ABSTRACT
Barakol is an active compound extracted from the leaves and flowers of the plant called Cassia siamea grown widely in Southeast Asia. There have been a number of reports on the chemical structure and properties of this compound since it was first extracted in 1969. The compound has been tested in various laboratories for its pharmacological properties with reference to the clinical use of the plant in traditional Thai medicines. For these studies it is necessary to establish the stability of the extracted barakol under various laboratory conditions. This report is the first to use high performance liquid chromatography with electrochemical detection to determine the extent of purity and stability of extracted barakol solution.
Subject(s)
Benzopyrans/analysis , Chromatography, High Pressure Liquid/methods , Phenalenes , Plants, Medicinal/chemistry , Rosales/chemistry , Benzopyrans/isolation & purification , ElectrochemistryABSTRACT
In many circumstances, rapid information is required about the effects of drugs on neurotransmitter release in brain, and a common method used is measurement of radiolabelled release from superfused brain slices or synaptosomes in vitro. However, the method requires expensive equipment and is not readily adapted to the measurement of endogenous release. The method described here uses readily available cheap chromatographic columns to measure both radiolabelled and endogenous dopamine (DA) release from striatal slices in repeated incubation samples. The results showed that the [3H]DA release is sensitive to temperature, K(+)-stimulation, and to both a DA agonist (pergolide) and an antagonist (eticlopride). Endogenous DA release was also stimulated by high K+ (20 mM) and sensitive to a DA agonist. Pergolide (100 microM) reduced both [3H]DA and endogenous DA release, while eticlopride (10 microM) increased [3H]DA, but not endogenous DA release. The results demonstrate an alternative cheap and quick way to study neurotransmitter release from brain in vitro.
Subject(s)
Corpus Striatum/metabolism , Dopamine/metabolism , Animals , Chromatography, Gel , Corpus Striatum/drug effects , Culture Techniques , Dopamine/analysis , Dopamine Agonists/pharmacology , Dopamine Antagonists/pharmacology , Dose-Response Relationship, Drug , Isotope Labeling , Male , Pergolide/pharmacology , Potassium/pharmacology , Rats , Salicylamides/pharmacology , Temperature , Tritium/metabolismABSTRACT
The present study investigated the effects of barakol on the in vitro release of endogenous and radiolabelled dopamine from rat striatal slices in comparison with the dopamine receptor agonists, quinelorane dihydrochloride (1 microM) and pergolide methanesulfonate (100 microM), and the dopamine receptor antagonist, S(-)-eticlopride hydrochloride (10 microM) using a semi-superfusion method and high-performance liquid chromatography with electrochemical detector measurement of endogenous dopamine. Barakol (1, 10 and 100 microM) reduced K(+)-stimulated endogenous dopamine release as did the dopamine D2 receptor agonists but had no effect on [3H]dopamine release. The inhibition of barakol (10 microM) on K(+)-stimulated endogenous dopamine release was antagonised by a dopamine D2 receptor antagonist, eticlopride. Barakol (0.1 nM-10 microM) had no effect on [3H]dopamine uptake except at the highest concentration (100 microM) when inhibition was observed. The results indicate that barakol might act as a dopamine agonist to inhibit endogenous dopamine release without a change in dopamine uptake.
Subject(s)
Anti-Anxiety Agents/pharmacology , Benzopyrans/pharmacology , Dopamine/metabolism , Neostriatum/metabolism , Phenalenes , Animals , Calcium/physiology , Cassia/chemistry , Chromatography, High Pressure Liquid , Dopamine Agonists/pharmacology , Dopamine D2 Receptor Antagonists , Electrochemistry , In Vitro Techniques , Male , Neostriatum/drug effects , Pergolide/pharmacology , Plant Extracts/pharmacology , Plants, Medicinal , Potassium/pharmacology , Rats , Receptors, Dopamine D2/agonistsABSTRACT
The behavioural effects of an extract of Cassia siamea, a plant used in Thai traditional medicine, and barakol, its active chemical, were studied on an elevated plus-maze compared with diazepam. An aqueous extract of C. siamea (1, 6, and 12 g/kg body wt., orally) produced a small increase in the percentage of the open: total number of arm entries and time, time spent on the end of the open arms, total number of arm entries, and number of rears/min. Barakol [10 mg/kg, intraperitoneally (IP)] significantly increased all of these behavioural parameters in a manner similar to diazepam (1 mg/kg, IP, 30 or 60 min before testing), except that barakol and not diazepam increased both the number of rears and total arm entries. Barakol at 25 and 50 mg/kg increased the percentage of the open: total number of arm entries and time and number of rears. The results indicate that barakol has anxiolytic properties similar to diazepam but differs from diazepam in that it also increases exploratory and locomotor behaviour, as shown by the number of rears and total arm entries.
