Phytochemical studies on the rhizomes of Etlingera elatior have resulted in the isolation of 1,7-bis(4-hydroxyphenyl)-2,4,6-heptatrienone (1), demethoxycurcumin (2), 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one (3), 16-hydroxylabda-8(17),11,13-trien-15,16-olide (4), stigmast-4-en-3-one, stigmast-4-ene-3,6-dione, stigmast-4-en-6beta-ol-3-one, and 5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol. Compounds 1 and 4 are new, and their structures were elucidated by analysis of spectroscopic data. Diarylheptanoids 1-3 were found to inhibit lipid peroxidation in a more potent manner than alpha-tocopherol.
Phytochemical studies on rhizome of Etlingera elatior have resulted in the isolation of 1,7-bis(4-hydroxyphenyl)-2,4,6-heptatrienone (1), demethoxycurcumin (2), 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one (3), 16-hydroxylabda-8(17),11,13-trien-16,15-olide (4), stigmast-4-en-3-one (5), stigmast-4-ene-3,6-dione (6), stigmast-4-en-6b-ol-3-one (7), 5α,8α-epidioxyergosta-6,22-dien-3β-ol (8). 1 and 4 were new compounds. Compounds 5 and 7 displayed high antitumour-promoting activity. Ethyl acetate extract showed a very significant cytotoxic activity against CEM-SS and MCF-7 cell lines (4 μg/ml and 6.25 μg/ml respectively). The antitumour-promoting activity was determined by EBV-EA assay and cytotoxic activity was determined by MTT assay.
Many plant-derived natural compounds have been reported previously to inhibit the production of important pro-inflammatory mediators such as nitric oxide, prostaglandin E2, TNF-alpha and reactive oxygen species by suppressing inducible enzyme expression via inhibition of the mitogen-activated protein kinase pathway and nuclear translocation of critical transcription factors. This study evaluates the effects of atrovirinone [2-(1-methoxycarbonyl-4,6-dihydroxyphenoxy)-3-methoxy-5,6-di-(3-methyl-2-butenyl)-1,4-benzoquinone)], a benzoquinone that we have previously isolated from Garcinia atroviridis, on two cellular systems that are repeatedly used in the analysis of anti-inflammatory bioactive compounds, namely, RAW 264.7 macrophage cells and whole blood. Atrovirinone inhibited the production of both nitric oxide and prostaglandin E2 from LPS-induced and IFN-gamma-induced RAW 264.7 cells and whole blood, with inhibitory concentration (IC)50 values of 4.62 +/- 0.65 and 9.33 +/- 1.47 micromol/L, respectively. Analysis of thromboxane B2 (TXB2) secretion from whole blood stimulated by either the cyclooxygenase (COX)-1 or the COX-2 pathway showed that atrovirinone inhibits the generation of TXB2 by both pathways, with IC50 values of 7.41 +/- 0.92 and 2.10 +/- 0.48 micromol/L, respectively. Analysis of IC50 ratios showed that atrovirinone was more COX-2 selective in its inhibition of TXB2, with a ratio of 0.32. Atrovirinone also inhibited the generation of intracellular reactive oxygen species and the secretion of TNF-alpha from RAW 264.7 cells in a dose-responsive manner, with IC50 values of 5.99 +/- 0.62 and 11.56 +/- 0.04 micromol/L, respectively. Lipoxygenase activity was also moderately inhibited by atrovirinone. Our results suggest that atrovirinone acts on important pro-inflammatory mediators possibly by the inhibition of the nuclear factor-kappaB pathway and also by the inhibition of the COX/lipoxygenase enzyme activity.
In a previous communication we showed that atrovirinone, a 1,4-benzoquinone isolated from the roots of Garcinia atroviridis, was able to inhibit several major proinflammatory mediators of inflammation. In this report we show that atrovirinone inhibits NO and PGE(2) synthesis through inhibition of iNOS and COX-2 expression. We also show that atrovirinone inhibits the secretion of IL-1beta and IL-6 in a dose dependent fashion whereas the secretion of IL-10, the anti-inflammatory cytokine, was enhanced. Subsequently we determined that the inhibition of proinflammatory cytokine synthesis and inducible enzyme expression was due to a dose-dependent inhibition of phosphorylation of p38 and ERK1/2. We also showed that atrovirinone prevented phosphorylation of I-kappaBalpha, which resulted in a reduction of p65NF-kappaB nuclear translocation as demonstrated by expression analysis. We conclude that atrovirinone is a potential anti-inflammatory drug lead that targets both the MAPK and NF-kappaB pathway.
Our preliminary screening has shown that curcumin derivative BDMC33 [2,6-bis(2,5-dimethoxybenzylidene)cyclohexanone] exerted promising nitric oxide inhibitory activity in activated macrophages. However, the molecular basis and mechanism for its pharmacological action is yet to be elucidated. The aim of this study was to investigate the anti-inflammatory properties of BDMC33 and elucidate its underlying mechanism action in macrophage cells. Our current study demonstrated that BDMC33 inhibits the secretion of major pro-inflammatory mediators in stimulated macrophages, and includes NO, TNF-α and IL-1β through interference in both nuclear factor kappaB (NF-κB) and mitogen activator protein kinase (MAPK) signaling cascade in IFN-γ/LPS-stimulated macrophages. Moreover, BDMC33 also interrupted LPS signaling through inhibiting the surface expression of CD-14 accessory molecules. In addition, the inhibitory action of BDMC33 not only restricted the macrophages cell (RAW264.7), but also inhibited the secretion of NO and TNF-α in IFN-γ/LPS-challenged microglial cells (BV-2). The experimental data suggests the inflammatory action of BDMC33 on activated macrophage-like cellular systems, which could be used as a future therapeutic agent in the management of chronic inflammatory diseases.
BACKGROUND AND PURPOSE: Andrographolide, the major phytoconstituent of Andrographis paniculata, was previously shown by us to have activity against breast cancer. This led to synthesis of new andrographolide analogues to find compounds with better activity than the parent compound. Selected benzylidene derivatives were investigated for their mechanisms of action by studying their effects on the cell cycle progression and cell death.
EXPERIMENTAL APPROACH: Microculture tetrazolium, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and sulphorhodamine B (SRB) assays were utilized in assessing the in vitro growth inhibition and cytotoxicity of compounds. Flow cytometry was used to analyse the cell cycle distribution of control and treated cells. CDK1 and CDK4 levels were determined by western blotting. Apoptotic cell death was assessed by fluorescence microscopy and flow cytometry.
KEY RESULTS: Compounds, in nanomolar to micromolar concentrations, exhibited growth inhibition and cytotoxicity in MCF-7 (breast) and HCT-116 (colon) cancer cells. In the NCI screen, 3,19-(2-bromobenzylidene) andrographolide (SRJ09) and 3,19-(3-chloro-4-fluorobenzylidene) andrographolide (SRJ23) showed greater cytotoxic potency and selectivity than andrographolide. SRJ09 and SRJ23 induced G(1) arrest and apoptosis in MCF-7 and HCT-116 cells, respectively. SRJ09 downregulated CDK4 but not CDK1 level in MCF-7 cells. Apoptosis induced by SRJ09 and SRJ23 in HCT-116 cells was confirmed by annexin V-FITC/PI flow cytometry analysis.
CONCLUSION AND IMPLICATIONS: The new benzylidene derivatives of andrographolide are potential anticancer agents. SRJ09 emerged as the lead compound in this study, exhibiting anticancer activity by downregulating CDK4 to promote a G(1) phase cell cycle arrest, coupled with induction of apoptosis.
Curcuma ochrorhiza ('temu putih') and C. heyneana ('temu giring') are two Zingiberaceous species which are commonly used in traditional medicine in Malaysia and Indonesia. Phytochemical investigations on these Curcuma species have resulted in the isolation of six sesquiterpenes, namely zerumbone (1), furanodienone (2), zederone (3), oxycurcumenol epoxide (4), curcumenol (5) and isocurcumenol (6), along with phytosterols stigmasterol and alpha-sitosterol. Compounds 1 and 2 were obtained for the first time for C. ochrorhiza while 4 was new to C. heyneana. The hexane extract of C. ochrorhiza and sesquiterpenes 1 and 3 showed very strong cytotoxicity activity against T-acute lymphoblastic leukaemia cells (CEM-SS), with IC(50) values of 6.0, 0.6 and 1.6 microg mL(-1), respectively. Meanwhile, constituents from C. heyneana (4-6) demonstrated moderate inhibition against CEM-SS in cytotoxic assay, with IC(50) values of 11.9, 12.6 and 13.3 microg mL(-1), respectively. The crude extracts and sesquiterpenes isolated were moderately active against certain bacteria tested in antimicrobial screening.
A bioassay-guided investigation of Melicope ptelefolia Champ ex Benth (Rutaceae) resulted in the identification of an acyphloroglucinol, 2,4,6-trihydroxy-3-geranylacetophenone or tHGA, as the active principle inhibiting soybean 15-LOX. The anti-inflammatory action was also demonstrated on human leukocytes, where the compound showed prominent inhibitory activity against human PBML 5-LOX, with an IC(50) value of 0.42 μM, very close to the effect produced by the commonly used standard, NDGA. The compound concentration-dependently inhibited 5-LOX product synthesis, specifically inhibiting cysteinyl leukotriene LTC(4) with an IC(50) value of 1.80 μM, and showed no cell toxicity effects. The anti-inflammatory action does not seem to proceed via redox or metal chelating mechanism since the compound tested negative for these bioactivities. Further tests on cyclooxygenases indicated that the compound acts via a dual LOX/COX inhibitory mechanism, with greater selectivity for 5-LOX and COX-2 (IC(50) value of 0.40 μM). The molecular features that govern the 5-LOX inhibitory activity was thus explored using in silico docking experiments. The residues Ile 553 and Hie 252 were the most important residues in the interaction, each contributing significant energy values of -13.45 (electrostatic) and -5.40 kcal/mol (electrostatic and Van der Waals), respectively. The hydroxyl group of the phloroglucinol core of the compound forms a 2.56Å hydrogen bond with the side chain of the carboxylate group of Ile 553. Both Ile 553 and Hie 252 are crucial amino acid residues which chelate with the metal ion in the active site. Distorting the geometry of these ligands could be the reason for the inhibition activity shown by tHGA. The molecular simulation studies supported the bioassay results and served as a good model for understanding the way tHGA binds in the active site of human 5-LOX enzyme.
Nine derivatives of three natural diarylheptanoids, curcumin, demethoxycurcumin and bisdemethoxycurcumin, were prepared. Their antioxidant, free radical scavenging, nitric oxide (NO) inhibitory and cytotoxic activities were evaluated and compared with those of the respective natural compounds. Curcumin (1), demethoxycurcumin (2), demethyldemethoxy-curcumin (C3), diacetyldemethoxycurcumin (AC2) and triacetyldemethylcurcumin (AC5) exhibited higher antioxidant activity than quercetin while products from demethylation of 1 and 2 exhibited higher free radical scavenging activity. Compounds AC2 and AC5 were found to be most active in inhibiting breast cancer cells (MCF-7) proliferation with IC50 values of 6.7 and 3.6 microM, respectively. The activity of AC2 is almost doubled and of AC5 almost tripled as compared to curcumin. Their selectivity towards different cell lines is also more noticeable. Compounds AC2 and AC5 also showed increased activity against a human prostate cancer cell line (DU-145) and non-small lung cancer cell line (NCI-H460) with IC50 values of 20.4, 16.3 and 18.3, 10.7 microM, respectively.
The increasing prevalence of neurodegenerative diseases has prompted investigation into innovative therapeutics over the last two decades. Non-steroidal anti-inflammatory drugs (NSAIDs) are among the therapeutic choices to control and suppress the symptoms of neurodegenerative diseases. However, NSAIDs-associated gastropathy has hampered their long term usage despite their clinical advancement. On the natural end of the treatment spectrum, our group has shown that cardamonin (2',4'-dihydroxy-6'-methoxychalcone) isolated from Alpinia rafflesiana exerts potential anti-inflammatory activity in activated macrophages. Therefore, we further explored the anti-inflammatory property of cardamonin as well as its underlying mechanism of action in IFN-γ/LPS-stimulated microglial cells. In this investigation, cardamonin shows promising anti-inflammatory activity in microglial cell line BV2 by inhibiting the secretion of pro-inflammatory mediators including nitric oxide (NO), prostaglandin E(2) (PGE(2)), tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). The inhibition of NO and PGE(2) by cardamonin are resulted from the reduced expression of inducible nitric oxide synthase (iNOS) and cycloxygenase-2 (COX-2), respectively. Meanwhile the suppressive effects of cardamonin on TNF-α, IL-1β and IL-6 were demonstrated at both protein and mRNA levels, thus indicating the interference of upstream signal transduction pathway. Our results also validate that cardamonin interrupts nuclear factor-kappa B (NF-κB) signalling pathway via attenuation of NF-κB DNA binding activity. Interestingly, cardamonin also showed a consistent suppressive effect on the cell surface expression of CD14. Taken together, our experimental data provide mechanistic insights for the anti-inflammatory actions of cardamonin in BV2 and thus suggest a possible therapeutic application of cardamonin for targeting neuroinflammatory disorders.
Cardamonin, a chalcone isolated from the fruits of a local plant Alpinia rafflesiana, has demonstrated anti-inflammatory activity in cellular models of inflammation. In this report, we evaluated the ability of cardamonin to suppress both NO and PGE2 synthesis, iNOS and COX-2 expression and enzymatic activity, and key molecules in the NF-kappaB pathway in order to determine its molecular target. Cardamonin suppressed the production of NO and PGE2 in interferon-gamma (IFN-gamma)- and lipopolysaccharide (LPS)-induced RAW 264.7 cells. This inhibition was demonstrated to be caused by a dose-dependent down-regulation of both inducible enzymes, iNOS and COX-2, without direct effect upon iNOS or COX-2 enzyme activity. Subsequently we determined that the inhibition of inducible enzyme expression was due to a dose-dependent inhibition of phosphorylation and degradation of I-kappaBalpha, which resulted in a reduction of p65NF-kappaB nuclear translocation. We conclude that cardamonin is a potential anti-inflammatory drug lead that targets the NF-kappaB pathway.
Some chalcones, such as hydroxychalcones have been reported previously to inhibit major pro-inflammatory mediators such as nitric oxide (NO), prostaglandin E(2) (PGE(2)), tumor necrosis factor-alpha (TNF-alpha) and reactive oxygen species production by suppressing inducible enzyme expression via inhibition of the mitogen-activated protein kinase (MAPK) pathway and nuclear translocation of critical transcription factors. In this report, the effects of cardamonin (2',4'-dihydroxy-6'-methoxychalcone), a chalcone that we have previously isolated from Alpinia rafflesiana, was evaluated upon two cellular systems that are repeatedly used in the analysis of anti-inflammatory bioactive compounds namely RAW 264.7 cells and whole blood. Cardamonin inhibited NO and PGE(2) production from lipopolysaccharide- and interferon-gamma-induced RAW cells and whole blood with IC(50) values of 11.4 microM and 26.8 microM, respectively. Analysis of thromboxane B(2) (TxB(2)) secretion from whole blood either stimulated via the COX-1 or COX-2 pathway revealed that cardamonin inhibits the generation of TxB(2) via both pathways with IC(50) values of 2.9 and 1.1 microM, respectively. Analysis of IC(50) ratios determined that cardamonin was more COX-2 selective in its inhibition of TxB(2) with a ratio of 0.39. Cardamonin also inhibited the generation of intracellular reactive oxygen species and secretion of TNF-alpha from RAW 264.7 cells in a dose responsive manner with IC(50) values of 12.8 microM and 4.6 microM, respectively. However, cardamonin was a moderate inhibitor of lipoxygenase activity when tested in an enzymatic assay system, in which not a single concentration tested was able to cause an inhibition of more than 50%. Our results suggest that cardamonin acts upon major pro-inflammatory mediators in a similar fashion as described by previous work on other closely related synthetic hydroxychalcones and strengthens the conclusion of the importance of the methoxyl moiety substitution on the 4' or 6' locations of the A benzene ring.
Phytochemical investigations on the methanolic extract of Melicope ptelefolia Champ ex Benth. resulted in the isolation of three new compounds, identified as 3beta-stigmast-5-en-3-ol butyl tridecanedioate (melicoester) (1), (2Z, 6Z, 10Z, 14Z, 18Z, 22Z, 26E)-3', 7', 11', 15', 19', 23', 27', 31'-octamethyldotriaconta-2, 6, 10, 14, 18, 22, 26, 30-octadecanoate (melicopeprenoate) (2) and p-O-geranyl-7"-acetoxy coumaric acid (3). The compounds were isolated along with twenty-one other known compounds, lupeol (4), oleanolic acid (5), kokusaginine (6) genistein (7), p-O-geranyl coumaric acid (8), 4-stigmasten-3-one (9), 3beta-hydroxystigma-5-en-7-one (10) cis-phytyl palmitate (11), dodecane, dodecan-1-ol, ceryl alcohol, hentriacontanoic acid, eicosane, n-amyl alcohol, caprylic alcohol, octatriacontane, nonatriacontane, hexatriencontan-1-ol, methyl octacosanoate, beta-sitosterol, beta-sitosterol glucoside. Structures of all the compounds were established on the basis of MS and 1D and 2D NMR spectral data, as well as comparison with reported data.
Synovial fibroblast has emerged as a potential cellular target in progressive joint destruction in rheumatoid arthritis development. In this study, BDMC33 (2,6-bis[2,5-dimethoxybenzylidene]cyclohexanone), a curcumin analogue with enhanced anti-inflammatory activity has been synthesized and the potency of BDMC33 on molecular and cellular basis of synovial fibroblasts (SF) were evaluated in vitro.
Bioassay-guided fractionation of a MeOH extract of tubers of Coleus tuberosus afforded the active anti-tumor-promoting compounds identified as the triterpenoid 2alpha,3beta-dihydroxyolean-12-en-28-oic acid (maslinic acid; CT2) and a phytosterol mixture (CT1). CT1 consists of stigmasterol (32%), beta-sitosterol (40.3%), and campesterol (27.7%) as determined by capillary gas chromatography. CT1 and CT2 showed very strong anti-tumor-promoting activities at IC(50) 0.7 microg/ml and 0.1 microg/ml, respectively, in a convenient, short-term in vitro assay, i.e., the inhibition of Epstein-Barr virus (EBV) activation induced by phorbol 12-myristate 13-acetate (PMA) and sodium butyrate. We report for the first time the anti-tumor-promoting activity of 2alpha,3beta-dihydroxyolean-12-en-28-oic acid and show that a mixture of stigmasterol, beta-sitosterol, and campesterol is more potent than the individual components in inhibiting tumor-promoting activity.
Four new chromone alkaloids, chrotacumines A-D (1-4), consisting of a 5,7-dihydroxy-2-methylchromone, an N-Me piperidine ring, and an ester side chain were isolated from Dysoxylum acutangulum, and their structures including absolute configurations were elucidated on the basis of spectroscopic data interpretation including 2D NMR, CD spectra, and X-ray analysis. The known compound rohitukine (5) showed moderate cytotoxicity against human HL-60 promyelocytic leukemia and HCT-116 colon cancer cells.
To isolate compounds from the roots of Garcinia cowa and to evaluated their cytotoxic activity against breast (MCF-7), prostate (DU-145), and lung (H-460) cell lines.
In a preliminary screen, Aaptos aaptos showed significant cytotoxic activity towards a panel of cell lines and was thus subjected to bioassay-guided isolation of the bioactive constituents. In addition to the known aaptamine, two new derivatives of the alkaloid were isolated from the bioactive chloroform fraction of the crude methanolic extract. Detailed analysis by NMR and mass spectroscopy enabled their identification to be 3-(phenethylamino)demethyl(oxy)aaptamine and 3-(isopentylamino)demethyl(oxy) aaptamine. The cytotoxic activities of the three alkaloids were further evaluated against CEM-SS cells.
Phytochemical studies on the leaves and trunk bark of Garcinia cantleyana yielded five caged-xanthonoids including one tetra- and four tri-prenylated xanthones, cantleyanone A (1), 7-hydroxyforbesione (2) and cantleyanones B-D (4-6), as well as a simple xanthone, 4-(1,1-dimethylprop-2-enyl)-1,3,5,8-tetrahydroxyxanthone (3). Eight other known compounds, deoxygaudichaudione A, gaudichaudione H, friedelin, garbogiol, macranthol, glutin-5-en-3beta-ol, and a mixture of sitosterol and stigmasterol were also isolated. Their structures were elucidated by means of spectroscopic data and comparison of their NMR data with literature values. Significant cytotoxicity against MDA-MB-231, CaOV-3, MCF-7 and HeLa cancer cell-lines was demonstrated by cantleyanones B-D, 7-hydroxyforbesione, deoxygaudichaudione A and macranthol, with IC(50) values ranging from 0.22 to 17.17 microg/ml.