Studies on Acorus Calamus, Part II

Abstract

The capacity to potentiate the sedative action of pentobarbitone by the volatile oil of Indian Acorus calamus has been used to screen various fractions of the oil for the presence of the principle responsible. The methods used for the removal of the oxygenated components of the oil did not remove the active material. The results show that the active principle resides in the hydrocarbon fraction of the oil or in an oxygenated component not removed by the methods employed. The volatile oil from the European Acorus calamus showed activity similar to the oil from the Indian drug.

Positive GABAA Receptor Modulators from Acorus calamus and Structural Analysis of (+)-Dioxosarcoguaiacol by 1D and 2D NMR and Molecular Modeling

“…(−)-Isoshyobunone (5) was much less efficient than its presumed precursor 3 46 (Figure 3; Table 2), which can only be explained by the varying C-2 substitution and the consequential conformational difference. Interestingly, 5 showed a weak (less than GABA EC [5][6][7][8][9][10] ) direct activation of the α 1 β 2 γ 2S GABA A receptor, whereas 3 did not evoke any agonistic effect. Only weak GABA A receptor modulation was found for (-)-acorenone (6).…”

“…[52][53][54] There are many reports of sedative and tranquillizing properties of Acorus extracts and essential oil in animal models, but the mechanism of action was not established up to now. [10][11][12][13][14][15]55 Given that β-asarone (1) is a major compound of the essential oil, its sedative and tranquillizing activities may be due to the GABA A receptor modulating properties of 1. The quantity of β-asarone in Acorus rhizome and essential oil, however, depends on the chemotype and thus varies considerably.…”

“…19 In order to determine GABA EC [5][6][7][8][9][10] (typically between 3 and 10 μM for receptors of the subunit combination α 1 β 2 γ 2S ), a concentration-response experiment with GABA concentrations ranging from 0.1 μM to 1 mM was performed. Stock solutions (10 mg/mL in DMSO) of A. calamus extract and open column fractions (1-21) were diluted to concentrations of 100 and 10 μg/mL, respectively, with bath solution containing GABA EC [5][6][7][8][9][10] . As previously described in a validated protocol, microfractions collected from the semipreparative HPLC separations were dissolved in 30 μL of DMSO and subsequently mixed with 2.97 mL of bath solution containing GABA EC [5][6][7][8][9][10] .…”

“…Stock solutions (10 mg/mL in DMSO) of A. calamus extract and open column fractions (1-21) were diluted to concentrations of 100 and 10 μg/mL, respectively, with bath solution containing GABA EC [5][6][7][8][9][10] . As previously described in a validated protocol, microfractions collected from the semipreparative HPLC separations were dissolved in 30 μL of DMSO and subsequently mixed with 2.97 mL of bath solution containing GABA EC [5][6][7][8][9][10] . 29 For concentration-response experiments, bath solution containing compounds 1-6 in concentrations ranging from 0.1 to 1000 μM was applied to the oocyte.…”

“…[7][8][9] Several in vivo studies support a sedative and tranquillizing action of the essential oil and of ethanolic and aqueous extracts of A. calamus. [10][11][12] Up to now, the underlying mechanism of action has remained elusive despite various investigations, even though the pharmacological effect could be mainly attributed to α-asarone and β-asarone. 11,[13][14][15] GABA A receptors are pentameric ligand-gated chloride ion channels that are activated by GABA, the major inhibitory neurotransmitter in the CNS.…”