Prostaglandin inhibitory and antioxidant components of Cistus laurifolius, a Turkish medicinal plant

As Cistus laurifolius has been used traditionally to treat inflammatory and rheumatic disorders, its leaves were tested for prostaglandin (PG) inhibitory and antioxidant activities. The leaf extract showed both activities, i.e., inhibitory effect at 300 microg/ml on PGE1- and E2-induced contractions in guinea pig ileum and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect. The separation guided by the activities shown by these dual assays provided sixteen compounds, 1-16. Known compounds 1-12 and 15 were identified as 3-O-methyl quercetin (1), 3,7-O-dimethyl quercetin (2), genkwanin (3), 3,7-O-dimethyl kaempferol (4), 3,4'-O-dimethyl quercetin (5), apigenin (6), 3,4'-O-dimethyl kaempferol (7), ellagic acid (8), beta-sitosterol-3-O-beta-glucoside (9), quercetin 3-O-alpha-rhamnoside (10), 5-O-p-coumaroyl quinic acid methyl ester (11), 1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-alpha-l-rhamnopyranoxypropyl)-2-methoxyphenoxy]-1,3-propanediol (12) and 2,3-dihydro-2-(4'-alpha-l-rhamnopyranosyloxy-3'-methoxyphenyl)-3-hydroxymethyl-7-methoxy-5-benzofuranpropanol (15). New lignan glycosides 13 and 14 were determined…