A new megastigmane from Kalanchoe tubiflora (Harvey) Hamet

One new megastigmane, (6S,7R,8R,9S)-6-oxaspiro-7,8-dihydroxymegastigman-4-en-3-one (1) (tubiflorone, 1), and ten known compounds were isolated and characterized from the EtOH extract of Kalanchoe tubiflora (Harvey) Hamet. Structures of these isolates were assigned based on spectroscopic analyses that included 1D and 2D NMR techniques, such as HMQC, HMBC, and NOESY. The anti-inflammatory activities of selected isolated compounds (1–6 and 9–11) were evaluated as inhibitory activities against lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW264.7 cell lines. Compounds 1–4, 6, 9, and 11 possessed nitric oxide inhibitory activity with IC₅₀ values ranging from 15.1 ± 0.9 to 98.9 ± 1.3 μM.     

Tanzawaic acid derivatives from a marine isolate of Penicillium sp. (SF-6013) with anti-inflammatory and PTP1B inhibitory activities

Chemical investigation of a marine-derived fungus Penicillium sp. SF-6013 resulted in the discovery of a new tanzawaic acid derivative, 2E,4Z-tanzawaic acid D (1), together with four known analogues, tanzawaic acids A (2) and D (3), a salt form of tanzawaic acid E (4), and tanzawaic acid B (5). Their structures were mainly determined by analysis of NMR and MS data, along with chemical methods. Preliminary screening for anti-inflammatory effects in lipopolysaccharide (LPS)-activated microglial BV-2 cells showed that compounds 1, 2, and 5 inhibited the production of nitric oxide (NO) with IC₅₀ values of 37.8, 7.1, and 42.5 μM, respectively. Compound 2 also inhibited NO production in LPS-stimulated RAW264.7 murine macrophages with an IC₅₀ value of 27.0 μM. Moreover, these inhibitory effects correlated with the suppressive effect of compound 2 on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW264.7 and BV2 cells. In addition, compounds 2 and 5 significantly inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with the same IC₅₀ value (8.2 μM).     

Novel degraded polycyclic polyprenylated acylphloroglucinol and new polyprenylated benzophenone from Hypericum sampsonii

Norhypersampsone A (1), a novel degraded polycyclic polyprenylated acylphloroglucinol (PPAP) derivative, 3-(2-hydroxy-7-methyl-3-methyleneoct-6-enyl)-5-isoprenyl-2,4,6-trihydroxybenzophenone (2), a new polyprenylated benzophenone derivative, and nine known compounds (3–11) were isolated from Hypericum sampsonii. Their structures were elucidated by comprehensive spectroscopic techniques. Compound 1 represents a novel cyclohexenone monocyclic-PPAP formed by losing the fragment of C-2–C-4 and the side chains at C-3 and C-5 in the phloroglucinol ring. The results of the inhibitory effects of compounds 1–11 on the nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages showed that compounds 1, 6–8, and 10 exhibited weak activities with IC₅₀ values in the range of 20.3–37.1 μM.     

Bioactive chemical constituents from the root bark of Morus australis

Two new pyranoflavonoids, morustralins A (1) and B (2), a new natural benzene derivative, one benzenoid (Z)-1-hydroxy-4-(2-nitroethenyl)benzene (3), and thirty known compounds were isolated and characterized from the root bark of Morus australis. The structures of the new compounds were established from spectroscopic and spectrometric analyses. Ten isolates (1–10) were examined for inhibitory effects on adenosine diphosphate (ADP)-, arachidonic acid (AA)-, and platelet-aggregating factor (PAF)-induced platelet aggregation. Among the tested compounds, compound 3 displayed the most significant inhibition of ADP- and AA-induced platelet aggregation with IC₅₀ values of 9.76 ± 5.54 and 9.81 ± 2.7 μM, respectively. In addition, eight purified compounds (3–10) were examined for inhibition of nitric oxide (NO) production in RAW 264.7 cells and six compounds (3–8) displayed significant inhibitory effects with IC₅₀ values ranging from 2.1 ± 0.3 to 6.3 ± 0.6 μM.     

Anti-inflammatory abietane diterpenoids from the seeds of Podocarpus nagi

In searching for naturally occurring anti-inflammatory agents, three new abietane-type diterpenoids, named 16-hydroxylambertic acid (1), 7-oxo-18-hydroxyferruginol (2), and 5α,12-dihydroxy-6-oxa-abieta-8,11,13-trien-7-one (3), were isolated from the seeds of Podocarpus nagi, together with three known compounds. The structures of the new compounds were elucidated by extensive analysis of NMR and HR-ESIMS data. All the new compounds were tested for nitric oxide (NO) inhibitory activities on lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Compound 1 significantly inhibited NO production with IC₅₀ value of 5.38 ± 0.17 μM, and suppressed inducible NO synthase (iNOS) expression in a dose-dependent manner, which were mediated through inhibiting the mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) activation.     

New flavone and eudesmane derivatives from Lawsonia inermis and their inhibitory activity against NO production

A new flavone derivative, 7-hydroxy-3,5-dimethoxy-6,8-dimethylflavone (1) and a new eudesmane derivative, eudesmane-4β,7α-diol (2), have been isolated from the aerial part of Lawsonia inermis, together with ten known compounds (3–12). The structures of two new compounds were determined through spectroscopic and MS analyses. All compounds were evaluated for their inhibitory effects on Nitric Oxide production in LPS-stimulated RAW264.7 cells and compounds 3, 4, 6, 7, 9, and 10 showed inhibition with IC₅₀ values of 8.11, 2.32, 1.87, 7.72, 2.18, and 6.34 μg/mL, respectively.     

Anti-inflammatory activity of benzophenone and xanthone derivatives isolated from Garcinia (Clusiaceae) species

Species of the genus Garcinia have been the source of many benzophenone and xanthone derivatives. Recent data regarding potent biological properties of natural compounds in Garcinia species led us to investigate the in vitro anti-inflammatory effect of three known xanthones, lichexanthone (1), 1,3,6,7-tetrahydroxyxanthone (2), 1,3,5,6-tetrahydroxyxanthone (3), two new xanthones 1-hydroxy-3,6,7-tri-O,O,O-triprenylxanthone (4), 1,6-dihydroxy-3,7-di-O,O-diprenylxanthone (5) and two benzophenones isoxanthochymol (6), guttiferone E (7), isolated from Garcinia nobilis and Garcinia punctata. The Griess assay was used for the measurement of nitric oxide (NO) production in RAW264.7 macrophages and the ferrous oxidation-xylenol orange assay was used to determine the 15-lipoxygenase (15-LOX) inhibitory activity. All the compounds had inhibitory effect on 15-LOX activity to different extents. Compound (7) had the highest anti-LOX activity with an IC₅₀ value of 43.05 μg/mL. At the highest studied concentration (25 μg/mL), compound (4) had the most potent inhibitory activity against NO release with a% of inhibition of 95.42% and less cytotoxic effect on RAW264.7 cells (% of cell viability of 81.40).The results presented here suggest that 1,3,5,6-tetrahydroxyxanthone (3) and guttiferone E (7) are promising inhibitors of NO production and 15-LOX activity. Further studies should be considered in order to elucidate the mechanism by which these compounds exert their inhibitory activities.     

Flavonoid glycosides from Barringtonia acutangula

Using various chromatographic separation techniques, ten flavonoid glycosides, including six new compounds namely barringosides A?F (1–6), were isolated from a methanol extract of the Barringtonia acutangula leaves. The structure elucidation was confirmed by spectroscopic analyses, including 1D and 2D NMR, and HR ESI MS. Their inhibitory effects on LPS-induced NO production in RAW264.7 cells were also evaluated. Among the isolated compounds, quercetin 3-O-β-d-(6-p-hydroxybenzoyl)galactopyranoside (9) showed significant effect with an IC₅₀ of 20.00 ± 1.68 µM. This is the first report of these flavonoid glycosides from Barringtonia genus and their inhibition on LPS-induced NO production in RAW264.7 cells was reported here for the first time.     

Withaphysalin-type withanolides from Physalis minima

Nine new withaphysalin-type withanolides (1–9), named physaminimins (G-O) were isolated from the whole plants of Physalis minima Linn. The structures of these compounds were elucidated based on spectroscopic methods (1D NMR, HSQC, HMBC, ROESY) and HRESIMS. Physaminimins G, H, and K showed inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in a macrophage (RAW264.7) cells with IC₅₀ values of 17.41 ± 1.04, 36.33 ± 1.95 and 21.48 ± 1.67 μM, respectively.     

Anti-inflammatory components of Euphorbia humifusa Willd.

Two new compounds, euphorbinoside (1) and dehydropicrorhiza acid methyl diester (2), along with 24 known compounds (3–26) were isolated from Euphorbia humifusa Willd. The effects of these compounds on soluble epoxide hydrolase (sEH) inhibitory activity were evaluated. Flavonoid compounds (10–21) exhibited high sEH inhibitory activity. Among them, compounds 12, 13, and 19 greatly inhibited sEH enzymatic activity, with IC₅₀ values as low as 18.05 ± 1.17, 18.64 ± 1.83, and 17.23 ± 0.84 μM, respectively. In addition, the effects of these compounds on lipopolysaccharide (LPS)-induced nitric oxide (NO) and tumor necrosis factor alpha (TNF-α) production by RAW 264.7 cells were investigated. Compounds 3–6, 8, 18, 20–23, and 25–26 inhibited the production of both NO and TNF-α, with IC₅₀ values ranging from 11.1 ± 0.9 to 45.3 ± 1.6 μM and 14.4 ± 0.5 to 44.5 ± 1.2 μM, respectively.     

Four new sesquiterpenoids as natural nitric oxide (NO) inhibitors from the rhizomes of Curcuma phaeocaulis

A new norsesquiterpene named phaeocaulisin N (1), and three new guaiane-type sesquiterpenes named phaeocaulisins O–Q (2–4), together with a known norsesquiterpene (5) were isolated from the rhizomes of Curcuma phaeocaulis. Their structures were established based on extensive spectroscopic analysis. Compounds 1 and 5, as far as we know, are the first example of 13-norguaiane-type sesquiterpenes isolated from the genus Curcuma. All of the isolated compounds were tested for inhibitory activity against LPS-induced nitric oxide production in RAW 264.7 macrophages. Compound 1 showed strong inhibitory activity on nitric oxide production with IC₅₀ value of 3.58 ± 0.17 μM.     

Triterpenoid saponins from Clematis chinensis and their inhibitory activities on NO production

Four new triterpenoid saponins, clematochinenoside H–K (1–4), and five known structures (5–9), were isolated from the roots and rhizomes of Clematis chinensis. Their structures were elucidated on the basis of spectroscopic evidence and hydrolysis products. All isolates were evaluated for inhibitory effects against nitric oxide (NO) production in LPS-induced RAW 246.7 macrophages. Monodesmosidic saponins (1–3, 5, and 6) with a free carboxylic acid function at C-28 exhibited potent inhibitory activities with IC₅₀ values in the range of 12.9–32.3 μM, where as bisdesmosidic saponin (4, and 7–9) showed modest inhibitory effects with the inhibition ratios (%) from 39.9 to 59.0 at 50 μM. In addition, the hydroxyl group at C-21 showed negative effect on the NO production inhibitory activity.     

Chemical constituents of Ligularia alticola Worosch. leaves and their biological activities

Seven eremophilane-type sesquiterpenes (1–7), six cycloartane derivatives (8–13) and α-amyrin acetate (14) were isolated from the leaves of the far-eastern plant Ligularia alticola Worosch. (Family Asteraceae). (4S,5R,8S,10R)-8-Ethoxyeremophil-7(11)-en-12(8)-olide (1), 8α,11-epidioxy-8β-methoxyeremophil-6-ene (2) and 29-norcycloartan-3α-ol (8) have not been previously reported. Fukinone α-epoxide (3) was isolated for the first time from a natural source. The structures of all the compounds were established by the extensive analysis of their 1D and 2D NMR spectra and HR ESI mass spectrometry. The absolute stereochemistry of 1 was determined by comparison of theoretical and experimental ECD spectra with the application of B3LYP-TDDFT and B3LYP-GIAO calculations as well as by NMR spectroscopy. Compound 1 showed cytotoxic action against human cancer HL-60, Raji, and THP-1 cell lines (IC₅₀ 12.6, 6.0 and 6.9 μM, respectively). Compounds 2 and 4 demonstrated significant cytotoxic activities against HL-60 (IC₅₀ 2.8 and 5.8 μM, respectively) and Raji cells (IC₅₀ 2.9 and 4.2 μM, respectively). Compound 6 was cytotoxic against Raji cells (IC₅₀ 4.6 μM). None of tested compounds were cytotoxic against RAW 264.7 cells. Compounds 1 and 4–7 significantly decreased intracellular ROS levels, induced by endotoxic LPS from Escherichia coli in RAW 264.7 murine macrophages.     

Inhibitory constituents of the heartwood of Dalbergia odorifera on nitric oxide production in RAW 264.7 macrophages

Two new isoflavanones (1 and 13), along with 25 known compounds (2–12, 14–27), were isolated from the EtOAc-soluble fraction of the heartwood of Dalbergia odorifera by following their potential to inhibit the LPS-induced nitric oxide production in RAW 264.7 cells. The structures of the isolated compounds were established by spectroscopic data such as ¹D, ²D NMR and MS spectrometry. Among the isolated compounds, (2S)-pinocembrin (26), showed the most potent inhibitory effect with IC₅₀ value of 18.1 μM.     

Rubiyunnanins C-H, cytotoxic cyclic hexapeptides from Rubia yunnanensis inhibiting nitric oxide production and NF-κB activation

Six new (rubiyunnanins C–H, 1–6) and five known (7–11) cyclic hexapeptides were isolated from the roots of Rubia yunnanensis (Franch.) Diels. The structures and stereochemistry of 1–6 were established by extensive spectroscopic analyses and chemical methods. All compounds (1–11) not only exhibited cytotoxic activities against a panel of eleven cancer cell lines with IC₅₀ values ranging from 0.001 to 56.24 μM, but also exerted inhibitory activities against nitric oxide (NO) production in LPS and IFN-γ-induced RAW 264.7 murine macrophages with IC₅₀ values ranging from 0.05 to 12.68 μM. Furthermore, this is the first time it is being reported that compounds 2 and 7–10 significantly inhibited TNF-α-induced NF-κB activation in HEK-293-NF-κB luciferase stable cells with IC₅₀ values of 35.07, 0.03, 1.69, 12.64 and 1.18 μM, respectively.     

Identification and biological evaluation of flavonoids from the fruits of Prunus mume

This Letter describes the identification of potent antioxidant and anti-osteoporosis agents from the fruits of Prunus mume. From the methanol extract, a novel flavan dimer, characterized as 2β,3β-epoxy-5,7,4′-trihydroxyflavan-(4α → 8)-epicatechin (1), was isolated along with five known flavonoids (2–6). Their structures were determined based on extensive spectroscopic analysis, including IR, HRESIMS, 1D- and 2D-NMR, and CD spectra. The antioxidant activities of compounds 1–6 were evaluated in terms of their peroxyl radical-scavenging (Trolox equivalent) and reducing capacities. All isolates showed potent peroxyl radical-scavenging and reducing activities at concentrations of 1–10 μM. Among them, compounds 1 and 2 were the most active at 1 μM. Anti-osteoporosis activities were investigated using both murine osteoblastic MC3T3-E1 cells and osteoclastic RAW 264.7 cells. Compounds 2, 3, and 6 significantly stimulated the differentiation of osteoblastic MC3T3-E1 cells to increase collagen synthesis or mineralization functions of osteoblasts. Compounds 1, 3, 4, and 6 significantly suppressed tartrate-resistant acid phosphatase (TRAP) activity in receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastic RAW 264.7 macrophage cells.     

Hypocreaterpenes A and B,cadinane-type sesquiterpenes from a marine-derived fungus,Hypocreales sp.

Two new cadinane-type sesquiterpenes, hypocreaterpenes A (1) and B (2), along with five known compounds (3–7) were isolated from a marine-derived fungus Hypocreales sp. strain HLS-104 isolated from a sponge Gelliodes carnosa. Their structures were determined by a combination of spectroscopic methods. All compounds were tested for the inhibitory effects on the nitric oxide (NO) production in lipopolysaccharide (LPS)-treated RAW264.7 cells. Among them, compounds 3 and 6 showed moderate anti-inflammatory activity with average maximum inhibition (E_max) values of 10.22% and 26.46% at 1 μM, respectively.     

Potential anti-inflammatory phenolic glycosides from the medicinal plant Moringa oleifera fruits

Bioassay-guided isolation and purification of the ethyl acetate extract of Moringa oleifera fruits yielded three new phenolic glycosides; 4-[(2′-O-acetyl-α-l-rhamnosyloxy) benzyl]isothiocyanate (1), 4-[(3′-O-acetyl-α-l-rhamnosyloxy)benzyl]isothiocyanate (2), and S-methyl-N-{4-[(α-l-rhamnosyloxy)benzyl]}thiocarbamate (3), together with five known phenolic glycosides (4–8). The structures of the new metabolites were determined on the basis of spectroscopic analyses including 1D- and 2D-NMR and mass spectrometry. The anti-inflammatory activity of isolated compounds was investigated with the lipopolysaccharide (LPS)-induced murine macrophage RAW 264.7 cell line. It was found that 4-[(2′-O-acetyl-α-l-rhamnosyloxy)benzyl]isothiocyanate (1) possessed potent NO–inhibitory activity with an IC₅₀ value of 1.67 μM, followed by 2 (IC₅₀ = 2.66 μM), 4 (IC₅₀ = 2.71 μM), and 5 (IC₅₀ = 14.4 μM), respectively. Western blots demonstrated these compounds reduced LPS-mediated iNOS expression. In the concentration range of the IC₅₀ values, no significant cytotoxicity was noted. Structure–activity relationships following NO-release indicated: (1) the isothiocyanate group was essential for activity, (2) acetylation of the isothiocyanate derivatives at C-2′ or at C-3′ of rhamnose led to higher activity, (3) un-acetylated isothiocyanate derivatives displayed eight times less activity than the acetylated derivatives, and (4) acetylation of the thiocarbamate derivatives enhanced activity. These data indicate compounds 1, 2, 4 and 5 are responsible for the reported NO-inhibitory effect of Moringa oleifera fruits, and further studies are warranted.     

The regulation of inflammatory cytokine secretion in macrophage cell line by the chemical constituents of Rhus sylvestris

In our preliminary screening study on the anti-inflammatory activity, eight triterpenes, one sterol, and one chalcone were isolated from the CH₂Cl₂-soluble extract of the stems and leaves of Rhus sylvestris Siebold and Zucc (Anacardiaceae). On the basis of their spectroscopic data, these compounds were identified as 10α-cucurbitadienol (1), glut-5-en-3-ol (2), β-amyrin acetate (3), β-amyrin (4) and lupeol (5), cycloart-24-en-3-one (6), cycloart-25-en-3,24-dione (7), 24-hydroxycycloart-25-en-3-one (8), β-sitosterol (9), and 2′-hydroxy-4,4′-dimethoxychalcone (10). All of them were isolated from this plant for the first. Furthermore, the compounds in non-cytotoxic concentrations (0–1.0 μM) were tested for their ability to block inflammatory cytokine secretion in the presence of LPS in the murine RAW264.7 macrophage cell line. Among the compounds that were tested, compounds 8 and 9 reduced the LPS-induced secretion of IL-6, as well as TNF-α, in a mouse RAW264.7 macrophage cell line. Moreover, compounds 2, 3, 7, and 10 specifically diminished only the secretion of TNF-α even in 0.01 μM concentrations. It is thus suggested that they are potential therapeutics of TNF-α-related diseases and conditions, such as transplant rejection, type II diabetes, and atherosclerosis.