpifolium’s decline-type population. We also identified 179 significantly expanded gene families compared with 12 other eudicots, some of which are involved in stress responses, such as the FRS–FRF family. We inferred that A. catalpifolium has experienced gene family expansions to cope with environmental stress in its evolutionary history. Finally, 109 candidate genes encoding key enzymes in the lignin biosynthesis pathway were identified in A. catalpifolium; of particular note were the large range and high copy number of cinnamyl alcohol dehydrogenase genes. The chromosome-level genome of A. catalpifolium presented here may serve as a fundamental genomic resource for better understanding endangered Acer species, informing future conservation efforts.

Safety Assessment of Acer tegmentosum Maxim. Water Extract: General Toxicity Studies in Sprague-Dawley Rats and Beagle Dogs With Re-evaluation of Genotoxic Potentials

Acer tegmentosum Maxim., commonly known as Manchurian stripe maple, is a deciduous tree belonging to the family of Aceraceae and has been traditionally used in folk medicine for its remedial effects in liver diseases and traumatic bleedings. With a growing body of experimental evidence for its pharmacological efficacies, such as neuroprotective, hepatoprotective, antioxidant, and anti-inflammatory activities, A. tegmentosum has gradually gained popularity as a health supplement and functional food. However, the large part of essential toxicity information still remained lacking despite the possibility of mutagenic potentials as previously suggested, posing safety concerns for human consumption. In this study, we evaluated 90-day repeated oral toxicity of A. tegmentosum Maxim. water extract (ATWE) in SD rats with acute toxicity assessment in beagle dogs, and reevaluated genotoxicity using a combination of in vitro and in vivo assays. During the oral study period, ATWE did not cause toxicity-related clinical signs and mortality in rodents without adverse effects observed in the analysis of hematology, serum biochemistry, and histopathology, establishing >5,000 mg/kg BW as the NOAEL. In addition, doses up to 5,000 mg/kg BW did not cause acute toxicity in beagle dogs. When assessed for genotoxicity using bacterial reverse mutation, chromosome aberration, and micronucleus formation, ATWE showed lack of mutagenicity and clastogenicity. These results demonstrated that AWTE was safe in the present preclinical study for systemic toxicity and genotoxicity at the tested doses, providing a guideline for safe use in humans.

The Influence of Locality on Phenolic Profile and Antioxidant Capacity of Bud Extracts

Gemmotherapy represents the most recent therapeutic technique that uses the properties of extracts from fresh meristematic plant tissues, mainly buds and sprouts, by macerating them in ethanol and glycerol. The harvesting time and the location can significantly affect the chemical composition of the buds. Therefore, this work aimed to point out the possible variability in the phenolic content and the antioxidant potential of extracts prepared from commonly grown trees in the Czech Republic. Extracts from buds collected during autumn and spring in three different localities were analysed using UHPLC-MS (ultra-high-pressure liquid chromatography) for the phenols profile. Five tests assays were used for the evaluation of the extract antioxidant potential. The sampling time positively affected the content of total phenols, flavonoids, and phenolic acids. The increased levels of total phenols and flavonoids in localities with high and medium pollution may be the result of the higher levels of NO and SO_2, the main air pollutants. However, surprisingly, the content of phenolic acid showed the highest values in the area with the lowest pollution. The results of antioxidant tests did not completely correlate with the levels of phenolic metabolites, which may be due to the involvement of other active molecules (e.g., ascorbate, tocopherol, or proline) in the antioxidant machinery.

Phytochemical Investigation, Antimicrobial, Antioxidant and Anticancer Activities of Acer cappadocicum Gled

The appearance of novel microbial resistance, diverse cancer ailment and several other morbidities such as appetite loss, hair loss, anemia, cell damage, etc., are among most critical situation that keeps the phytochemical quest on. Thus, this study characterized the antimicrobial, antioxidant, and anticancer potentials of a rarely accessed Acer cappadocicum gled (AC) population thriving in a remote Palas Valley in northern Pakistan. Leaf extracts of the plant were prepared in organic solvents with different polarities through maceration. Extracts were subjected to antimicrobial, antioxidant, and anticancer activities using agar well, DPPH and cell viability assays. A. cappadocicum methanolic extract (ACM) significantly inhibited bacterial growth, followed by n-butanolic extract (ACB) with the second-highest bacterial inhibition. Similar activity was observed against mycelial growth inhibition in plant-fungal pathogen by ACM and ACB. However, human pathogenic fungi did not affect much by extracts. In antioxidant assessment, the chloroform extract (ACC) showed strong scavenging activity and in cytotoxic evaluation, extracts restricted growth proliferation in cancer cells. The inhibitory evidence of extracts, potent scavenging ability, and low cell viability of human-derived cell lines supports the antimicrobial, antioxidant and anticancerous potential of A. cappadocicum. It advances our quest for natural product research.

Role of Oxidative Stress and Nrf2/KEAP1 Signaling in Colorectal Cancer: Mechanisms and Therapeutic Perspectives with Phytochemicals

Colorectal cancer still has a high incidence and mortality rate, according to a report from the American Cancer Society. Colorectal cancer has a high prevalence in patients with inflammatory bowel disease. Oxidative stress, including reactive oxygen species (ROS) and lipid peroxidation, has been known to cause inflammatory diseases and malignant disorders. In particular, the nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-related protein 1 (KEAP1) pathway is well known to protect cells from oxidative stress and inflammation. Nrf2 was first found in the homolog of the hematopoietic transcription factor p45 NF-E2, and the transcription factor Nrf2 is a member of the Cap 'N' Collar family. KEAP1 is well known as a negative regulator that rapidly degrades Nrf2 through the proteasome system. A range of evidence has shown that consumption of phytochemicals has a preventive or inhibitory effect on cancer progression or proliferation, depending on the stage of colorectal cancer. Therefore, the discovery of phytochemicals regulating the Nrf2/KEAP1 axis and verification of their efficacy have attracted scientific attention. In this review, we summarize the role of oxidative stress and the Nrf2/KEAP1 signaling pathway in colorectal cancer, and the possible utility of phytochemicals with respect to the regulation of the Nrf2/KEAP1 axis in colorectal cancer.

Ginnalin A Binds to the Subpockets of Keap1 Kelch Domain To Activate the Nrf2-Regulated Antioxidant Defense System in SH-SY5Y Cells

Ginnalin A (GA), a polyphenol from the red maple, was reported to be a potential ROS scavenger or an activator of nuclear factor erythroid-2 related factor 2 (Nrf2) in cancer cells. However, whether GA could activate Nrf2 in neuronal cells and the exact mode of action are unknown. We performed molecular docking calculations, which revealed that GA fits well into the five subpockets of the Kelch-like ECH-associated protein1 (Keap1) Kelch domain via hydrogen bonding and hydrophobic interaction. Our cytotoxicity assays demonstrate that pretreating SH-SY5Y cells with 20 μM GA effectively prevents cells from oxidative assault by 6-hydroxydopamine (6-OHDA). Fluorescence imaging indicates that upon the GA pretreatment, Nrf2 dissociates from the Keap1-Nrf2 complex and translocates into nucleus to activate the cellular antixodant system. Real-time qPCR quantification and Western blotting verified that the GA pretreatment elevates NAD(P)H quinone oxidoreductase-1 (NQO1) by more than 4.6-fold, heme oxygenase (HO-1) by about 1.2-fold, and the glutamate-cysteine ligase catalytic (GCLC) subunit by 0.7-fold. The higher antixidant protein levels, along with increased glutathione concentration, decrease intracellular reactive oxygen species and alleviate the 6-OHDA-induced oxidative damage. Silence of Nrf2 abrogates the cytoprotection of the GA pretreatment, confirming that the Keap1/Nrf2-ARE (antioxidant response element) pathway is solely responsible for the GA's biological effects. GA is a promising natural compound for sensitizing neuronal cells' antioxidative defense system to offset oxidative stress, a condition closely linked to the pathogenesis of Parkinson's disease.

Transcriptomic and metabolomic analyses of non-structural carbohydrates in red maple leaves

Plant sugars serve to balance nutrition, regulate development, and respond to biotic and abiotic stresses, whereas non-structural carbohydrates (NSCs) are essential energy sources that facilitate plant growth, metabolism, and environmental adaptation. To better elucidate the mechanisms of NSCs in red maple, ultrahigh-performance liquid chromatograph Q extractive mass spectrometry (UHPLC-QE-MS) and high-throughput RNA-sequencing were performed on green, red, and yellow leaves from a selected red maple mutant. In green leaves, the fructose phosphorylation process exhibited greater flux. In yellow leaves, sucrose and starch had a stronger capacity for synthesis and degradation, whereas in red leaves, there was a greater accumulation of trehalose and manninotriose. ArTPS5 positively regulated amylose, which was negatively regulated by ArFBP2, whereas ArFRK2 and ArFBP13 played a positive role in the biosynthesis of Sucrose-6P. Sucrose-6P also regulated anthocyanins and abscisic acid in red maple by affecting transcription factors. The results of this paper can assist with the control and optimization of the biosynthesis of NSCs in red maple, which may ultimately provide the foundation for influencing sugar production in Acer.

Anti-inflammatory activity of naturally occuring diarylheptanoids - A review

Inflammation involving the innate and adaptive immune systems is a normal response to infection. However, if it becomes uncontrolled, inflammation may result in autoimmune or auto inflammatory disorders, neurodegenerative diseases or cancers. The currently available anti-inflammatory drug therapy is often not successful or induces severe side effects. Thus, the search of new therapeutic options for the treatment of inflammation is highly required. Medicinal plants have been an interesting source for obtaining new active compounds. Diarylheptanoids characterized by a 1, 7-diphenylheptane structural skeleton, are a class of secondary plant metabolites that have gained increasing interest over the last few decades due to a wide variety of biological activities. This review covers 182 natural linear or macrocyclic diarylheptanoids described in the period of 1982 to 2020 with anti-inflammatory activities evaluated using quantified in vitro and/or in vivo assays. All of these data highlight the pharmacological potential of these natural compounds to act as anti-inflammatory drugs.

Genome-wide supermatrix analyses of maples (Acer, Sapindaceae) reveal recurring inter-continental migration, mass extinction, and rapid lineage divergence

Acer (Sapindaceae) is an exceptional study system for understanding the evolutionary history, divergence, and assembly of broad-leaved deciduous forests at higher latitudes. Maples stand out due to their high diversity, disjunct distribution pattern across the northern continents, and rich fossil record dating back to the Paleocene. Using a genome-wide supermatrix combining plastomes and nuclear sequences (~585 kb) for 110 Acer taxa, we built a robust time-calibrated hypothesis investigating the evolution of maples, inferring ancestral ranges, reconstructing diversification rates over time, and exploring the impact of mass-extinction on lineage accumulation. Contrary to fossil evidence, our results indicate Acer first originated in the (north)eastern Palearctic region, which acted as a source for recurring outward migration. Warm conditions favored rapid Eocene-onward divergence, but ranges and diversity declined extensively as a result of the Plio-Pleistocene glacial cycles. These signals in genome-wide sequence data corroborate paleobotanical evidence for other major woody north-temperate groups, highlighting the significant (disparate) impact of climatic changes on the evolution, composition, and distribution of the vegetation in the northern hemisphere.

Integrating transcriptomic and metabolomic analysis of hormone pathways in Acer rubrum during developmental leaf senescence

BACKGROUND

To fully elucidate the roles and mechanisms of plant hormones in leaf senescence, we adopted an integrated analysis of both non-senescing and senescing leaves from red maple with transcriptome and metabolome data.

RESULTS

Transcription and metabolite profiles were generated through a combination of deep sequencing, third-generation sequencing data analysis, and ultrahigh-performance liquid chromatograph Q extractive mass spectrometry (UHPLC-QE-MS), respectively. We investigated the accumulation of compounds and the expression of biosynthesis and signaling genes for eight hormones. The results revealed that ethylene and abscisic acid concentrations increased during the leaf senescence process, while the contents of cytokinin, auxin, jasmonic acid, and salicylic acid continued to decrease. Correlation tests between the hormone content and transcriptional changes were analyzed, and in six pathways, genes closely linked with leaf senescence were identified.

CONCLUSIONS

These results will enrich our understanding of the mechanisms of plant hormones that regulate leaf senescence in red maple, while establishing a foundation for the genetic modification of Acer in the future.

Distinct Evolutionary Patterns of NBS-Encoding Genes in Three Soapberry Family (Sapindaceae) Species

Nucleotide-binding site (NBS)-type disease resistance genes (R genes) play key roles in plant immune responses and have co-evolved with pathogens over the course of plant lifecycles. Comparative genomic studies tracing the dynamic evolution of NBS-encoding genes have been conducted using many important plant lineages. However, studies on Sapindaceae species have not been performed. In this study, a discrepant number of NBS-encoding genes were identified in the genomes of Xanthoceras sorbifolium (180), Dinnocarpus longan (568), and Acer yangbiense (252). These genes were unevenly distributed and usually clustered as tandem arrays on chromosomes, with few existed as singletons. The phylogenetic analysis revealed that NBS-encoding genes formed three monophyletic clades, RPW8-NBS-LRR (RNL), TIR-NBS-LRR (TNL), and CC-NBS-LRR (CNL), which were distinguished by amino acid motifs. The NBS-encoding genes of the X. sorbifolium, D. longan, and A. yangbiense genomes were derived from 181 ancestral genes (three RNL, 23 TNL, and 155 CNL), which exhibited dynamic and distinct evolutionary patterns due to independent gene duplication/loss events. Specifically, X. sorbifolium exhibited a “first expansion and then contraction” evolutionary pattern, while A. yangbiense and D. longan exhibited a “first expansion followed by contraction and further expansion” evolutionary pattern. However, further expansion in D. longan was stronger than in A. yangbiense after divergence, suggesting that D. longan gained more genes in response to various pathogens. Additionally, the ancient and recent expansion of CNL genes generated the dominance of this subclass in terms of gene numbers, while the low copy number status of RNL genes was attributed to their conserved functions.

Cytoprotective effects of a proprietary red maple leaf extract and its major polyphenol, ginnalin A, against hydrogen peroxide and methylglyoxal induced oxidative stress in human keratinocytes

Phytochemicals from functional foods are common ingredients in dietary supplements and cosmetic products for anti-skin aging effects due to their antioxidant activities. A proprietary red maple (Acer rubrum) leaf extract (Maplifa™) and its major phenolic compound, ginnalin A (GA), have been reported to show antioxidant, anti-melanogenesis, and anti-glycation effects but their protective effects against oxidative stress in human skin cells remain unknown. Herein, we investigated the cytoprotective effects of Maplifa™ and GA against hydrogen peroxide (H2O2) and methylglyoxal (MGO)-induced oxidative stress in human keratinocytes (HaCaT cells). H2O2 and MGO (both at 400 μM) induced toxicity in HaCaT cells and reduced their viability to 59.2 and 61.6%, respectively. Treatment of Maplifa™ (50 μg mL-1) and GA (50 μM) increased the viability of H2O2- and MGO-treated cells by 22.0 and 15.5%, respectively. Maplifa™ and GA also showed cytoprotective effects by reducing H2O2-induced apoptosis in HaCaT cells by 8.0 and 7.2%, respectively. The anti-apoptotic effect of Maplifa™ was further supported by the decreased levels of apoptosis associated enzymes including caspases-3/7 and -8 in HaCaT cells by 49.5 and 19.0%, respectively. In addition, Maplifa™ (50 μg mL-1) and GA (50 μM) reduced H2O2- and MGO-induced reactive oxygen species (ROS) by 84.1 and 56.8%, respectively. Furthermore, flow cytometry analysis showed that Maplifa™ and GA reduced MGO-induced total cellular ROS production while increasing mitochondria-derived ROS production in HaCaT cells. The cytoprotective effects of Maplifa™ and GA in human keratinocytes support their potential utilization for cosmetic and/or dermatological applications.

Acer okamotoanum inhibits adipocyte differentiation by the regulation of adipogenesis and lipolysis in 3T3‑L1 cells

Acer okamotoanum is reported to have various antioxidant, anti‑inflammatory and beneficial immune system effects. The anti‑adipocyte differentiation effects and mechanisms of the ethyl acetate (EtOAc) fraction of an A. okamotoanum extraction was investigated in 3T3‑L1 adipocyte cells. Treatment with differentiation inducers increased the level of triglycerides (TGs) in 3T3‑L1 adipocyte cells compared with an untreated control. However, the EtOAc fraction of A. okamotoanum significantly decreased TGs. Treatment with 1, 2.5 and 5 µg/ml showed weak activity, but TG production was inhibited at 10 µg/ml compared with the control. In addition, A. okamotoanum caused a significant downregulation of proteins related to adipogenesis, such as γ‑cytidine‑cytidine‑adenosine‑adenosine‑thymidine/enhancer binding protein‑α, ‑β and peroxisome proliferator‑activated receptor‑γ, compared with the untreated control. Furthermore, A. okamotoanum significantly upregulated lipolysis related protein, hormone‑sensitive lipase and the phosphorylation of adenosine monophosphate‑activated protein kinase (AMPK). Therefore, these results indicate that A. okamotoanum suppressed adipogenesis and increased lipolysis and the activation of AMPK, suggesting a protective role in adipocyte differentiation.

Synthesis and Comparative Structure-Activity Study of Carbohydrate-Based Phenolic Compounds as α-Glucosidase Inhibitors and Antioxidants

Twenty-one natural and unnatural phenolic compounds containing a carbohydrate moiety were synthesized and their structure-activity relationship (SAR) was evaluated for α-glucosidase inhibition and antioxidative activity. Varying the position of the galloyl unit on the 1,5-anhydro-d-glucitol (1,5-AG) core resulted in changes in the α-glucosidase inhibitory activity and notably, particularly strong activity was demonstrated when the galloyl unit was present at the C-2 position. Furthermore, increasing the number of the galloyl units significantly affected the α-glucosidase inhibition, and 2,3,4,6-tetra-galloyl-1,5-AG (54) and 2,3,4,6-tetra-galloyl-d-glucopyranose (61) exhibited excellent activities, which were more than 13-fold higher than the α-glucosidase inhibitory activity of acertannin (37). Moreover, a comparative structure-activity study suggested that a hemiacetal hydroxyl functionality in the carbohydrate core and a biaryl bond of the 4,6-O-hexahydroxydiphenoyl (HHDP) group, which are components of ellagitannins including tellimagrandin I, are not necessary for the α-glucosidase inhibitory activity. Lastly, the antioxidant activity increased proportionally with the number of galloyl units.

Metabolite Profiling of Two Maple-Derived Products Using Dereplication Based on High-Performance Liquid Chromatography-Diode Array Detector-Electrospray Ionization-Time-of-Flight-Mass Spectrometry: Sugar Maple Bark and Bud Hot-Water Extracts

Recent studies about hot-water extracts from sugar maple (Acer saccharum Marsh.) bark and buds demonstrated that they contain high amounts of phenolic structures that may be used as antioxidant food additives. However, the detailed chemical composition of these maple-derived extracts has yet to be determined. By performing high-performance liquid chromatography-diode array detector-high-resolution mass spectrometry (HPLC-DAD-HRMS)-based dereplication, we were able to spike and classify almost 100 metabolites in each hot-water extract. The sugar maple bark hot-water extract is rich in simple phenolic compounds and phenylpropanoid derivatives, while bud extract contains predominantly flavonoids, benzoic acids, and their complex derivatives (condensed and hydrolyzable tannins). Among those chemical structures, we tentatively identified 69 phenolic compounds potentially reported for the first time in the genus Acer. Considering the growing commercial demand in natural products, the phenolic fingerprints of sugar maple bark and bud hot-water extracts will help in promoting these two maple-derived products as new sources of bioactive compounds in the food, nutraceutical, and cosmetic industries.

Rubus chingii Hu: A Review of the Phytochemistry and Pharmacology

Rubus chingii Hu (R. chingii), referred to as "Fu-Pen-Zi" in Chinese, has great medicinal and dietary values since ancient times. The dried fruits of R. chingii have been widely used in traditional Chinese medicine (TCM) for the treatment of kidney enuresis and urinary frequency for centuries. According to current findings, R. chingii has been reported to contain a variety of chemical constituents, mostly triterpenoids, diterpenoids, flavonoids, and organic acids. These compounds have been demonstrated to be the major bioactive components responsible for pharmacological effects such as anticomplementary, anticancer, antioxidant, antimicrobial, and anti-inflammatory functions. Therefore, this review focused on the up-to-date published data of the literature about R. chingii and comprehensively summarized its phytochemistry, pharmacology, quality control, and toxicity to provide a beneficial support to its further investigations and applications in medicines and foods.

De novo genome assembly of the endangered Acer yangbiense, a plant species with extremely small populations endemic to Yunnan Province, China

BACKGROUND

Acer yangbiense is a newly described critically endangered endemic maple tree confined to Yangbi County in Yunnan Province in Southwest China. It was included in a programme for rescuing the most threatened species in China, focusing on "plant species with extremely small populations (PSESP)".

FINDINGS

We generated 64, 94, and 110 Gb of raw DNA sequences and obtained a chromosome-level genome assembly of A. yangbiense through a combination of Pacific Biosciences Single-molecule Real-time, Illumina HiSeq X, and Hi-C mapping, respectively. The final genome assembly is ∼666 Mb, with 13 chromosomes covering ∼97% of the genome and scaffold N50 sizes of 45 Mb. Further, BUSCO analysis recovered 95.5% complete BUSCO genes. The total number of repetitive elements account for 68.0% of the A. yangbiense genome. Genome annotation generated 28,320 protein-coding genes, assisted by a combination of prediction and transcriptome sequencing. In addition, a nearly 1:1 orthology ratio of dot plots of longer syntenic blocks revealed a similar evolutionary history between A. yangbiense and grape, indicating that the genome has not undergone a whole-genome duplication event after the core eudicot common hexaploidization.

CONCLUSION

Here, we report a high-quality de novo genome assembly of A. yangbiense, the first genome for the genus Acer and the family Aceraceae. This will provide fundamental conservation genomics resources, as well as representing a new high-quality reference genome for the economically important Acer lineage and the wider order of Sapindales.

Transcriptome analysis based on a combination of sequencing platforms provides insights into leaf pigmentation in Acer rubrum

BACKGROUND

Red maple (Acer rubrum L.) is one of the most common and widespread trees with colorful leaves. We found a mutant with red, yellow, and green leaf phenotypes in different branches, which provided ideal materials with the same genetic relationship, and little interference from the environment, for the study of complex metabolic networks that underly variations in the coloration of leaves. We applied a combination of NGS and SMRT sequencing to various red maple tissues.

RESULTS

A total of 125,448 unigenes were obtained, of which 46 and 69 were thought to be related to the synthesis of anthocyanins and carotenoids, respectively. In addition, 88 unigenes were presumed to be involved in the chlorophyll metabolic pathway. Based on a comprehensive analysis of the pigment gene expression network, the mechanisms of leaf color were investigated. The massive accumulation of Cy led to its higher content and proportion than other pigments, which caused the redness of leaves. Yellow coloration was the result of the complete decomposition of chlorophyll pigments, the unmasking of carotenoid pigments, and a slight accumulation of Cy.

CONCLUSIONS

This study provides a systematic analysis of color variations in the red maple. Moreover, mass sequence data obtained by deep sequencing will provide references for the controlled breeding of red maple.