Two new phragmalin-type limonoids orthoesters from Entandrophragma candollei

Two new phragmalin-type limonoids orthoesters, encandollens A and B(1 and 2), were isolated from the stem barks of Entandrophragma candollei collected in Ghana. The structures of these compounds were elucidated on the basis of HR-ESI-MS, ~1 H and ^(13) C NMR, HSQC, HMBC, and ROESY data. Compound 1 was a rare C-15 enolic acyl phragmalin-type limonoid orthoester. Compounds 1 and 2 exhibited weak inhibitory effects on NO production in lipopolysaccharide(LPS)-induced RAW 264.7 cells.

4种常用装饰装修木材表面特性分析

对筒状非洲楝、水曲柳、古夷苏木和杉木4种常用装饰装修木材表面特性进行测定分析,结果表明:在CIE(1976)L*a*b*色空间中,筒状非洲楝和古夷苏木明度L*平均值较低,属于深材色树种;杉木明度L*平均值为70.28,属于较高明度。从整体分布情况来看,4种常用装饰装修木材的a*和b*都分布在0以上,明度分布在40以上,色调标号都分布在YR的区间;古夷苏木和水曲柳木材表面润湿性大于筒状非洲楝和杉木。

3种木材涂饰前后表面视觉性质差异的研究

测定分析了筒状非洲楝Entandrophragma cylindricum,古夷苏木Guibourtia tessmannii和水曲柳Fraxinus mandschurica木材醇酸清漆涂饰前后表面视觉性质的差异。结果表明,涂饰处理降低了3种木材表面的明度(L*)和红绿轴色品指数(a*)值,其中,古夷苏木的L*变化差异最大,明度降低明显;水曲柳的红绿轴色品指数差(Δa*)绝对值最大,相比处理前更偏向绿色;3种木材透明涂饰后的黄蓝轴色品指数(b*)均有所升高,黄蓝轴色品指数差(Δb*)绝对值由大到小分别为水曲柳>古夷苏木>筒状非洲楝,数值越大越趋于黄色;总体色差(ΔE*)变化差异不大,涂饰对3种木材的总体色差影响不明显。