Isolation and partial characterization of alkylferulate from Entada africana (Guill. & Perr.) stem bark extract

Investigation of the bioactive constituents of Entada africana crude extract afforded the isolation of alkylferulate. The hexane soluble portion of acetone/methanol (1:1v/v) crude stem bark extract of Entada africana was subjected to column chromatography on silica gel 60 (60-200) mesh size. Gradient column elution yielded an isolate coded AC4 with Rf value of 0.65 in hexane/diethyl ether (3:2). The isolate was characterized using IR, NMR and in comparison with literature data. The analysis of spectroscopic data and literature comparison strongly suggests that AC4 is an alkylferulate; a known hypolipidemic agent in addition to other biological uses. The isolation of alkylferulate partly lays credence to the use of Entada africana in traditional medicine practice

Isolation and characterization of Stigmasta-7, 22-dien-3-ol (α-Spinasterol) from Entada africana stem bark crude extract

The phytochemical  investigation of the stem bark extracts of Entada africana led to the isolation and characterization of Stigmasta-7,22-dien-3-ol from the dichloromethane soluble portion of acetone/methanol (1:1v/v) crude extract. The powdered stem bark sample of Entada africana was defatted with hexane and extracted with acetone/methanol (1:1v/v) mixture. The dichloromethane soluble fraction was purified on a low pressure column containing silica gel 60 (60-200 mesh). The purification afforded an isolate coded Enac3 (85 mg) with Rf value of 0.404 in hexane/ethyl acetate (4:1). The isolate was characterized using IR, NMR data and in comparison with literature. Analysis of spectroscopic data and literature comparison suggests Enac3 as stigmasta-7, 22-dien-3-ol. The isolation of stigmasta-7, 22-dien-3-ol from the stem bark of Entada africana suggests the presence of useful bioactive principles which could be exploited for medicinal purposes

Nanocomposites Transformed from Polystyrene Waste/Antimony, Barium and Nickel Oxides Nanoparticles with Improved Mechanical Properties

In this experiment, the oxide nanoparticles were synthesized via chemical precipitation and the nanocomposites were produced using in situ polymerization method with varying nanoparticles contents ranged from 0 to 5 g. The mechanical properties of the nanocomposites were investigated and compared with the values obtained for untreated polystyrene. It was observed that the mechanical properties were higher for the nanocomposites and increase with increasing nanoparticle concentrations in the samples. It can be observed that the untreated polystyrene gave a tensile strength of 945.25 N/mm2.  At high nanoparticle content of 5 g, the nanocomposite containing NiO nanoparticles showed a tensile strength of 973.83 N/mm2 while nanocomposite containing BaO nanoparticles gave a tensile strength of 968.19 N/mm2 and nanocomposite containing Sb2O3 nanoparticle gave a tensile strength of 955.53 N/mm2. The results indicate that the tensile strength and percentage elongation of all the nanocomposites improved with the addition of metal oxides nanoparticles compared with the untreated polystyrene. Slight decrease in percentage reduction in area of the nanocomposites was recorded. Conclusively, with these results, the PS/NiO nano composite showed a better trend of behaviour due to better interfacial interaction between the nanofillers and the polymer matrix followed by PS/BaO and PS/Sb2O3 nanocomposites. It is recommended that during the production of polymer nanocomposite, PS/NiO, PS/BaO and PS/Sb2O3 nanocomposites could be used as reinforcements in the construction of buildings to add structural stability to the building

Phytochemical and Chromatographic Studies of the Polar Extracts of the Leaves of Cassia alata Linn.

The dried leaves of cassia alata Linn were pulverized and extracted successively with hexane, ethylacetate, methanol and water in that order. Phytochemical screening of the methanol extract and water extract (polar extracts) showed that both extracts contained anthraquinones, flavonoids and saponins. Methanol extract, however, contained terpenes in addition to those mentioned above. Thin layer chromatography gave three fractions for each of the extracts. The Rf values for methanol extract fractions Me1, Me2, Me3 and water extract fractions We1, We2, We3 were 0.402, 0.646, 0.744and 0.333, 0.583, 0.833 respectively.  Crude extracts as well as the purified fractions were tested on five bacteria (Escherichia coli, Salmonella typhi, Streptococcus pneumonia, Yesinia enterocolitica and Shiggela sonnei) and two fungi pathogens (Microsporum audouinii and Trichophyton mentagrophyte). Methanol fraction Me3, accounted for the antifungal activity while water fractions We2 and We3 accounted for the antibacterial activity. Key Words: Cassia alata, antibacterial activity, anthraquinone, purgative