Nitric Oxide Production Inhibitory Activity Research Articles

New 19(10 → 9)abeo-euphane-type triterpenoids from Trichilia dregeana leaves and NO production inhibitory activities

Phytochemical investigation of the EtOAc soluble fraction from leaves of Trichilia dregeana Sond. (Meliaceae) afforded naturally rare four new pentacyclic triterpenoids (1–4), together with five known pentacyclic analogs (5–8, and 11) and two steroids (9 and 10). Their structures were elucidated by extensive spectroscopic techniques such as 1D and 2D NMR and HRESIMS data analyses. The absolute configuration of 1 was determined by using the single-crystal X-ray diffraction analysis. The nitric oxide (NO) production inhibitory assay indicated that the EtOAc fraction as well as 4 and 7 inhibited the NO production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells with the IC50 values of 83.53 μg/mL and 81.31 and 85.71 μM, respectively. Compounds 1–4 are rare 19(10 → 9)abeo-euphane-type triterpenoids bearing a 3,10-ether bridge. To the best of our knowledge, this study is the first isolation of triterpenoids with the 3,10-ether bridge in their skeleton from the genus Trichilia, providing new insights into the chemodiversity of the terpenoids in T. dregeana.

Structure-activity relationship of anti-inflammatory meroterpenoids isolated from Dictyopteris polypodioides in RAW264 cells.

In this study, we explored anti-inflammatory compounds from the brown alga Dictyopteris polypodioides and isolated 7 meroterpenoids. Their anti-inflammatory activities were evaluated using the lipopolysaccharide (LPS)-stimulated mouse macrophage cell line, RAW264. Yahazunol (1) exhibited similar nitric oxide (NO) production inhibitory activity as zonarol (2), which has previously been shown to be an anti-inflammatory compound. Yahazunol (1), zonarol (2), and isozonarol (3) inhibited not only nitric oxide production but also inducible nitric oxide synthase (iNOS), interleukin-6 (IL6), and C-C motif chemokine ligand 2 (CCL2) mRNA expression in RAW264 cells. The structure-activity relationships of the 11 compounds, including their synthetic analogs, revealed the significance of the hydroquinone moiety in the anti-inflammatory activity of these sesquiterpenoids in RAW264 cells. Diacetylated zonarol (9) exhibited an activity comparable to that of zonarol as a result of intracellular deacetylation. These results provide new insights into the anti-inflammatory activity of hydroquinone-containing natural products.

Identification and nitric oxide production inhibitory activity of phenolic derivatives from the trunks of Gnetum latifolium

Phytochemical investigation of the trunks from Gnetum latifolium led to the isolation of a novel phenolic glucoside, 2E-2,4-di-(3,4-dihydroxyphenyl)but-2-en-1-yl-O-β-D-glucopyranoside (1), along with five known stilbene derivatives (2–6). Their structures were determined mainly using high-resolution electrospray ionisation mass spectrometry and nuclear magnetic resonance spectroscopic analyses, followed by comparisons of observed spectral data with reported values. The novel compound 1 in G. latifolium was found to be useful as a chemotaxonomic marker. Biological evaluation revealed that compound 6 had remarkable inhibitory effects on nitric oxide production, with a half-maximal inhibitory concentration (IC50) value of 4.85 ± 0.20 µM, which was much higher than that of the positive control dexamethasone (IC50 = 14.20 ± 0.54 µM).

3D and 2D-QSAR Studies on Natural Flavonoids for Nitric Oxide Production Inhibitory Activity

Background: Nitric oxide (NO), an important second messenger molecule, regulates numerous physiological responses, while excessive NO generates negative effects on the circulatory, nervous and immune systems. Recently, some natural flavonoids were reported to possess the capability of inhibiting LPS-induced NO production. To fully understand the nature of their own NO inhibitory activity, it is necessary to address the structural requirements of flavonoids as NO inhibitors. Objective: The objective of this work was to develop efficient QSAR models for predicting the NOinhibitory activity of new flavonoids and improving insights into the critical properties of the chemical structures that were required for the ideal NO production inhibitory activities. Methods: To provide insights into the structural basis of flavonoids as NO inhibitors, 3D quantitative structure-activity relationship (3D-QSAR) and 2D-QSAR models were developed on a dataset of 55 flavonoids using comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA) and hologram quantitative structure-activity relationship (HQSAR) approaches. method: CoMFA, CoMSIA combining HQSAR methods were employed on a series of flavonoids to generate 3D and 2D-QSAR models. Results: The statistically significant models for CoMFA, CoMSIA and HQSAR resulted in crossvalidated coefficient (q2) values of 0.523, 0.572 and 0.639, non-cross-validated coefficient (r2) values of 0.793, 0.828 and 0.852, respectively. The robustness of these models was further affirmed using a test set of 18 compounds, which resulted in predictive correlation coefficients (r2 pred) of 0.968, 0.954 and 0.906. Furthermore, the models-derived contour maps were appraised for activity trends for the molecules analyzed. result: Comparative Molecular Field Analysis (CoMFA), Comparative Molecular Similarity Indices Analysis (CoMSIA) combining hologram quantitative structure-activity relationship (HQSAR) methods were employed on a series of flavonoids to generate 3D and 2D-QSAR models. Result: The obtained models can be used to predict the activities of new flavonoids and identify the key structural features affecting the NO inhibitory activities. Conclusion: The 3D and 2D-QSAR models constructed in this paper were efficient in estimating the NO inhibitory activities of flavonoids and facilitating the design of flavonoid-derived NO production inhibitors. other: none

The most commonly used spices in Thai traditional medicine: in vitro evaluation of anti-hyperglycemic, antioxidant, polyphenol content, and nitric oxide production inhibitory activities

Background and purpose: Diabetes mellitus is a persistent hyperglycemic condition. Thai cuisine and medicine incorporate spices: nutmeg, mace, clove buds, cardamom, cinnamon, and coriander. The in vitro impacts of these spices on anti-diabetic, antioxidant, anti-inflammatory, and total phenolic and flavonoid content were assessed. Experimental approach: Alpha-amylase and alpha-glucosidase inhibition assays were conducted. Antioxidant potential was measured through DPPH and ABTS assays. Anti-inflammatory activity was determined by inhibiting nitric oxide generation in RAW 264.7 cells. Total phenolic content was quantified using the Folin Ciocalteu method, while total flavonoid content was estimated via the aluminum chloride colorimetric method. Findings/Results: Ethanolic and aqueous extracts of a blend of spices (Siam cardamom, nutmeg, mace, and clove buds), denoted as 4-GlurE and 4-GlurA, displayed concentration-dependent inhibition of alpha-glucosidase, with IC50 values of 0.373 and 0.435 mg/mL, respectively. 4-GlurE and 4-GlurA exhibited antioxidant activity, by ABTS·+ radical and DPPH scavenging capabilities. 4-GlurE demonstrated anti-inflammatory potential by reducing nitric oxide generation (IC50: 43.95 ± 2.47 μg/mL). 4-GlurE and 4-GlurA possessed total phenolic content (TPC) of 122.47 ± 1.12 and 148.72 ± 0.14 mg GAE/g, respectively. 4-GlurE exhibited a higher total flavonoid content (TFC) compared to the aqueous extract (340.33 ± 4.77 and 94.17 ± 3.36 mg QE/g). Cinnamon and clove aqueous extracts were more potent than acarbose in alpha-glucosidase inhibition with the highest antioxidant activity. Polyphenol levels (TPC and TFC) exhibited strong correlations with antioxidant capacity. Conclusions and implications: Findings are consistent with the traditional use of 4-Glur, with cinnamon, for diabetes prevention and treatment.

Chemical constituents from the medicinal herb-derived fungus Chaetomium globosum Km1226

BackgroundEndophytic fungi have proven to be a rich source of novel natural products with a wide-array of biological activities and higher levels of structural diversity.ResultsChemical investigation on the liquid- and solid-state fermented products of Chaetomium globosum Km1226 isolated from the littoral medicinal herb Atriplex maximowicziana Makino resulted in the isolation of compounds 1–14. Their structures were determined by spectroscopic analysis as three previously undescribed C13-polyketides, namely aureonitol C (1), mollipilins G (2), and H (3), along with eleven known compounds 4–14. Among these, mollipilin A (5) exhibited significant nitric oxide production inhibitory activity in LPS-induced BV-2 microglial cells with an IC50 value of 0.7 ± 0.1 µM, and chaetoglobosin D (10) displayed potent anti-angiogenesis property in human endothelial progenitor cells (EPCs) with an IC50 value of 0.8 ± 0.3 µM.ConclusionsThree previously unreported compounds 1–3 were isolated and identified. Mollipilin A (5) and chaetoglobosin D (10) could possibly be developed as anti-inflammatory and anti-angiogenic lead drugs, respectively.

Antimycobacterial and nitric oxide production inhibitory activities of limonoids isolated from Trichilia lepidota subsp. schumanniana (Harms) T.D.Penn

Six previously undescribed intact limonoids together with four known compounds were isolated from the seeds of Trichilia lepidota subsp. schumanniana (Harms) T.D.Penn. Their structures were characterized based on one- and two-dimensional nuclear magnetic resonance spectra, infrared, ultraviolet, mass spectroscopy results, and optical rotation. All compounds were evaluated for their ability to inhibit nitric oxide production in cultures of RAW 264.7 macrophages stimulated by lipopolysaccharide, cytotoxicity and growth of Mycobacterium tuberculosis strains H37Rv and M299. The compounds 7-deacetyl-11β,12α-diacetoxy-14,15-epoxyazadirone (5) and walsurin E (9) were the most potent in inhibiting nitric oxide production, although the compounds 1-deshydroxy-12α-acetoxymunronin N (1) and 6α,12α-dihydroxyazadirone (6) also showed controlled potential of this mediator, in addition to being potent growth inhibitors of Mycobacterium tuberculosis H37RV and M299, without cytotoxicity interference. Ring intact limonoids isolated from Trichilia lepidota subsp. schumanniana seeds are a new source of bioactive substances that may be used in the future against diseases such as tuberculosis and other processes related to inflammation.

Four New Flavonoid C-Glycosides Isolated from Achyranthes aspera and Their Nitric Oxide Production Inhibitory Activities.

A chemical study of the methanol extract of the aerial parts of Achyranthes aspera led to the isolation of four new flavonoid C-glycosides (1-4) along with eight known analogs (5-12). Their structures were elucidated by a combination of spectroscopic data analysis, HR-ESI-MS, 1D and 2D NMR spectra. All the isolates were evaluated their NO production inhibitory activity in LPS-activated RAW264.7 cells. Compounds 2, 4, and 8-11 showed significant inhibition with IC50 values ranging from 25.06 to 45.25 μM, compared to that of the positive control compound, L-NMMA, IC50 value of 32.24 μM, whereas the remaining compounds were weak inhibitory activity with IC50 values over 100 μM. This is the first report of 7 from Amaranthaceae family, and 11 from the genus Achyranthes.

A new iridoid glucoside from the roots of Morinda officinalis

A new iridoid glucoside, moridoside (1), and nine known compounds, asperulosidic acid (2), 6-O-epi-acetylscandoside (3), geniposidic acid (4), 2-hydroxymethylanthraquinone (5), 2-hydroxymethyl-3-hydroxyanthraquinone (6), damnacanthol (7), lucidine-ω-methyl ether (8), 2-hydroxy-1-methoxyanthraquinone (9), and 3,8-dihydroxy-1,2-dimethoxyanthraquinone (10) were isolated from the methanol extract of Morinda officinalis How. roots. Their structural identification was carried out based on the spectroscopic evidence. All compounds were evaluated for their nitric oxide (NO) production inhibitory activities in LPS-stimulated RAW264.7 macrophages. Compounds 5-7 significantly inhibited the production of NO with IC50 values of 28.4, 33.6, and 30.5 μM, respectively.

Flavonoids from the Roots of Sophora flavescens and Their Potential Anti-Inflammatory and Antiproliferative Activities

The phytochemical investigation of the roots of the traditional Chinese medicinal plant Sophora flavescens led to the isolation of two novel prenylflavonoids with an unusual cyclohexyl substituent instead of the common aromatic ring B, named 4',4'-dimethoxy-sophvein (17) and sophvein-4'-one (18), and 34 known compounds (1-16, 19-36). The structures of these chemical compounds were determined by spectroscopic techniques, including 1D-, 2D-NMR, and HRESIMS data. Furthermore, evaluations of nitric oxide (NO) production inhibitory activity against lipopolysaccharide (LPS)-treated RAW264.7 cells indicated that some compounds exhibited obvious inhibition effects, with IC50 ranged from 4.6 ± 1.1 to 14.4 ± 0.4 μM. Moreover, additional research demonstrated that some compounds inhibited the growth of HepG2 cells, with an IC50 ranging from 0.46 ± 0.1 to 48.6 ± 0.8 μM. These results suggest that flavonoid derivatives from the roots of S. flavescens can be used as a latent source of antiproliferative or anti-inflammatory agents.

Natural Compounds Isolated from African Mistletoes (Loranthaceae) Exert Anti-Inflammatory and Acetylcholinesterase Inhibitory Potentials: In Vitro and In Silico Studies

Despite the medicinal uses of Phragmanthera capitata, Globimetula dinklagei and Tapinanthus bangwensis against memory loss, convulsions and pain, their efficacy against brain-dysfunction diseases and inflammation models has not yet been studied. Therefore, this study aims to investigate the anti-inflammatory and acetylcholinesterase (AChE) inhibitory potentials of their crude extracts and isolated natural compounds by combining in vitro and in silico experiments. Crude extracts and isolated compounds were tested in vitro for their AChE inhibitory activity by using Ellman’s method. Additionally, their anti-inflammatory activity was determined by evaluating the nitric oxide (NO) production inhibitory activity in lipopolysaccharide-stimulated RAW 264.7 macrophage cells and the 15-lipoxygenase (15-LOX) inhibitory activity by using the ferrous oxidation xylenol orange assay. Furthermore, the in silico efficacy of natural compounds was investigated against ten putative target enzymes relevant in Alzheimer’s disease (AD) pathogenesis and inflammation. It was found that the crude extracts had weak to moderate inhibitory potential against AChE, with the extract of T. bangwensis being the most active (50% inhibitory concentration (IC50) = 48.97 µg/mL). Six natural compounds, namely, 3-O-β-D-glucopyranosyl-28-hydroxy-α-amyrin (2), apigenin- 8-C-β-D-glucopyranoside (3), globimetulin B (5), globimetulin C (6), bangwaursene B (8) and 3β-acetoxy-11,12-epoxytaraxerol (9), were identified for the first time as having anti-AChE potential, among which (9) had the highest efficacy with an IC50 of 13.89 µM. Among the anti-AChE compounds, (5) was also efficient against NO production and 15-LOX, and the data are in agreement with the docking score. In summary, compounds (5) and (9) are the most prominent lead compounds that should be further tested experimentally against molecular targets of AD and inflammation.

Chemical Constituents and Bioactive Principles from the Mexican Truffle and Fermented Products of the Derived Fungus Ustilago maydis MZ496986.

To look in-depth into the traditional Mexican truffle, this study investigated the phytochemical and pharmacological properties of field-collected corn galls and the fermentate of its pathogen Ustilago maydis MZ496986. Here, we established the chemical profiles of both materials via the gradient HPLC-UV method and successfully identified six previously unreported chemical entities, ustilagols A-F (1-6), and 17 known components. Compounds 3, 5, and 9 exhibited potent nitric oxide production inhibitory activities in murine brain microglial BV-2 cells (IC50 = 6.7 ± 0.5, 5.8 ± 0.9, and 3.9 ± 0.1 μM) without cytotoxic effects. DIMBOA (9) also attenuates lipopolysaccharide (LPS)-stimulated NF-κB activation in RAW 264.7 macrophages (IC50 = 58.1 ± 7.2 μM). Ustilagol G (7) showed potent antiplatelet aggregation in U46619-stimulated human platelets (IC50 = 16.5 ± 5.3 μM). These findings highlighted the potential of corn galls and U. maydis MZ496986 fermentate as functional foods for improving inflammation-related discomforts and vascular obstruction.

Polypunctosides E-K: seven new steroidal saponins from Polygonatum punctatum Royle ex Kunth and their nitric oxide production inhibitory activities.

Polygonatum punctatum Royle ex Kunth is a high-value medicinal plant found in old natural forests. A phytochemical study on the roots of this plant led to the isolation of seven new steroidal saponins including four furostans (1-4) and three furospirostans (5-7). Their structures were elucidated as (25R)-26-O-(β-D-glucopyranosyl)-furost-5-ene-3β,17α,22α,26-tetraol 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (1), (25R)-26-O-(β-D-glucopyranosyl)-furost-5-ene-3β,14α,17α,22α,26-pentaol 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (2), (25R)-26-O-(β-D-glucopyranosyl)-furost-5-ene-22α-methoxy-3β,17α,26-triol 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (3), (25R)-26-O-(β-D-glucopyranosyl)-furost-5-ene-22α-methoxy-3β,17α,26-triol 3-O-[α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)]-[acetoxy-(→ 6)]-β-D-galactopyranoside (4), 26-O-(β-D-glucopyranosyl)-14α,17α-dihydroxynuatigenin 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (5), 26-O-(β-D-glucopyranosyl)-17α-hydroxynuatigenin 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (6), and 26-O-(β-D-glucopyranosyl)-14α-hydroxynuatigenin 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (7) by extensive spectroscopic analyses, including infrared, high-resolution electrospray ionization mass spectrometry, and one- and two-dimensional nuclear magnetic resonance spectroscopy. Compounds 1-7 inhibited nitric oxide production in lipopolysaccharide activated RAW264.7 cells with IC50 values ranging from 41.5 ± 3.2 to 62.2 ± 3.7µM, compared to 33.8 ± 2.6µM for the positive control compound L-NMMA.

Phytochemical constituents from Elsholtzia ciliata (Thunb.) Hyl. and their nitric oxide production inhibitory activities

A new megastigmane glycoside, (3S,4R,7E)-megastigma-5,7-diene-9-one-3,4-diol 3-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside (1) and a new cyanogenic glycosyl derivative, (S)-2-(6′-O-R-rosmarinoyl-β-D-glucopyranosyloxy)-phenylacetonitrile (2) were isolated from the methanol extract of the Elsholtzia ciliata together with twelve known compounds, 1-O-β-D-glucopyranosyl-2-hydroxy-4-allylbenzene (3), citrusin C (4), 1,2-di-O-β-D-glucopyranosyl-4-allylbenzene (5), manglieside B (6), 4-allyl-2-hydroxyphenyl 1-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (7), (-)-isolariciresinol 3α-β-D-glucopyranoside (8), 7R,8R-threo-4,7,9-trihydroxy-3,3′-dimethoxy-8-O-4′-neolignan-9′-O-β-D-glucopyranoside (9), 7R,8R-threo-4,7,9,9′-tetrahydroxy-3-methoxy-8-O-4′-neolignan-9′-O-β-D-glucopyranoside (10), cedrusin-4-O-β-D-glucopyranoside (11), icariside E3 (12), everlastoside L (13) and rosmarinic acid (14). Their chemical structures were elucidated on the basic of extensive 1D and 2D-NMR experiments, as well as their mass spectroscopic data. The absolute configurations of the compounds 1 and 2 were successfully indicated by both theoretical and calculated CD spectra. Compounds 3–7, 9 and 10 potential inhibited NO production in LPS-activated RAW264.7 cells with IC50 values of 6.71, 8.97, 12.38, 14.27, 16.13, 13.54, 16.27 µM, respectively, compared to that of the positive control of N G-monomethyl-L-arginine acetate (L-NMMA), IC50 = 32.51 µM.

Kadsindutalignans A–C: three new dibenzocyclooctadiene lignans from Kasura induta A.C.Sm. and their nitric oxide production inhibitory activities

Phytochemical study on the methanol extract of the stems and leaves of Kadsura induta led to the isolation of six dibenzocyclooctadiene lignans, including three new compounds named kadsindutalignans A–C (1–3), and three known ones, heteroclitalignan B (4), kadsuphilin C (5) and kadsulignan E (6). Their structures were elucidated based on extensive spectroscopic analyses, including HRESIMS, 1D- (1H NMR and 13C NMR), 2D-NMR (HSQC, HMBC, 1H-1H COSY and NOESY), and experimental circular dichroism (CD) spectra. All the isolates inhibited NO production in LPS-activated RAW264.7 cells with IC50 values in the range from 5.67 ± 0.54 µM to 38.19 ± 2.03 µM, compared to that of the positive control of N G-monomethyl-L-arginine acetate (L-NMMA) with an IC50 value of 8.90 ± 0.48 µM. Interestingly, the new compound 2 showed potential inhibition of NO production with an IC50 value of 5.67 ± 0.54 µM, which was higher than that of the positive control.

Divergent Synthesis of Nerolidol-type Sesquiterpenoids Produced by Soil Bacterium from an Identical Starting Material via Diepoxide Precursors: Stereochemical Revision and Absolute Configuration of a THF Natural Product

A divergent asymmetric synthesis of two nerolidol-type sesquiterpenoids with a five- or a six-membered ether ring was established from an identical commercially available trans,trans-farnesyl acetate through the cyclization of diepoxide precursors under simple acidic or neutral conditions, respectively. In addition, the relative configuration of a nerolidol-type sesquiterpenoid with a tetrahydrofuran ring was revised. Its absolute configuration was determined by its asymmetric synthesis and a modified Mosher’s analysis. Furthermore, the cytotoxicity and nitric oxide production inhibitory activity of the synthesized compounds were assessed.

Polyphenols from the Peels of Punica granatum L. and Their Bioactivity of Suppressing Lipopolysaccharide-Stimulated Inflammatory Cytokines and Mediators in RAW 264.7 Cells via Activating p38 MAPK and NF-κB Signaling Pathways.

Punica granatum L. (Punicaceae) is a popular fruit all over the world. Owning to its enriched polyphenols, P. granatum has been widely used in treating inflammation-related diseases, such as cardiovascular diseases and cancer. Twenty polyphenols, containing nine unreported ones, named punicagranins A–I (1–9), along with eleven known isolates (10–20), were obtained from the peels. Their detailed structures were elucidated based on UV, IR, NMR, MS, optical rotation, ECD analyses and chemical evidence. The potential anti-inflammatory activities of all polyphenols were examined on a lipopolysaccharide (LPS)-induced inflammatory macrophages model, which indicated that enhancing nitric oxide (NO) production in response to inflammation stimulated in RAW 264.7 cells was controlled by compounds 1, 3, 5–8, 10, 11, 14 and 16–20 in a concentration-dependent manner. The investigation of structure–activity relationships for tannins 6–8 and 12–20 suggested that HHDP, flavogallonyl and/or gallagyl were key groups for NO production inhibitory activity. Western blotting indicated that compounds 6–8 could down-regulate the phosphorylation levels of proteins p38 MAPK, IKKα/β, IκBα and NF-κB p65 as well as inhibit the levels of inflammation-related cytokines and mediators, such as IL-6, TNF-α, iNOS and COX-2, at the concentration of 30 μM. In conclusion, polyphenols are proposed to be the potential anti-inflammatory active ingredients in P. granatum peels, and their molecular mechanism is likely related to the regulation of the p38 MAPK and NF-κB signaling pathways.

Bioactive constituents isolated from the Sri Lankan endemic plant Artocarpus nobilis and their potential to use in novel cosmeceuticals

Two novel compounds, dicarbonyl ester (2) and artolankanin A (3) were isolated from the sequential ethyl acetate and ethanol extracts of stem bark of A. nobilis along with the known compounds, artonin E (1) and artobiloxanthone (4) by bioassay-guided fractionation using a combination of normal phase and size exclusion column chromatography. Their structures were elucidated by spectroscopic techniques, including NMR (1H, 13C, APT, 1H–1H COSY, HSQC, and HMBC), Mass, IR, and UV. The isolated compounds were evaluated for DPPH free radical scavenging activity, tyrosinase, elastase, hyaluronidase, and A5-lipoxygenase enzyme inhibitory activities lipopolysaccharide-induced nitric oxide production inhibitory activity in SIM-A9 microglial cells. Artonin E exhibited marked tyrosinase and A5-lipoxygenase enzyme inhibitory activities and NO inhibition activity in LPS-stimulated microglia cells having IC50 values of 60.92 ± 3.45, 56.38 ± 1.05, and 23.94 ± 1.08 µg/mL, respectively. Kinetic studies showed that the tyrosinase inhibitory activity of artonin E is via a noncompetitive inhibition mechanism. Further, artolankanin A and artobiloxanthone exhibited good A5-lipoxygenase enzyme inhibitory activity having IC50 values of 59.48 ± 1.06 and 62.45 ± 2.25 µg/mL, respectively. Insights from molecular docking and molecular dynamics simulations align with these experimental observations and propose plausible mechanisms of inhibition. Collectively these results suggest that these compounds have the potential to be used as depigmenting and anti-inflammatory agents.

Pandatonkinosides A and B: two new phenolic glycosides from the roots of Pandanus tonkinensis and their nitric oxide production inhibitory activities

Two new phenolic glycosides, 4-(3-hydroxypropyl)-2,6-dimethoxyphenol β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (1), trans-cinnamyl alcohol 9-O-(6′-O-β-D-apiofuranosyl)-β-D-glucopyranoside (2), together with nine known phenolic glycosides (3-11) were isolated from the roots of Pandanus tonkinensis. Their structures were determined by extensive analysis of HRESIMS and NMR spectral data, as well as by comparison of their spectral data (including CD spectra) with those reported in the literature. Compounds 1-4 and 6-11 inhibited NO production in LPS-activated RAW264.7 cells with IC50 values in the range from 0.80 ± 0.06 µM to 43.38 ± 3.92 µM, whereas compound 5 was inactive. The NO production inhibitory activities of compounds 1, 4, 8, and 10 with IC50 values of 10.16 ± 1.05, 0.80 ± 0.06, 1.10 ± 0.13, and 2.79 ± 0.21 µM, respectively, are as potent as that of the positive control of N G-monomethyl-L-arginine acetate (L-NMMA) with an IC50 value of 9.80 ± 0.78 µM.

Evaluation of antioxidant, enzyme inhibition, nitric oxide production inhibitory activities and chemical profiles of the active extracts from the medicinal and edible plant: Althaea officinalis

To develop the medicinal and edible plant resources of Althaea officinalis Linn in Europe and other places, this study concentrated on the bioactive ingredients of its different extracts. The phytochemical compositions of MeOH extracts were evaluated by UPLC-DAD-ESI-Q-TOF-MSn analysis. The in vitro antioxidant properties, enzymes inhibitory effects and nitric oxide (NO) production inhibitory activities of fractions obtained from the aerial parts of Althaea officinalis (APAO) were evaluated. The results identified 76 compounds, including 8 phenolic acids, 17 flavonoids, 6 coumarins, 9 triterpenes and 11 alkaloids. Fr. C-2 of APAO was found to have the highest TPC (175.8 ± 1.5 mg GAE/g) and TFC (466.9 ± 5.0 mg RE/g) with the highest antioxidant capacity in DPPH, ABTS, CUPRAC, FRAP and β-carotene bleaching assays. Fr. A showed noticeable inhibition of α-glucosidase with an IC50 value of 3.8 ± 0.1 μg/mL. However, Fr. B displayed stronger inhibitory activity on 5-lipoxygenase than quercetin, with the IC50 value of 8.4 ± 1.6 μg/mL. In addition, Fr. B also possessed potent inhibitory activities on NO production toward LPS-activated RAW 264.7 Cells with an IC50 value of 15.7 ± 1.6 μg/mL. Our findings suggest that different Althaea officinalis extracts may be considered sources of phenolic and flavonoid compounds with high potential as natural antioxidants, anti-inflammatory agents and blood sugar regulators. In addition, they can also be used in food and nutraceutical products with enhanced bioactivities.