V Butterweck

..This review integrates new findings of possible mechanisms that may underlie the antidepressant action of St John's wort and its active constituents with a large body of existing literature...

..It can be speculated that, when administered together with these compounds, a significant accumulation of hypericin in rat plasma in the presence of both polyphenols might be responsible for the observed increased in vivo activity...

..125I]CYP binding to beta-adrenergic receptors was found to be decreased after 8 weeks treatment with imipramine, whereas AV-extract had no effect on beta-receptor binding...

..Hypericum perforatum L. (St. John's wort; SJW) is one of the leading psychotherapeutic phytomedicines and great effort has been devoted to clarifying its mechanism of action...

..01). Our data clearly show that long-term, but not short-term administration of St. John's wort and its active constituent hypericin modify levels of neurotransmitters in brain regions involved in the pathophysiology of depression...

..From our present data, we propose that cooperative effects of hypericin and procyanidin B2 are of important relevance for the acute, but not for the chronic effects of this polycylic quinone...

..Further, it can be speculated that this effect might be related to hyperoside and isoquercitrin which are major flavonoids in the extract...

..We also could show that hyperforin contributes to the beneficial properties of SJW extract, confirming the hypothesis that the crude SJW extract contains several constituents with antidepressant activity...

..However, imipramine appears to be more effective in blocking stress effects on the HPA axis than the plant extract...

..Compared to the SJW extracts and single compounds the effect of imipramine on beta-AR-binding was more pronounced in both treatment paradigms...

..Except for quercetin, quercitrin and astilbin all compounds were active. To exclude false positive results in the FST the validity was checked in open field experiments and in the FST after 12 days of daily treatment...

..In addition pronounced effects on the central nervous system were shown. Taking these relevant therapeutic properties into account further experimental and clinical studies seem to be necessary and promising...

..In conclusion, an aqueous ALE, caffeic acid derivatives and flavones exerted XO inhibitory effects in vitro but a hypouricemic activity could not be confirmed after oral administration...

..Although there are some open questions, the bulk of data suggests that several groups of active compounds are contributing to the antidepressant efficacy of the plant extract...

..Effective screening tools that accurately predict metabolic herb-drug interactions would offer a tremendous advantage because it is not possible to study all potential herb-drug interactions in clinical trials...

..These results indicate that AV extract is an effective anxiolytic agent, and suggest that the anxiolytic-like activities of this plant are mainly mediated via the GABAergic system...

..1 mg/kg. In conclusion, using open field stress as a psychological stressor to induce hyperthermia in mice we were able to detect putative anxiolytic effects of SJW extract and single consituents...

..The present study clearly demonstrated that EGB exerts an antidepressant effect in these two behavioral models...

..Moreover, the total soluble phenolic contents of the extract and fractions were measured using the Folin-Ciocalteau reagent and the quantitative analysis of flavone C-glycosides major constituents was performed by HPLC...

..In the present paper clinical significant SJW interactions are critically evaluated against the background of hyperforin...

..These phenomena may be included in key mechanisms of the development of depression...

..These results suggest that, unlike SJW, the recommended dose of AV (3.3 mg/kg/d) would not influence hepatic CYP3A and intestinal P-gp in rats...

..Efforts to identify all possible interactions will lead to limitless investigations and to inconsistent decisions...

..These data suggest that IL-6 plays an important role in the control of emotionality, but not in the regulation of body temperature after psychological stress...

..These findings in pharmacological tests-a reduction of the frequency of hot flush equivalents and hints on antidepressant activity of Cimicifuga extracts-are in good agreement with the therapeutical responses in climacteric women...

..These data suggest that hyperforin and hyperforin derivatives are not involved in the regulation of genes that control HPA axis function...

..The concentration of potentially contributing compounds may crucially influence the magnitude of observed interaction and impair direct comparison of studies in which different juices have been used...

..divinorum...

..Thus, our data suggests that the hypothermic--and therefore the sleep-inducing--effects of hops extract are possibly mediated through activation of melatonin receptors...

..Based on their relatively low concentrations (< or =3 microg/mL) in citrus, the clinical relevance of these interactions needs to be further elucidated in in vivo studies...

..5- to 1.8-fold, respectively. In conclusion, the effect of GFJ on P-gp activity seems to depend on the variety, the concentration of compounds in the juice, and the composition of different ingredients...