Copper(II) triflate promoted multicomponent catalytic clubbing of piperazinyl-thiazoloquinolines and thiazolocoumarins as antimicrobials.

Step economical, multicomponent construction of two series based on quinoline and coumarin ring systems was carried out. Annulation towards the 2-piperazinylthiazole system was established in satisfactory yields, using copper(II) triflate. These multicomponent reaction products were examined for their potential inhibitory effect against two Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus), three Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae) and two fungal species (Aspergillus niger and Candida albicans). In vitro pharmacological screening data demonstrated that the majority of the compounds were found to possess a significant broad-spectrum antimicrobial (25-50 µg/mL of MIC) potential and the results were comparable to control drugs. The structural assignments of final products were done on the basis of IR, 1H NMR, 13C NMR spectroscopy, and elemental analysis. The structure-activity relationship (SAR) was explored to facilitate further development of this class of compounds.

Synthesis, biological evaluation, and molecular docking of N-{3-[3-(9-methyl-9H-carbazol-3-yl)-acryloyl]-phenyl}-benzamide/amide derivatives as xanthine oxidase and tyrosinase inhibitors.

Claisen-Schmidt condensation of 3-formyl-9-methylcarbazole with various amides of 3-aminoacetophenone afforded N-{3-[3-(9-methyl-9H-carbazol-3-yl)-acryloyl]-phenyl}-benzamide/amide derivatives. All compounds were investigated for their in vitro xanthine oxidase (XO), tyrosinase and melanin production inhibitory activity. Most of the target compounds had more potent XO inhibitory activity than the standard drug (IC(50) = 4.3-5.6 µM). Interestingly, compound 7q bearing cyclopropyl ring was found to be the most potent inhibitor of XO (IC(50) = 4.3 µM). Molecular modelling study gave an insight into its binding modes with XO. Compounds 7a, 7d, 7e, 7g, and 7k were found to be potent inhibitors of tyrosinase (IC(50) = 14.01-17.52 µM). These results suggest the possible use of these compounds for the design and development of novel XO and tyrosinase inhibitors.

Synthesis and antioxidant, cytotoxicity and antimicrobial activities of novel curcumin mimics.

Claisen-Schmidt condensation of 3-(1,2,3,6-tetrahydro-1-methylpyridin-4-yl)-2,4,5- trimethoxybenzaldehyde 3 and various aromatic, heterocyclic and alicyclic amides of 3- aminoacetophenone 6(a-s) afforded novel curcumin mimics. All the synthesized compounds were characterized by IR, (1)H NMR, Mass spectroscopy and evaluated for antioxidant, cytotoxicity and antimicrobial activity. Out of the 20 compounds screened, compounds 7i, 7l, 7q, and 7n have shown excellent radical scavenging activity, compounds 7o, 7t, 7f, and 7r have shown significant xanthine oxidase inhibition, and compounds 7a, 7k and 7l were found to be potent inhibitors of selected cancer cell lines. Compounds 7h, 7t, 7l, 7i, and 7e have shown good antibacterial activity, whereas compounds 7j, 7f, 7o, 7h, and 7t exhibited significant antifungal activity.

Temperature-dependent studies on the total phenolics, flavonoids, antioxidant activities, and sugar content in six onion varieties.

Heating effect on total phenol, flavonoids, antioxidant activity, and sugar content of six onion varieties has been quantitatively investigated to explore the effect of different temperatures. The onion varieties comprised one red-skinned variety, two white-skinned varieties, and three yellow-skinned varieties. The heating temperature was scanned at 80°C, 100°C, 120°C, and 150°C for 30 minutes each, and quantitative analysis was performed relative to the powdered onion at ambient temperature. Quercetin, glucosides and sugar content were analyzed using high-performance liquid chromatography. The total phenolic and antioxidant content increased in all six varieties. The total flavonoid levels showed a considerable change. On heating the onion samples at 120°C for 30 minutes, the red-skinned variety showed the highest level of total phenolic content [13712.67 ± 1034.85 µg of gallic acid equivalent/g dry weight (µg GAE/g DW)] and total flavonoids [3456.00 ± 185.82 µg of quercetin equivalents/g dry weight (µg Q/g DW)], whereas the content of total phenolics and total flavonoids were 13611.83 ± 341.61 µg GAE/g DW and 3482.87 ± 117.17 µg Q/g DW, respectively, for the yellow-skinned (Sunpower) variety. Quercetin and its glucoside contents increased up to 120°C and then decreased at 150°C, whereas the sugar content continuously decreased with heating. All cultivars showed the same pattern in the heating effect, and the predominant flavonoids were destroyed at higher temperatures. Therefore, it is improper to expose onion powder to a temperature higher than 120°C.

Antioxidant, α-glucosidase and xanthine oxidase inhibitory activity of bioactive compounds from maize (Zea mays L.).

Chemical investigations into maize (Zea mays L.) kernels yielded phenolic compounds, which were structurally established using chromatographic and spectroscopic methods. The isolated phenolic compounds from maize kernel were examined in vitro for their antioxidant abilities by DPPH (2,2-diphenyl-1-picryl hydrazine) radical, OH radical scavenging activity, and reducing ability, along with α-glucosidase and xanthine oxidase (XO) inhibition. The isolated maize phenolics revealed significant xanthine oxidase and α-glucosidase inhibitory activity to that of allopurinol and acarbose in vitro and in vivo, respectively. The kinetics study with xanthine oxidase revealed competitive type of inhibition by isolated maize vanillic acid (M2), ferulic acid (M5), 3'-methoxyhirsutrin (M7), and peonidin-3-glucoside (M10) as compared to control allopurinol. Overall, with few exceptions, all the phenolic compounds from maize kernel revealed significant biological activities with all parameters examined. Also, the phenolic compounds from maize were found to be more reactive toward DPPH radical and had considerable reducing ability and OH radical scavenging activity. These findings suggest that maize kernel phenolic compounds can be considered as potential antioxidant, α-glucosidase, and XO inhibitory agents those might be further explored for the design of lead antioxidant, antidiabetic and antigout drug candidates using in vivo trials.

In vitro evaluation of selected benzimidazole derivatives as an antioxidant and xanthine oxidase inhibitors.

2-Aryl-1-arylmethyl-1H-benzimidazole derivatives having different side chains on the structure were examined in vitro for their antioxidant abilities by 2,2-diphenyl-1-picryl hydrazine radical scavenging activity, reducing ability, OH radical scavenging activity, inhibition of polyphenol oxidase and xanthine oxidase. Overall, with few exceptions, all the 2-aryl-1-arylmethyl-1H-benzimidazoles showed moderate biological activity with all parameters examined. The 2-aryl-1-arylmethyl-1H-benzimidazoles were found to be reactive toward 2,2-diphenyl-1-picryl hydrazine radical and had considerable reducing ability, with significant xanthine oxidase inhibition. With few exceptions, all the compounds under study were found to possess moderate-to-poor OH radical scavenging activity and inhibited polyphenol oxidase significantly. These findings suggest that these 2-aryl-1-arylmethyl-1H-benzimidazoles can be considered as potential antioxidant and xanthine oxidase inhibitory agents, those might be further, explored for the design of lead antioxidant and antigout drug candidates using in vivo trials.

In vitro anti-inflammatory and xanthine oxidase inhibitory activity of Tephrosia purpurea shoot extract.

The methanolic extract of Tephrosia purpurea (Leguminosae) shoots was evaluated in-vitro for its anti-inflammatory and xanthine oxidase inhibitory activity. Anti-inflammatory activity was measured by the Diene-conjugate, HET-CAM and beta-glucuronidase methods. The enzyme inhibitory activity was tested against isolated cow milk xanthine oxidase. The average anti-inflammatory activity of T. purpurea shoot extract in the concentration range of 1-2 microg/mL in the reacting system revealed significant anti-inflammatory activities, which, as recorded by the Diene-conjugate, HET-CAM and beta-glucuronidase assay methods, were 45.4, 10.5, and 70.5%, respectively. Screening of the xanthine oxidase inhibitory activity of the extract in terms of kinetic parameters revealed a mixed type of inhibition, wherein the Km and Vmax values in the presence of 25 to 100 microg/mL shoot extract was 0.20 mM/mL and 0.035, 0.026, 0.023 and 0.020 microg/min, while, for the positive control, the Km and Vmax values were 0.21 mM/mL and 0.043 microg/min, respectively. These findings suggest that T. purpurea shoot extract may possess constituents with good medicinal properties that could be exploited to treat the diseases associated with oxidative stress, xanthine oxidase enzyme activity and inflammation.

Synthesis and biological evaluation of beta-chloro vinyl chalcones as inhibitors of TNF-alpha and IL-6 with antimicrobial activity.

A series of beta-chloro vinyl chalcones have been synthesized by Claisen-Schmidt condensation. beta-chloro vinyl aldehyde has been synthesized by the Vilsmayer-Hack formylation reaction. The structures of the newly synthesized compounds were confirmed by 1H NMR, IR and Mass spectral analysis. All the compounds were evaluated for their anti-inflammatory activity (against TNF-alpha and IL-6) and antimicrobial (antibacterial and antifungal) activity. Compounds 5a, 5d, 5e, 5g and 5i exhibited promising activity against IL-6 with 58-83% inhibition at 10 microM concentration. None of the compound was found to be cytotoxic in CCK-8 cells at 10 microM concentration. Whereas compounds 5b, 5d, 5e and 5i showed very good antibacterial activity and compounds 5a, 5b, 5e and 5i showed good antifungal activity.