NO Inhibitory Activity Research Articles

New obovatol trimeric neolignans with NO inhibitory activity from the leaves of Magnolia officinalis var. biloba.

Six new obovatol trimeric neolignans, houpulignans A-F (1-6) were isolated from the leaves of Magnolia officinalis var. biloba. Their structures were determined on the basis of the interpretation of HRESIMS, NMR data, and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 are the first examples of neolignans derived from three units of obovatol bearing a rare 1,4-benzodioxepane moiety. Compound 3 possesses a benzodihydropyran ring, meanwhile three units of obovatol in 4-6 are connected by an alkyl chain. Compounds 1-3 inhibited NO production in LPS-stimulated RAW264.7 cells with IC50 values of 8.01, 20.21, and 4.05µM, respectively.

Anti-inflammatory activities of isopimara-8(14),-15-diene diterpenoids and mode of action of kaempulchraols P and Q from Kaempferia pulchra rhizomes

Inflammation is an extensively recognized link to many pathological diseases. It is a host response for protection from infections and tissue damage. Infections trigger acute inflammation; however, persistent infection will contribute to chronic inflammation and higher disease susceptibility. Deregulated inflammatory responses can cause excessive or long-lasting tissue damage, manifested as cancer, immune disorders, diabetes, etc. NF-κB is a central mediator of pro-inflammatory gene induction and functions in both innate and adaptive immune cells; therefore, the anti-inflammatory regulation of NF-κB is needed. Natural products reportedly play an important role in controlling the inflammatory response pathways. However, the anti-inflammatory activities of isopimara-8-(14),15-diene diterpenoids have not yet been fully elucidated. To elucidate the anti-inflammatory activities of the isopimara-8(14),15-diene diterpenoids, we investigated 21 isopimara-8(14),15-diene diterpenoids previously isolated from Kaempferia pulchra rhizomes. Eleven compounds exhibited NO inhibitory activity against lipopolysaccharide (LPS)-induced RAW264.7 cells, with IC50 values ranging from 30 to 100 μM. Furthermore, the most potent kaempulchraols P and Q, with IC50 values of 39.88 and 36.05 μM, respectively, inhibited the NF-κB-mediated transactivation of a luciferase reporter gene, IL-6 production, and COX-2 expression, with an effective dose of 25 μM. These findings provide new insights into the anti-inflammatory activities of the isopimara-8(14),15-diene diterpenoids.

Anti-inflammatory kavalactones from Alpinia zerumbet

Alpinia zerumbet (Pers.) B.L.Burtt & R.M.Sm. (Zingiberaceae) is a perennial plant native to the East Indies and is widely distributed in South America, Oceania, and Asia. The mature fruits of the plant have been used in traditional medicine in China. In this study, we compared the chemical constituents in the methanol extracts of the leaves, the placenta, the pericarps, and the seeds obtained from the same plant using LC-MS, and we examined the NO inhibitory activities of the respective extracts and the isolated compounds. As a result of LC-MS analyses, kavalactone derivatives (1–6) were detected in the methanol extracts of the leaves, placenta, and pericarps. Of these, compound 6 was identified as a new asymmetrical cyclobutane dimer of 5,6-dehydrokawain. Quantitative analysis showed that the total amounts of kavalactone derivatives were highest in the methanol extract of the pericarps. Moreover, the results of measurements of the anti-inflammatory activity revealed that the pericarps extract showed the strongest activity. The compounds responsible for the anti-inflammatory activity of the extracts from A. zerumbet were identified. Of these, five were known kavalactone derivatives and one was a new kavalactone derivative (aniba dimer C). The results showed that the pericarps of A. zerumbet are a rich source of kavalactone derivatives, and that the pericarps of A. zerumbet can be utilized as an important medicinal resource.

Effect of heat processing on the chemical constituents and NO-suppressing activity of Bletilla Tuber.

Bletilla Tuber (dried tuber of Bletilla striata) is used as an astringent hemostatic medicine for the treatment of ulcers, bleeding, and burns in traditional Chinese medicine (TCM). The Chinese Pharmacopoeia describes the heat processing methods used on raw tubers of Bletilla striata to produce the herbal medicine "Bletilla Tuber". In this study, we compared the chemical constituents of well-processed Bletilla Tuber (BT1) and normally processed Bletilla Tuber (BT2) derived from the same origin. In addition, as an indicator of the hemostatic activity of Bletilla Tuber, the NO inhibitory activities of extracts obtained from BT1 and BT2 and the isolated compounds were examined. As a result of LC-MS analysis, three types of compounds, glucosyloxybenzyl 2-isobutylmalates, bibenzyl derivatives and phenanthrene derivatives, were detected. Comparison of the chemical profiles of the extracts indicated that the relative contents of glucosyloxybenzyl 2-isobutylmalates had changed by heat processing, whereas the relative contents of bibenzyls and phenanthrenes had not changed. The extracts of BT1 and BT2 showed similar IC50 values on NO production suppressing activity. Furthermore, phenanthrenes and bibenzyls were identified as the compounds responsible for suppressing the NO activity. These results suggest that the biological activities, such as the anti-inflammatory and hemostatic activities, of Bletilla Tuber are not affected by heat processing.

Design, Synthesis and Investigation of the Potential Anti-Inflammatory Activity of 7-O-Amide Hesperetin Derivatives.

To develop new anti-inflammatory agents, a series of 7-O-amide hesperetin derivatives was designed, synthesized and evaluated for anti-inflammatory activity using RAW264.7 cells. All compounds showed inhibitory effect on LPS-induced NO production. Among them, 7-O-(2-(Propylamino)-2-oxoethyl)hesperetin (4d) and 7-O-(2-(Cyclopentylamino)-2-oxoethyl)hesperetin (4k) with hydrophobic side chains exhibited the most potent NO inhibitory activity (IC50 = 19.32 and 16.63 μM, respectively), showing stronger inhibitory effect on the production of pro- inflammatory cytokines tumor necrosis factor (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) than indomethacin and celecoxib at 10 μM. The structure-activity relationships (SARs) suggested that the 7-O-amide unit was buried in a medium-sized hydrophobic cavity of the bound receptor. Furthermore, compound 4d could also significantly suppress the expression of inducible nitric oxide synthase enzymes (iNOS) and cyclooxygenase-2 (COX-2), through the nuclear factor-kappa B (NF-κB) signaling pathway.

Synthesis, in vitro and in vivo biological evaluation of novel lappaconitine derivatives as potential anti-inflammatory agents

Lappaconitine (LA), a natural compound with a novel C18-diterpenoid alkaloid skeleton, displayed extensive biological profile. Recent research on LA is focused mainly on its anti-tumor and analgesic effects, and therefore we aimed to investigate its anti-inflammatory potential. A series of novel LA derivatives with various substituents on the 20-N position was designed and synthesized. In the initial screening of LA derivatives against NO production, all the target compounds, except compound E2, exhibited excellent inhibitory ability relative to that of LA. Particularly, compound A4 exhibited the most potent inhibition with IC50 of 12.91 μmol/L. The elementary structure–activity relationships (SARs) of NO inhibitory activity indicated that replacement of the benzene ring with an electron donating group could improve the anti-inflammatory efficacy. Furthermore, compound A4 shows an anti-inflammatory mechanism by inhibiting NO, PGE2, and TNF-α generation via the suppression of NF-κB and MAPK signaling pathways. Notably, compound A4 could exert a significant therapeutic effect on LPS-induced acute lung injury (ALI) in vivo. Based on the above research, we further investigated the preliminary pharmacokinetic property of A4 in rats. Therefore, compound A4 could be a promising candidate for the development of anti-inflammatory agents in the future.

Bioactive triterpene glycosides from the fruit of Stauntonia hexaphylla and insights into the molecular mechanism of its inflammatory effects.

Chromatography of the ethanol extract of the medicinal fruit Stauntonia hexaphylla resulted in the purification of 26 compounds (1-26), including two undescribed triterpene saponins 1 and 2 (hexaphylosides A and B). Their structures were confirmed by spectroscopic data, including IR, HR QTOF MS, 1H, 13C NMR, COSY, HMQC, HMBC, and TOCSY, and HPLC sugar analysis after acid hydrolysis. The anti-inflammatory effects of the high-purity constituents (1-26) on lipopolysaccharide (LPS)-induced RAW264.7 macrophage cells were investigated by screening nitric oxide production. The NO inhibitory activity of compounds 6 and 10 with the IC50 values of 1.33 and 1.10 µM, respectively. The structure-activity relationships (SAR) of the isolated compounds were also analyzed. Furthermore, compounds 6 and 10 inhibited the protein expression inducible nitric oxide synthase (iNOS), and cyclooxygenase (COX)-2 via Western blotting analysis. This showed that compounds 6 and 10 contributed to the anti-inflammatory effects of S. hexaphylla fruit, which could be developed as a natural nutraceutical and functional food ingredient.

Chemical Constituents of the Aerial Parts of Scoparia dulcis and Anti-cancer, Anti-inflammatory Activities

In Vietnam, the medicinal plant Scoparia dulcis is used for the treatment of bronchitis, gastric disorders, antidiabetes, hypertension, hepatitis etc. In this paper, experiments was designed to evaluate in vitro anticancer and anti-inflammatory activities and isolate phytochemicals from methanol extracts of Scoparia dulcis whole plants. The chemical investigation of methanol fraction of Scoparia dulcis led to the isolation of benzoxazinone (1), phenylethanoid (2), flavone (3), and lignan (4) glycosides. The bioactivity results indicated that crude ethanol and ethyl acetate extracts had potent cytotoxic activity toward the HepG2 cancer cell with IC50 of 47.03 μg/mL and 36.04 μg/mL, respectively. Interestingly, crude ethanol and ethyl acetate extracts had the NO inhibitory activity, with inhibition of 56.9 % or 74.7 % at 30 μg/mL and 97.3% or 82.9 % at 100 μg/mL, respectively. In addition, the hexane extract at concentrations of 100 μg/ml demonstrated anti-inflammatory activity through the inhibition of nitric oxide production of 76.7%.

Chemical Constituents of the Aerial Parts of Scoparia Dulcis and Anti-Cancer, Anti-Inflammatory Activities

In Vietnam, the medicinal plant Scoparia dulcis is used for the treatment of bronchitis, gastric disorders, antidiabetes, hypertension, hepatitis etc.1 In this paper, experiments was designed to evaluate in vitro anticancer and anti-inflammatory activities and isolate phytochemicals from methanol extracts of Scoparia dulcis whole plants. The chemical investigation of methanol fraction of Scoparia dulcis led to the isolation of benzoxazinone (1), phenylethanoid (2), flavone (3), and lignan (4) glycosides. The bioactivity results indicated that crude ethanol and ethyl acetate extracts had potent cytotoxic activity toward the HepG2 cancer cell with IC50 of 47.03 μg/mL and 36.04 μg/mL, respectively. Interestingly, crude ethanol and ethyl acetate extracts had the NO inhibitory activity, with inhibition of 56.9 % or 74.7 % at 30 μg/mL and 97.3% or 82.9 % at 100 μg/mL, respectively. In addition, the hexane extract at concentrations of 100 μg/ml demonstrated anti-inflammatory activity through the inhibition of nitric oxide production of 76.7%.

Cytochalasins and polyketides from the fungus Diaporthe sp. GZU-1021 and their anti-inflammatory activity

Four new compounds: diaporthichalasins A-C (1–3) and biatriosporin N (7), along with six known compounds (4–6 and 8–10) were separated from the culture of the fungus Diaporthe sp. GZU-1021. The absolute configurations of 1–3 were determined by quantum chemical calculations, X-ray diffraction, and spectroscopic analysis. The structure of 4 was analyzed by X-ray crystallography analysis for the first time. All of the isolates were evaluated on the production of nitric oxide in lipopolysaccharide-induced microglial cells (RAW 264.7 cells). Compounds 5–10 exhibited significant inhibitory effects against nitric oxide production with IC50 values from 1.94 to 16.5 μM than positive control (indomethacin, IC50 = 29.7 μM). This is the first time tetrahydroxanthone dimer (10), as a novel carbon skeleton possessing NO inhibitory activity, was reported.

Free radical scavenging and anti-inflammatory potential of a protein hydrolysate derived from salmon bones on RAW 264.7 macrophage cells.

Salmon bones, a waste by-product from the salmon industry, were used as a protein hydrolysate source for the production of bioactive peptides. The aim of this work was to evaluate the potential antioxidant and anti-inflammatory properties of salmon bone protein hydrolysate (SBPH). Salmon bones were hydrolyzed by separately using one of four proteases (Alcalase, Favourzyme, Neutrase and papain) at various concentrations (10, 25 and 50 mg mL-1 ), where the SBPH derived from 10 mg mL-1 papain hydrolysis exhibited the highest nitric oxide (NO) radical scavenging activity. After ultrafiltration, the MW < 0.65 kDa fraction showed the strongest NO inhibitory activity and was further fractionated by gel filtration chromatography (G1 and G2 fractions) and reverse-phase high-performance liquid chromatographic fractionation of the G1 fraction, from which the three main peaks (H1, H2 and H3) were found to have a marked NO-inhibitory activity and their peptide sequences were determined. Moreover, the G1 fraction was shown to inhibit both the lipopolysaccharide (LPS)-induced NO production and the LPS-induced inducible NO synthase , interleukin-6, tumor necrosis factor-α and induced NO production and the LPSCOX-2 mRNA levels in RAW 264.7 cells. Salmon bones from the salmon fisheries and farming industry were utilized by enzymatic hydrolysis for the production of valuable peptides. The results of this study suggested that bioactive peptides derived from salmon bones would be alternative anti-inflammation materials in functional resources. © 2019 Society of Chemical Industry.

Anti-hyperglycemic and hypolipidemic activity of Leea indica

Leea indica (Burm.f) Merr is a well-known traditional Chinese medicine. Leaves of Leea indica have multiple pharmacological activities like Antitumour, Analgesic, Antiviral, Sedative and Anxiolytic and NO inhibitory activities. It has long been used as a folk medicine for the treatment of Cardiac diseases, Diabetes, Fever, headache, dizziness, soreness, eczema, sprain, leprosy, bone fracture, body pain, muscle spasms, diarrhoea and dysentery. Scientific studies are not yet carried out to prove the antihyperglycemic activity. To evaluate antihyperglycemic and hypolipidemic activity of Leea indica leaves in alloxan (150 mg/kg) induced diabetic rats. Alcoholic and hydroalcoholic extracts were evaluated for its toxicity (3000 mg/kg) and for antihyperglycemic activity (200 and 400 mg/kg) using glucose tolerance test and alloxan induced model for 21 days. Statistical data indicated significant decrease in blood glucose, triglycerides, total cholesterol, LDL cholesterol, VLDL cholesterol, aspartate amino transferase, alanine amino transferase, creatinine, urea and increased HDL cholesterol, liver glycogen levels when compared to standard drug glibenclamide (10 mg/kg). Hydrolcoholic extract of Leea indica at higher dose was found to be more effective than alcoholic extract. These results reveal that Leea indica has beneficial effect in reducing blood glucose and lipid levels indicating its efficient antihyperglycemic and hypolipidemic activity.

Panitins A-G: Coumarin derivatives from Murraya paniculata from Guangxi Province, China show variable NO inhibitory activity

Seven previously undescribed coumarin derivatives, panitins A‒G, an ethoxylated artifact, and 34 known analogues, were isolated from the roots of Murraya paniculata. Their structures were elucidated on the basis of comprehensive analysis of 1D and 2D NMR and HRMS spectroscopic data, and comparison with the data reported in literature. The absolute configurations of undescribed compounds were assigned via comparison of the specific rotation, Mosher's method, exciton chiral method, and comparison of calculated and experimental ECD data. Panitin D, trans-dehydroosthol, and exotimarin I showed potent inhibition against LPS-induced NO production in BV-2 microglial cells with IC50 values of 19.6 ± 2.3, 12.4 ± 0.9, and 26.9 ± 0.8 μM, respectively.

Two new bioactive lignans from leaves and twigs of Cleistanthus concinnus Croizat

Two new lignans (1–2), along with five known compounds (3-7) with different structures were isolated from leaves and twigs of Cleistanthus concinnus Croizat. The new lignans were elucidated as (7′R,8′S)-3,3′,5′-trimethoxy-4,4′-dihydroxy-7-en-7′,9- epoxy-8,8′-lignan (1) and (7′R,8′S)-3,3′-dimethoxy-4,4′-dihydroxy-7-en-7′,9-epoxy-8, 8′-lignan (2) by comprehensive spectroscopic analysis including 1D and 2D NMR as well as HREIMS and comparing their NMR data with known compounds in the literature. Among these isolated compounds, compound 1, 2, 3, and 6 were tested for anti- inflammatory effects by inhibiting NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Compound 1, 2, and 6 exhibit NO inhibitory activity.

Nitric Oxide Synthesis Inhibition and Anti-Inflammatory Effect of Polypeptide Isolated from Chicken Feather Meal in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages.

SUMMARYNitric oxide (NO) plays a key role in the pathogenesis of inflammation and has been implicated in endotoxin-induced tissue injury. Chicken feather meal is a rich source of amino acids that may serve as a peptide hydrolysate to inhibit NO activity. Anti-inflammatory hydrolysates of chicken feather meal were prepared and fractionated into five samples based on molecular mass. The smallest fraction (<0.65 kDa) exhibited the highest NO inhibitory activity without cytotoxicity towards macrophage RAW 264.7 cells. Further subfractions were sufficient to obtain amino acid sequences by Q-TOF LC-MS/MS ESI analysis. Of these, the SNPSVAGVR (885.97 Da) peptide and its corresponding pure synthetic peptide have inhibitory activity against NO production by RAW 264.7 cells (IC50=(55.2±0.2) mM) without cytotoxicity. Reverse transcriptase polymerase chain reaction (RT-PCR) and quantitative real-time RT-PCR results revealed that the peptide of the obtained fraction reduced transcript expression levels of the pro-inflammatory cytokines iNOS, TNF-α, COX-2 and IL-6 in lipopolysaccharide-stimulated RAW 264.7 cells. These results suggest that the peptides derived from the chicken feather meal protein could potentially be used as a promising ingredient in functional foods or nutraceuticals against inflammatory diseases.

Chemical constituents from the bark of bauhinia purpurea and their NO inhibitory activities

Phytochemical studies led to the isolation of a new phenylpropanoid glucoside, named purpuroside (1), along with eight known compounds (2–9) from the bark of Bauhinia purpurea. The structure of the new compound was elucidated on the basis of its spectroscopic data. The absolute configuration of compound 2 was verified by X-ray diffraction analysis. Compounds 1, 2, 7, 8, and 9 inhibited NO production in mouse peritoneal macrophages with IC50 values from 35.5 to 63.0 μM.

Lactone ring-opening seco-guaianolide involved heterodimers linked via an ester bond from Artemisia argyi with NO inhibitory activity

Investigation into the chemical diversity of Artemisia argyi led to the discovery of four new (1–4) and one known (5) guaianolide sesquitenpenoid dimers linked via ester bond, and five other known mono-sesquiterpenoids (6–10). Their structures were determined via extensive spectroscopic data, and the absolute configurations of these compounds were elucidated by calculated ECD analysis and chemical method. The dimeric sesquiterpenoids exhibited NO production inhibitory activity with IC50 values ranging from 7.02 to 32.1 μM. The studies further suggested that compound 2 inhibited inflammatory responses via suppression of the expression of iNOS, resulting from activation of nuclear factor-kappaB (NF-κB) and phosphorylation of MAPKs (ERK and p38).

Anti-inflammatory and anti-cancer activity of citral: Optimization of citral-loaded solid lipid nanoparticles (SLN) using experimental factorial design and LUMiSizer®

Essential oils containing monoterpenes are widely used in pharmaceuticals and cosmetic products on account of their wide range of bioactive properties (including anti-cancer activity). Two monoterpenes (citral and geraniol) were firstly tested for their anti-inflammatory activity in a RAW 264.7 cell line, demonstrating citral to have enhanced capacity to inhibit NO production (ca. 84% for citral and 52% for geraniol at the lowest tested concentration of 5 µg/ml). As citral showed higher NO inhibitory activity than geraniol, to measure the level of cytotoxicity of citral, AlamarBlue reduction assay was run in two cell models (non-tumoral HaCaT and tumoral A431). Citral exhibited a strong cytotoxic effect in both cell lines, i.e. cell viability lower that 10% after 24 h exposure at 100 µg/ml of monoterpene. An optimized solid lipid nanoparticles (SLNs) formulation for citral was further developed by design of experiments (22 factorial design), followed by accelerated stability testing (LUMiSizer®). An optimal SLN composed of 1 wt% of citral, 4 wt% of lipid and 2.5 wt% surfactant were successfully produced by hot high pressure homogenization (hot HPH) showing a mean particle size (Z-Ave) of 97.7 nm and polydispersity index of 0.249. The produced formulations were analyzed in a high-end dispersion analyzer LUMiSizer® to characterize any demixing phenomena, demonstrating to be long-term stable at room temperature (25 °C), exhibiting very low instability indices (0.032 after production and 0.042 after one month of storage).

New C-2 diastereomers of flavanone glycosides conjugated with 3-hydroxy-3-methylglutaric acid from the pericarp of Citrus grandis (L.) Osbeck

Two new 3-hydroxy-3-methylglutaryl (HMG) flavanone 7-O-diglycosides, cigranosides A and B (1 and 2), the known naringenin 7-(2′′-α-rhamnosyl-6′′-(3′′′′-hydroxy-3′′′′-methylglutaryl)-glucoside (melitidin, 3), their common biosynthetic precursor flavanone 7-O-diglycoside (naringin, 4), and one known flavone 7-O-diglycoside (rhoifolin, 5) were isolated from the pericarp of Citrus grandis (L.) Osbeck. The structures of these compounds were elucidated by spectroscopic and chemical techniques. The relative ratios and absolute configurations of the C-2 diastereomers of compounds 1, 2 and 4 were determined by online normal-phase HPLC-CD using a Chiralcel column. The absolute configuration of the HMG fragment in compounds 1–3 was assigned to be S through spectroscopic analysis of the mevalonamide obtained by amidation and reduction of the HMG moiety. The NO inhibitory activities of compounds 1–5 were evaluated using lipopolysaccharide-induced RAW264.7 cells. Compounds 1–5 were not cytotoxic to RAW264.7 cells at 10 μM.

Furan fragment isomerized mexicanolide-type Limonoids from the stem barks of Khaya senegalensis

Four new mexicanolide-type limonoids with isomerized furan fragment khaysenelides G–J (1–4) were isolated from the stem barks of Khaya senegalensis. Their structures were elucidated on the basis of (1D and 2D) NMR and HRESIMS, and the normal furan rings in 1-4 were isomerized to hydroxybutenolide moieties. Bioactivities screening of new compounds indicated that 1 showed potent cytotoxicities against MDA-MB-231 and HepG2 human cancer cell lines with IC50 values of 6.02 and 8.98 μM, and significant NO inhibitory activities in LPS-activated RAW 264.7 macrophages with IC50 values of 3.51 μM.