A mild and efficient route to tetraketones (2-22) has been developed by way of tetraethyl ammonium bromide (Et 4 N þ Br 2 ) mediated condensation of dimedone (5,5-dimethylcyclohexane-1,3-dione, 1) with a variety of aldehydes. All these compounds showed significant lipoxygenase inhibitory activity and moderate to strong antioxidant potential. mM) also showed strong antioxidant activity compared to the standard (IC 50 ¼ 44.7 mM). This study is likely to lead to the discovery of therapeutically efficient agents against very important disorders including inflammation, asthma, cancer and autoimmune diseases.

A new lignan rhamnoside, racemiside (1), has been isolated from the ethyl acetate-soluble fraction of Cotoneaster racemiflora, along with scopoletin (2), 7,8-dimethoxy-6-hydroxycoumarin (3), 3,3',4'-tri-O-methylellagic acid (4), and cereotagloperoxide (5), reported for the first time from this species. All of them showed profound antioxidative activities in the DPPH assay.

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Two new limonoids, kostchyienones A (1) and B (2), along with 12 known compounds 3-14 were isolated from the roots of Pseudocedrela kostchyi. Compound (7) was isolated for the first time from a natural source. Their structures were elucidated on the basis of spectroscopic evidence. Compounds 1-6 and 13-14 gave IC50 values ranging from 0.75 to 5.62 μg/mL for antiplasmodial activity against chloroquine-sensitive (Pf3D7) and chloroquine-resistant (PfINDO) strains of Plasmodium falciparum. Compound 5 showed moderate potential cytotoxicity against the HEK239T cell line with an IC50 value of 22.2±0.89 μg/mL. The antiplasmodial efficacy of the isolated compounds supports the medicinal value of this plant and its potential to provide novel antimalarial drugs.