One-pot synthesis of acid-base bifunctional catalysts for biodiesel production.

Acid-base bifunctional heterogeneous solid catalysts, known as the active site with base-acid properties, exhibited relatively good performance on the transesterification for soybean oil for green fuel production. We investigated the use of niobium and three alkali metal oxides (Li, Na, and K) as MyNbOX (M = Li, Na, K) composite as acid-base catalysts for biodiesel production. MyNbOX catalysts were prepared using a simple solid-state reaction, mixing, and grinding niobium dioxide with alkali metal carbonates calcined at 800 °C in air for 4 h. XRD, BET, FE-SEM, TEM and TPD techniques were employed for catalysts characterization. The highest biodiesel yield (98.08%) was achieved under the transesterification condition of 65 °C, 6 h, 24 methanol/oil molar ratio and 2 wt% of LiNbO3 as the catalyst. The results showed that LiNbO3 could be efficiently reused at least 10 cycles with an insignificant reduction in the biodiesel yield. The physicochemical properties of the biodiesel were further studied and compared with the ASTM and the EN biodiesel specifications. The results showed that the properties of the biodiesel produced complied with the international standard specifications.

New 4-methylidene sterols from the marine sponge Theonella swinhoei.

A series of 4-methylidene sterols including three new compounds 1-3, were isolated from the marine sponge Theonella swinhoei. The structures of new compounds were determined on the basis of spectroscopic analyses. Compounds 3, 5, and 6 showed cytotoxicities against U937, MCF-7, and PC-9 cancer cells with IC50 in the range of 1.6-8.8 µM. The new compound 3 exhibited remarkable proapoptotic activity in breast cancer cells. Mechanically, 3 significantly triggered reactive oxygen species (ROS) accumulation resulting in apoptosis and DNA damage in breast cancer cells.

Pedicularioside A from Buddleia lindleyana inhibits cell death induced by 1-methyl-4-phenylpyridinium ions (MPP+) in primary cultures of rat mesencephalic neurons.

Parkinson's disease is characterized by the progressive degeneration of midbrain dopaminergic neurons. Buddleia lindleyana is a traditional Chinese herb, commonly called Zui Yu Cao. The purification and identification of pedicularioside A and other phenylethanoid glycosides from this plant have been reported. However, their neuroprotective effects on the 1-methyl-4-phenylpyridinium ion (MPP(+))-induced death of rat mesencephalic neuron primary cultures and the precise mechanism of this protection remains unclear. We used the 3-(4, 5-dimethylthiozol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay for cellular growth to examine the effects of five phenylethanoid glycosides isolated from B. lindleyana, including pedicularioside A, leucosceptoside A, isoacteoside, acteoside, and arenariside, on the viability of mesencephalic neurons treated with MPP(+). Of the compounds tested, pedicularioside A exhibited the greatest degree of protection from MPP(+)-induced cell death. We also observed a marked increase in the number of tyrosine hydroxylase immunoreactive neurons. Pedicularioside A inhibited expression of the caspase-3 gene and cleavage of poly (ADP-ribose) polymerase (PARP) in cultures exposed to MPP(+). Our results suggest that pedicularioside A has a neuroprotective effect to improve the survival of mesencephalic neurons (dopaminergic neurons and non-dopaminergic neurons). The mode of action appears to be the inhibition of caspase-3 gene expression, thereby protecting mesencephalic neurons from MPP(+)-induced cell death.