Butea monosperma bark extract mediated green synthesis of silver nanoparticles: Characterization and biomedical applications

AbstractThe work deals with an environmentally benign process for the synthesis of silver nanoparticle using Butea monosperma bark extract which is used both as a reducing as well as capping agent at room temperature. The reaction mixture turned brownish yellow after about 24h and an intense surface plasmon resonance (SPR) band at around 424nm clearly indicates the formation of silver nanoparticles. Fourier transform-Infrared (FT-IR) spectroscopy showed that the nanoparticles were capped with compounds present in the plant extract. Formation of crystalline fcc silver nanoparticles is analysed by XRD data and the SAED pattern obtained also confirms the crystalline behaviour of the Ag nanoparticles. The size and morphology of these nanoparticles were studied using High Resolution Transmission Electron Microscopy (HRTEM) which showed that the nanoparticles had an average dimension of ∼35nm. A larger DLS data of ∼98nm shows the presence of the stabilizer on the nanoparticles surface. The bio-synthesized silver nanoparticles revealed potent antibacterial activity against human bacteria of both Gram types. In addition these biologically synthesized nanoparticles also proved to exhibit excellent cytotoxic effect on human myeloid leukemia cell line, KG-1A with IC50 value of 11.47μg/mL

Modulation of morphology and efficacy of new CB1 receptor antagonist using simple and benign polymeric additives

1014-1021The compound 1, [(1H-[1]benzoxepino[5,4-c]pyrazole-3-carboxamide, 8-chloro-1-(2,4-dichlorophenyl)-4,5-dihydro-N- 1-piperidinyl], a known CB1 modulator has been synthesized and characterized by IR, NMR and single Crystal X-ray study. The single crystal study of 1 displays a number of halogen bonds leading to 1-D network along with other weak noncovalent interactions. The CB1 modulator 1 inherently possesses extremely low solubility in water, which makes its application as drug difficult, and this may be attributed to multiple halogen bonds present in the crystal structure. A series of polymer additives, which are Generally Regarded As Safe (GRAS), have been explored to investigate whether they can modulate the halogen bond present in 1 through formation of various non-bonded interactions. Surprisingly, these polymers are found to change crystal morphology, crystal packing while retaining efficacy and bioavailability. The polymer molecular weight is found to play a significant role in crystal morphology modification especially in case of polyethylene glycol (PEG). The formation of new polymorphic forms of 1 and modification of halogen bond has been established using powder X-ray diffraction and IR study, respectively, in case of PEG 4000, PVPK-30, PVA polymers and compound 1 adducts

Degradation of Methyl Parathion, a common pesticide and fluorescence quenching of Rhodamine B, a carcinogen using β-d glucan stabilized gold nanoparticles

Natural carbohydrate polymer β-d-glucan extracted from Tricholoma crassum (Berk.) Sacc. predominantly linked by β-glycosidic bonds have been used to synthesize gold nanoparticles (Au NPs). As glucan is water soluble, the Au NPs are prepared in water medium, a green solvent. The morphology and characterization of the synthesized Au NPs have been confirmed by various techniques, like TEM, EDX, XRD, UV–Vis and FT-IR spectroscopic studies. The obtained Au NPs exhibits chemosensing property against Methyl Parathion, a group of highly toxic organophosphorous pesticide, extensively used as an agricultural chemical. Degradation of parathion using Au NPs lead to water-soluble products thereby reducing the toxicity of Methyl Parathion by disrupting the thiophosphate-ester linkage. The synthesized Au NPs also act as a good fluorescence quencher of Rhodamine B, a common fluorophore and carcinogenic compound, obeying Stern-Volmer equations. The β-d-glucan capped Au NPs are safe having possible medicinal usage. Keywords: β-d-Glucan, Gold nanoparticles, Green synthesis, Methyl Parathion, Fluorescence quenche