Synthesis and properties of 11-(3,5-di-tert-butyl-2-hydroxyphenylcarbamoyl)undecanoic acid, a new amphiphilic antioxidant

One-pot, three-component, iron-catalyzed synthesis of benzimidazoles via domino C-N bond formation

An efficient one-pot, three-component process for the synthesis of benzimidazole derivatives using a catalytic amount of Fe(iii) porphyrin has been developed. The reaction proceeds via domino C-N bond formation and cyclization reactions of benzo-1,2-quinone, aldehydes and ammonium acetate as a nitrogen source to selectively produce benzimidazole. A number of benzimidazole derivatives have been synthesized using this method in high yields under mild reaction conditions.

The Antibacterial, Antitumor Activities, and Bioactive Constituents’ Identification of Alectra sessiliflora Bacterial Endophytes

Due to increased antimicrobial resistance against current drugs, new alternatives are sought. Endophytic bacteria associated with medicinal plants are recognized as valuable sources of novel secondary metabolites possessing antimicrobial, antitumor, insecticidal, and antiviral activities. In this study, five bacterial endophytes were isolated and identified from the medicinal plant, Alectra sessiliflora, and their antibacterial and antitumor activities were investigated. In addition, the crude extracts of the endophytes were analyzed using gas chromatography (GC) coupled with time-of-flight mass spectrometry (TOF-MS). The identified bacterial endophytes belong to three genera viz Lysinibacillus, Peribacillus, and Bacillus, with the latter as the dominant genus with three species. Ethyl acetate extracts from the endophytes were used for antimicrobial activity against eleven pathogenic strains through minimum inhibitory concentration (MIC). The antitumor activity against the Hela cervical, Hek 293 kidney, and A549 lung carcinoma cells was determined by the MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay. Lysinibacillus sp. strain AS_1 exhibited broad antibacterial activity against the pathogenic strains with MIC values ranging from 4 to 8 mg/ml, while Bacillus sp. strain AS_3 displayed MIC of 0.25 mg/ml. Crude extracts of Lysinibacillus sp. strain AS_1, Peribacillus sp. strain AS_2, and Bacillus sp. strain AS_3 showed growth inhibition of more than 90% against all the cancer cell lines at a concentration of 1,000 μg/ml. Untargeted secondary metabolite profiling of the crude extracts revealed the presence of compounds with reported biological activity, such as antimicrobial, antioxidant, anti-inflammatory, antitumor, and antidiabetic properties. This study reported for the first time, bacterial endophytes associated with A. sessiliflora with antibacterial and antitumor activities.

Biochemical fingerprint and pharmacological applications of Barleria noctiflora L.f. leaves

Background Antioxidant and antihistamine agents from Barleria noctiflora L.f. as natural source due to the existing modern medicine give various adverse effects to overcome these problems with natural products. MethodsB. noctiflora leaves extract was fractionated with column chromatography; the homogenized fractions were monitored with thin layer chromatography (TLC) and characterized by using UV-visible, FT-IR, 1H NMR, 13C NMR and mass spectrometry spectral studies. The volatile phytoconstituents of B. noctiflora extract were analysed by gas chromatography-mass spectrometry. Phytoconstituents from B. noctiflora leaves extract were screened for their antioxidant and antihistamine potential in vitro (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid radical decolouration assay, nitric oxide radical scavenging activity, superoxide radical scavenging activity and hydrogen peroxide radical scavenging activity) and in silico (molecular docking), respectively. Results Antioxidant and antihistamine barlerinoside has been isolated and characterized from the leaves of B. noctiflora L.f. Barlerinoside revealed their free-radical scavenging ability on OH-, OH•, NO-, O2- and H2O2 radicals and found high percentage inhibition against OH- radical at the IC50 value of 50.45±2.52  µg. The methanol (MeOH) extract of B. noctiflora leaves contains cyclotene; N,N-dimethylglycine; tetrahydrocyclopenta [1,3] dioxin-4-one; phenol, 2-methoxy-; benzofuran, 2-methyl-; 1,4:3,6-dianhydro-α-d-glucopyranose; 2-methoxy-4-vinylphenol; 1,3;2,5-dimethylene-l-rhamnitol; levoglucosan and bicyclo[2.2.2]oct-7-ene-2,5-dione as being the major compounds. Among phytoconstituents present in the extract, the hexestrol; 1,2-benzenedicarboxylic acid, bis(2-methylpropyl) ester; 1-(3,6,6-trimethyl-1,6,7,7a-tetrahydrocyclopenta[c]pyran-1-yl) ethanone; megastigmatrienone; furan interacted with histamine H1 receptor and bind at GLU-177 and ASP-178 with high binding energy score -13.95, -13.41, -12.56, -12.03, and -11.72 kcal/mol, respectively, and the expected hydrolysed products of compound-1a and compound-1b from barlerinoside showed -8.91 and -8.68 kcal/mol binding energy against the histamine H1 receptor. This showed that the active ligands exactly bind with active binding site of the protein. ConclusionsWe can conclude that isolated barlerinoside from B. noctflora L.f. has potent antioxidant activity against synthetic free radicals and antihistamine activity against histamine H1 receptor.

A new ONO3− trianionic pincer ligand with intermediate flexibility and its tungsten alkylidene and alkylidyne complexes

This report details the synthesis and characterization of the semi-flexible [ON^CH2O]H₃ (1) ligand and its W(vi)-alkylidene and alkylidyne complexes.

Intramolecular cyclization–decyclization of new sterically hindered diiminophenol. Synthesis and coordination abilities

The novel benzoxazole I undergoes a fast intramolecular decyclization and demonstrates either a neutral or anionic coordination type in cadmium complexes.

Synthesis and biological evaluation of copper (II) complexes of sterically hindered o-aminophenol derivatives as antimicrobial agents

Cu(II) complexes with 4,6-di(tert-butyl)-2-aminophenol (I) and 2-anilino-4,6-di(tert-butyl)phenol (II) have been synthesized and characterized by means of elemental analysis, TG/DTA, FT-IR, UV-vis, ESR, and conductance measurements. The compounds I and II can coordinate in their singly deprotonated forms and behave as bidentate O,N-coordinated ligands; their CuL(2) complexes are characterized by CuN(2)O(2) coordination modes and square planar geometry. In vitro antimicrobial screening against Gram-positive and Gram-negative bacteria, yeasts, and moulds indicated that the compound I and its Cu(II) complex were more active than Questiomycin B, the compound II, and its Cu(II) complex.

Synthesis and antimicrobial evaluation of new 2-substituted 5,7-di-tert-butylbenzoxazoles

Various synthetic pathways of the 30 novel 2-substituted 5,7-di-tert-butylbenzoxazoles as new potential antimicrobial drugs are discussed. The 28 intermediates are described as well. The compounds were characterized by 1H and 13C NMR spectra, MS spectra, IR/UV spectra and by means of CHN analysis. The purity of the final compounds was checked by HPLC and their lipophilicity (log K) was also determined by means of RP-HPLC. In the present study, the correlation between RP-HPLC retention parameter log K (the logarithm of capacity factor K) and various calculated log P data is shown. The target compounds were tested for their in vitro antimycobacterial activity. Several compounds showed antituberculotic activity comparable with or higher than the standard isoniazide. In vitro cytotoxicity testing of the most active benzoxazoles and isoniazide as a reference drug was performed using MTT assay and compared with isoniazide as a reference drug. Structure-activity relationships among the chemical structures, the physical properties and the biological activities of the evaluated compounds are discussed in the article.

Novel (3,5-di-tert-butyl-2-hydroxy-phenylcarbamoyl)-alkanoic acids as potent antioxidants

A series of novel phenolic antioxidants of amphiphilic structure has been synthesized. Investigations into the influence of aliphatic spacer length and nature of a hydrophilic anchor on the antioxidant activity allowed elucidating certain structure requirements for the membrane-addressed antioxidant designing.