Inhibitory effects of flavonoids isolated from Fragaria ananassa Duch on IgE-mediated degranulation in rat basophilic leukemia RBL-2H3

Neurotrophic phenolic glycosides from the roots of Armoracia rusticana

Armoracia rusticana P. G. Gaertner. belongs to the Brassicaceae family and has aroused scientific interest for its anti-inflammatory and anticancer activities. In a continuing investigation to discover bioactive constituents from A. rusticana, we isolated 19 phenolic glycosides including three undescribed flavonol glycosides and one undescribed neolignan glycoside from MeOH extract of this plant. Their structures were elucidated based on NMR spectroscopic analysis (1H, 13C, 1H-1H COSY, HSQC, and HMBC), HRESIMS, and chemical methods. The determination of their absolute configuration was accomplished by ECD and LC-MS analysis. All the compounds were assessed for their potential neurotrophic activity through induction of nerve growth factor in C6 glioma cell lines and for their anti-neuroinflammatory activity based on the measurement of inhibition levels of nitric oxide production and pro-inflammatory cytokines (i.e., IL-1β, IL-6, and TNF-α) in lipopolysaccharide-activated microglia BV-2 cells.

Chemical Constituents of Euphorbia stracheyi Boiss (Euphorbiaceae)

Euphorbia stracheyi Boiss was used for hemostasis, analgesia, and muscular regeneration in traditional Chinese medicine. To study the chemical constituents of E. stracheyi, the ethyl acetate part of the methanol extract of the whole plant was separated by silica gel, sephadex LH-20 column chromatography, and semi-preparative HPLC. The isolation led to the characterization of a new lathyrane type diterpenoid, euphostrachenol A (1), as well as eleven known compounds (2-11), including a lathyrane, three ingenane-type and two abietane-type diterpenoids, two ionones, and two flavonoids. The structures of these compounds were established using 1D- and 2D-NMR experiments, mass spectrometry, and X-ray crystallographic experiments. The MTT method was used to determine the cytotoxic activity of five cancer cell lines (Leukemia HL-60, lung cancer A-549, liver cancer SMMC-7721, breast cancer MCF-7, and colon cancer SW480) on the isolated compounds. However, only compound 4 showed moderate cytotoxicity against these cell lines, with IC₅₀ values ranging from 10.28 to 29.70 μM, while the others were inactive. Our chemical investigation also confirmed the absence of jatrophane-type diterpenoids in the species, which may be related to its special habitat.

Characterization of Antioxidant and α-Glucosidase Inhibitory Compounds of Cratoxylum formosum ssp. pruniflorum and Optimization of Extraction Condition

Cratoxylum formosum ssp. pruniflorum (Kurz.) Gogel (Guttiferae), called kuding tea, is widely distributed in Southeast Asia. In this study, the constituents and biological activity of C. formosum ssp. pruniflorum were investigated. Extract of its leaves, roots and stems showed antioxidant and α-glucosidase inhibitory activity. Interestingly, comparison of the metabolite profiles of leaves, roots and stems of C. formosum ssp. pruniflorum by LC-MS analysis showed a great difference between the roots and leaves, whereas the roots and stems were quite similar. Purification of the roots and leaves of C. formosum ssp. pruniflorum through various chromatographic techniques resulted in the isolation of 25 compounds. The structures of isolated compounds were elucidated on the basis of spectroscopic analysis as 18 xanthones, 5 flavonoids, a benzophenone and a phenolic compound. Among them, a xanthone (16) and a benzophenone (19) were first reported from nature. Evaluation of biological activity revealed that xanthones had a potent α-glucosidase inhibitory activity, while flavonoids were responsible for the antioxidant activity. To maximize the biological activity, yield and total phenolic content of C. formosum ssp. pruniflorum, extraction conditions such as extraction solvent, time and temperature were optimized using response surface methodology with Box-Behnken Design (BBD). Regression analysis showed a good fit of the experimental data, and the optimal condition was obtained as MeOH concentration in EtOAc, 88.1%; extraction time, 6.02 h; and extraction temperature 60.0 °C. α-Glucosidase inhibitory activity, yield and total phenolic content under the optimal condition were found to be 72.2% inhibition, 10.3% and 163.9 mg GAE/g extract, respectively. These results provide useful information about C. formosum ssp. pruniflorum as functional foods for oxidative stress-related metabolic diseases.

Fragaria × ananassa cv. Senga Sengana Leaf: An Agricultural Waste with Antiglycation Potential and High Content of Ellagitannins, Flavonols, and 2-Pyrone-4,6-dicarboxylic Acid

Strawberry leaves are considered a valuable waste material; so far, mainly due to their antioxidant properties. Since the annual production of this crop is high, our study aimed to thoroughly examine the chemical composition and antidiabetes-related bioactivity of Fragaria × ananassa leaf of its popular and productive cultivar Senga Sengana. Leaves from three different seasons, collected after fruiting, were extensively analyzed (UHPLC-qTOF-MS/MS, HPLC-DAD). Some individual components were isolated and quantified, including specific flavonol diglycosides (e.g., 3-O-[β-xylosyl(1‴→2″)]-β-glucuronosides). The separated quercetin glycosides were tested in an antiglycation assay, and their methylglyoxal uptake capacity was measured. In addition, the biodegradable polyester precursor 2-pyrone-4,6-dicarboxylic acid (PDC) was confirmed at relatively high levels, providing further opportunity for strawberry leaf utilization. We want to bring to the attention of the food, pharmaceutical, and cosmetic industries the Senga Sengana strawberry leaf as a new botanical raw material. It is rich in PDC, ellagitannins, and flavonols—potent glycation inhibitors.

LC-MS/MS metabolomics-facilitated identification of the active compounds responsible for anti-allergic activity of the ethanol extract of Xenostegia tridentata

In vivo and in vitro anti-allergic activities of ethanol extract of Xenostegia tridentata (L.) D.F. Austin & Staples were investigated using passive cutaneous anaphylaxis reaction assay and RBL-2H3 cell degranulation assay, respectively. The crude ethanol extract exhibited promising activities when compared with the known anti-allergic agents, namely dexamethasone and ketotifen fumarate. The ethyl acetate subfraction showed the highest anti-allergic activity among various sub-partitions and showed better activity than the crude extract, consistent with the high abundance of total phenolic and flavonoid contents in this subfraction. LC-MS/MS metabolomics analysis and bioassay-guided isolation were then used to identify chemical constituents responsible for the anti-allergic activity. The results showed that major components of the ethyl acetate subfraction consist of 3,5-dicaffeoylquinic acid, quercetin-3-O-rhamnoside, kaempferol-3-O-rhamnoside and luteolin-7-O-glucoside. The inhibitory activity of the isolated compounds against mast cell degranulation was validated, ensuring their important roles in the anti-allergic activity of the plant. Notably, besides showing the anti-allergic activity of X. tridentata, this work highlights the role of metabolomic analysis in identifying and selectively isolating active metabolites from plants.

Combined Computational NMR and Molecular Docking Scrutiny of Potential Natural SARS-CoV-2 Mpro Inhibitors

In continuation of the search for potential drugs that inhibit the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in this work, a combined approach based on the modeling of NMR chemical shifts and molecular docking is suggested to identify the possible suppressors of the main protease of this virus among a number of natural products of diverse nature. Primarily, with the aid of an artificial neural network, the problem of the reliable determination of the stereochemical structure of a number of studied compounds was solved. Complementary to the main goal of this study, theoretical modeling of NMR spectral parameters made it feasible to perform a number of signal reassignments together with introducing some missing NMR data. Finally, molecular docking formalism was applied to the analysis of several natural products that could be chosen as prospective candidates for the role of potential inhibitors of the main protease. The results of this study are believed to assist in further research aimed at the development of specific drugs based on the natural products against COVID-19.

Aromatic Constituents from the Leaves of Actinidia arguta with Antioxidant and α-Glucosidase Inhibitory Activity

As the leaf of Actinidia arguta has shown antioxidant activity, a study was conducted to identify the active ingredients. Forty-eight compounds were isolated from the leaves of A. arguta through various chromatographic techniques. Further characterization of the structures on the basis of 1D and 2D NMR and MS data identified several aromatic compounds, including phenylpropanoid derivatives, phenolics, coumarins, flavonoids and lignans. Among them, five compounds were newly reported, naturally occurring, and named argutosides A-D (1-4), which consist of phenylpropanoid glycosides that are conjugated with a phenolic moiety, and argutoside E (5), which is a coumarin glycoside that is conjugated with a phenylpropanoid unit. The isolated compounds showed good antioxidant and α-glucosidase inhibitory activity with differences in activity depending on the structures. Molecular docking analysis demonstrated the interaction between the hydroxyl and carbonyl groups of compounds 1 and 5 with α-glucosidase. Taken together, the leaves of A. arguta are rich in aromatic compounds with diverse structures. Therefore, the leaves of A. arguta and their aromatic components might be beneficial for oxidative stress and glucose-related diseases.

Davidones F and G, Two Novel Flavonoids from Sophora davidii (Franch.) Skeels

An unprecedented novel flavanone davidone F (1) with a seven-membered ring side chain, and a novel flavanonol davidone G (2), along with 11 known flavonoids, were isolated from the ethyl acetate fraction of Sophora davidii (Franch.) Skeels. Their planar structures were established by UV, IR, HRESIMS, 1D and 2D NMR data. The relative configurations of 1 and 2 were determined by calculation of NMR chemical shift values, the absolute configuration of 1 and 2 were assigned by comparing their experimental and calculated electronic circular dichroism (ECD) spectra. Moreover, compounds 1–13 were screened for the translocation activity of glucose transporter 4 (GLUT-4), and the fluorescence intensity was increased to the range of 1.56 and 2.79 folds. Compounds 1 and 2 showed moderate GLUT-4 translocation activity with 1.64 and 1.79 folds enhancement, respectively, at a concentration of 20 μg/mL.

Inhibitory Effects of Twenty-Nine Compounds From Potentilla longifolia on Lipid Accumulation and Their Mechanisms in 3T3-L1 Cells

Potentilla longifolia Willd. ex D.F.K.Schltdl., which is a kind of traditional Chinese herb, is often referred to as "Ganyancao" in China, which means "the herb is effective in the treatment of liver inflammation". Three new (ganyearmcaoosides A and B and ganyearmcaoic acid A; 1-3) and 26 known compounds (4-29) were isolated from the 95% ethanol extract of the dried aerial parts of this plant, of which 21 were isolated for the first time from this plant. The chemical structures of these compounds were elucidated using NMR and HR-ESI-MS analysis. The inhibitory effects of the 29 compounds with safe concentrations on the lipid accumulation in 3T3-L1 cells were evaluated using photographic and quantitative assessments of lipid contents by Oil Red O staining, and measurement of the triglyceride levels. Comprehensive analysis showed that compound 12 (3,8-dimethoxy-5,7,4'- trihydroxyflavone) showed the best inhibitory effect on lipid accumulation such as reducing the accumulation of oil droplets and triglyceride level, and was superior to the reference in positive control. Western blot analysis and RT-PCR results showed that compound 12 enhanced the phosphorylations of AMPK and ACC, and inhibited the expressions of adipogenesis-related proteins or genes including SREBP1c, FAS, SCD1, GPAT, PPARγ and C/EBPα, and thereby significantly inhibited lipid accumulation in a concentration-dependent manner. P. longifolia and its bioactive compounds could be promising as potential therapeutic agents for diseases related to lipid accumulation in the future.

Metabolomics Approach Expands the Classification of Propolis Samples from Midwest Brazil

Propolis samples collected from five areas in Mato Grosso do Sul state, Midwest Brazil, comprising portions of the Cerrado, Pantanal, and Atlantic Forest ecosystems, were investigated for metabolomic profiles and evaluated for antioxidant and antitumor potential. Chemical profiles were determined by HPLC-DAD-MS/MS data and evaluated using principal component analysis and hierarchical clustering analysis to discern chemical composition patterns. Based on phytogeographical origin and chemical composition, 20 potential markers were identified and five groups were distinguished: (I) Cerrado/Central, (II) Atlantic Forest/South, (III) Cerrado-Pantanal transition area/Northwest, (IV) Cerrado/North, and (V) Pantanal/West. Drawing on HPLC-DAD-MS/MS and NMR data, 47 compounds were successfully or tentatively identified, including prenylated phenylpropanoids, flavonoids, isoflavonoids, and di- and triterpenoids, among other constituents. Isoflavonoids, typically found in red propolis from Northeast Brazil, are being reported for the first time in a propolis sample from the Midwest. A new prenylated aromatic compound, (E)-3-[4-hydroxy-3-(2-hydroxy-3-methylbut-3-en-1-yl)-5-(3-methylbut-2-en-1-yl)phenyl]propenoic acid, was obtained. Samples in group II exhibited promising antitumor potential against prostate and breast carcinoma cells, as did samples in groups III and IV against the latter cell line. The sample in group I, despite containing the highest amount of total phenolic compounds and being the only sample to exhibit scavenging activity against DPPH, was not the most cytotoxic against the cell lines tested.

In vitro anti-allergic activity of Moringa oleifera Lam. extracts and their isolated compounds

BACKGROUND

Moringa oleifera Lam. is a commonly used plant in herbal medicine and has various reported bioactivities such as antioxidant, antimicrobial, anticancer and antidiabetes. It is rich in nutrients and polyphenols. The plant also has been traditionally used for alleviating allergic conditions. This study was aimed to examine the anti-allergic activity of M. oleifera extracts and its isolated compounds.

METHOD

M. oleifera leaves, seeds and pods were extracted with 80% of ethanol. Individual compounds were isolated using a column chromatographic technique and elucidated based on the nuclear magnetic resonance (NMR) and electrospray ionisation mass spectrometry (ESIMS) spectral data. The anti-allergic activity of the extracts, isolated compounds and ketotifen fumarate as a positive control was evaluated using rat basophilic leukaemia (RBL-2H3) cells for early and late phases of allergic reactions. The early phase was determined based on the inhibition of beta-hexosaminidase and histamine release; while the late phase was based on the inhibition of interleukin (IL-4) and tumour necrosis factor (TNF-α) release.

RESULTS

Two new compounds; ethyl-(E)-undec-6-enoate (1) and 3,5,6-trihydroxy-2-(2,3,4,5,6-pentahydroxyphenyl)-4H-chromen-4-one (2) together with six known compounds; quercetin (3), kaempferol (4), β-sitosterol-3-O-glucoside (5), oleic acid (6), glucomoringin (7), 2,3,4-trihydroxybenzaldehyde (8) and stigmasterol (9) were isolated from M. oleifera extracts. All extracts and the isolated compounds inhibited mast cell degranulation by inhibiting beta-hexosaminidase and histamine release, as well as the release of IL-4 and TNF-α at varying levels compared with ketotifen fumarate.

CONCLUSION

The study suggested that M. oleifera and its isolated compounds potentially have an anti-allergic activity by inhibiting both early and late phases of allergic reactions.

Identification of potential inflammatory inhibitors from Aster tataricus

Aster tataricus L.f. is a traditional Eastern Asian herbal medicine used for the relief of cough-related illnesses. In this study, 32 known compounds and two novel monoterpene glycosides were isolated from the roots of A. tataricus. With the aid of reported data, elucidation of the root-extract components was carried out using a multitude of spectroscopic techniques. All isolates were investigated for their ability to inhibit nitric oxide (NO) secretion in lipopolysaccharide-activated RAW264.7 cells. Compound 7 remarkably suppressed NO production with an IC₅₀ value of 8.5 µM. In addition, compound 7 exhibited significant inhibitory activity against the production of inflammatory cytokines (prostaglandin E₂, interleukin-6, and interleukin-1 beta) and the expression of inflammatory enzymes (inducible nitric oxide synthase and cyclooxygenase-2) via inhibition of nuclear factor-kappa B activation. Moreover, compound 7 effectively prevented the downstream activation of the mitogen-activated protein kinase signaling pathway by inhibiting phosphorylation of c-Jun N-terminal kinases, extracellular signal-regulated kinases, and p38. These results outline compound 7 as a potential inhibitor for the broad treatment of inflammatory diseases, such as atopic dermatitis, asthma, and various allergies.

A Review on the Dietary Flavonoid Tiliroside

Among flavonoid derivatives, tiliroside is a flavonoid contained in several edible plants or specific plant parts (fruits, leaves, or roots). These parts are often widely used as both food and medicines, in the treatment of various ailments and, in some cases, as food supplements. Considering the easy access to many publications concerning tiliroside and the lack of a review that summarizes the current progress in studies on its safety, efficacy, and presence in the plant kingdom, we present here a review paper on tiliroside and its principal derivatives. The paper also highlights the basic knowledge regarding this molecule, its derivatives, and the analytical approaches used for extraction and quantification, as well as reports on the biological activities against different key enzymes linked to various human diseases. The reported information is also devoted to highlighting the concept "learn from nature to discover new products," particularly in the development of new drugs, food supplements, and nutraceuticals, starting from a natural lead compound such as tiliroside and improving its biological activities (and selectivities) against a specific target for therapeutic purposes.

Castanea mollissima shell prevents an over expression of inflammatory response and accelerates the dermal wound healing

ETHNOPHARMACOLOGICAL RELEVANCE

Castanea mollissima shell (CMS) has been used for wound healing in China as traditional medicine. The shell is directly applied on the wounded skin as fine powder or as water maceration.

AIM OF THE STUDY

To investigate the wound healing activity of CMS and the potential mechanism of anti-inflammatory activity.

MATERIALS AND METHODS

The effects of ethanol extract of CMS (ECMS) on nitricoxide (NO), tumor necrosis factor (TNF)-α and interleukin (IL)- 6 productions in lipopolysaccharide (LPS)-treated RAW 264.7 cells were explored by enzyme linked immunosorbent assay (ELISA) in vitro. To study wound healing properties of ECMS in vivo, excision and incision wound models were performed on rats. Inflammatory cytokines from wound biopsies such as NO, TNF-α and IL-6 production were tested by ELISA. mRNA levels of iNOS, cyclooxygenase (COX) -2 and TNF-α were detected by real-time Polymerase Chain Reaction (PCR), and protein levels of IL-1β and Heme Oxygenase (HO) -1 were analyzed by Western blotting.

RESULTS

ECMS potently inhibited LPS-induced production of IL-6, NO and TNF-α in RAW 264.7 cells. The presence of quercetin, kaempferol, ursolic acid and gallic acid in ECMS might be responsible for its anti-inflammatory activity. 3% and 5% w/w ECMS significantly accelerated the wound healing process in both wound models, evidenced by the faster rate of wound contraction, epithelialization, increased hydroxyproline content, high tensile strength, decreased level of inflammatory markers compared to the control group. Histopathological studies also revealed the amelioration of wound healing by re-epithelialization, collagenation and vascularization of wounded skin sample in ECMS treated groups.

CONCLUSION

The experimental data revealed that CMS had ability to prevent exaggerated inflammation and accelerates wound epithelialization and might be beneficial for healing dermal wounds.

Polycyclic polyprenylated acylphloroglucinols and biphenyl derivatives from the roots of Garcinia nuntasaenii Ngerns. & Suddee

Seven previously undescribed compounds, including three polycyclic polyprenylated acylphloroglucinols (garcinuntins A-C), three biphenyl derivatives (garcinuntabiphenyls A-C) and a lanostane triterpene (garcinuntine), along with thirteen known compounds were isolated from the root of Garcinia nuntasaenii Ngerns. & Suddee. Their structures were elucidated on the basis of spectroscopic techniques. For garcinuntins A-C, the absolute configurations were confirmed by the combination of single X-ray crystallography and ECD calculations. Anti-HIV activity using anti-HIV-1 reverse transcriptase and syncytium inhibition assays, and cytotoxic activity against a panel of cultured mammalian cancer cell lines of isolated compounds were investigated.

Monoamine oxidases inhibitors from Colvillea racemosa: Isolation, biological evaluation, and computational study

Bioassay-guided fractionation and chemical investigation of Colvillea racemosa stems led to identification of two new α, β-dihydroxydihydrochalcones, colveol A (1) and colveol B (2) along with fifteen known compounds. The structures were elucidated via interpretation of spectroscopic data. The absolute configurations of the dihydrochalcones 1 and 2 were assigned by a combination of chemical modification and electronic circular dichroism data. The isolated compounds were evaluated for their inhibition activity toward recombinant human monoamine oxidases (rhMAO-A and -B). Compound 1 demonstrated preferential inhibition against hMAO-A isoenzyme (IC₅₀ 0.62μM, SI_A/B 0.02) while S-naringenin (13) and isoliquiritigein (15) demonstrated preferential hMAO-B inhibition (IC₅₀ 0.27 and 0.51μM, SI_A/B 31.77 and 44.69, respectively). Fisetin (11) showed inhibition against hMAO-A with IC₅₀ value of 4.62μM and no inhibitory activity toward hMAO-B up to 100μM. Molecular docking studies for the most active compounds were conducted to demonstrate the putative binding modes. It suggested that 1 interacts with Gln215, Ala111, Phe352, and Phe208 amino acid residues which have a role in the orientation and stabilization of the inhibitor binding to hMAO-A, while S-naringenin (13) occupies both entrance and substrate cavities and interacts with Tyr326, a critical residue in inhibitor recognition in hMAO-B.

Inhibitory effect of Zizania latifolia chloroform fraction on allergy-related mediator production in RBL-2H3 cells

Zizania latifolia exhibits anti-inflammatory and anti-allergic effects; however, the mechanisms behind these effects are unknown. Here the ethanol extract of Z. latifolia was partitioned using hexane, chloroform, ethyl acetate, butanol, and water. Subsequently, the anti-allergic effects of these fractions were evaluated in vitro. The results showed that the chloroform fraction of Z. latifolia inhibited the release of β-hexosaminidase and tumor necrosis factor (TNF-α) from RBL-2H3 cells stimulated with dinitrophenyl-bovine serum albumin (DNP-BSA). In addition, this fraction suppressed the expression of cyclooxygenase-2 (COX-2) and inhibited the activation of mitogen-activated protein kinases (MAPKs). The results obtained suggest that the chloroform fraction of Z. latifolia inhibited mast cell-mediated allergic inflammatory responses.

OM-X®, Fermented Vegetables Extract Suppresses Antigen-Stimulated Degranulation in Rat Basophilic Leukemia RBL-2H3 Cells and Passive Cutaneous Anaphylaxis Reaction in Mice

OM-X® is a hand-made and naturally manufactured probiotic supplement. This fermented food product is made from vegetables, fruits, seaweeds and mushrooms, using 12 strains of lactic acid bacteria and bifidobacteria. OM-X® is also known to have beneficial health properties, and some of its components show effects on antigen (Ag)-stimulated degranulation activity, indicating that OM-X® may be useful in the treatment of allergy responses and symptoms. In this study, we evaluated the inhibitory effects of OM-X® on Ag-stimulated degranulation in rat basophilic leukemia RBL-2H3 cells, clarified the underlying mechanisms, and determined the active compounds in OM-X® for suppression of degranulation. Treatment with OM-X® gradually suppressed Ag-stimulated degranulation throughout the maturation period. OM-X® also gradually produced melanoidins by lactic acid bacterial fermentation during the maturation process. There was a high correlation between the suppression levels of Ag-stimulated degranulation and the browning of OM-X®. Furthermore, the inhibition of Ag-stimulated degranulation by OM-X® was found to be partially due to the direct inactivation of NADPH oxidase. To elucidate the in vivo effects of OM-X®, type I allergy model mice were orally administered with OM-X®, and the passive cutaneous anaphylaxis (PCA) reaction was measured. OM-X® intake remarkably suppressed the PCA reaction. Taken together, our findings suggest that OM-X® could be a beneficial food to ameliorate allergic reactions.

Effects of Cudrania tricuspidata Fruit Extract and Its Active Compound, 5,7,3',4'-Tetrahydroxy-6,8-diprenylisoflavone, on the High-Affinity IgE Receptor-Mediated Activation of Syk in Mast Cells

Cudrania tricuspidata fruit extract contains a rich source of prenylated flavonoids with potential antiatherosclerotic, hepatoprotective, and anti-inflammatory properties. However, the effect of C. tricuspidata fruit extracts and its active compounds on the high-affinity IgE receptor (FcεRI)-mediated signaling remains unknown. In the present study, the effect of methanol extract from the fruits of C. tricuspidata (MFC) and its active compound, 5,7,3',4'-tetrahydroxy-6,8-diprenylisoflavone (THDPI), on FcεRI-mediated signaling in mast cells was investigated. MFC and THDPI suppressed mast cell degranulation and Ca(2+) influx. MFC also interfered with IgE-FcεRI interaction and decreased FcεRIβ mRNA expression in mast cells. Furthermore, MFC and THDPI inhibited the phosphorylation of Syk, LAT, and PLCγ and F-actin redistribution. These results indicate that MFC and its active compound, THDPI, inhibit mast cell activation through the inhibition of FcεRI-mediated Syk activation, suggesting a therapeutic potential for controlling mast cell activation in inflammatory and/or allergic processes.

Neolignan inhibitors of antigen-induced degranulation in RBL-2H3 cells from the needles of Pinus thunbergii

The ethanolic extract of the needles of Pinus thunbergii was found to suppress antigen mediated degranulation of rat basophilic leukemia (RBL-2H3) cells. A new neolignan glycoside, named pinusthunbergiside A (1), as well as six known neolignan glycosides (2-7) were isolated from the ethanolic extract using bioassay-guided fractionation. Their structures were elucidated by a combination of 1D and 2D NMR, HRESI-MS, and circular dichroism (CD) data. Compounds 2-7 were found for the first time in this plant. The inhibitory effects of isolated constituents on the release of β-hexosaminidase from RBL-2H3 cells were examined, and compounds 2, 3, 5, and 6 were found to show the inhibitory activity with IC₅₀ values ranging between 52.3 and 75.3 μM.

Kaempferol, a potential cytostatic and cure for inflammatory disorders

Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many edible plants (e.g., tea, broccoli, cabbage, kale, beans, endive, leek, tomato, strawberries, and grapes) and in plants or botanical products commonly used in traditional medicine (e.g., Ginkgo biloba, Tilia spp, Equisetum spp, Moringa oleifera, Sophora japonica and propolis). Its anti-oxidant/anti-inflammatory effects have been demonstrated in various disease models, including those for encephalomyelitis, diabetes, asthma, and carcinogenesis. Moreover, kaempferol act as a scavenger of free radicals and superoxide radicals as well as preserve the activity of various anti-oxidant enzymes such as catalase, glutathione peroxidase, and glutathione-S-transferase. The anticancer effect of this flavonoid is mediated through different modes of action, including anti-proliferation, apoptosis induction, cell-cycle arrest, generation of reactive oxygen species (ROS), and anti-metastasis/anti-angiogenesis activities. In addition, kaempferol was found to exhibit its anticancer activity through the modulation of multiple molecular targets including p53 and STAT3, through the activation of caspases, and through the generation of ROS. The anti-tumor effects of kaempferol have also been investigated in tumor-bearing mice. The combination of kaempferol and conventional chemotherapeutic drugs produces a greater therapeutic effect than the latter, as well as reduces the toxicity of the latter. In this review, we summarize the anti-oxidant/anti-inflammatory and anticancer effects of kaempferol with a focus on its molecular targets and the possible use of this flavonoid for the treatment of inflammatory diseases and cancer.

Separation and structure elucidation of a new homoflavanol derivative from Pteridium aquilinum (L.) Kuhn

A novel homoflavanol derivative (1) with an unprecedented skeleton, as well as two known flavonoids kaempferol (2) and quercetin (3), was isolated from the plant Pteridium aquilinum (L.) Kuhn, and the structure and relative stereochemistry of the new compound (1) were elucidated on the basis of spectroscopic data.

Syntheses and anti-allergic activity of 2-((bis(trimethylsilyl)methylthio/methylsulfonyl)methyl)-5-aryl-1,3,4-oxadiazoles

A new class of sila-substituted 1,3,4-oxadiazoles was synthesized by a convenient synthetic method. Both silathio/silasulfonyl acetic acids were efficiently condensed with benzohydrazides in the presence of phosphorus oxychloride to give sila-substituted 1,3,4-oxadiazoles in high yields. The compounds displayed variable extent of anti-allergic activity on IgE/Ag-stimulated RBL-2H3 cells at 50 and 100 μM concentrations. Compounds having sulfonyl moiety with bis(trimethylsilyl)-1,3,4-oxadiazoles (5a-c), exhibited better anti-allergic activities than those of compounds having sulphur moiety with bis(trimethylsilyl)-1,3,4-oxadiazoles (4a-c).

Inhibitory effect of eriodictyol on IgE/Ag-induced type I hypersensitivity

Mast cells are the principal effector cells involved in the allergic response, through the release of histamine. We investigated the effect of eriodictyol, derived from the painted maple and yerba santa, on mast cell degranulation and on an allergic response in an animal model. We also investigated its effect on the expression of the ceramide kinase (CERK) involved in calcium-dependent degranulation, and on ceramide activation by multiple cytokines. Eriodictyol suppressed the release of beta-hexosaminidase, a marker of degranulation, and the expression of interleukin (IL)-4 mRNA. It inhibited the expression of CERK mRNA, reduced the ceramide concentration in antigen-stimulated mast cells, and suppressed the passive cutaneous anaphylaxis (PCA) reaction in mice in a dose-dependent manner. These results suggest that eriodictyol can inhibit mast cell degranulation through inhibition of ceramide kinase, and that it might potentially serve as an anti-allergic agent.