Partial [αMe]Aun scan of [l‐Leu11‐OMe]‐trichogin GA IV,a membrane active synthetic precursor of the natural lipopeptaibol

Abstract: We synthesized using solution‐phase methods three analogs of [l ‐Leu¹¹‐OMe] trichogin GA IV, a membrane active synthetic precursor of the lipopeptaibol antibiotic in which the N‐terminal n‐octanoyl group and each of the three Aib residues in positions 1, 4 and 8 are replaced by an acetyl group and the lipophilic C^α,α‐disubstituted glycine l ‐(αMe)Aun, respectively [partial (αMe)Aun scan]. FT‐IR absorption and CD analyses unequivocally show that the main three‐dimensional structural features of [l ‐Leu¹¹‐OMe] trichogin GA IV are preserved in the analogs. Also, [l ‐Leu¹¹‐OMe] trichogin GA IV and the three N^α‐acetylated l ‐(αMe)Aun analogs exhibit strictly comparable membrane‐modifying properties. Taken together, these results strongly favor the conclusion that a shift of the long hydrocarbon moiety from the N^α‐blocking group to the side‐chain of the 1, 4 or 8 residue does not have any significant effect on the conformational properties or the membrane activity of [l ‐Leu¹¹‐OMe] trichogin GA IV and, by extension, of the natural lipopeptaibol.     

Design,Synthesis, and in vitro antitubercular activity of 1,2,3‐triazolyl‐dihydroquinoline derivatives

In the quest for new active molecules against Mycobacterium tuberculosis, a series of dihydroquinoline derivatives possessing triazolo substituents were efficiently synthesized using click chemistry. The structure of 6l was evidenced by X‐ray crystallographic study. The newly synthesized compounds were evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv (ATCC27294). The compounds 6a , 6g, and 6j (MIC: 3.13 μg/ml) showed promising activity when compared to the first‐line drug such as ethambutol. In addition, the structure and antitubercular activity relationship were further supported by in silico molecular docking studies of the active compounds against 3IVX.PDB (crystal structure of pantothenate synthetase in complex with 2‐(2‐(benzofuran‐2‐ylsulfonylcarbamoyl)‐5‐methoxy‐1H‐indol‐1‐yl)acetic acid).     

4‐Substituted‐1‐phenyl‐1H‐pyrazolo[3,4‐d]pyrimidine Derivatives: Design,Synthesis, Antitumor and EGFR Tyrosine Kinase Inhibitory Activity

Four series of some 4‐substituted‐1‐phenyl‐1H‐pyrazolo[3,4‐d]pyrimidine derivatives 5a – f , 6a – f , 8a – f , and 9a – f were designed to be screened for their antitumor activity. All compounds were evaluated against breast (MCF‐7) and lung (A‐549) cell lines. Six compounds 5a , 5b , 6b , 6e , 9e , and 9f displaying activity against both cell lines were further estimated for their EGFR‐TK inhibitory activity where they revealed 41–91% inhibition and compound 6b elicited the highest activity (91%). A docking study of these compounds into the ATP‐binding site of EGFR‐TK demonstrated their binding mode where H‐bonding interaction with Met793 through N¹ of pyrimidine or N² of pyrazole was observed.     

From pro defensins to defensins: synthesis and characterization of human neutrophil pro α‐defensin‐1 and its mature domain

Abstract: Human neutrophil α‐defensins (HNPs) are small, cationic, Cys‐rich antimicrobial proteins that play important roles in innate immunity against infectious microbes such as bacteria, fungi and enveloped viruses. Synthesized as inactive precursors in vivo (pre‐proHNPs), HNPs are activated through proteolytic removal of the inhibitory pro‐peptide required for subcellular sorting and correct folding. We seek to understand the molecular basis for the recognition between the 45‐residue pro‐peptide and the C‐terminal functional domain. Here we described, total chemical synthesis of the 75‐residue human neutrophil pro α‐defensin‐1 (proHNP1) via native chemical ligation. After oxidative folding, proHNP1 is cleaved by cyanogen bromide at the Met⁴⁵–Ala⁴⁶ peptide bond to release the mature form. The native disulfide connectivity in HNP1, i.e. Cys¹–Cys⁶, Cys²–Cys⁴ and Cys³–Cys⁵, is verified by mass mapping of peptide fragments generated by proteolytic digestion and Edman degradation. Fluorescence spectroscopy studies and antimicrobial activity assays further support that synthetic proHNP1 and HNP1 are correctly folded. While largely unstructured in aqueous solution, the pro‐peptide binds to HNP1 intermolecularly with an apparent K_d value of 6.2 μm at pH 7.4, confirming the mode of intramolecular inactivation of human α‐defensin precursors.     

Facile synthesis of Nα‐protected‐l‐α,γ‐diaminobutyric acids mediated by polymer‐supported hypervalent iodine reagent in water

Abstract: Hofmann rearrangement of N^α‐Boc‐l ‐Gln‐OH mediated by a polymer‐supported hypervalent iodine reagent poly[(4‐diacetoxyiodo)styrene] (PSDIB) in water afforded N^α‐Boc‐l ‐α,γ‐diaminobutyric acid (Boc‐Dab‐OH, 1 ) in 87% yield. N^α‐Z‐derivative (Z‐Dab‐OH, 2 ) was prepared with PSDIB in 83% yield. Since the reaction of N^α‐Fmoc‐Gln‐OH by this procedure did not proceed because of the insolubility of Fmoc‐Gln‐OH in aqueous media, we synthesized Fmoc‐Dab(Boc)‐OH ( 5 ) from 2 in 54% yield. Polymyxin B heptapeptide (PMBH) which contains four Dab residues was successfully synthesized in a solution‐phase synthesis.     

Synthesis and in‐vitro Cytotoxic Evaluation of Novel Pyridazin‐4‐one Derivatives

A new series of N‐aryl‐4‐oxo‐1,4‐dihydro‐pyridazine‐3‐carboxylic acids has been synthesized by condensation of aryldiazonium with 4‐hydroxy‐6‐methyl‐2‐pyrone. Some of these compounds exhibited in‐vitro cytotoxic activity with moderate to excellent growth inhibition against the murine P815 mastocytoma cell line. Compound 5b showed an important cytotoxic activity against cell line P815 (IC₅₀ = 0.40 μg/mL).     

Synthesis and In Vitro Antibacterial Activity of 7‐(3‐Alkoxyimino‐4‐methyl‐4‐methylaminopiperidin‐1‐yl)‐fluoroquinolone Derivatives

A series of novel 7‐(3‐alkoxyimino‐4‐methyl‐4‐methylaminopiperidin‐1‐yl)fluoroquinolone derivatives were designed, synthesized, and characterized by ¹H‐NMR, MS, and HRMS. These fluoroquinolones were evaluated for their in‐vitro antibacterial activity against representative Gram‐positive and Gram‐negative strains. Generally, all of the target compounds have considerable antibacterial activity against the tested forty strains, and exhibit exceptional potency in inhibiting the growth of methicillin‐sensitive Staphylococcus aureus (MSSA) and methicillin‐resistant S. aureus (MRSA) ATCC33591 (MICs: 0.06 to 2 μg/mL). In particular, compounds 14 , 19 , 28 , and 29 are fourfold more potent than ciprofloxacin against MSSA 08‐49. Compounds 23 , 26 , and 27 are twofold more potent than ciprofloxacin against MRSA ATCC33591 and MSSA ATCC29213. In addition, compound 14 exhibits excellent activity (MIC: 0.06 μg/mL) against Acinetobactes calcoaceticus, which is two‐ to 16‐fold more potent than the reference drugs gemifloxacin, levofloxacin, and ciprofloxacin.     

Synthesis and In Vitro Antibacterial Activity of (2S)‐N‐(Substitutedphenyl)‐1‐[(2R)‐2‐[(Formylhydroxyamino)Methyl]‐1‐Oxohexyl]‐2‐Pyrrolidinecarboxamides as Potential Peptide Deformylase Inhibitors

Gram‐positive organisms have re‐emerged as the major hospital pathogens, which make the unmet medical needs for antibacterial therapy even worse. In searching for potent agents against Gram‐positive pathogens, novel (2S)‐N‐(substitutedphenyl)‐1‐[(2R)‐2‐[(formylhydroxyamino)methyl]‐1‐oxohexyl]‐2‐pyrrolidinecarboxamides, analogues of peptide deformylase inhibitor LBM‐415 were designed, synthesized and evaluated for their antibacterial activities in vitro. Many of these compounds exhibited high potency against Gram‐positive organisms compared with reference agent: LBM‐415.     

Synthesis and Biological Evaluation of Novel FtsZ‐targeted 3‐arylalkoxy‐2,6‐difluorobenzamides as Potential Antimicrobial Agents

Novel series of 3‐O‐arylalkylbenzamide and 3‐O‐arylalkyl‐2,6‐difluorobenzamide derivatives were synthesized and evaluated for their on‐target activity and antibacterial activity. The results indicated that the 3‐O‐arylalkyl‐2,6‐difluorobenzamide derivatives possessed much better on‐target activity and antibacterial activity than the 3‐O‐arylalkylbenzamide derivatives. Among them, 3‐O‐chlorobenzyl derivative 36 was the most effective in antibacterial activity (0.5, 4, and 8 μg/mL) against Bacillus subtilis ATCC9372, methicillin‐resistant Staphylococcus aureus ATCC29213, and penicillin‐resistant Staphylococcus aureus PR, while 3‐O‐methylbenzyl derivative 41 only exhibited the most potent activity (2 μg/mL) against Staphylococcus aureus ATCC25923.     

Antibacterial activity of 15‐residue lactoferricin derivatives

Abstract: Lactoferricins are a class of antibacterial peptides isolated after gastric‐pepsin digest of the mammalian iron‐chelating‐protein lactoferrin. For investigation of antibacterial activity, we prepared short synthetic derivatives of bovine, human, caprine, murine and porcine lactoferricins with 15‐amino‐acid residues of high sequence homology. The peptides corresponded to amino‐acid residues 17–31 of the mature bovine lactoferrin. Only the bovine and caprine derivatives displayed measurable antibacterial activity, with the bovine one having a minimal inhibitory concentration of 24 µm and being 10 times more active than the caprine one against Escherichia coli. An alanine‐scan of the bovine lactoferricin derivative was performed to identify specific amino acids that were important for the antibacterial activity. We found that neither of the two tryptophan residues (Trp 6 and Trp 8) present in the bovine lactoferricin derivative could be replaced by alanine without a major loss of antibacterial activity. The other lactoferricin derivatives tested contained only one tryptophan residue (Trp 6). Modified human, caprine and porcine lactoferricin derivatives containing two tryptophan residues (Trp 6 and Trp 8) displayed minimal inhibitory concentrations of 74, 174 and 219 µm , respectively, which represented up to a six‐fold increase in antibacterial activity. The alanine‐scan also revealed that the antibacterial activity was increased when acetamidomethyl‐protected cysteine and unprotected glutamine (Cys 3 and Gln 7) were replaced with alanine. Only the bovine lactoferricin derivative and a few of its alanine‐modified derivatives displayed measurable activity against Staphylococcus aureus.     

Evaluation of new base‐labile2‐(4‐nitrophenylsulfonyl)ethoxycarbonyl (Nsc)‐amino acids for solid‐phase peptide synthesis

Abstract: The 2‐(4‐nitrophenylsulfonyl)ethoxycarbonyl (Nsc) group is a new base‐labile protecting group for solid‐phase peptide synthesis, completely interchangeable with the fluorenylmethoxycarbonyl (Fmoc) protecting group, but with certain advantages. In this paper, we report a methodology with N^α‐Nsc‐protected amino acids for the synthesis of some melanotropins important to our research, namely, γ‐melanocyte‐stimulating hormone (γ‐MSH), its [Nle³]‐analogue, and a cyclic α‐MSH/β‐MSH hybrid. We developed an efficient protocol for the synthesis of the cyclic MSH analogue that yielded this peptide in > 98% purity. The γ‐MSH synthesis, which gave problems with both the Boc and Fmoc strategies, yielded the desired peptide by Nsc‐chemistry but was accompanied by side products. Finally, the Nle³‐γ‐MSH analogue was synthesized more efficiently using the Fmoc strategy, suggesting that Nsc‐chemistry might not be the best methodology for certain sequences.     

Quaternary ammonium salts substituted by 5‐phenyl‐1,3,4‐oxadiazole‐2‐thiol as novel antibacterial agents with low cytotoxicity

Twenty‐one novel 5‐phenyl‐1,3,4‐oxadiazole‐2‐thiol (POT) substituted N‐hydroxyethyl quaternary ammonium salts ( 6a–g , 7a–g , 8a–g ) were prepared and characterized by FTIR, NMR, and elemental analysis. Compounds 6a , 6c , and 8a were confirmed by X‐ray single‐crystal diffraction. They display the unsurpassed antibacterial activity against Staphylococcus aureus, α‐H‐tococcus, Escherichia coli, P. aeruginosa, Proteus vulgaris, Canidia Albicans, especially 6g , 7g , 8 g with dodecyl group. Compounds 8a–d with N,N‐dihydroxyethyl and POT groups display unsurpassed antibacterial activity and non‐toxicity. The structure–activity relationships indicate that POT and flexible dihydroxyethyl group in QAS are necessary for antibacterial activity and cytotoxicity. SEM and TEM images of E. coli morphologies of 8d show the antibacterial agents can adhere to membrane surfaces to inhibit bacterial growth by disrupting peptidoglycan formation and releasing bacterial cytoplasm from cell membranes.     

Chemical synthesis and receptor binding of catfish somatostatin: a disulfide‐bridged β‐d‐Galp‐(1→3)‐α‐d‐GalpNAc O‐glycopeptide*

Abstract: The glycopeptide hormone catfish somatostatin (somatostatin‐22) has the amino acid sequence H‐Asp‐Asn‐Thr‐Val‐Thr‐Ser‐Lys‐Pro‐Leu‐Asn‐Cys‐Met‐Asn‐Tyr‐Phe‐Trp‐Lys‐Ser‐Arg‐Thr‐Ala‐Cys‐OH; it includes a cyclic disulfide connecting the two Cys residues, and the major naturally occurring glycoform contains d ‐GalNAc and d ‐Gal O‐glycosidically linked to Thr⁵. The linear sequence was assembled smoothly starting with an Fmoc‐Cys(Trt)‐PAC‐PEG‐PS support, using stepwise Fmoc solid‐phase chemistry. In addition to the nonglycosylated peptide, two glycosylated forms of somatostatin‐22 were accessed by incorporating as building blocks, respectively, N^α‐Fmoc‐Thr(Ac₃‐α‐D‐GalNAc)‐OH and N^α‐Fmoc‐Thr(Ac₄‐β‐D‐Gal‐(1→3)‐Ac₂‐α‐D‐GalNAc)‐OH. Acidolytic deprotection/cleavage of these peptidyl‐resins with trifluoroacetic acid/scavenger cocktails gave the corresponding acetyl‐protected glycopeptides with free sulfhydryl functions. Deacetylation, by methanolysis in the presence of catalytic sodium methoxide, was followed by mild oxidation at pH 7, mediated by N^α‐dithiasuccinoyl (Dts)‐glycine, to provide the desired monomeric cyclic disulfides. The purified peptides were tested for binding affinities to a panel of cloned human somatostatin receptor subtypes; in several cases, presence of the disaccharide moiety resulted in 2‐fold tighter binding.     

Relative inhibitory activity of bile acids against 12‐O‐tetradecanoylphorbol‐13‐acetate‐induced inflammation,and chenodeoxycholic acid inhibition of tumour promotion in mouse skin two‐stage carcinogenesis

Objectives Bile acids are present in Bezoar Bovis and Fel Ursi, traditionally used as antipyretics and antispasmodics. However the anti‐inflammatory activity of individual bile acids and related compounds has not yet been investigated. In this paper, we report the structure–activity relationships influencing the anti‐inflammatory activity of a variety of structurally different bile acid derivatives and also the inhibitory activity of chenodeoxy‐cholic acid against tumour promotion. Methods Fifty derivatives of bile acids were examined for their inhibitory activity against the induction of oedema in mouse ear by application of 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA). Also, the effect of chenodeoxycholic acid was studied in mouse skin in which tumours had been induced by topical application of 7,12‐dimethylbenz[a]anthracene (DMBA) and promoted by TPA. Key findings Many bile acid derivatives had an inhibitory effect against TPA‐induced ear oedema at a similar grade to that of indometacin. Chenodeoxycholic acid, methyl 3α,7α,15α‐trihydroxy‐5β‐cholan‐24‐oate and methyl 3α,7α,15β‐trihydroxy‐5β‐cholan‐24‐oate showed the most potent activity with an ID50 value of 71–110 nmol/ear, a level corresponding to that of hydrocortisone (69 nmol/ear). Furthermore, chenodeoxycholic acid markedly suppressed tumour‐promoting activity by TPA following initiation by DMBA in mouse skin. Conclusions This is the first report on the anti‐inflammatory activity of bile acids on TPA‐induced inflammatory ear oedema in mice. Chenodeoxycholic acid, methyl 3α,7α,15α‐trihydroxy‐5β‐cholan‐24‐oate and methyl 3α,7α,15β‐trihydroxy‐5β‐cholan‐24‐oate showed the most potent activity, at a level corresponding to that of hydrocortisone. Furthermore, chenodeoxycholic acid markedly inhibited tumour promotion in a two‐stage carcinogenesis model in mouse skin.     

Synthesis of morphine‐[N‐methyl‐14C]‐6‐β‐D‐glucuronide

Protected morphine‐6‐glucuronide was converted into morphine‐[N‐methyl‐¹⁴C]‐6‐glucuronide by a three‐step procedure. Methyl (3‐pivaloylmorphin‐6‐yl 2,3,4‐tri‐O‐isobutyryl‐β‐D‐glucopyranosid)uronate was N‐demethylated by treatment with 1‐chloroethyl chloroformate to afford protected normorphine‐6‐glucuronide as its hydrochloride salt. The normorphine‐6‐glucuronide derivative was alkylated with iodomethane‐[¹⁴C] in the presence of potassium carbonate to produce C‐14 labelled protected morphine‐6‐glucuronide. Finally, hydrolysis of the protecting groups using 5% sodium hydroxide solution gave morphine‐[N‐methyl‐¹⁴C]‐6‐β‐D‐glucuronide with a specific activity of 41.8 mCi mmol^?1 and radiochemical purity of 99.2% (HPLC). Copyright © 2002 John Wiley & Sons, Ltd.     

Amino acid–azetidine chimeras: synthesis of enantiopure 3‐substituted azetidine‐2‐carboxylic acids

Abstract: Azetidine‐2‐carboxylic acid (Aze) analogs possessing various heteroatomic side chains at the 3‐position have been synthesized by modification of 1‐9‐(9‐phenylfluorenyl) (PhF)‐3‐allyl‐Aze tert‐butyl ester (2S,3S)‐ 1 . 3‐Allyl‐Aze 1 was synthesized by regioselective allylation of α‐tert‐butyl β‐methyl N‐(PhF)aspartate 13 , followed by selective ω‐carboxylate reduction, tosylation, and intramolecular N‐alkylation. Removal of the PhF group and olefin reduction by hydrogenation followed by Fmoc protection produced nor‐leucine–Aze chimera 2 . Regioselective olefin hydroboration of (2S,3S)‐ 1 produced primary alcohol 23 , which was protected as a silyl ether, hydrogenated and N‐protected to give 1‐Fmoc‐3‐hydroxypropyl‐Aze 26 . Enantiopure (2S,3S)‐3‐(3‐azidopropyl)‐1‐Fmoc‐azetidine‐2‐carboxylic acid tert‐butyl ester 3 was prepared as a Lys–Aze chimera by activation of 3‐hydroxypropyl–Aze 26 as a methanesulfonate and displacement with sodium azide. Moreover, orthogonally protected azetidine dicarboxylic acid 4 was synthesized as an α‐aminoadipate–Aze chimera by oxidation of alcohol 26 . These orthogonally protected amino acid–Aze chimeras are designed to serve as tools for studying the influence of conformation on peptide activity.     

Synthesis of α‐ and β‐Pyran Naphthoquinones as a New Class of Antitubercular Agents

A series of α‐ and β‐pyran naphthoquinones (lapachones) have been synthesized and evaluated for their in‐vitro antibacterial activity against Mycobacterium tuberculosis strain H37Rv (ATCC 27294) using the Alamar‐Blue susceptibility test; the activity was expressed as the minimum inhibitory concentration (MIC) in μg/mL. The synthetic methodology consisted of the formation of methylene and aryl o‐quinone methides (o‐QMs) generated by Knoevenagel condensation of 2‐hydroxy‐1,4‐naphthoquinone with formaldehyde and arylaldehydes. These o‐QMs then undergo facile hetero Diels–Alder reactions with dienophiles in aqueous ethanol media. Some naphthoquinones exhibited inhibition with MIC values of 1.25 μg/mL, similar to that of pharmaceutical concentrations currently used in tuberculosis treatment. These results justify further research into the value of these quinones as part of an original treatment for tuberculosis.     

Increased antibacterial activity of 15‐residue murine lactoferricin derivatives

Abstract: LFM W8 is a synthetic 15‐residue lactoferricin derivative (H₂N‐EKCLRWQWEMRKVGG‐COOH), corresponding to residues 16–30 of the mature murine lactoferrin protein except that the asparagine residue in position 8 of the native peptide is replaced with tryptophan. We have previously reported that the two tryptophan residues in positions 6 and 8 are of crucial importance for the antibacterial activity of many lactoferricin derivatives but, despite fulfilling this requirement, LFM W8 is inactive against Escherichia coli and Staphylococcus aureus. In order to solve this puzzle, a quantitative structure–antibacterial activity relationship study of synthetic LFM W8 derivatives was performed by replacing the glutamate residues in positions 1 and 9 with arginine or alanine, and the valine residue in position 13 with tyrosine. The results from the study were analyzed using multivariate data analysis. The derived mathematical model clustered the peptides into distinct groups which reflected their antibacterial activities, pointed out correlations between different structural parameters, highlighted the structural parameters that were important for antibacterial activity, and enabled us to predict the activity of a 15‐residue bovine lactoferricin derivative. The results showed that net charge and micelle affinity, as determined from the ratio of α‐helicity in sodium dodecyl sulfate micelles and in 1,1,1,3,3,3‐hexafluoro‐2‐propanol, were the most important structural parameters affecting antibacterial activity. The most active derivative, LFM R1,9 W8 Y13, displayed a minimal inhibitory concentration of 10 and 12 µm against E. coli and S. aureus, respectively. This represented more than 50‐fold and 40‐fold increases in antibacterial activity, respectively, compared with LFM W8.     

Exploration of 5‐(5‐nitrothiophen‐2‐yl)‐4,5‐dihydro‐1H‐pyrazoles as selective,multitargeted antimycobacterial agents

We report the biological evaluation of 5‐(5‐nitrothiophen‐2‐yl)‐4,5‐dihydro‐1H‐pyrazole derivatives against bacteria, eukaryotic cell lines and the assessment of their mechanisms of action to determine their prospects of being developed into potent antituberculosis agents. The compounds were evaluated for their antibacterial property against Mycobacterium tuberculosis H37Rv, multidrug‐resistant M. tuberculosis, Mycobacterium bovis BCG, Mycobacterium aurum, Escherichia coli, and Staphylococcus aureus using high‐throughput spot‐culture growth inhibition assay. They were found to be selective toward slow‐growing mycobacteria and Gram‐positive bacteria. In M. bovis BCG, they exhibited a bactericidal mode of action. Cytotoxicity was assessed in human THP‐1 and murine RAW 264.7 cell lines, and the compounds showed a lower cytotoxicity potential when compared with their antibacterial activity. They were found to be excellent whole‐cell efflux pump inhibitors of the mycobacterial surrogate M. aurum, performing better than known efflux pump inhibitor verapamil. The 5‐nitrothiophene moiety was identified for the first time as a prospective inhibitor scaffold of mycobacterial arylamine N‐acetyltransferase enzyme, which is the key enzyme in metabolizing isoniazid, a first‐line antituberculosis drug. The two aforementioned findings make the compounds potential hits in the development of adjunctive tuberculosis therapy.     

Discovery of Novel 2‐(piperidin‐4‐yl)‐1H‐benzo[d]imidazole Derivatives as Potential Anti‐Inflammatory Agents

A novel 2‐(piperidin‐4‐yl)‐1H‐benzo[d]imidazole derivative 5 with good anti‐inflammatory activity was identified from our in‐house library. Based on hit compound 5 , two series of 2‐(piperidin‐4‐yl)‐1H‐benzo[d]imidazole derivative 6a – g and 7a – h were designed and synthesized as novel anti‐inflammatory agents. Most of synthesized compounds exhibited good inhibitory activity on NO and TNF‐α production in LPS‐stimulated RAW 264.7 macrophages, in which the compound 6e showed most potent inhibitory activity on NO (IC₅₀ = 0.86 μm ) and TNF‐α (IC₅₀ = 1.87 μm ) production. Further evaluation revealed that compound 6e displayed more potent in vivo anti‐inflammatory activity than ibuprofen did on xylene‐induced ear oedema in mice. Additionally, Western blot analysis revealed that compound 6e could restore phosphorylation level of IκBα and protein expression of p65 NF‐κB in LPS‐stimulated RAW 264.7 macrophages.