In vitro antimicrobial and antimycobacterial activity of some chalcones and their derivatives

In this study, novel series of chalcone derivatives, namely, 4-[4-(3-phenyl-acryloyl)-phenylamino]-chromen-2-one (5a–k) have been synthesized from the intermediate 4-(4-acetyl-phenylamino)-chromen-2-one (4). Cyclization reaction of chalcone (5a–k) with hydrazine hydrate, guanidine nitrate, and malononitrile gives the corresponding 4-[4-(1-acetyl-5-phenyl-4,5-dihydro-1H-pyrazol-3-yl)-phenylamino]-chromen-2-one (6a–k), 4-[4-(2-amino-6-phenyl-pyrimidin-4-yl)-phenylamino]-chromen-2-one (7a–k), and 2-amino-6-[4-(2-oxo-2H-chromen-4-ylamino)-phenyl]-4-phenyl-nicotinonitrile (8a–k) derivatives were synthesized. The newly synthesized compounds were evaluated for their antimycobacterial activity and antimicrobial activity against eight bacteria (S. aureus, B. cereus, E. coli, P. aeruginosa, K. pneumoniae, S. typhi, P. vulgaris, and S. flexneri) and four fungi (A. niger, C. albicans, A. fumigatus, and A. clavatus).     

Efficient synthesis of piperazine-2,6-dione and 4-(1H-indole-2-carbonyl)piperazine-2,6-dione derivatives and their evaluation for anticancer activity

Condensation of iminodiacetic acid 1 with various amines i.e., cyclohexanamine, 1-(3-aminopropyl)imidazole, pyridin-2-ylmethanamine, pyridin-3-ylmethanamine, pyridin-4-ylmethanamine, 2-morpholinoethanamine, thiophen-2-ylmethanamine, 2-(thiophen-2-yl)ethanamine, furan-2-ylmethanamine, 2-(pyrrolidin-1-yl)ethanamine, and 1-(3-aminopropyl) pyrrolidin-2-one 2a–k under microwave irradiation gave the corresponding piperazine-2,6-dione derivatives 3a–k in quantitative yields. Piperazine-2,6-dione derivatives 3a–k on condensation with 1H-indole-2-carboxylic acid under microwave irradiation gave the corresponding 4-(1H-indole-2-carbonyl)piperazine-2,6-dione derivatives 4a–k in quantitative yields. All the synthesized compounds (3a–k & 4a–k) were purified by crystallization and characterized by spectroscopic means. On screening at a concentration of 10 μM, compounds 3k, 4e, 4i breast (T47D), 4j lung (NCI H-522), 3i colon (HCT-15), 4e ovary (PA-1), and 4g liver (HepG-2) exhibited good anticancer activity.     

Synthesis and characterization of flurbiprofen hydrazide derivatives as potential anti-HCV, anticancer and antimicrobial agents

A novel series of new flurbiprofen hydrazide derivatives 2-(2-fluorobiphenyl-4-yl)-N′-[(substituted phenyl/5-nitro-2-furyl)methylene]propanehydrazide (3a–k), 2-(2-fluorobiphenyl-4-yl)-N-(2-substituted-4-oxo-1,3-thiazolidine-3-yl)propanamide (4a–b, 4d–k), 2-[2-(2-fluorobiphenyl-4-yl) propanoyl]-N-substituted hydrazinecarbothioamide (5a–h) and 2-(2-fluorobiphenyl-4-yl)-N′-[(3-methyl-4-oxo-1,3-thiazolidin-2-ylidene]propanehydrazide (6a–b, 6e and 6g) has been synthesized in this study. All synthesized compounds were screened for antimicrobial activity against various bacterial and fungal strains. Additionally, compounds were evaluated for the ability to inhibit Hepatitis C virus NS5B polymerase. The most active 4-thiazolidinone compound was 4k (SGK119) with 67.0 % and thiosemicarbazide compound was 5d (SGK123) with 69.50 % inhibition at 200 μM against hepatitis C virus NS5B RNA polymerase. Anticancer activity of the selected compounds (3i, 3j, 3h, 4d, 4i and 6b) was determined at a single dose towards the full panel of 60 human cancer cell lines by the National Cancer Institute (NCI). 2-(2-Fluoro-4-biphenylyl)-N-[2-[4-(trifluoromethyl)phenyl]-4-oxo-1,3-thiazolidine-3-yl]propanamide 4d, containing thiazolidinone ring, demonstrated the most marked effect with 20.80 % growth percent on leukaemia cancer cell line SR at 10^?5 M. The results demonstrated that none of the compounds tested have anticandidal and antifungal activities, but two of them (4a and 4i) showed antibacterial inhibition against Micrococcus luteus, and Staphylococcus cohnii and Staphylococcus aureus, respectively.     

Synthesis and antitumor activity evaluation of 2-arylisoquinoline-1,3(2H,4H)-diones in vitro and in vivo

Six 2-(2-acylaminobenzothiazol-6-yl)isoquinoline-1,3(2H,4H)-diones (1a–1f) and five 2-arylisoquinoline-1,3(2H,4H)-diones (1g–1k) were synthesized by refluxing homophthalic anhydrides with 2-acylaminobenzothiazolyl-6-amine or substituted aniline in glacial acetic acid. The cytotoxic activities of 1a–1k were evaluated via MTT method against A431, A549, and PC3. Compound 1b relatively displayed a higher cytotoxic activity than the others. The antitumor effect of 1b were evaluated in established nude mice PANC-1 xenograft model. The results suggest that compound 1b could potentially inhibit tumor growth.     

Synthesis of some benzoxazinyl pyrazolone arylidenes as potent antimicrobials and antioxidants

2-[2-(3-Methyl-5-oxo-4,5-dihydro-1H-pyrazol-1-yl)-2-oxoethyl]-2H-1,4-benzoxazin-3(4H)-one (3) was obtained starting from methyl-(3,4-dihydro-3-oxo-2H-1,4-benzoxazin-2-yl) acetate (1) through the corresponding hydrazide (2). Condensation of (3) with different aromatic aldehydes under Knoevengel condensation afforded 2-{2-[3-methyl-4-(2-methylbenzylidine)-5-oxo-4,5-dihydro-1H-pyrazol-1-yl]-2-oxoethyl}-2H-1,4-benzoxazin-3(4H)-ones (4a–k). The structures of the compounds were determined by FT-IR, ¹H NMR, ¹³C NMR, mass spectral data, and elemental analysis. All the synthesized compounds were screened for their in vitro antimicrobial and antioxidant studies.     

Synthesis and biological studies of a novel series of 4-(4-(1H-imidazol-1-yl)phenyl)-6-arylpyrimidin-2-amines

A novel series of eleven 4-(4-(1H-imidazol-1-yl)phenyl)-6-arylpyrimidin-2-amines has been prepared from synthesized 3-[4-(1H-imidazol-1-yl) phenyl]prop-2-en-1-ones and evaluated for phosphodiesterase (PDE) inhibition and antimicrobial activities. N-arylation of imidazole with 4-fluorobenzaldehyde using hexadecyltrimethylammonium bromide as catalyst gave 4-(1H-imidazol-1-yl) benzaldehyde which on treatment with substituted acetophenones yielded corresponding chalcones (1a–1k). Each chalcone on further reaction with guanidine hydrochloride resulted in title compounds (2a–2k). Pyrimidines thus synthesized were subjected to biological studies. Some compounds showed marked activities in PDE inhibition and anti-bacterial and anti-fungal bioassays.     

Synthesis,antimicrobial, and antioxidant activity of benzofuran barbitone and benzofuran thiobarbitone derivatives

The synthesis of novel series of benzofuran derivatives, containing barbitone moiety, 5-[(2/4-substitutedphenyl)(5-substituted-1-benzofuran-2-yl) methylidene]pyrimidin-2,4,6(1H,3H,5H)-trione (4a–i) and thiobarbitone moiety, 5-[(2/4-substitutedphenyl)(5-substituted-1-benzofuran-2-yl)methylidene]-2-thioxodihydropyrimidin-4,6(1H, 5H)-dione (5a–i) have been reported. The target compounds (4a–i) and (5a–i) were synthesized by the Knoevenagel condensation of (5-substituted-1-benzofuran-2-yl)(2/4-substitutedphenyl) methanone (3a–i) with barbituric acid and thiobarbituric acid, respectively, in acid medium. These compounds were screened for the antimicrobial and antioxidant activities. From antimicrobial activity results it was found that compounds 4a, 5a, 4c, and 5c displayed good antibacterial and antifungal activity against all tested strains. Further, the synthesized compounds were studied for docking on the enzyme, Glucosamine-6-phosphate synthase and the compounds 4c and 5c have emerged has an active antimicrobial agent with least binding energy (?5.27 and ?4.85 kJ mol^?1). Compounds 4e, 4f, 5e, and 5f showed promising free radical scavenging activity and compounds 5a and 5b showed good chelating ability with Fe²⁺ ions.     

Synthesis and characterization of new types of 2-(6-methoxy-2-naphthyl)propionamide derivatives as potential antibacterial and antifungal agents

A series of novel 2-(6-methoxy-2-naphthyl)propionamide derivatives have been efficiently synthesized in excellent yields via the reaction of naproxenoyl chloride with different amino compounds. Most of the synthesized compounds were screened in vitro for their antibacterial and antifungal activities. Most of the compounds showed significant antibacterial and antifungal activities, reaching, in certain cases, the same level of antimicrobial activity as the standard antibacterial agent Ampicilline and antifungal agent Flucanazole. N-(4-(N-arylsulfamoyl)phenyl)-2-(6-methoxynaphthalen-2-yl)propanamide (4a–c), 4-(4-fluorobenzylidene)-2-(1-(6-methoxynaphthalen-2-yl)ethyl)oxazol-5(4H)-one (10b), 2-(6-methoxynaphthalen-2-yl)-N-((5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl)propanamide (12), and N-((4-amino-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl)-2-(6-methoxynaphthalen-2-yl)propanamide (13) were found to be the most potent compounds against most of the tested strains. The antimicrobial activity was further supported by using MIC technique. Structure activity relationship studies revealed several matching pairs.     

Synthesis of some new indolo[2,3-c]isoquinolinyl pyrazoles, -1,3,4-oxadiazoles and their biological activities

A new series of novel compounds [10-substituted 6H, 7H-indolo[2,3-c]isoquinolin-5-one-6-yl]carbohydrazides (3a–c), 1-[10-substituted 6H, 7H-indolo[2,3-c]isoquinolin-5-one-6-yl]fomyl-, -3′,5′-dimethylpyrazoles (4a–c), -3′,5′-diphenylpyrazoles (5a–c), -3′-methylpyrazol-5′-ones (6a–c) and -1′,3′,4′-oxidiazole-2′-thiones (7a–c) linked to indoloisoquinoline at position-6 through formyl bridge was prepared. The structures of these newly synthesized compounds were confirmed by their spectral studies and elemental analysis. These compounds have been screened for their antimicrobial and antioxidant activities. Compounds 4a, 4b, 5a, 5b, 5c, 6b, 7a, and 7c exhibited the maximum zone of inhibition against A. niger, A. flavus, and A. fumigatus. Compounds 4a, 5a, 5c, 6b, 6c, 7a, and 7b showed good antibacterial activity. Compounds 4b, 4c, 5b, 5c, 6a, 6b, 7a, 7b, and 7c showed good radical scavenging activity compared with standards.     

Synthesis and antibacterial evaluation of 3,3′-diindolylmethane derivatives

Various 3,3′-diindolylmethane (DIM) derivatives were synthesized and the antibacterial activity of these compounds were tested against ten bacterial strains and their minimum inhibitory concentration (MIC) values were determined. The MIC values of derivatives 3a–d and 5a–e were ranging from 125 to 500 μg/mL. Among these derivatives, 2-(di(1H-indol-3-yl)methyl)phenol (5a) and 3-((1H-indol-3-yl)(pyridin-3-yl)methyl)-1H-indole (5d) exhibited potent activity, showing MIC values 6.5–62.5 μg/mL against Gram positive and Gram negative bacteria. Hemolytic assay of these active DIM derivatives did not show considerable toxic effect on the normal human erythrocytes.     

Synthesis, characterization, and SAR studies of new (1H-indol-3-yl)alkyl-3-(1H-indol-3-yl)propanamide derivatives as possible antimicrobial and antitubercular agents

In this article, we report herein the SAR studies of a series of (1H-indol-3-yl)alkyl-3-(1H-indol-3-yl)propanamide 10(a–j), 11(a–j). The synthesized compounds were evaluated for their preliminary in vitro antibacterial, antifungal activity and were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv strain. The synthesized compounds displayed interesting antimicrobial activity.     

Synthesis and antiviral activity of new 3-methyl-1,5-diphenyl-1H-pyrazole derivatives

A new series of 4-substituted 3-methyl-1,5-diphenyl-1H-pyrazoles 4–11 has been synthesized and evaluated for its in vitro antiviral activity and cytotoxicity against herpes simplex virus type-1 grown on Vero African green monkey kidney cells through plaque-reduction assay method using acyclovir as a positive control. The synthesis was achieved through Claisen-Schmidt condensation reaction of 3-methyl-1,5-diphenyl-1H-pyrazole-4-carbaldehyde (3) with acetophenone derivatives to give various enones 4a–f which are considered an important synthon for the construction of different heterocyclic rings as isoxazoline, pyrazoline, pyrimidine, pyridine, and fused pyridine via several synthetic routes. Biological evaluation of the prepared compounds showed that 3-(4-methylphenyl)-5-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl)-4,5-dihydroisoxazole (5f), 6-(4-methylphenyl)-N-[(3-(methylsulfanyl)phenyl)]-4-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl)pyrimidin-2-amine (7), 6-(4-bromophenyl)-4-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl)-2-oxo-1,2-dihydropyridine-3-carbonitrile (8), and 2-amino-6-(4-bromophenyl)-4-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl) pyridine-3-carbonitrile (9) exhibited strong antiviral activity with IC₅₀ (0.02, 0.04, 0.03, 0.03), respectively, compared to the used reference drug. The synthesized compounds were characterized by physical constants and the structures of the title compounds were confirmed by IR, ¹H NMR, mass spectra, and elemental analyses.     

Antitumour activity of 5-[(2E)-1-(1H-benzimidazol-2-yl)-3-substituted phenylprop-2-en-1-ylidene] pyrimidine-2,4,6(1H,3H,5H)-triones against Dalton’s ascitic lymphoma in mice

A new series of novel benzimidazole derivatives containing barbitone moiety (5a–f) was synthesized by a Knoevenagel condensation of (2E)-1-(1H-benzimidazol-2-yl)-3-phenylprop-2-en-1-ones (4a–f) and barbituric acid in the presence of catalytic amount of acetic acid medium. All the final structures were assigned on the basis of IR, ¹H NMR and mass spectra analysis. Acute toxicity studies were performed initially to determine the safety of titled derivatives and the ED ₅₀ value was calculated 50 mg/kg. All the final derivatives were screened for antitumour activity against Dalton’s ascitic lymphoma in mice. All the new candidates at a dose of 50 mg/kg showed a good antitumour activity against DLA-bearing mice when compared to the standard 5-fluro uracil. Among the final derivatives (5e), 5-[(2E)-1-(1H-benzimidazol-2-yl)-3-(3-nitrophenyl) prop-2-en-1-ylidene] pyrimidine-2,4,6(1H,3H,5H)-trione was found to be most potent antitumour in nature.     

Synthesis, DNA affinity, and antimicrobial activity of 4-substituted phenyl-2,2′-bichalcophenes and aza-analogues

A series of bichalcophene monoamidines 4a–f were synthesized from the corresponding mononitriles 3a–f via a direct reaction with LiN(TMS)₂ followed by deprotection with ethanolic HCl (gas). Bichalcophene mononitriles 3a–f were synthesized via palladium-catalyzed coupling reactions. Thus, a Stille coupling reaction was performed to prepare 6-[5-(thiophen-2-yl)furan-2-yl]nicotinonitrile (3e), when 6-(5-bromofuran-2-yl)nicotinonitrile was allowed to react with 2-n-tributyltin thiophene. The tested bichalcophenes showed a wide range of DNA and protein degradation effect as judged from agarose gel and SDS-PAGE, respectively. Bichalcophenes 3a–f and 4a–f have broad-spectrum antibacterial efficacy being highly active against both Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa, and Escherichia coli) bacterial strains. The antifungal activity of these bichalcophene series against Saccharomyces cerevisiae was demonstrated. The MIC of bichalcophenes 3a–f and 4a–f against various microorganisms was also determined. The tested bichalcophenes mimic SOD like activity and inhibited the superoxide radical generation.     

Synthesis and cytotoxicity of novel 4-(4-(substituted)-1H-1,2,3-triazol-1-yl)-N-phenethylbenzenesulfonamides

A new series of 4-(4-(substituted)-1H-1,2,3-triazol-1-yl)-N-phenethylbenzenesulfonamide derivatives 5 were synthesized through the Click approach and evaluated for their cytotoxic activity against four cancer cell lines (HuCCA-1, HepG2, A549, and MOLT-3). Most of the synthesized triazoles 5 displayed cytotoxicity against MOLT-3 cell line, except for analogs 5a–c and 5e. Significantly, 4-phenyltriazoles (5a and 5n), 4-(naphthalen-2-yloxy)methyltriazole 5d, as well as 4-((2-oxo-2H-chromen-7-yl)oxy)methyltriazole 5l showed higher cytotoxic activity against HepG2 cells than the reference drug, etoposide. Interestingly, the 4-phenyltriazole 5a was the most potent and promising compound with IC₅₀ value of 9.07 μM against HepG2 cell line. The analog 5a also exerted the highest cytotoxic activity against HuCCA-1 cells. This finding provides the novel lead molecules for further development.     

Synthesis and antitubercular activity of novel pyrazole–quinazolinone hybrid analogs

A series of 2-(substituted-phenyl)-3-(((3-(pyridin-4-yl)-1-(p-tolyl)-1H-pyrazol-4-yl)methylene)amino)-quinazolin-4(3H)-ones have been synthesized. The structures of the synthesized compounds were assigned on the basis of IR, ¹H NMR, ¹³C NMR, and mass spectral data, while their abilities to inhibit growth of Mycobacterium tuberculosis in vitro have been determined. The results show that compounds 5a, 5c, 5d, 5g, and 5k exhibited excellent antitubercular activity with percentage inhibition of 96, 90, 94, 93, and 92, respectively at a minimum inhibitory concentration (MIC) of <6.25 μg/mL, whereas compounds 5b, 5e, 5f, 5h, 5i, 5j, and 5l exhibited moderate- to- good antitubercular activity with percentage inhibition of 68, 70, 67, 64, 59, 73, and 67, respectively, at a MIC of >6.25 μg/mL. From the secondary screening, the actual MIC of compounds 5a, 5c, 5d, 5g, and 5k are <3.125.     

Synthesis, antioxidant, and antibacterial studies of phenolic esters and amides of 2-(1-benzofuran-2-yl) quinoline-4-carboxylic acid

A new series of phenolic esters 2(a–j) and amides 3(a–c) of 2-(1-benzofuran-2-yl) quinoline-4-carboxylic acid were synthesized by the reaction of 2-(1-benzofuran-2-yl)-quinoline-4-carboxylic acid (1) with various substituted phenols and secondary amines using ethyl-(N′,N′-dimethylamino)propyl carbodiimide hydrochloride (EDC.HCl) as a coupling agent. The newly synthesized compounds were evaluated for in vitro antioxidant and antibacterial activity. Among all tested compounds 2a, 2c, 2e, and 2h showed good chelating ability with Fe⁺² ions, whereas compounds 2g and 2j exhibited good scavenging activity with DPPH free radicals. Concerning antibacterial activities compounds 2a, 2b, 2c, and 2h were found to be equipotent to ampicillin against Enterococcus sp and Staphylococcus aureus, while compound 2e is found to be as potent as ampicillin against Pantoea Dispersa and Ochrobactrum sp. amide derivatives 3(a–c) were found to be less potent when compared to standard.     

Synthesis, pharmacological activity evaluation and molecular modeling of new polynuclear heterocyclic compounds containing benzimidazole derivatives

Novel heterocyclic compounds containing benzimidazole derivatives were synthesized from 2-(1Hbenzimidazol-2-yl) acetonitrile (1) and arylhydrazononitrile derivative 2 was obtained via coupling of 1 with 4-methyl phenyldiazonium salt, which was then reacted with hydroxylamine hydrochloride to give amidooxime derivative 3. This product was cyclized into the corresponding oxadiazole derivative 4 upon reflux in acetic anhydride. Compound 4 was refluxed in DMF in the presence of triethylamine to give the corresponding 5-(1H-benzimidazol-2-yl)-2-p-tolyl-2H-1,2,3-triazol-4-amine 6. Treatment of compound 6 with ethyl chloroformate afforded 2,6-dihydro-2-(4-methylphenyl)-1,2,3-triazolo[4″,5″-4′,5′]pyrimido[1,6-a]benzimidazole-5(4H)-one (8). 1,2-bis(2-cyanomethyl-1H-benzimidazol-1-yl)ethane-1,2-dione (10) was synthesized via the condensation reaction of 2-(1H-benzimidazol-2-yl) acetonitrile (1) and diethyloxalate. The reactivity of compound 10 towards some diamine reagents was studied. The in vitro antimicrobial activity of the synthesized compounds was investigated against several pathogenic bacterial strains such as Escherichia coli O157, Salmonella typhimurium, E. coli O119, S. paratyphi, Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes and Bacillus cereus. The results of MIC revealed that compounds 12a–c showed the most effective antimicrobial activity against tested strains. On the other hand, compounds 12a, b exhibited high activity against rotavirus Wa strain while compounds 12b, c exhibited high activity against adenovirus type 7. In silico target prediction, docking and validation of the compounds 12a–c were performed. The dialkylglycine decarboxylase bacterial enzyme was predicted as a potential bacterial target receptor using pharmacophorebased correspondence with previous leads; giving the highest normalized scores and a high correlation docking score with mean inhibition concentrations. A novel binding mechanism was predicted after docking using the MOE software and its validation.     

Antimicrobial screening of novel synthesized benzimidazole nucleus containing 4-oxo-thiazolidine derivatives

As a part of systematic investigation of synthesis, characterization and antimicrobial screening of some novel 3-(2-(6-methyl-1H-benzo[d]imidazol-2-yl)phenyl)-2-(aryl)thiazolidin-4-ones (3a–l), have been synthesized from Schiff bases of N-arylidene-2-(6-methyl-1H-benzo[d]imidazol-2-yl)anilines, (2a–l). The Schiff bases (2a–l) were prepared by condensation of different aldehydes with 2-(6-methyl-1H-benzo[d]imidazol-2-yl)aniline (1). The compound (1) was obtained from 2-amino benzoic acid and 4-methylbenzene-1,2-diamine. All the synthesized compounds were screened for in vitro antibacterial and antifungal activities on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus pyogenes, Candida albicans, Aspergillus niger, and Aspergillus clavatus. The structures of the compounds synthesized were elucidated by IR, ¹H-NMR, ¹³C-NMR, and mass spectra.     

Non-imidazole histamine H3 ligands: part V. synthesis and preliminary pharmacological investigation of 1-[2-thiazol-4-yl- and 1-[2-thiazol-5-yl-(2-aminoethyl)]-4-n-propylpiperazine derivatives

Series of 1-[2-thiazol-4-yl-(2-aminoethyl)]- and 1-[2-thiazol-5-yl-(2-aminoethyl)]-4-n-propylpiperazine derivatives have been prepared and in vitro tested as H₃-receptor antagonists (the electrically evoked contraction of the guinea-pig jejunum). It appeared that by comparison of homologous pairs, the 1-[2-thiazol-5-yl-(2-aminoethyl)]-4-n-propylpiperazines (3a,b and 4a–d) have much higher potency than their analogous 1-[2-thiazol-4-yl-(2-aminoethyl)]-4-n-propylpiperazines (2a–k). Based on the obtained results, we observed the 5-position of 2-methyl-2-R-aminoethyl substituents in the thiazole ring is favourable for histamine H₃ receptor antagonist activity, whereas its presence in position 4 leads, almost in each case, to strong decrease of activity.