Isolation of pharmacologically active benzodiazepine receptor ligands from Tilia tomentosa (Tiliaceae)

Assessment of luteolin (3′,4′,5,7-tetrahydroxyflavone) neuropharmacological activity

“…Luteolin had previously been reported not to displace [ 3 H]flunitrazepam binding to central benzodiazepine receptors (BDZ-R) (IC 50 > 100 M) [21]. In our experiments we have determined that luteolin has in fact the ability to displace [ 3 H]flunitrazepam binding, though exhibiting a low affinity for these receptors, with a K i in the high (60.1) M range.…”

“…Recently, we have reported on the isolation of luteolin-7-O-(2-rhamnosylglucoside) from Passiflora edulis Sims and demonstrated its anxiolytic-like activity [25]. Luteolin is a widespread flavonoid aglycon that was reported as devoid of specific affinity for BDZ-receptor binding site [21], but its psychopharmacological activity is presently unknown. Considering (1) the close structural similarity with other active flavones ( Fig.…”

“…Amongst these reports flavonoid derivatives with a flavone-like structure such as apigenin [16,17], chrysin [18] and wogonin [19] have been reported for their anxiolytic-like activity in different animal models of anxiety. These flavonoids with BDZ-receptor specificity and/or anxiolytic activity have been isolated from medicinal plants traditionally used in folk medicine for their anxiolytic/sedative properties such as Passiflora coerulea [20], Matricaria recutita [16], Tilia tomentosa [21], Jatropha cilliata [22], Salvia guaranitica [23], Matricaria chamomilla [17], Ziziphus jujuba [24]. Recently, we have reported on the isolation of luteolin-7-O-(2-rhamnosylglucoside) from Passiflora edulis Sims and demonstrated its anxiolytic-like activity [25].…”

Anxiolytic and sedative-like effects of flavonoids from Tilia americana var. mexicana: GABAergic and serotonergic participation

“…mexicana collected from three different regions of Mexico produce anxiolytic and sedative-like effect equivalent to those of Tilia species previously reported and thus underline the medicinal properties accredited to the genus. 7,14,17,18 Moreover, no difference in the tranquilizing activity was found between Tilia leaves and inflorescences. These findings reinforce the medicinal properties mentioned for Tilia and provide evidence that leaves can also be used for therapeutic purposes.…”

“…With respect to their therapeutic importance as anxiolytic and sedative-like compounds, it has been demonstrated that flavonoids such as quercetin, rutin and kaempferol elicit Central Nervous System activity involving the inhibitory GABAergic system. 18,26,27 As described, rutin was the other abundant flavonoid detected in the active extract; it is known that plants increase glycosylated aglicone production as a mechanism to avoid damage. 28 This property of plants is also an advantage in folk medicine, since they can be used as tranquilizers, among other therapeutic properties.…”