• Archives of Pharmacal Research
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• v.19 no.6
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• pp.480-485
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• 1996

Brain GABA transaminase is inactivated by preincubation with antidepressant/antipanic drug pheneizine (${\beta}$ethylphenylhydrazine) (mixing molar ratio 10:1) at pH 7.4. The reaction of enzyme with phenelzine was monitored by absorption and fluorescence spectroscopic methods. The inactive enzyme was fully reconstituted by addition of cofactor pyridoxal-5-phosphate. This result implies that the blocking of 1 mol of pyridoxal-5-phosphate per enzyme dimer is needed for inactivation of the enzyme. The time course of the reaction is significantly affected by the substrate .alpha.-ketoglutarate, which afforded complete protection against the loss of catalytic activity. The kinetic studies shows that phenelzine reacts with the cofactor of enzyme with a second-order rate constant of $2.1{\times}10^3M^{-1}s^{-1}$. It is postulated that the antidepressant/antipanic drug phenelzine is able to elevate the neurotransmitter GABA levels in central nervous system by inhibitory action on GABA degradative enzyme GABA transaminase.

• Korean Journal of Pharmacognosy
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• v.49 no.2
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• pp.85-102
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• 2018

A drug interaction is a situation in which a substance affects the activity of a drug, synergistically or antagonistically, when both are administered together. It has been shown that orally taken ginsenosides are deglycosylated by intestinal bacteria to give ginsenosides metabolites, which has been considered to be genuine pharmacological constituents and to exhibit drug interactions. Animal experimental results demonstrated that ginsenoside metabolites play an important role in the inhibitory or inductive action of both CYPs (cytochrome p450) and P-gp (p-glycoprotein), thereby can be applied as metabolic modulator to drug interactions. Very few are known on the possibility of drug interaction if taken the recommended dose of ginseng, but it has been found to act as CYPs inductor and P-gp inhibitor in any clinical trial, suggesting the risk that side effects will occur. It has been recently reported that interactions might also exist between ginseng and drugs such as warfarin, phenelzine, imatinib and raltegravir. Moreover, medicinal plants are increasingly being taken in a manner more often associated with prescription medicines. Therefore, considering the extensive applications of ginseng for safety, the aim of this review is to present a comprehensive overview of ginseng and drug interactions based upon pharmacodynamic and pharmacokinetic evidences.