Psoralen and isopsoralen, furocoumarins isolated from the plant Psoralea corylifolia L., were demonstrated to exhibit in vitro inhibitory actions on monoamine oxidase (MAO) activities in rat brain mitochondria, preferentially inhibiting MAO-A activity over MAO-B activity. This inhibition of enzyme activities was found to be dose-dependent and reversible. For MAO-A, the IC50 values are 15.2±1.3μM psoralen and 9.0±0.6μM isopsoralen. For MAO-B, the IC50 values are 61.8±4.3μM psoralen and 12.8±0.5μM isopsoralen. Lineweaver-Burk transformation of the inhibition data indicates that inhibition by both psoralen and isopsoralen is non-competitive for MAO-A. The Ki values were calculated to be 14.0μM for psoralen and 6.5μM for isopsoralen. On the other hand, inhibition by both psoralen and isopsoralen is competitive for MAO-B. The Ki values were calculated to be 58.1μM for psoralen and 10.8μM for isopsoralen. These inhibitory actions of psoralen and isopsoralen on rat brain mitochondrial MAO activities are discussed in relation to their toxicities and their potential applications to treat affective disorders.

Fractionation of the xanthine oxidase inhibitory methanol extract of Conyza bonariensis afforded three glycosides, in addition to nine known compounds including amyrin, b-sitostero1 daucosterol, syringic acid 3-hydroxy-5-methoxybenzoic acid, eugenol 4-Oglucopyranoside, and luteolin, apigenin and takakin 8-O-glucuronide. The structures of the glycosides were established by a combination of spectroscopic methods (IR, MS, 1Hand 13C NMR, DEPT, COSY, HMQC and HMBC) as 4-hydroxypyridin-3-carboxylic acid 4-O-glucopyranoside, 8-hydroxy-6,7-dihydrolinalool 8-O-glucopyranoside and bonaroside [viz. 1,3,4,12-tetrahydroxy-2-(9-hexadecenoylamino) octadecane 1-O-glucopyranoside]. The in vitro enzyme assay showed that syringic acid and takakin 8-O-glucuronide displayed weak inhibitory activity against xanthine oxidase with IC50 values of 500±41μM and 170±12μM, respectively.

Curcuma longa (turmeric) is a well-known indigenous herbal medicine. The aqueous extracts, when administered orally to the mice from 140 to 560mg/kg for 14 days, were able to elicit dose-dependent relation of immobility reduction in the tail suspension test and the forced swimming test in mice. The effects of the extracts at the dose of 560mg/kg were more potent than that of reference antidepressant fluoxetine. The extracts, at the dose of 140mg/kg or above for 14 days, significantly inhibited the monoamine oxidize A (MAO) activity in mouse whole brain at a dose-dependent manner, however, oral administration of the extract only at a dose of 560mg/kg produced observable MAO B inhibitory activity in animal brain. Fluoxetine showed only a tendency to inhibit MAO A and B activity in animal brain in the study. Neither the extracts of C. longa nor fluoxetine, at the doses tested, produced significant effects on locomotor activity. These results demonstrated that C. longa had specifically antidepressant effects in vivo. The activity of C. longa in antidepression may mediated in part through MAO A inhibition in mouse brain.

There is increasing evidence that psychological stress and depression trigger changes in various biochemical parameters in animals and in human subjects. In order to study these effects, the impact of chronic mild stress (CMS) on rats, and of the subsequent administration of Banxia-houpu decoction and fluoxetine, were studied regarding their effects on the following biochemical parameters: 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels in various brain regions, natural killer (NK) cell and lymphokineactivated killer (LAK) cell activities in spleen, serum lipid profiles including total cholesterol (TC), high density lipoprotein cholesterol (HDLc), low density lipoprotein cholesterol (LDLc) and triglyceride (TG), liver superoxide dismutase (SOD) and nitric oxide synthase (NOS) activities, serum malondialdehyde (MDA), and interleukin-2 (IL-2) levels. The effects of drug administration on preference behavior for consumption of sucrose solution were also assessed. Rats subjected to CMS exhibited a reduction in sucrose intake, 5-HT, 5-HIAA, IL-2, TC, HDLc and LDLc levels, as well as, diminished NK cell and LAK cell activities. Conversely, liver SOD and NOS activities and serum TG and MDA levels were increased following CMS exposures. Administration of Banxia-houpu decoction and fluoxetine produced beneficial effects on the stressed rats by improving sucrose consumption. This behavioral change was accompanied by amelioration of numbers CMS-induced biochemical changes. Banxiahoupu decoction is a traditional Chinese prescription containing pinellia tuber, magnolia bark, hoelen, perilla herb and ginger rhizome, and has been used for centuries in China to treat mental diseases including depression and schizophrenia. However, the pharmacological profile of the decoction is different from that of fluoxetine. These findings uggest that the therapeutic actions of Banxia-houpu decoction are due to a combination of multiple biochemical effects, and may help to elucidate the mechanisms through which distinct biochemical parameters play a role in the etiology of depression.

Banxia-houpu decoction, a traditional Chinese medicine has been used in the treatment of depression. The present study confirmed that oral administration of polysaccharides from Banxia-houpu decoction, exhibited a reduction in the immobility time in the tail suspension and in the forced swimming tests in mice in a timedependent manner. This effect at a dose of 320mg/kg was more potent than that at a dose of 640mg/kg. The polysaccharides from Banxia-houpu decoction were active in animal models of depression with comparable effects to known antidepressants. The oral administration of the polysaccharides at a low dose for 4 weeks resulted in a significant increase in the monoamine neurotransmitter 5-hydroxytryptamine (5-HT) and dopamine (DA) levels in whole mouse brain, but produced no significant increase in 5-hydroxyindoleacetic acid (5-HIAA) and norepinephrine (NE) concentrations. The effect of polysaccharides on the brain neurotransmitter levels appeared to be quite different from the effect of fluoxetine, a serotonin specific reuptake inhibitor. The results indicate that the mode of action of polysaccharides from Banxia-houpu decoction in depression might be related to both 5-HT and DA systems. Copyright.