Payel Mitra

Supramolecular frameworks of binuclear dioxomolybdenum(VI) complexes with ONS donor ligands using 4,4′-azopyridine as a pillar: crystal structure, DFT calculations and biological study

Three new isostructural pillared binuclear dioxomolybdenum(VI) complexes [(MoO2L1)2(4,4′-azpy)] (1), [(MoO2L2)2(4,4′-azpy)] (2) and [(MoO2L3)2(4,4′-azpy)] (3) [where, 4,4′-azpy = 4,4′-azobis-(pyridine)] containing tridentate binegative Schiff base ligands (H2L1, H2L2 and H2L3) obtained by the condensation of salicylaldehyde and substituted salicylaldehyde with S-benzyl dithiocarbazate have been reported for the first time. These complexes have been characterized by spectroscopic and electrochemical studies. In all the complexes (1–3), 4,4′-azpy behaves as an auxiliary spacer and bridges the Mo(VI) centers giving rise to neutral 3D supramolecular frameworks. The cavities formed by hydrogen bonding interactions are capable of hosting guest molecules. The crystal structures reveal that each molybdenum site in the binuclear complexes adopts a distorted octahedral geometry. The morphology and structures of the complexes are further examined by SEM. Thermal behavior has been investigated to study the framework stabilities of these structures. Supportive DFT calculations on the complexes have been carried out. These ligands and complexes 1–3 have significant antimicrobial and antioxidant properties.

In Vitro Protective Ability of Ramaria aurea Against Free Radical and Identification of Main Phenolic Acids by HPLC

Free radical scavenging activity of Ramaria aurea, an edible mushroom, naturally grown in Shilong, India, was evaluated. A heat-stable, polyphenol-rich extract (RauPre) was prepared from the dried basidiocarps and analyzed. The major chemical constituent of RauPre was phenols (26.86 μg gallic acid equivalents [GAE] mg−1 of dry extract); flavonoids, β-carotene, lycopene, and ascorbic acid were present in minor amounts. Main phenolic acids identified by high performance liquid chromatography (HPLC) were caffeic acid > cinnamic acid > gallic acid. Results from antioxidant assays demonstrated potential for superoxide and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity (EC50 0.283 mg mL−1 and 0.384 mg mL−1, respectively). RauPre chelated ferrous ion (EC50 0.95 mg mL−1) and had Fe3+ to Fe2+ reducing power (EC50 1.025 mg mL−1). The activity of 1 mg of RauPre was equivalent to 86.7 μg ascorbic acid for total antioxidant capacity.

Antioxidative Activity, Mycochemical, and Phenolic Profile of Termitomyces clypeatus, a Wild Edible Mushroom from the Lateritic Zone of West Bengal

ABSTRACT The antioxidant properties, mycochemical, and phenolic profiling of Termitomyces clypeatus, an edible mushroom from the lateritic region of West Bengal, India, was done. Antioxidant activity was evaluated by hydroxyl radical, superoxide radical, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay, chelating ability, reducing power, and total antioxidant capacity assays. Their EC50 values ranged from 8.25 µg.mL–1 to 1.008 mg.mL–1. Among the mycochemical constituents, phenols, ascorbic acid, and flavonoids were higher than β-carotene and lycopene. The analysis of the phenolic compounds performed by high-performance liquid chromatography (HPLC) revealed the presence of pyrogallol (50.34 µg.mg–1).

Phytochemical Study and Antioxidative Property of Ethanolic Extract from Termitomyces clypeatus.

Article history: Received on: 11/03/2016 Revised on: 22/04/2016 Accepted on: 01/06/2016 Available online: 28/07/2016 The present study documents the phytochemical screening and antioxidant properties of ethanolic extract of Termitomyces clypeatus. Phytochemical constituents like phenols, flavonoids and ascorbic acid were much higher than β carotene and lycopene. The analysis of the phenolic compounds performed by HPLC, revealed the presence of pyrogallol (0.223 μg/mg) and cinnamic acid (0.095 μg/mg). Antioxidant activity was evaluated through superoxide radical scavenging assay, DPPH radical scavenging assay, chelating ability, reducing power and total antioxidant capacity determining assays. Their EC50 values ranged from 0.21 μg/ml to 3.22 mg/ml. Result implies that T. clypeatus can not only serve as a food supplement but also be used as treatment for various oxidative stress related diseases.