Structural and Immunological Features of PR-10 Allergens: Focusing on the Major Alder Pollen Allergen Aln g 1.

Today, allergies have become a serious problem. PR-10 proteins are clinically relevant allergens that have the ability to bind hydrophobic ligands, which can significantly increase their allergenicity potential. It has been recently shown that not only the birch pollen allergen Bet v 1 but also the alder pollen allergen Aln g 1, might act as a true sensitizer of the immune system. The current investigation is aimed at the further study of the allergenic and structural features of Aln g 1. By using qPCR, we showed that Aln g 1 was able to upregulate alarmins in epithelial cells, playing an important role in sensitization. With the use of CD-spectroscopy and ELISA assays with the sera of allergic patients, we demonstrated that Aln g 1 did not completely restore its structure after thermal denaturation, which led to a decrease in its IgE-binding capacity. Using site-directed mutagenesis, we revealed that the replacement of two residues (Asp27 and Leu30) in the structure of Aln g 1 led to a decrease in its ability to bind to both IgE from sera of allergic patients and lipid ligands. The obtained data open a prospect for the development of hypoallergenic variants of the major alder allergen Aln g 1 for allergen-specific immunotherapy.

Cloning and characterization of NADPH-dependent double-bond reductases from Alnus sieboldiana that recognize linear diarylheptanoids as substrates.

Diarylheptanoids are secondary metabolites of plants that comprise a C6-C7-C6 scaffold. They can be broadly classified into linear-type and cyclic-type diarylheptanoids based on their chemical structures. Actinorhizal trees, such as Casuarina, Alnus, and Myrica, which form nodule symbiosis with actinomycetes Frankia, produce cyclic diarylheptanoids (CDHs); in Alnus sieboldiana Matsum. in particular, we have reported that the addition of CDHs leads to an increase in the number of nodules. However, the information available on the biosynthesis of CDHs is scarce. A greater number of plants CDHs (including those isolated from actinorhizal trees) with a saturated heptane chain have been isolated compared with linear, non-cyclic diarylheptanoids. To identify the genes involved in the synthesis of these compounds, genes with significant sequence similarity to existing plant double-bond reductases were screened in A. sieboldiana. This report describes the isolation and characterization of two A. sieboldiana double-bond reductases (AsDBR1 and AsDBR2) that catalyze the NADPH-dependent reduction of bisdemethoxycurcumin and curcumin. The optimum pH for the two enzymes was 5.0. The apparent Km values for bisdemethoxycurcumin and NADPH were 4.24 and 3.53 µM in the case of AsDBR1, and 2.55 and 2.13 µM for AsDBR2. The kcat value was 9.4-fold higher for AsDBR1 vs. AsDBR2 when using the bisdemethoxycurcumin substrate. Interestingly, the two AsDBRs failed to reduce the phenylpropanoid monomer.

Comparative Analyses of Bioactive Compounds in Inonotus obliquus Conks Growing on Alnus and Betula.

Inonotus obliquus grows in the Northern Hemisphere on some living broadleaved tree species as a pathogen, causing stem rot. In Estonia, the fungus is well known in the Betula species but can also be found on Alnus. Sterile conks of I. obliquus contain different bioactive compounds, but the quantitative and comparative research of these compounds in conks on different host species is limited. In the current work, I. obliquus was isolated and, evidently, determined from Alnus incana (L.) Moench., Alnus glutinosa (L.) Gaertn., and Betula pendula Roth, and the content of bioactive compounds in conks on these hosts were analysed. All the analysed conks sampled from A. incana and B. pendula contained betulin that varied from 111 to 159 µg/g. A significantly (p < 0.05) higher betulinic acid content was found in conks sampled from A. incana when compared with B. pendula: 474−635 and 20−132 µg/g, respectively. However, the conks from Betula were richer in total polyphenols, flavonols, and glucans. The content of inotodiol was quite similar in the conks from A. incana (7455−8961 µg/g) and B. pendula (7881−9057 µg/g). Also, no significant differences in the lanosterol content were found between the samples from these two tree species. To the best of our knowledge, this study is the first investigation of the chemical composition of I. obliquus parasitizing on Alnus. The results demonstrate that the bioactive compounds are promising in conks of I. obliquus growing not only on Betula but also on the Alnus species. It supports the opportunity to cultivate I. obliquus, also on the Alnus species, thus increasing the economic value of growing this tree species in forestry.

Evaluation of Phytochemistry and Pharmacological Properties of Alnus nitida.

In the current study, the anti-inflammatory and analgesic potential of Alnus nitida (leaves and fruits) was evaluated in the Sprague-Dawley rat. Traditionally, A. nitida was used for the treatment of inflammatory ailments. However, A. nitida leaves and fruits have not been yet reported regarding any potential medicinal effects. Leaves/fruits of A. nitida were extracted with methanol and fractionated to attain n-hexane, chloroform, ethyl acetate and aqueous fractions. These extracts were then evaluated for in vivo analgesic and anti-inflammatory potential. For in vivo anti-inflammatory activity, carrageenan-induced paw edema assay, Freunds' complete adjuvant-induced edema, xylene-induced ear edema and histamine-induced paw edema models were used in rats, which showed significant (p < 0.01) reduction (70−80%) in edema in comparison of inflammatory controls. On other hand, for the analgesic assessment, hot plate assay and acetic acid-induced writhing tests were used, which showed a significant (p < 0.01) rise in latency time (40−60%) as compared with pain-induced controls. These results were comparable with standard drugs in a concentration-dependent manner and no mortality or toxicity was observed during all experiments. Then, for the identification of chemical constituents gas chromatography−mass spectrometry (GC-MS) analysis was performed, which indicated the presence of neophytadiene, 3,7,11,15-Tetramethyl-2-hexadecen-1-ol, phytol and vitamin E, justifying the use of A. nitida to treat inflammatory disorders.

Chemical Characteristics of Ethanol and Water Extracts of Black Alder (Alnus glutinosa L.) Acorns and Their Antibacterial, Anti-Fungal and Antitumor Properties.

The aim of this study was to identify polyphenolic compounds contained in ethanol and water extracts of black alder (Alnus glutinosa L.) acorns and evaluate their anti-cancer and antimicrobial effects. The significant anti-cancer potential on the human skin epidermoid carcinoma cell line A431 and the human epithelial cell line A549 derived from lung carcinoma tissue was observed. Aqueous and ethanolic extracts of alder acorns inhibited the growth of mainly Gram-positive microorganisms (Staphylococcus aureus, Bacillus subtilis, Streptococcus mutans) and yeast-like fungi (Candida albicans, Candida glabrata), as well as Gram-negative (Escherichia coli, Citrobacter freundii, Proteus mirabilis, Pseudomonas aeruginosa) strains. The identification of polyphenols was carried out using an ACQUITY UPLC-PDA-MS system. The extracts were composed of 29 compounds belonging to phenolic acids, flavonols, ellagitannins and ellagic acid derivatives. Ellagitannins were identified as the predominant phenolics in ethanol and aqueous extract (2171.90 and 1593.13 mg/100 g DM, respectively) The results may explain the use of A. glutinosa extracts in folk medicine.

Screening method for chromatographic analysis of diarylheptanoids in alder bark extracts.

An experimentally proven novel analytical approach for chromatographic analysis of diarylheptanoids in grey alder (Alnus incana) and black alder (Alnus glutinosa) bark matrices was established. A method for qualitative and quantitative determination of oregonin (dominant diarylheptanoid) and semiquantitative analysis of related diarylheptanoids from alder bark using a photodiode array (PDA) detector coupled to a high-resolution mass spectrometer (QTOF-MS) was developed. A comparison of different liquid chromatography detectors (UV, MS and ELS) showed that only a combination of them is applicable for comprehensive analysis of multicomponent extracts. A total of sixteen different diarylheptanoids were simultaneously identified and semi-quantified in alder bark extracts. This is the first report of the method for individual and total diarylheptanoid determination in alder bark extracts, discussed in detail. The liquid chromatography complex is suggested as a tool for the reliable identification and quality control of the diarylheptanoids containing extracts isolated from the Alnus species and their dominant component - oregonin. The semiquantitative methodology established, and the dominant compound quantification provided means for assessing comparative sample complexities.

Alnus sibirica Compounds Exhibiting Anti-Proliferative, Apoptosis-Inducing, and GSTP1 Demethylating Effects on Prostate Cancer Cells.

Alnus sibirica (AS) is distributed in Korea, Japan, China, and Russia and has reported anti-oxidant, anti-inflammatory, and reducing activities on atopic dermatitis-like skin lesions, along with other beneficial health properties. In the present study, we tried to prove the cancer-preventive activity against prostate cancer. The extracted and isolated compounds, oregonin (1), hirsutenone (2), and hirsutanonol (3), which were isolated from AS, were tested for anti-proliferative activity. To do this, we used the MTT assay; NF-κB inhibitory activity, using Western blotting; apoptosis-inducing activity using flow cytometry; DNA methylation activity, using methylation-specific polymerase chain reaction in androgen-dependent (LNCaP) and androgen-independent (PC-3) prostate cancer cell lines. The compounds (1-3) showed potent anti-proliferative activity against both prostate cancer cell lines. Hirsutenone (2) exhibited the strongest NF-κB inhibitory and apoptosis-inducing activities compared with oregonin (1) and hirsutanonol (3). DNA methylation activity, which was assessed for hirsutenone (2), revealed a concentration-dependent enhancement of the unmethylated DNA content and a reduction in the methylated DNA content in both PC-3 and LNCaP cells. Overall, these findings suggest that hirsutenone (2), when isolated from AS, may be a potential agent for preventing the development or progression of prostate cancer.

Factors Affecting Foliar Oregonin and Condensed Tannin in Red Alder (Alnus rubra Bong.): Phytochemicals Implicated In Defense Against Western Tent Caterpillar (Malacosoma californicum Packard).

Past work shows a significant negative correlation between foliar oregonin concentration and western tent caterpillar (Malacosoma californicum Packard) feeding on red alder (Alnus rubra Bong.). Above an oregonin threshold of 20% leaf dry weight, little feeding by caterpillars is observed. Concentrations of defensive chemicals are influenced by plant genotype, environmental conditions, insect feeding, and the interactions of these factors. Our objective was to measure the effects of nitrogen (N) availability and wounding on foliar oregonin and condensed tannin concentrations in red alder genotypes. One-year-old seedlings from 100 half-sib red alder families were treated with two levels of ammonium nitrate (NH4NO3) for two growing seasons in a common garden. In the second year, leaves from 50 families from the fertilization experiment were used in a bioassay feeding experiment to determine the effects of N fertilization and genotype on WTC damage, and to identify a subset of 20 families with a range of damage to analyze for phytochemical composition. In separate experiments, wound-induction treatments were conducted outdoors and, in a greenhouse using the N treated trees in their third and fourth year, respectively. Foliar condensed tannin, oregonin and N concentrations were measured and ranked among the plant genotypes, and between the two N treatments and two wounding treatments. Results showed that oregonin and condensed tannin concentrations varied among the alder genotypes. Leaf N concentration was negatively correlated with concentration of oregonin. Neither of the measured phenolic compounds responded to wounding. The results suggest that red alder foliar oregonin and condensed tannin are likely constitutive defenses that are largely determined by genotype, and that the negative correlation of defense compounds with plant internal N status holds in this N-fixing tree.

Lignan from Alnus japonica Inhibits Adipocyte Differentiation via Cell Cycle and FOXO1 Regulation.

In the present study, we isolated a lignan ((-)-(2R,3R)-1,4-O-diferuloylsecoisolariciresinol, DFS) from Alnus japonica and evaluated its antiobesity potential in vitro. We also determined its mechanism of action in a mouse pre-adipocyte 3T3-L1 cell line. DFS dose- and day-dependently inhibited adipogenesis by downregulation of adipogenic factors and lipid metabolism-regulating factors during adipocyte differentiation. In particular, DFS suppressed cell cycle-regulating factors and induced G0/G1 cell cycle arrest, implying that it had an inhibitory effect on mitotic clonal expansion which occurred at an early stage of adipogenesis. DFS also suppressed adipogenesis through decreasing Akt phosphorylation and increasing the level of Forkhead box protein-O1 (FOXO1). These results suggest that DFS may be a pharmacological candidate for the development of antiobesity, therapeutic, and nutraceutical products.

Positive effect of natural antioxidant oregonin from Alnus incana bark on ram semen quality stored at 5 °C for 48 h.

The maintenance of high vitality and motility of ram's spermatozoa during storage at low temperatures has a crucial role for successful fertilization. This study evaluates the effect of the natural antioxidant oregonin on ram semen quality, stored at 5 °C for 48 h. Еighteen ejaculates (three repetitions for 6 ejaculates) from three local breed rams, collecting by artificial vagina, with volume > 1 ml, concentration > 1 × 109/ml and mass motility >3.5 were used for chilling. Each ejaculate was separated in two equal parts, diluted with Tris-glucose-glycerol-egg yolk extender with no oregonin or supplemented with 100µÐœ oregonin until adjustment of the sperm concentration to 200 × 106 cells/ml and stored at 5 °C for 48 h. The semen quality assessment was based on the main kinematic (by CASA analysis), morphological parameters (by BrightVit kit staining) and mitochondrial status (by MitoView staining) of the spermatozoa on 0, 24 and 48 h of storage, and on in vivo fertility test. Oregonin did not impair the morphology and kept sustained motility of ram spermatozoa stored at 5 °C for 48 h. The curvilinear velocity indicated faster movement of the oregonin treated sperms that corresponded with high percent of spermatozoa with active mitochondria in these samples. The fertilizing capacity of spermatozoa was preserved and pregnancy rate in the experimental group was 80% versus 60% in control. In conclusion, this study provides a new data about positive effect of the natural antioxidant oregonin, supplemented to the extender, on chilled ram semen quality, including fertilizing ability.

Anti-Inflammatory Effects of Alnus Sibirica Extract on In Vitro and In Vivo Models.

Alnus sibirica extracts (ASex) have long been used in Oriental medicine to treat various conditions. To provide a scientific basis for this application and the underlying mechanism, we investigated the anti-inflammatory effects of ASex in vitro and in vivo. The in vitro model was established using human dermal fibroblasts (HDFs) treated with inflammatory stimulants (lipopolysaccharide, tumor necrosis factor-alpha, interferon-gamma). Lactate dehydrogenase and reverse transcription-polymerase chain reaction showed that ASex inhibited the increased expression of acute-phase inflammatory cytokines. The in vivo model was established by inducing skin inflammation in NC/Nga mice via the repeated application of house dust mite (HDM) ointment to the ears and back of the mice for eight weeks. HDM application increased the severity of skin lesions, eosinophil/mast cell infiltration, and serum immunoglobulin E levels, which were all significantly decreased by ASex treatment, demonstrating the same degree of protection as hydrocortisone. Overall, ASex showed excellent anti-inflammatory effects both in vitro and in vivo, suggesting its potential as an excellent candidate drug to reduce skin inflammation.

Inhibition of autophagy sensitizes lignan-induced endoplasmic reticulum stress-mediated cell death.

Relationship between autophagy and endoplasmic reticulum (ER) stress and their application to treat cancer have been actively studied these days. Recently, a lignan [(-)-(2R, 3R)-1,4-O-diferuloylsecoisolariciresinol, DFS] from Alnus japonica has been found to reduce the viability of colon cancer cells. In this study, we have observed DFS-induced autophagy in a variety of cancer cell lines. In addition, DFS led to ER stress, based on the activation of unfolded protein response (UPR) transducers and an elevated expression of UPR target genes in prostate and colon cancer cells. Further investigation has shown that DFS triggered the activation of AMP-activated protein kinase (AMPK) signaling and nuclear translocation of transcription factor EB (TFEB). Furthermore, the cytotoxicity of DFS was potentiated by the co-treatment of autophagy inhibitor in these cancer cells. This study has provided a noble implication that the combination of DFS and autophagy inhibition exerts a synergistic effect in cancer treatment.

Activation of JNK and p38 in MCF-7 Cells and the In Vitro Anticancer Activity of Alnus hirsuta Extract.

JNK and p38 are important mitogen-activated protein kinases (MAPKs) that respond to stress stimuli. The stress-activated MAPKs associated with apoptotic cell death play vital roles in mammalian cells. Alnus hirsuta, which contains abundant diarylheptanoids derivatives, is a valuable medicinal plant. The CHCl3 extract (AHC) containing platyphyllenone (1) and platyphyllone (3) as main compounds showed in vitro anticancer effects. We report the biological activities of A. hirsuta extract associated with the regulation of apoptosis and JNK and p38 in MCF-7 breast cancer cells. Levels of phospho-JNK and phospho-p38 by AHC treatment were evaluated by enzyme-linked immunosorbent assay (ELISA). ROS production, apoptotic effect, and DNA contents of the cells were measured by flow cytometry. The two diarylheptanoids 1 and 3 and the AHC extract exhibited cytotoxic effects on MCF-7 cells in MTT assay, with IC50 values of 18.1, 46.9, 260.0 µg/mL, respectively. AHC induced ROS generation and elevated the endogenous levels of phospho-JNK and phospho-p38. AHC resulted in apoptosis and cell cycle arrest. We suggest that the antitumor effect of A. hirsuta extract is achieved by apoptosis promotion and cell cycle arrest mediated by the activation of JNK and p38 signaling pathway via ROS generation.

Biogenetic study of the emissions of species: Pinus radiata, Eucalyptus globulus Labill and Alnus acuminata in Riobamba canton, Ecuador.

Background: Air pollution is one of the biggest problems in the world, and it is generated by industrial production, vehicular flow and use of fossil fuels, leaving aside other important emission sources such as vegetation. The aim of this research is to quantify the emissions of natural volatile organic compounds produced by the forest species: Eucalyptus globulus L., Pinus radiata and Alnus acuminata in Riobamba, Ecuador. Methods: Identification of plant coverings in the years 2014 and 2017was performed using geographic information systems tools, complemented with the application of the Guenther model for the calculation of monoterpenes and other organic volatile compounds; thus, to analyze the relationship between meteorological variables and concentrations of volatile organic compounds and nitrogen dioxide per species. Results: Mathematical calculation of emissions in Riobamba showed that Eucalyptus globulus L. registered higher emissions in the years 2014-2017, followed by Pinus radiata and Alnus acuminata. These emissions are due to the vegetation cover covering each species. The analysis of volatile organic compounds in forest plantations in air is directly related to the emissions represented in the environment and correlated with the meteorological variables of temperature, global solar radiation and wind velocity. The proposed method manages to estimate concentrations of monoterpenes and volatile organic compounds for the two examined seasons, presenting the influence of the species introduced in this study such as Eucalyptus globulus L. and Pinus radiata, with a reduction in their emissions (less area found in the year 2017, with respect to 2014). However, the emission of Alnus acuminata can be quantified only in 2017, since in 2014 no records of this species were found. Conclusions: Volatile organic compound concentrations in the air are directly related to the emissions represented spatially and correlated with the meteorological variables of temperature, global solar radiation and wind velocity.

Chemical profiles of birch and alder bark by ambient mass spectrometry.

Desorption atmospheric pressure photoionization (DAPPI) is an ambient mass spectrometry (MS) technique that allows the analysis of both polar and nonpolar compounds directly from the surfaces of various sample types. Here, DAPPI was used to study the chemical profiles in different parts of birch and alder tree barks. Four distinct fractions of Betula pendula (silver birch) bark were collected from three different developmental stages of the stem, after which the chemical profiles of the different tissue types were measured. Of special interest were triterpenoids, a class of important defensive substances, which are found in the bark of the silver birch. Additionally, the chemical profiles of lenticels and the surrounding surfaces in the phellem of B. pendula (silver birch), Alnus glutinosa (black alder), and Alnus incana (gray alder) were screened with DAPPI. Another ambient MS technique, laser ablation atmospheric pressure photoionization (LAAPPI), was further used for the mass spectrometry imaging of lenticels on the B. pendula phellem. All the studied birch bark fractions showed individual chemical profiles in DAPPI. The mass spectra from the young apical stem and the transition zone resembled each other more than the mature stem. Instead, the phellem was found to contain a high amount of triterpenoids in all the developmental stages of the stem. The most intense peaks in the DAPPI mass spectra of the birch bark fractions were those of betulin and lupeol. Betulinic and betulonic acid peaks were intense as well, and these compounds were detected especially in the lenticels of the tree samples. Graphical abstract.

Alnus Sibirica Extracts Suppress the Expression of Inflammatory Cytokines Induced by Lipopolysaccharides, Tumor Necrosis Factor-α, and Interferon-γ in Human Dermal Fibroblasts.

The effects of Alnus sibirica (AS) extracts on cytokine expression induced by inflammatory stimulants were examined in human dermal fibroblasts (HDFs) and RAW264.7 cells. The anti-oxidative effect and effect on cell viability of AS extracts were evaluated, and four extracts with the highest anti-oxidative effects were selected. HDFs and RAW264.7 cells were treated with inflammatory stimulants, and the expression of cytokines involved in acute (IL-6 and IL-10) and chronic (IL-18) inflammation, the initiation of the immune response (IL-33), and non-specific immune responses (IL-1ß, IL-8, and TNF-α) were determined using a reverse-transcription polymerase chain reaction. LPS increased the expression of all the cytokines, except for IL-18; however, AS extracts, particularly AS2 and AS4, reduced this increase, and TNF-α treatment markedly increased the expression of cytokines related to non-specific immune responses. IFN-γ treatment induced no significant changes, except for increased IL-33 expression in HDFs. AS extracts inhibited the increase in the expression of IL-33 and other cytokines in HDFs. Thus, the exposure of HDFs and RAW264.7 cells to inflammatory stimulants increased the expression of cytokines related to all the inflammatory processes. HDFs are involved not only in simple tissue regeneration but also in inflammatory reactions in the skin. AS2 and AS4 may offer effective therapy for related conditions.

Polyphenol Characterization, Antioxidant and Skin Whitening Properties of Alnus cordata Stem Bark.

In this study, we investigated the phenolic composition of the crude extract (MeOH 80 %) of Alnus cordata (Loisel.) Duby stem bark (ACE) and its antioxidant and skin whitening properties. RP-LC-DAD analysis showed a high content of hydroxycinnamic acids (47.64 %), flavanones (26.74 %) and diarylheptanoids (17.69 %). Furthermore, ACE exhibited a dose-dependent antioxidant and free-radical scavenging activity, expressed as half-maximal inhibitory concentration (IC50 ): Oxygen radical absorbance capacity (ORAC, IC50 1.78 µg mL-1 )>Trolox equivalent antioxidant capacity (TEAC, IC50 3.47 µg mL-1 )>2,2-Diphenyl-1-picrylhydrazyl (DPPH, IC50 5.83 µg mL-1 )>ß-carotene bleaching (IC50 11.58 µg mL-1 )>Ferric reducing antioxidant power (FRAP, IC50 17.28 µg mL-1 ). Moreover, ACE was able to inhibit in vitro tyrosinase activity (IC50 77.44 µg mL-1 ), l-DOPA auto-oxidation (IC50 39.58 µg mL-1 ) and in an in vivo model it exhibited bleaching effects on the pigmentation of zebrafish embryos (72 h post fertilization) without affecting their development and survival. In conclusion, results show that A. cordata stem bark may be considered a potential source of agents for the treatment of skin disorders due to its bleaching properties and favorable safety profiles, associated to a good antioxidant power.

Inhibitory Effects on NO Production and DPPH Radicals and NBT Superoxide Activities of Diarylheptanoid Isolated from Enzymatically Hydrolyzed Ehthanolic Extract of Alnus sibirica.

Alnus sibirica (AS) is geographically distributed in Korea, Japan, Northeast China, and Russia. Various anti-oxidant, anti-inflammation, anti-atopic dermatitis and anti-cancer biological effects of AS have been reported. Enzymatic hydrolysis decomposes the sugar bond attached to glycoside into aglycone which, generally, has a superior biological activity, compared to glycoside. Enzymatic hydrolysis of the extract (EAS) from AS was processed and the isolated compounds were investigated-hirsutanonol (1), hirsutenone (2), rubranol (3), and muricarpon B (4). The structures of these compounds were elucidated, and the biological activities were assessed. The ability of EAS and the compounds (1-4) to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and Nitroblue tetrazolium (NBT) superoxide, and to inhibit NO production was evaluated in vitro. EAS showed more potent antioxidant and anti-inflammatory activity than AS. All investigated compounds showed excellent antioxidant and anti-inflammatory activities.

Ameliorative effect of Alnus japonica ethanol extract on colitis through the inhibition of inflammatory responses and attenuation of intestinal barrier disruption in vivo and in vitro.

Inflammatory bowel disease (IBD) is chronic inflammation of the gastrointestinal tract caused by high levels of pro-inflammatory cytokines and epithelial barrier dysfunction. Alnus japonica Steud. (Betulaceae) has been used in traditional Asian medicine. However, the potential of A. japonica for the treatment of intestinal inflammation has not been investigated. This study investigated the effects of ethanol extract from A. japonica bark (AJE) on colonic mucosa injury in mice with dextran sodium sulfate (DSS)-induced colitis. Treatment with AJE ameliorated pathological damage and the histopathologic features of DSS-induced colitis. The administration of AJE also inhibits DSS-induced pro-inflammatory cytokines expression, including interleukin (IL)-1ß, IL-6, tumor necrosis factor (TNF)-α, and cyclooxygenase (COX)-2. Notably, AJE administration attenuated the reduction of tight junction proteins, zonula occludens (ZO)-1 and occludin, in DSS-induced colitis. In addition, AJE increased heme oxygenase (HO)-1 expression and prevented DSS-induced apoptosis in colonic epithelial cells. Furthermore, in vitro studies demonstrated that AJE inhibits TNF-α-induced IL-8, IL-1ß, and COX-2 expression in human intestinal epithelial HT-29 cells and tert-butyl hydroperoxide-induced reduction of ZO-1 and occludin expression in human intestinal epithelial Caco-2 cells. AJE-induced HO-1 protein expression was also found in both HT-29 and Caco-2 cells. Taken together, our findings demonstrated that AJE inhibits intestinal inflammation and protects against intestinal barrier disruption in mice with DSS-induced colitis in vivo and human intestinal epithelial cells in vitro. These results suggest that AJE might have beneficial effects for the treatment of IBD.

Oregonin from Alnus incana bark affects DNA methyltransferases expression and mitochondrial DNA copies in mouse embryonic fibroblasts.

Oregonin is an open-chain diarylheptanoid isolated from Alnus incana bark that possesses remarkable antioxidant and anti-inflammatory properties, inhibits adipogenesis, and can be used in the prevention of obesity and related metabolic disorders. Here, we aimed to investigate the effects of oregonin on the epigenetic regulation in cells as well as its ability to modulate DNA methylating enzymes expression and mitochondrial DNA (mtDNA) copies. Our results show that oregonin altered the expression of DNA methyltransferases and mtDNA copy numbers in dependency on concentration and specificity of cells genotype. A close correlation between mtDNA copy numbers and mRNA expression of the mtDnmt1 and Dnmt3b was established. Moreover, molecular modeling suggested that oregonin fits the catalytic site of DNMT1 and partially overlaps with binding of the cofactor. These findings further extend the knowledge on oregonin, and elucidate for the first time its potential to affect the key players of the DNA methylation process, namely DNMTs transcripts and mtDNA.