Novel 3,5-diaryl pyrazolines and pyrazole as low-density lipoprotein (LDL) oxidation inhibitor

Iridoid glycosides isolated fromOldenlandia diffusa inhibit LDL-oxidation

An iridoid glycoside, oldenlandoside III (5) was isolated from the n-butanol fraction of methanol extracts of the aerial parts of Oldenlandia diffusa Roxb. along with six others previously characterized iridoid glycosides; geniposidic acid (1), scandoside (2), feretoside (3), 10-omicron-benzoylscandoside methyl ester (4), asperulosidic acid (6) and deacetylasperulosidic acid (7). Compounds 1, 2, and 7 inhibited LDL-oxidation, and showed 63.3+/-2.0, 62.2+/-1.6, and 63.8+/-1.5% inhibition, respectively, at a concentration of 20 microg/mL.

Antioxidant activities of a new lignan and a neolignan from Saururus chinensis

A new diarylbutane lignan, 2'-hydroxy dihydroguaiaretic acid (4), and a known 8-O-4'-type neolignan, machilin D (5), were isolated from the ethyl acetate extracts of the underground parts of Saururus chinensis. Compounds 4 and 5 exhibited low-density lipoprotein (LDL)-antioxidant activity in the thiobarbituric acid-reactive substances (TBARS) assay (4: IC(50)=3.3 microM and 5: IC(50)=3.8 microM), the lag time of conjugated diene production, the relative electrophoretic mobility (REM) of ox-LDL, the apoB-100 fragmentation on copper-mediated LDL oxidation and the macrophage-mediated LDL oxidation, and radical DPPH scavenging activity.