Toxicity of Bioactive Molecule Andrographolide against Spodoptera litura Fab and Its Binding Potential with Detoxifying Enzyme Cytochrome P450

Spodoptera litura Fab. is a polyphagous pest causing damage to many agriculture crops leading to yield loss. Recurrent usage of synthetic pesticides to control this pest has resulted in resistance development. Plant-derived diterpenoid compound andrographolide was isolated from the leaves of Andrographis paniculata. It was analysed by gas chromatography-mass spectroscopy and quantified by HPLC. Nutritional indices and digestive enzymatic profile were evaluated. Third, fourth and fifth instar larvae were treated with different concentrations of andrographolide. At 3, 6 and 9 ppm-treated concentrations the larvae showed decreased RGR, RCR, ECI, ECD values with adverse increase in AD. The digestive enzymes were significantly inhibited when compared with control. Conspicuously, andrographolide showed pronounced mortality of S. litura by inhibition of enzyme secretion and intake of food. The binding ability of andrographolide with CYTP450 showed high affinity with low binding energy. Andrographolide has the potential to be exploited as a biocontrol agent against S. litura as an eco-friendly pesticide.     

Copolymers of 2-vinyl-4,4-dimethylazlactone with styrene and ethyl α-hydroxymethylacrylate

The monomer reactivity ratios for copolymerization of 2-vinyl-4,4-dimethylazlactone (VA) and ethyl α-hydroxymethylacrylate (EHMA) were 0.20–0.24 and 0.53–0.74, respectively, which show that EHMA is slightly more reactive with VA than with itself and should lead to random copolymers favoring alternation. The VA–styrene (VA–St) system also has a tendency to form random copolymers but with increased tendency for alternation with both r₁ and r₂ between 0.18–0.22. T_g's of VA–EHMA and VA–St copolymers varied between 100 and 136°C, and 96 and 117°C, respectively. Thermolysis of VA–EHMA copolymers resulted in crosslinking via the ring-opening reaction of VA groups by EHMA alcohols, followed by transesterification involving EHMA units at higher temperatures leading to highly crosslinked structures. The performed dimer of EHMA and VA was also synthesized and found to be an effective crosslinking agent in free radical vinyl polymerizations.     

Design and synthesis of 4-(1-(4-chlorobenzyl)-2,3-dioxoindolin-5-yl)-1 -(4-substituted/unsubstituted benzylidene) semicarbazide:Novel agents with analgesic,anti-inflammatory and ulcerogenic properties

A new series of isatin semicarbazide derivatives(7a-7j) were synthesized and characterized by spectroscopic means and elemental analysis.Analgesic and anti-inflammatory screening was performed using tail-flick technique and the carrageenan-induced foot paw edema test respectively.The ulcerogenicity was also determined for all the compounds.Some of the compounds showed moderate enhancement of the activity.Among the synthesized derivatives,compound 7d showed higher analgesic, antiinflammatory and one-third of ulcer index of the reference drug.     

Micromanipulation of Mechanically Compliant Organic Single-Crystal Optical Microwaveguides

Flexible organic single crystals are evolving as new materials for optical waveguides that can be used for transfer of information in organic optoelectronic microcircuits. Integration in microelectronics of such crystalline waveguides requires downsizing and precise spatial control over their shape and size at the microscale, however that currently is not possible due to difficulties with manipulation of these small, brittle objects that are prone to cracking and disintegration. Here we demonstrate that atomic force microscopy (AFM) can be used to reshape, resize and relocate single-crystal microwaveguides in order to attain spatial control over their light output. Using an AFM cantilever tip, mechanically compliant acicular microcrystals of three N-benzylideneanilines were bent to an arbitrary angle, sliced out from a bundle into individual crystals, cut into shorter crystals of arbitrary length, and moved across and above a solid surface. When excited by using laser light, such bent microcrystals act as active optical microwaveguides that transduce their fluorescence, with the total intensity of transduced light being dependent on the optical path length. This micromanipulation of the crystal waveguides using AFM is non-invasive, and after bending their emissive spectral output remains unaltered. The approach reported here effectively overcomes the difficulties that are commonly encountered with reshaping and positioning of small delicate objects (the “thick fingers” problem), and can be applied to mechanically reconfigure organic optical waveguides in order to attain spatial control over their output in two and three dimensions in optical microcircuits.     

Near Supramolecular Isomorphism Involving Homologous Solvents: Pyrimethaminium Terephthalate Methanol Solvate and Pyrimethaminium Terephthalate Ethanol Solvate

Abstract  

Two nearly isostructural pseudopolymorphic forms of pyrimethaminium terephthalate have been synthesized and their supramolecular architectures analyzed. In both the crystals, the protonated pyrimethamine (PMN) cation interacts with the carboxylate anion via N–H···O hydrogen bonds to form the robust R₂²(8) motif. The centrosymmetrically (N–H···N) paired PMN cations are bridged on either sides by interaction of the solvent molecules with the amino groups (N–H···O) of PMN cations. The combination of two R₂²(8) motifs formed between the PMN cations and PMN cation solvent, leads to the formation of the complementary DADA (D = hydrogen bonded donor, A = hydrogen bonded acceptor) array of quadruple hydrogen bonds. The solvent molecule further interacts with the corresponding anion via O–H···O hydrogen bonds. Moreover, both the solvates exhibit several edge to face stacking interactions. They have in common, two C–H···π interactions; one between the symmetry related cations and other between the cation and anion. The molecular packing of the ethanol solvate is further strengthened by C–H···O and C–H···π interaction between the solvent and the ions.     

Brønsted acid assisted activation of imide carbonyl group: regioselective synthesis of isoindoloisoquinolinone alkaloid (±)-nuevamine

Activation of imide carbonyl group with trifluoromethanesulfonic acid facilitates the intramolecular cyclization of phenethylphthalimides to give a fused isoindoloisoquinolinone skeleton. The first one pot regioselective synthesis of isoindoloisoquinolinone alkaloid (±)-nuevamine has been successfully executed using this methodology.