Coumarins and flavones from the fruit and root extracts of Micromelum integerrimum

A phytochemical investigation of the fruit and root extracts of Micromelum integerrimum resulted in the isolation and identification of a new compound, integerravone (1), together with 23 known compounds (2–24). Their structures were characterized by spectroscopic methods as well as comparisons made from the literature. Compounds 2, 3–15, 17–18 and 20–23 were evaluated for their cytotoxicities against the colon cancer cell line, HCT116. All of them were inactive at 50?µM. Most of the phenolic compounds were evaluated for their antioxidant activity using the DPPH assay. Compounds 14 and 22–24 showed antioxidant activity with IC₅₀ values ranging from 24.83-135.05?µM.     

Synthesis and evaluation of some new 5-(hetaryl)thiazoles as potential antimicrobial agents

In continuing our efforts to find new effective antimicrobial agents for overcoming the problem of microbial resistance, a new series of functionalized 5-hetarylthiazoles have been designed and synthesized starting from readily accessible 1-(2-allylamino-4-methylthiazol-5-yl)ethanone (3). The structures of newly synthesized compounds were confirmed by elemental analyses, spectral data, and chemical transformations. The synthesized compounds were evaluated in vitro for their antimicrobial activity against some human pathogenic bacterial and fungal strains. The compounds 7, 18, and 24 exhibited higher antibacterial activity with minimum inhibitory concentration (MIC) values ranging from (0.03–0.06?µg/mL) than ampicillin (MIC, 0.12?µg/mL) against Streptococcus pneumoniae. Whereas compounds 4, 22, and 24 revealed higher antifungal potency than amphotericin B against Aspergillus fumigatus. The structure and antimicrobial activity relationship was also discussed.     

Synthesis and biological evaluation of novel fused indolo [3, 2-c] [1,8] naphthyridine derivatives as potential antibacterial agents

Nine novel fused indolo [1,8] naphthyridine derivatives were synthesized using the Povarov reaction, in a one-pot system, and were fully characterized by spectroscopic techniques such as FT-IR, NMR, TOF-MS, and elemental analysis. Furthermore, their antibacterial activities against six bacterial strains were assessed. The results of the bioassay demonstrated that compounds 4a, 4c, and 4i showed good inhibitory effect with a MIC value ranging from 0.04687 to 0.09375?µM against Bacillus cereus and Staphylococcus aureus. The toxicity of 4a–i, evaluated through mutagenicity test against Salmonella typhimurium TA 98 and TA100 strains, revealed that there was no significant increase in the number of revertant colonies in comparison with the control, sodium azide.     

Antifungal activity of Mongolian medicinal plant extracts

Abstract

The in vitro antifungal activity of extracts obtained from 14 medicinal plants of the mongolian flora were investigated by measuring their minimal inhibitory concentration (MIC) against fungi cause of cutaneous diseases such as Candida species, dermatophytes and Malassezia furfur. Among the species examined, Stellaria dichotoma L., Scutellaria scordifolia L. Aquilegia sibirica Fisch. Et Schrenk. and Hyoscyamus niger L. extracts demonstrated antifungal activity against all studied fungi. In particular, S. scordifolia L. methanol extract, obtained at room temperature, showed the best activity against Candida spp., Malassezia furfur and dermatophytes with GMMIC₅₀ values of 22?µg/mL, 64?µg/mL and 32?µg/mL, respectively. The flavones, luteolin and apigenin, identified in S. scordifolia extracts, and rutin identified in S. dichotoma and Hyoscyamus niger L. extracts, could be responsible of the observed antifungal activity.     

A new depsidone derivative from mangrove sediment derived fungus Lasiodiplodia theobromae

A new depsidone derivative botryorhodine I (1), along with eight known compounds (2-9) were obtained from solid rice cultures of the fungal strain, Lasiodiplodia theobromae M4.2-2 isolated from a mangrove sediment sample. The structures of the isolated compounds were elucidated on the basis of 1?D and 2?D NMR analysis as well as by HRESIMS. All compounds were evaluated for their cytotoxic potential against the mouse lymphoma cell line L5178Y as well as for their antibacterial activities against a panel of Gram-positive and Gram-negative bacterial strains. Compound 3 revealed potent cytotoxic activity with an IC₅₀ of 7.3?µM whereas compound 7 showed selective anti-bacterial activity against different S. aureus and E. faecium bacterial strains with MIC value of 25?µg/ml.     

Synthesis,EGFR-TK inhibition and anticancer activity of new quinoxaline derivatives

Abstract

Ethyl 4-substituted-3-oxo-quinoxaline-2-carboxylates 3–5 were obtained via alkylation of ethyl 3-oxo-3,4-dihydroquinoxaline-2-carboxylate (1). Compound 1 was heterocyclized using hydrazines, ethylenediamine, and ethanolamine to give pyrazoloquinoxalines 6, 7, diazepinoquinoxaline 8, and oxazepinoquinoxaline 10. The quinoxaline-2-carboxamides 9, 11, 12 were prepared via condensation of compound 1 with different amines. Compound 1 was thiated using Lawesson’s reagent affording quinoxaline-3-thione 13, in fair yield. In addition, the reaction of 4-methyl-3-oxoquinoxaline 3 with some binucleophiles led to a series of new oxoquinoxaline derivatives 14–18. The molecular structure of compounds 1, 3, and 9 was confirmed by X-ray crystallography.

The anti-proliferative activity showed that among all the tested compounds, compounds 3, (IC₅₀ 2.51?±?3.0, 4.22?±?1.6 and 2.27?±?1.9?µM), 11 (IC₅₀ 1.32?±?2.61, 1.41?±?1.23 and 1.18?±?1.91?µM) and 17 (IC₅₀ 1.72?±?1.32, 1.85?±?0.94 and 1.92?±?4.83?µM) showed noteworthy anti-proliferative effects against the three cancer cell lines, HCT116, HePG2 and MCF7, respectively, compared to the reference drugs doxorubicin (IC₅₀ 1.41?±?0.58, 0.90?±?0.62 and 1.01?±?3.02?µM) and erlotinib (IC₅₀ 1.63?±?0.81, 1.57?±?0.62 and 1.49?±?0.54?µM). Compounds 3 (0.899?nM), 11 (0.508?nM) and 17 (0.807) showed strong EGFR inhibitory activity compared to Erlotinib (0.439?nM) and these results are in agreement with the docking study. These results suggest that compounds could probably be promising anticancer agents with EGFR inhibitory activity.     

Pyranocarbazoles from Murraya koenigii (L.) Spreng. as antimicrobial agents

The bioassay guided fractionation of methanolic extract of Murraya koenigii (L.) Spreng. leaves resulted in the isolation of seven pyranocarbazoles. These were evaluated against four bacterial strains and ten Candida sp. including two matched pair of fluconazole sensitive/resistant clinical isolates. Out of seven, three i.e. Koenine (mk279), Koenigine (mk309) and Mahanine (mk347) exhibited significant antibacterial activity MIC90 3.12–12.5 μg/mL against bacterial strains Streptococcus aureus and Klebsiella pneumonia compared with standard drug Kanamycin MIC90 12.5 μg/mL. However, only mk309 was found active against variety of Candida species MIC90 12.5–100 μg/mL. It was observed that hydroxylation at C-6 and C-7 positions in the studied pyranocarbazoles activate the bioactivity. Simultaneously, decrease in Log P value compares with ?H and ?O?CH3 substituted derivatives. The study is focused on selective antifungal and antibacterial activity of pyranocarbazoles on bacterial strains S. aureus, K. pneumonia and variety of Candida species with structure activity relationship observations.     

Synthesis,antimicrobial activity and QSAR studies of 2,5-disubstituted benzoxazoles

In this study, a new series of 2,5-disubstituted benzoxazoles was synthesized and their structures were elucidated by elemental analysis, MASS, ¹H-NMR, ¹³C-NMR and IR spectral data. Newly and previously synthesized 2,5-disubstituted benzoxazole derivatives were evaluated for antibacterial and antifungal activity against standard strains and their drug-resistant isolates. Microbiological results showed that the compounds presented a large spectrum of activity having MIC values of 250–7.8 µg mL^?1 against the tested microorganisms. Among the newly synthesized derivatives 3–22, compound 11 was the most active against Candida krusei out of all; however, it was one dilution less potent than standard drug fluconazole. In addition, all the new and previous compounds were more active than standard drugs ampicillin trihydrate and rifampicin against Pseudomonas aeruginosa and its gentamicin-resistant isolate. The 2D-QSAR (Quantitative Structure–Activity Relationship) analysis of a set of newly and previously synthesized benzoxazoles tested for growth inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA) was also performed by using multivariable regression analysis. The activity contributions for substituent effects of these compounds were determined from the correlation equation for predictions of the lead optimization.     

Synthesis,cytotoxicity, in-vitro antibacterial screening and in-silico study of novel thieno[2,3-b]pyridines as potential pim-1 inhibitors

Abstract

A novel series of thieno[2,3-b]pyridines was prepared via an one-step protocol in excellent yields. The protocol involved the reaction of pyridine-2(1H)-thiones with the appropriate halogen containing reagents in ethanolic sodium ethoxide solution under stirring at 80?°C for 2?h. The new thienopyridines were screened against different bacterial and fungal strains. Thieno[2,3-b]pyridine-2-carboxylate 9a showed the most effective antibacterial activities against each of Staphylococcus aureus and Escherichia coli with MIC/MBC values of 9.9/19.8 and 19.8/39.5?µM, respectively, when compared with Ciprofloxacin. 9a was the most effective compound against MRSA with inhibition zone of 16.2?±?0.6?mm, when compared with Gentamicin. Moreover, 9a exhibited the best cytotoxic activity against each of HEPG2 and MCF-7 cell lines with IC₅₀ values of 25.7 and 30.53?µM, respectively, when compared with Doxorubicin. The in-silico study was performed to predict the capability of new thienopyridines as potential inhibitors of pim-1 kinase.     

Two new bioactive triterpenoids from the roots of Colubrina asiatica

Abstract

Two new ceanothane triterpenes, 3,7-O,O-dibenzoyl ceanothic acid methylester (1) and 3-O-acetyl-7-O-benzoyl ceanothic acid methylester (2), along with nine known compounds (3–11), were isolated from the roots of Colubrina asiatica. The isolated compounds were identified by spectroscopic evidence. Compounds 1 and 2 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values of 4.67 and 3.07?µg/mL, respectively. Compound 2 also showed antimycobacterial activity against Mycobacterium tuberculosis (MIC 6.25?µg/mL). In addition, compounds 1, 2, 10 and 11 showed cytotoxicity against three cancer cell lines (KB, NCI-H187 and MCF-7) with IC₅₀ values ranging from 8.32 to 46.72?µg/mL.     

Synthesis of nitrogen-containing monoterpenoids with antibacterial activity

Abstract

Incorporation of the Beckmann rearrangement into the presented research resulted in the formation of nitrogen-containing terpenoid derivatives originating from naturally occurring compounds. Both starting monoterpenes and obtained derivatives were subjected to estimation of their antibacterial potential. In the presented study, Staphylococcus aureus was the most sensitive to examined compounds. The Minimal Inhibitory Concentration (MIC) experiments performed on S. aureus demonstrated that the (?)-menthone oxime (?)-8 and (+)-pulegone oxime (+)-13 had the best antibacterial activity among the tested derivatives and starting compounds. Their MIC₉₀ value was 100?µg/mL. The obtained derivatives were also evaluated for their inhibitory activity against bacterial urease. Among the tested compounds, three active inhibitors were found – oxime 14 and lactams (?)-15 and 16 limited the activity of Sporosarcina pasteurii urease with K_i values of 174.3?µM, 43.0?µM and 4.6?µM, respectively. To our knowledge, derivative 16 is the most active antiureolytic lactam described to date.     

Synthesis of spirooxindoles promoted by the deep eutectic solvent,ZnCl2+urea via the pseudo four-component reaction: anticancer,antioxidant, and molecular docking studies

Abstract

Various spirooxindoles (7a–c, 8a–c, 9a–c, and 10a–c) were efficiently synthesized using deep eutectic solvent ZnCl₂+urea and well characterized using IR, ¹H NMR, and ¹³C NMR spectroscopic techniques. The biological screening results showed that the compound 9a exhibited potent anticancer activity against MCF7 and HeLa cell lines with IC₅₀ values 6.47?±?0.01 and 9.14?±?0.32?µM, respectively. The compound 7c exhibited potent activity against the HeLa cell line with IC₅₀ value 6.81?±?0.01?µM. The compound 9a exhibited a potent antioxidant activity with IC₅₀ value 7.34?±?0.17?µM. The comparative molecular docking study against the cancer proteins EGFR and HER2 revealed that the EGFR was the best target protein receptor for the target compounds. Among all the compounds, the compound 9a exhibited the least binding energy ?10.72?kcal/mol against the protein EGFR (PDB ID: 4HJO).     

Insecticidal,cytotoxic and anti-phytopathogenic fungal activities of chemical constituents from the aerial parts of Ferula sinkiangensis

Abstract

A new rare monoterpene coumarin (1) and its two known analogues (2–3), together with two sesquiterpenes (6–7) and ferulic acid (8) were isolated from the aerial parts of Ferula sinkiangensis. The structure of new compound was established on the basis of 1D and 2D NMR data and HRESIMS data interpretation. Insecticidal, cytotoxic and anti-phytopathogenic fungal activities of isolated compounds were evaluated against third-instar larvae of Spodoptera exigua and its cell line, and three plant pathogenic fungi respectively. Compounds 1–3 and 6–7 were found to be more effective contact toxicity to S. exigua with the corrected mortality values of 38.89%-58.89% at 10?μg/larva doses for 24?h. Further studies showed that compounds 3 and 6 exhibited cell growth inhibitory activity against S. exigua cell line with the EC₅₀ values of 22.78 and 14.64?µM for 72?h. In addition, compound 6 exhibited potent antifungal activity with MICs?=?16–32?µg/mL.     

1,2-Benzisoxazole-3-acetamide derivatives as dual agents for DPP-IV inhibition and anticancer activity

Abstract

Herein, we have designed various benzisoxazole acetamide derivatives with and without glycine spacer as DPP-IV inhibitors. Compounds 9a–d and 11a–e were synthesized and screened for their in vitro DPP-IV inhibition. Compounds 11a and 11c showed moderate activity for DPP-IV inhibition, whereas other remained inactive at 25–200?µM concentrations. DPP-IV inhibition can be a good strategy for modulating diabetes and cancer; hence, we have screened compounds 9a–d and 11a–e for their anticancer activity using MTT assay against A549 and MCF7 cell lines. Compounds 9a–d without glycine spacer have shown good anticancer activity compared to compounds 11a–e with glycine spacer. Compound 9b has shown moderate activity with IC₅₀ values 4.72?±?0.72 and 4.39?±?0.809?µM against A549 and MCF7 cell lines, respectively. Interestingly, compound 9c with cyano group has shown very good anticancer activity with IC₅₀ 2.36?±?0.34?µM against MCF7 cell line as compared to fluorouracil with IC₅₀ 45.04?±?1.02?µM.     

Protein tyrosine phosphatase 1B inhibitors from a marine-derived fungal strain aspergillus sp. SF-5929

Abstract

In the course of our continuing investigation of bioactive secondary metabolites from marine-derived fungal strains, a racemate of a novel diphenolic derivative named (±)-tylopilusin D (1) along with ten previously known secondary metabolites (2–11) were isolated from a marine-derived fungal strain Aspergillus sp. SF-5929. Their structures were elucidated mainly by analysis of NMR and MS data. In addition, the inhibitory effects of the isolated compounds against protein tyrosine phosphatase 1B (PTP1B) activity were evaluated, and compounds 1, 2, and 5–7 inhibited PTP1B activity with IC₅₀ values ranging from 3.3 to 8.1?µM. Kinetics studies suggested that compounds 1, 2, and 5 had noncompetitive inhibitory effects against PTP1B.     

Design,synthesis, antimicrobial evaluations and in silico studies of novel pyrazol-5(4H)-one and 1H-pyrazol-5-ol derivatives

A new series of 1,4-disubstituted 3-methylpyrazol-5(4H)-one derivatives were synthesized by reacting various substituted aromatic aldehydes with 3-methylpyrazol-5(4H)-one derivatives through Knoevenagel condensation by conventional as well as by exposure to microwave irradiations. After that newly synthesized compounds of 1,4-disubstituted 3-methyl-1H-pyrazol-5-ol were prepared from these derivatives by reduction reaction of sodium borohydride at 0–5 °C. Sixty-four heterocyclic compounds containing a pyrazole moiety were synthesized with good to excellent yields (51 to 91%). Compounds (3d, 3m, 4a, 4b, 4d, and 4g) showed potent antibacterial activity against MSSA (Methicillin-susceptible strains of Staphylococcus aureus) and MRSA (Methicillin-resistant strains of Staphylococcus aureus) with MIC (the minimum inhibitory concentration) ranging between 4 and 16 µg/mL as compared to ciprofloxacin (MIC = 8–16 µg/mL). Compounds (4a, 4h, 4i, and 4l) showed potent antifungal activity against Aspergillus niger with MIC ranging between 16 and 32 µg/mL as compared to fluconazole (MIC = 128 µg/mL). In particular, compound 4a exhibited the strongest activity among the synthesized compounds in both bacterial and fungal strains with MIC ranging between 4 and 16 µg/mL. Furthermore, the nine most active compounds showed a good ADMET (absorption, distribution, metabolism, excretion, and toxicity) profile in comparison to ciprofloxacin and fluconazole as reference drugs. Molecular docking predicted that DHFR (dihydrofolate reductase) protein from Staphylococcus aureus and NMT (N-myristoyl transferase) protein from Candida albicans are the most suitable targets for the antimicrobial activities of these potent compounds.     

Bioactive xanthoquinodins and epipolythiodioxopiperazines from Chaetomium globosum 7s-1, an endophytic fungus isolated from Rhapis cochinchinensis (Lour.) Mart

Abstract

A new xanthoquinodin B9 (1), together with two known xanthoquinodins, xanthoquinodin A1 (2) and xanthoquinodin A3 (3), three epipolythiodioxopiperazines, chetomin (4), chaetocochin C (5) and dethio-tetra(methylthio)chetomin (6), and four other compounds, chrysophanol (7), emodin (8), alatinone (9), and ergosterol (10) were isolated from the endophytic fungus Chaetomium globosum 7s-1, isolated from Rhapis cochinchinensis (Lour.) Mart. All isolated structures were established based on their spectroscopic data analyses. Compounds 1–6 showed antibacterial activity against Gram positive bacteria with MICs ranging from 0.02?pM to 10.81 µM. Compounds 1–6 also exhibited cytotoxicity against KB, MCF-7 and NCI-H187 cancer cell lines (IC₅₀ 0.04–18.40 µM). However, they were cytotoxic towards a normal cell line (Vero cell) with IC₅₀ values ranging from 0.04 to 3.86 µM.     

Diastereoselective Synthesis and Antifungal Activity of Glycosyl Isoxazolines

Abstract

Glycosyl nitrile oxides, generated in situ by reaction of glycosyl oximes (3a, 3b, 4) with N‐chlorosuccinimide and DBU, on 1,3‐dipolar cycloaddition with substituted alkenes resulted in glycosyl isoxazolines (5, 7–28) in diastereoselective manner. The extent of diastereoselection varies with the nature of substituents both in sugar and alkenes. The compounds synthesized were screened in vitro against many fungi wherein two of the compounds (12, 23) showed significant inhibition against Sporothrix schenckii, Trychophyton mentagrophytes, and Cryptococcus neoformans with MIC of 12.5 and 6.25 µg/mL, respectively.     

Antibacterial and cytotoxic activities of phenolic constituents from the stem extracts of Spatholobus parviflorus

Abstract

A new 2-arylbenzofuran, spathobenzofuran (1), together with ten known compounds including a 2-arylbenzofuran, three pterocarpans and six isoflavones were isolated from the acetone crude extract of the stems of Spatholobus parviflorus. All compounds were characterised by spectroscopic methods. Compound 4 was active (MIC 8?µg/mL) against Gram-negative Pseudomonas aeruginosa TISTR 781 while compound 2 had modest activity against Gram-positive Staphylococcus aureus TISTR 1466 with a MIC value of 16?µg/mL. All isolated compounds showed no cytotoxicity against Vero and KB cells.     

Different Heterocycles Functionalized s‐Triazine Analogues: Design,Synthesis and In Vitro Antimicrobial,Antituberculosis, and Anti‐HIV Assessment

Some new quinolone condensed s‐triazine derivatives endowed with different heterocycles and 4‐aminobenzonitrile moiety has been synthesized and examined for their bioactivities against eight bacteria (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus vulgaris, and Shigella flexneri), two fungi (Aspergillus niger, Candida albicans) by using agar streak dilution method, and Mycobacterium tuberculosis H37Rv by using Lowenstein and Jensen MIC method. Upon preliminary biological screening, it was observed that the majority of the compounds were found to possess a significant broad spectrum antimicrobial (MICs: 6.25–25 µg/mL) and antitubercular (MIC: 12.5 µg/mL) potential. Hence, anti‐HIV activity against two types of HIV viral strains [HIV‐1 (III_B) and HIV‐2 (ROD)] has been carried out using the MTT assay. From this bioassay, we have identified some potent inhibitors acting as anti‐HIV‐1 agents (IC₅₀: 4.45 µg/mL) with promising therapeutic index of 16 for analogue 7 h. The structural assignments of the new products were carried out on the basis of IR, ¹H NMR, ¹³C NMR spectroscopy, and elemental analysis.