Starch bio-based composite active edible film functionalized with Carum carvi L. essential oil: antimicrobial, rheological, physic-mechanical and optical attributes.

In the present study, the antimicrobial, rheological, mechanical, barrier and optical properties of Carrageenan and Manihot esculenta (composite) starch biobased edible film incorporated with caraway (Carum carvi L.) essential oil (EO) were investigated. The Minimum Inhibitory Concentration (MIC) of caraway oil against B. cereus, E. coli, P. aeruginosa and S. aureus were found to be 0.6, 1.4, 1.4 and 0.8% respectively. The Gas Chromatography- Mass Spectroscopy (GC-MS) of caraway EO expressed a distinct chromatogram peak for phenolic compounds. Rheological results of Film-Forming Solution (FFS) revealed solid-like viscoelastic behavior. Incorporation of caraway EO in the film caused significant (P < 0.05) increase in moisture, moisture absorption, bio-degradability in terms of film solubility, L value, total color difference (ΔE), haziness and transparency value, however, significantly (P < 0.05) decreased tensile strength and whiteness index were observed. The zone of inhibition of caraway EO incorporated films against all test bacteria were highly significant (P < 0.01) than control whereas antibacterial activity was found more towards gram-positive bacteria than gram-negative bacteria. No significant (P>0.05) changes in thickness, density, water activity, swelling, elongation at break, water vapor transmission rate, a and b value were observed with increasing caraway EO concentration. These results with some good rheological, physic-mechanical, antimicrobial and optical characteristics suggest the application of such active film into a variety of foods with improved food safety and quality. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-021-05028-1.

Application of HR-MAS NMR spectroscopy for studying chemotype variations of Withania somnifera (L.) Dunal.

Withania somnifera (L.) Dunal (Solanaceae), commonly known as Ashwagandha, is one of the most valued Indian medicinal plants with a number of pharmaceutical and nutraceutical applications. Metabolic profiling has been performed by HR-MAS NMR spectroscopy on fresh leaf and root tissue specimens from four chemotypes of W. somnifera. The HR-MAS NMR spectroscopy of lyophilized defatted leaf tissue specimens clearly distinguishes resonances of medicinally important secondary metabolites (withaferin A and withanone) and its distinctive quantitative variability among the chemotypes. A total of 41 metabolites were identified from both the leaf and root tissues of the chemotypes. The presence of methanol in leaf and root tissues of W. somnifera was detected by HR-MAS NMR spectroscopy. Multivariate principal component analysis (PCA) on HR-MAS (1) H NMR spectra of leaves revealed clear variations in primary metabolites among the chemotypes. The results of the present study demonstrated an efficient method, which can be utilized for metabolite profiling of primary and secondary metabolites in medicinally important plants.

Histamine H4 receptor: a novel target for inflammation therapy.

Histamine, a low molecular weight amine has been extensively studied for its various pharmacological profiles. Until recently histamine was thought to act on three receptors - H1, H2 and H3. Merely a decade back, sequencing of human genome has revealed a new histamine receptor - H4 receptor. This 390 amino acid sequenced receptor has around 38% homology with histamine H3 receptor besides; the pharmacological profile of the protein is quite different from other histamine receptors. H4 receptor is mainly expressed in mast cells and leukocytes and involves various physiological functions related to inflammation and allergy. Potent selective H4 receptor agonists and antagonists have been synthesized and in vivo studies have indicated their action on H4 receptor. In this review, structure, expression, homology sequence of H4 receptor among the different species has been documented. Further, structure activity relationship (SAR) of H4 ligands on the basis of their nucleus has been discussed in depth. In addition, anti-inflammatory effects of H4 receptor antagonists, with special emphasis to JNJ7777120, a selective H4 receptor antagonist have been focused exhaustively.

Synthesis, anti-bacterial and anti-fungal activities of some novel Schiff bases containing 2,4-disubstituted thiazole ring.

A series of arylidene-2-(4-(4-methoxy/bromophenyl) thiazol-2-yl) hydrazines (4a-z) and 1-(4-(4-methoxy/bromophenyl) thiazol-2-yl)-2-cyclohexylidene/cyclopentylidene hydrazines (5a-b/6a-b) were synthesized, characterized and screened for their antimicrobial activities. The structures of synthesized compounds were established by spectroscopic (FT-IR, (1)H NMR, (13)C NMR, Mass) and elemental analyses. Both the anti-bacterial and anti-fungal activities with MIC values of compounds were evaluated. The results of anti-bacterial screening reveal that among all the compounds screened eight compounds showed moderate to good anti-bacterial activity while ten of the newly synthesized compounds displayed good to excellent anti-fungal activity. Among the tested compounds, the most effective compounds with MIC value in the range of 6.25-25 microg/ml are 4a, 4n, 4z, 5a, 5b, 6a and 6b against three fungal strains viz. Candida albicans, Cryptococcus neoformans and Aspergillus flavus.

Synergistic antimicrobial activity of tea & antibiotics.

Tea leaves are known for its antibacterial activity against many microorganisms. In this study we attempted to describe the synergistic antimicrobial activity of tea and antibiotics against enteropathogens. Antimicrobial activity of boiled water tea extract and organic solvent extract were studied against Salmonella typhimurium 1402/84, S. typhi, S. typhi Ty2a, Shigella dysenteriae, Yersinia enterocolitica C770, and Escherichia coli (EPEC P2 1265) determining minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and death rate kinetics at MBC of tea extract in presence of subinhibitory concentration of antibiotic. Both green tea or black tea extracts effectively inhibited the growth of S. typhimurium 1402/84, S. typhi, S. typhi Ty2a, S. dysenteriae, Y. enterocolitica C770, and E.coli (EPEC P2 1265). However, the growth inhibitory concentration of tea extract was lower for green tea as compared to black tea extract. Antimicrobial activity of green tea tea methanol: water extract tea was better as compared to boiled water tea extract of green tea. Based on death rate kinetics results, S.typhi Ty2a appeared to be highly sensitive and Y. enterocolitica C770 the most resistant. Chloramphenicol and tea extract in combination inhibited the growth of S.dysenteriae at 2.5 microg/ml chloramphenicol (MIC 5 microg/ml) and 5.094 mg/ml black tea extract (MIC 9.089 mg/ml). Tea extract showed synergistic activity with chloramphenicol and other antibiotics like gentamycin, methicillin and nalidixic acid against test strains.