No abstract

A number of pyrazole-oxadiazole conjugates were synthesized and evaluated for their ability to function as antiproliferative agents on various human cancer cell lines. These conjugates are comprised of pyrazole and oxadiazole scaffolds closely attached to each other without any spacer as two structural classes. The Type I class has a trimethoxy substituent and the type II class has a 3,4-(methylenedioxy) substituent on their A rings. Among these conjugates 11a, 11d and 11f manifest potent cytotoxicity with IC50 values ranging from 1.5 μM to 11.2 μM and inhibit tubulin polymerization with IC50 values of 1.3 μM, 3.9 μM and 2.4 μM respectively. The cell cycle assay showed that treatment with these conjugates results in accumulation of cells in the G2/M phase and disrupts the microtubule network. Elucidation of zebrafish embryos revealed that the conjugates cause developmental defects. Molecular docking simulations determined the binding modes of these potent conjugates at the colchicine site of tubulin.

The influence of pasteurization on storage stability of sweet sorghum juice and subsequent bioconversion to ethanol was studied. Juice samples were pasteurized at three different temperatures, i.e., 70°C for 10 min, 80°C for 5 min and 90°C for 2 min and were further stored at three different temperatures of 35, 40 and 45°C. The storage shelf life of the sorghum juice was observed to be extended for 21 days without compromising the ethanol conversion efficiency. Consistent fermentation efficiencies were observed for the juice samples pasteurized at 70°C followed by storage at 45°C, pasteurized at 80°C followed by storage at 40°C and pasteurized at 90°C followed by storage at 35°C and these samples showed an ethanol yield in the range of 0.473-0.477, 0.461-0.47 and 0.466-0.473 g g-1 , respectively. Hence, the juice samples pasteurized at 90°C and stored at 35°C was deemed as the superior preservation condition as it was close to ambient temperature and increased the shelf life of sweet sorghum juice. The highest fermentation efficiency of 93 % was observed after 48 h of fermentation.

Sweet sorghum bagasse represents a potential low-cost biomass which can be valorized to produce different value-added lignocellulosic platform chemicals of economic importance. The focus of the present study is the pretreatment of sweet sorghum bagasse for efficient delignification, separation of pure cellulose and its structural characterization. Sweet sorghum bagasse was subjected to mechanical commutation followed by steam washing, organosolv extraction (methanol and toluene, 1:2) and alkaline hydrogen peroxide treatment for efficient delignification. Chemical analysis revealed that cellulose, hemicellulose and lignin content (per cent recovered) after different pretreatment was 720 g (98 %), 6 g (1.1 %) and 20 g (0.9 %), respectively. Structural characterization of untreated sweet sorghum bagasse and recovered cellulose was performed using FT-IR, CP-MAS 13 C NMR spectroscopy, XRD, and thermogravimetric analyses. The cellulose preparation obtained after chemical pretreatments had typical cellulose structure with high crystallinity as compared to the untreated substrate. SEM micrographs revealed the surface topography wherein the waxy layer on the surface of this material disappeared and the texture became thinner and striated. The pretreatment methods employed were able to produce cellulose of high purity with [98 % lignin removal.

Sweet sorghum is an ideal feedstock for ethanol production, in view of the increased global demand for biofuels. Sweet sorghum juice is a perishable commodity and the stalk juice has a short shelf life (4-5 h) postcrushing due to its high fermentable sugar content and the rapid sugar degradation during storage is due to the metabolic activities of contaminating spoilage bacteria. Hence, the preservation of the juice is required for quality retention and to extend the storage shelf life of the juice. In the present study, the effect of chemical preservatives to extend the storage stability of sweet sorghum juice and its later bioconversion to ethanol was studied. Among the chemical preservatives evaluated, the juice samples spiked with sodium benzoate and sorbic acid delayed the increase in reducing sugars and thus prevented browning of juice during storage. Sodium benzoate and sorbic acid-spiked samples showed a decrease in the total sugar content from 13.03 to 10.7 % and 11.35 to 10.16 %, respectively, over a storage period of 96 h. Ethanol yield was in the range of 0.425-0.475 g g-1 and 0.405-0.445 g g-1 with optimal efficiency of 93 and 92 % for sodium benzoate and sorbic acid, respectively, while the control showed a reduction in yield from 0.36 to 0.26 g g-1 and efficiency by 57 %. Sodium benzoate (at 1,000 ppm concentration) was identified as suitable preservative to retain the quality and extend the storage shelf life of fresh sweet sorghum juice up to 2 days at 37°C.