Effects of 3,3′-di-O-methylquercetin on guinea-pig isolated smooth muscle

Abstract

The effects of the flavone 3,3'-di-O-methylquercetin (DOMQ) have been examined and compared with those of quercetin, on guinea-pig isolated ileum, trachea, and main pulmonary artery (MPA). Except for transient contractions induced by low concentrations (10(-8)-3 x 10(-6) M), DOMQ and quercetin (up to 3 x 10(-4) M) caused reduction of the tone and the phasic contractions of the ileum. A23187 reversed the inhibitory effects of quercetin but not those of DOMQ. DOMQ and quercetin caused concentration-dependent relaxation of the trachea and the adrenaline-contracted MPA. DOMQ shifted to the right the concentration-effect curves induced by acetylcholine on the ileum and the trachea, and by adrenaline on MPA and those induced by CaCl2 on ileum, trachea and MPA. DOMQ also inhibited the contractions induced, in Ca2+-free EGTA-containing buffer, by histamine on ileum and by adrenaline on MPA. These observations suggest that DOMQ inhibits Ca2+ influx, Ca2+ release from intracellular stores and, more likely, Ca2+ binding to intracellular receptor proteins.

Relaxant Effects of Quercetin Methyl Ether Derivatives in Isolated Guinea Pig Trachea and their Structure-Activity Relationships

“…cell culture in bioreactors (6,7). The bioreactors used in these studies were, however, of much smaller volumenot exceeding 1 I -than the bioreactor we used.…”

“…There are many pharmacological reports about quercetin (2)(3)(4)(5), but very few about quercetin methyl ether derivatives. Quercetin 3,3'-dimethyl ether has been reported to relax the ileum, trachea and main pulmonary artery of guinea pigs (6). Quercetin 3,3',4',7-tetramethyl ether (QTME) has been reported to have an antimutagenic effect (7).…”

Antimicrobial Activity of Extracts of Herbal Plants used in the Traditional Medicine of Bahrain

“…Recently, biologically active compounds and extracts isolated from plant species used in herbal medicine in Bahrain have been the centre of interest (Miller and Moms, 1988;Abbas et al, 1992, Abdulla et al, 1989Yoshizaki et al, 1987;Smith and Banks, 1986). However, the antimicrobial activity of these extracts and compounds against microorganisms has been poorly investigated (Mahasneh, 1986;Ghazal et al, 1992;Abbas et al, 1992).…”

Antimicrobial activity of Polygonum equisetiforme extracts and flavonoids

“…The biological and antimicrobial activity of some isoflavonoids and flavonoids isolated from different plant sources is of interest (Abdulla et al, 1989;Smith and Banks, 1986). In Jordan there are 11 species of the genus Polygonurn (Zohary, 1966), including Polygonurn equisetiforrne which is a perennial herbaceous plant distributed throughout Palestine, upper and lower Gallilee and the Jordan Valley, Ammon and Moab.…”